Rozprawy doktorskie na temat „Supramolecular coordination polymers”

We have designed and synthesized boradiazaindacene (BODIPY) derivatives, appropriately functionalized for metal ion mediated supramolecular polymerization. Thus, ligands for 2- and 2,6-terpyridyl and bipyridyl functionalized BODIPY dyes were synthesized through Sonogashira couplings. These new fluorescent building blocks are responsive to metal ions in a stoichiometry dependent manner. Octahedral coordinating metal ions such as Zn(II), result in polymerization at a stoichiometry which corresponds to two terpyridyl ligands to one Zn(II) ion. However, at increased metal ion concentrations, the dynamic equilibria are re-established in such a way that, monomeric metal complex dominates. The position of equilibria can easily be monitored by 1H NMR and fluorescence spectroscopy. As expected, open shell Fe(II) ions while forming similar complex structures, quench the fluorescence emission of all four functionalized BODIPY ligands.

Thesis (Ph.D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2009.
Committee Chair: Marcus Weck; Committee Member: Bunz, Uwe; Committee Member: Collard, David; Committee Member: Jones, Christopher; Committee Member: Payne, Christine

La formation de polymères de coordination poreux et chiraux ainsi que leur utilisation pour des processus énantiosélectifs est actuellement un des domaines de grand intérêt en chimie. La formation de ces matériaux est rendue possible par le biais des concepts développés dans le domaine de la tectonique moléculaire. Les travaux présentés dans cette thèse s’inscriventdirectement dans cette thématique. Les synthèses de tectons organiques chiraux sont présentées. Leur combinaison avec divers centres métalliques, via différentes méthodes de cristallisation, a permis l’obtention de monocristaux qui ont été étudiés par diffraction des rayons X sur monocristal. Dans un premier temps, des polymères de coordination homochiraux, obtenus par l’utilisation de tectons dotés de sites coordinants neutres sont présentés. Des réseaux de type cuboïde présentant des canaux monodimensionnels au sein de leur architecture sont notamment décrits. Par la suite, des édifices mono- et bi-dimensionnels de géométries diverses sont discutés. Pour certains de ces cristaux, des interactions de plus faible énergie que la liaison de coordination permettent la formation de réseaux moléculaires de plus haute dimensionnalité. Enfin, dans une dernière partie, l’utilisation de tectons dotés de sites coordinants chargés est discutée. Des réseaux tridimensionnels homochiraux poreux et robustes sont décrits. Ces derniers sont des candidats de choix pour des procédés énantiosélectifs de séparation. Leur propension à encapsuler des gaz (N2 et CO2) est présentée
The synthesis and the use of porous chiral coordination polymers for enantioselective processes are of current interest and prime importance in chemistry. These crystalline materials are mainly obtained by combinations of well-designed organic tectons and properly chosen metallic components. This thesis deals with the synthesis of organic chiral building blocks and their combinations with a variety of metallic salts leading to chiral coordination networks. In a first part, the use of tectons bearing neutral coordinating sites is described. Homochiral cuboid architectures displaying monodimensional channels are presented. In the second part, mono- and bi-dimensional networks of various geometries are described. In some cases, within crystals, interactions lower in energy than the coordination bond are observed and are responsible for the formation of molecular networks of higher dimensionality. Finally, the use of organic tectons displaying charged interaction sites is presented. Their combination with metallatectons under thermal treatments affords robust tridimensional homochiralarchitectures displaying cavities. These materials are interesting candidates for enantioselective recognition and separation. Their gas adsorption propensity (N2 and CO2) is briefly discussed

L’essor de la chimie supramoléculaire et plus particulièrement de la tectonique moléculaire a rendu la formation de matériaux poreux hautement organisés possible. La fonctionnalisation de tels composés favorise leur utilisation pour de nombreuses applications. Les travaux présentés dans cette thèse ont été consacrés aux réseaux moléculaires poreux homochiraux ainsi que leur utilisation pour le stockage de gaz, la reconnaissance et la séparation d’énantiomères.Le premier chapitre décrit la synthèse de divers ligands organiques optiquement purs et leur assemblage avec des sels de cuivre pour l’obtention de monocristaux. Les isothermes d’adsorption de chacun de ces composés cristallins ont été mesurés via des analyses BET et le stockage de N2,CO2 et CH4 ont été évalué.Le second chapitre s’intéresse à l’utilisation de ces mêmes composés chiraux pour la reconnaissance des énantiomères (L)- et (D)-tryptophane. Des tests de séparation énantiosélective de molécules aminées ou dérivées d’amides sont également exposés.Le dernier chapitre décrit la formation de réseaux moléculaire mono- et tridimensionnels par l’association de ligands organiques avec des sels métalliques variés. Leurs structures cristallines ont pu être déterminées par diffraction des rayons X sur monocristal
The development in supramolecular chemistry and more particularly in molecular tectonics has madepossible the formation of porous and highly organized materials. The functionalization of suchcompounds favored their use for various applications. This PhD work is about the application ofporous homochiral coordination networks for storage, enantioselective recognition or separation.The first chapter deals with the synthesis of chiral ligands and their combinations with copper salts toenable the formation of single crystals. Their adsorption isotherms were evaluated by BETmeasurements. Storage of N2, CO2 and CH4 by these crystalline architectures was also evaluated.The second part describes the use of these chiral compounds for enantioselective recognition of (L)-and (D)-tryptophan. Tests of enantioselective separation of amines or amides were also carried out.The last part of this work deals with the formation of mono- or tridimensional coordination polymersby combinations of organic ligands and a variety of metallic salts. Their structures were determinedby X-ray diffraction on single crystal

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FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais
Este trabalho consiste na síntese e caracterização de complexos inéditos envolvendo as espécies oxocarbônicas ácido esquárico e croconato, o pseudo-oxocarbono croconato violeta, bem como os ligantes nitrogenados derivados piridínicos 4,4’-dimetil-2,2’-bipiridina (MBP), 1,3-bis(4-piridil)propano (BPP) e 2,3,5,6-tetraquis(α-piridil)pirazina (TPP) e os sítios metálicos de Co(II), Ni(II) e Cu(II). Adicionalmente realizou-se sínteses envolvendo o sítio metálico de Mn(II). Utilizou-se diversas técnicas analíticas e espectroscópicas para a caracterização dos compostos sintetizados, tais como, análise elementar (CHN), análise térmica (TG/DTA) e espectroscopia vibracional (IV e Raman). Foram obtidos seis complexos envolvendo a espécie esquarato, dos quais três contêm o ligante 4,4’-dimetil-2,2’-bipiridina (MBP), denominados: [Co(MBP)2(C4O4)] (1), [Ni(MBP)3](C4O4).3H2O (2) e {[Cu2(MBP)2(C4O4)2(H2O)4]}n (3) e três o ligante 2,3,5,6-tetraquis(α-piridil)pirazina (TPP): [Co2(TPP)(C4O4)2(H2O)2)]2H2O (4), [Ni2(TPP)(C4O4)(H2O)2Cl2]7H2O (5) e [Cu2(TPP) (H2O)2Cl2)] (C4O4)2H2O (6). Os complexos (2), (3) e (6) tiveram suas estruturas determinadas por difração de raios X de monocristal. O composto (3) apresentou-se como um polímero de coordenação que se estende em uma dimensão através do ligante esquarato, coordenado em ponte entre dois sítios de Cu(II) pelo modo µ-1,2-bis(monodentado). O referido ligante oxocarbônico apresentou-se nos compostos (2) e (6) como contra-íon. As sínteses envolvendo a espécie oxocarbônica croconato de potássio levaram à obtenção de sete compostos inéditos denominados: {[Co(MBP)2(NO3)]2+.[Co(C5O5)2(H2O)4]2-} .6H2O (7), [Ni(MBP)2(C5O5)] (8), [Cu(MBP)(C5O5)(H2O)] (9), {[Mn2(BPP)2(C5O5)2(H2O)4].3H2O}n (10), {[Co2(BPP)2(C5O5)2(H2O)4].2H2O}n (11), {[Ni2(BPP)3(C5O5)2(H2O)4].5H2O}n (12) e {[Cu(BPP)(C5O5)(H2O)3]}n (13), em que MBP consiste no ligante nitrogenado 4,4’-dimetil-2,2’-bipiridina e BPP no 1,3-bis(4-piridil)propano. Os compostos (7), (8) e (10) tiveram suas estruturas determinadas por difração de raios X de monocristal. O complexo (7) apresentou-se dinuclear, sendo constituído por uma porção catiônica e outra aniônica que apresenta dois íons croconato coordenados pelo modo monodentado, enquanto que (8) é mononuclear com o diânion croconato coordenado ao Ni(II) pelo modo 1,2-bidentado, tais complexos apresentaram arranjos supramoleculares, sendo que em (7) a presença de interações de hidrogênio estendem o arranjo em duas dimensões e em (8) interações do tipo empacotamento π estende o arranjo supramolecular em uma dimensão. O composto (10) apresentou-se como um polímero de coordenação bidimensional em que tanto o ligante nitrogenado BPP, numa conformação TG (trans-gauche), quanto um dos diânions croconato, apresentaram-se coordenados em ponte entre dois sítios metálicos de Mn(II). Tal rede polimérica apresenta caminhos fechados cuja topologia estrutural é (6,3). O referido polímero apresenta dois íons croconato com modos de coordenação distintos, um deles se coordena ao sítio de Mn(II) pelo modo 1,2-bidentado e outro em ponte pelo inusitado modo µ-1,2-bis(monodentado), o qual não apresenta relatos na literatura. Observou-se que a folha bidimensional apresentou-se entrelaçada paralelamente à outra folha equivalente, gerando uma estrutura interpenetrada. Através das sínteses envolvendo o pseudo-oxocarbono croconato violeta obteve-se dois compostos denominados: [Co(MBP)2(CV)] (14) que envolve o ligante nitrogenado 4,4’-dimetil-2,2’-bipiridina (MBP) e {[Mn(BPP)2(H2O)2](CV)2-.2H2O}n (15) que envolve o ligante 1,3-bis(4-piridil)propano (BPP). O composto (15) teve sua estrutura determinada por difração de raios X de monocristal, a qual apresenta dois ligantes BPP, numa conformação TG (trans-gauche), coordenados em ponte entre dois sítios de Mn(II) gerando um arranjo polimérico unidimensional em que os diânions croconato violeta atuam como contra-íons. Observou-se a presença de interações de hidrogênio na estrutura, as quais foram responsáveis pelos arranjos supramoleculares bi e tridimensional.
This work presents the synthesis and characterization of novel complexes of Co(II), Ni(II) and Cu(II) involving the oxocarbons species, squaric acid and croconate ion, the pseudo-oxocarbon croconate violet dianion as well as the nitrogen ligands derived from pyridine 4,4’-dimethyl-2,2'-bipyridine (MBP), 2,3,5,6-tetrakis(α-pyridyl)pyrazine (TPP) and 1,3-bis(4-pyridyl)propane (BPP). Additionally, some syntheses involving the Mn(II) metal ion were realized. We used various analytical and spectroscopic techniques for characterization of the compounds such as elemental analysis (CHN), thermal analysis (TG/DTA) and vibrational spectroscopy (IR and Raman). We obtained six complexes involving the species squarate. Three of them contain the ligand 4,4’-dimethyl-2,2'-bipyridine (MBP), named: [Co(MBP)2 (C4O4)] (1), [Ni(MBP)3](C4O4).3H2O (2) and {[Cu2(MBP)2(C4O4)2(H2O)4]}n (3) and the other three contain the ligand 2,3,5,6 tetrakis(α-pyridyl)pyrazine (TPP): [Co2(TPP)(C4O4)2(H2O)2)]2H2O (4), [Ni2(TPP)(C4O4)(H2O)2Cl2]7H2O (5) and [Cu2(TPP)(H2O)2Cl2)](C4O4)2H2O (6). The complexes (2), (3) and (6) had their structures determined by single crystal X-ray diffraction analysis. The compound (3) is an one-dimensional coordination polymer extended through squarate ion coordinated to the Cu(II) sites in the µ-1,2-bis(monodentate) bridging mode. The oxocarbon ligand acts as counter-ion in compounds (2) and (6). The synthesis involving the croconate ion led to the taking of seven novel compounds named: {[Co(MBP)2(NO3)]2+[Co(C5O5)2(H2O)4]2-}.6H2O (7), [Ni(MBP)2(C5O5)] (8), [Cu(MBP)(C5O5)(H2O)] (9), {[Mn2(BPP)2(C5O5)2(H2O)4].3H2O}n (10), {[Co2(BPP)2(C5O5)2(H2O)4].2H2O}n (11), {[Ni2(BPP)3(C5O5)2(H2O)4].5H2O}n (12) and {[Cu(BPP)(C5O5)(H2O)3]}n (13). The compounds (7), (8) and (10) had their structures determined by single crystal X-ray diffraction analysis. The complex (7) is dinuclear, consisting of one cationic and one anionic portion that has two croconate ions coordinated to the metal center in a monodentate fashion, while compound (8) is mononuclear with croconate dianion coordinated to Ni(II) in the 1,2-bidentate mode. In compound (7) it can be noticed the presence of hydrogen interactions extending the arrangement into two dimensions, while in (8), π-π stacking interactions extend the supramolecular arrangement in one dimension. Compound (10) is a two-dimensional coordination polymer where both BPP nitrogen ligands adopt a TG (trans-gauche) conformation. The polymer has two croconate ions with different coordination modes, one adopts the 1,2-bidentate mode and the other acts in an unusual -1,2-bis(monodentate) bridging mode, which has no reports in the literature. This 2-D polymer network presents (6,3) structural topology. Two 2-D sheets interlocked each other in a parallel way generating an interpenetrated structure. Through the synthesis involving the croconate violet dianion was obtained two compounds, named: [Co(MBP)2(CV)] (14) and {[Mn(BPP)2(H2O)2](CV).2H2O)]}n (15). Compound (15) had its structure determined by single crystal X-ray diffraction analysis. It has two BPP ligands, in the TG (trans-gauche) conformation, bridging two sites of Mn(II) generating a one-dimensional polymeric array in which the croconato violet dianions act as counter-ions. There is the presence of hydrogen bonding interactions in the structure which are responsible for the extension of the supramolecular arrangements into two and three dimensions.

Les travaux décrits dans ce manuscrit utilisent les principes de la tectonique moléculaire pour générer des polymères de coordination hautement fluorés et /ou chiraux pour une application potentielle en séparation chirale. La synthèse de 13 porphyrines de type A2B2 substituées en position méso par deux pyridines et par deux chaines fluorées et/ou alkyles a été mise au point. Des réseaux de coordination ont été obtenus en présence de Zn(II) et de Cd(II) et caractérisés par diffraction des RX sur monocristal (DRX). Une analyse systématique des interactions supramoléculaires et notamment de interactions F---F présentes à l’état solide a été conduite. Des réseaux à base de liaisons halogènes ont également été obtenus en présence de di- et tri-iodoarènes et caractérisés par DRX.Le premier chapitre est une introduction générale sur la tectonique moléculaire, le deuxième chapitre décrit les voies des synthèses utilisées pour générer les ligands chiraux et fluorés et leur caractérisation à l’état solide. Le troisième chapitre présente la structure des réseaux mono, bi, et tridimensionnels formés en présence de Zn(II) ou de Cd(II), l’analyse structurale met en évidence un nombre croissant d’interaction F---F en fonction du nombre de fluors présents à la périphérie du macrocycle porphyrinique. Le dernier chapitre se concentre sur l’utilisation des liaisons halogènes de type N---I impliquant des porphyrines ou des tectons de type bipyridine et une série d’ iodofluoroarenes
This manuscript focuses on the use of molecular tectonics to generate chiral and / or fluorinated coordination polymers based on porphyrin building blocks for potential application in chiral separation. Synthesis of novel A2B2 fluorinated porphyrin tectons is described and their combinations with metal ions and haloarenes molecules are characterized by X-Ray diffraction.The first chapter gives a general introduction on molecular tectonics; the second chapter focuses on the synthetic routes used for the synthesis of highly fluorinated and/or chiral porphyrins and their solid state characterization by X-Ray diffraction analysis, highlighting the importance of the number of fluorine atoms present at the periphery of the tecton on the crystal packing. The third chapter presents the mono-, bi- and three dimensional networks formed by a combination of the porphyrins with Zn(II) or Cd(II). In the solid state, short F---F contacts were observed depending on the number of fluorine atoms present on the porphyrin backbone. The last chapter focuses on the use of halogen bonds, by merging the neutral porphyrin or bipyridine tectons with a series of iodofluoroarenes. The crystalline materials described in this work can be used as potential candidates for the separation of chiral and fluorinated molecules

In this research project, reduction or complete elimination of organic solvents is explored in the synthesis of cyclic imides using a technique that brings reagents into favorable position to react. Cocrystal Controlled Solid-State Synthesis (C3Sy3), takes advantage of supramolecular interactions such as hydrogen bonding and π-π stacking to form a cocrystal which can sequential be heated to complete the condensation reaction and produce a desirable product. Twenty-five successful condensation reactions result in high and clean yield. C3Sy3 of cyclic imides with auxiliary hydrogen bonding moieties like carboxylic acid, carboxylate or pyridyl groups are amenable to form additional solid-state materials. These moieties are useful in forming coordinate covalent bonds with metal cations. Using these C3Sy3 synthesized molecules as ligands, various Metal-Organic Materials (MOMs) are self-assembled. These MOMs offer unique qualities owing to the properties of the cyclic imides. With the addition of accessible carbonyl groups, they may participate as hydrogen bond acceptors or hydrophilic groups. Various degrees of rotation of N-phenyl substituents around the imide plane allow for structural flexibility as a route to supramolecular isomers in MOMs. The ease in imide synthesis may allow the fast scale-up of these ligands for industrial application. Similar ligands are generally synthesized by cross-coupling or substitution reactions that require expensive catalyst and various organic solvents. Metal-organic materials are a class of compounds amenable to crystal engineering owing to the directional coordinate covalent bonds between metal or metal clusters and organic ligands. They are characterized by X-ray diffraction, spectroscopy, volumetric and gravimetric analysis. The C3Sy3 imides were used to construct various MOMs, from discrete nanostructures to extended 3-periodic frameworks that possess viable internal space for applications pertaining to porous materials. Structural characterization by single crystal X-ray diffraction and structure-function relations are addressed. Gas sorption experiments show that many of these materials are structurally robust and retain crystallinity after evacuation. Ion exchange and guest uptake experiments using the synthesized materials demonstrate their potential as agents for sequestration. The bottom-up synthesis of metal-organics materials is leading the field of crystal engineering with built-in properties, showing promise by combining attributes from both inorganic and organic components.

L’objectif de mon travail de thèse était de développer de nouvelles approches vers des objets moléculaires et vers des assemblages supramoléculaires stimulables par transferts d’électrons. Au cours de ce travail, nous avons conçu, synthétisé et caractérisé de nombreux systèmes (supra)moléculaires dont la structure peut être bouleversée par le déclenchement de processus de π-dimérisation impliquant des radicaux π-conjugués électrogénérés à base de motifs 4,4’-bipyridiums, plus connu sous le nom de viologène. Le contrôle rédox des phénomènes d’auto-association est abordé dans un premier temps avec des tectons porphyriniques électroactivables capables de s’assembler, en présence de cucurbit[8]urile, sous l’effet d’une stimulation électrique centrée sur des substituants de type viologène. Nous avons notamment démontré que l’augmentation du nombre d’unités viologène sur un tecton donné permet de favoriser les phénomènes de réorganisation intramoléculaires impliqués dans les assemblages, une découverte qui ouvre de larges perspectives dans le domaine des assemblages commutables. Dans une seconde approche, nous avons développé des pinces et des clips moléculaires électro-activables susceptibles de former des matériaux auto-assemblés via l’établissement d’interactions supramoléculaires (type donneur/accepteur) entre des motifs auto-complémentaires introduits sur chaque tecton. Nos travaux ont permis de montrer l’influence de la taille et de la flexibilité de la plateforme organique choisie pour relier les motifs viologène sur les propriétés de reconnaissance et de dimérisation de ce type de molécule. Dans une dernière partie, nous décrivons la formation de polymères de coordination construits par assemblage d'un ligand ditopique à base de 4,4'-bipyridium avec du palladium, utilisé à la fois comme vecteur de la polymérisation et comme charnière inorganique favorisant la dimérisation intramoléculaire des formes réduites. Les résultats présentés révèlent que la formation de polymères / oligomères de coordination en solution peut être contrôlée par une stimulation électrique appropriée
The aim of this thesis is to develop new approaches toward “smart” redox-responsive molecular and/or supramolecular systems involving viologen units as key elements. In all cases, the metamorphic processes have been actuated by changing the redox state of the viologen units from their dicationic to cation radical states. The driving force of this reorganization is the non‐covalent and fully reversible dimerization process between the viologen cation radicals. The first part of the thesis describes the formation of supramolecular assemblies involving carefully designed poly-viologen based tectons and cucurbit[n]uril cavitands. The second part deals with the development of viologen-based redox-responsive molecular clips and tweezers with their detailed investigations of their molecular recognition and self-assembling properties. Finally, the last part describes another concept of redox-responsive assembly involving palladium and a ditopic viologen-ligand as building elements. The self-association between the metal ions and the ligands leads to the formation of coordination polymers/oligomers which can be dissociated by reduction of the viologen centers into well-defined discrete molecules

Metallosupramolecular chemistry involves the construction of nanoscale molecular assemblies by reacting metal atoms with bridging organic ligands. The metal atoms act as a type of molecular ‘glue’ binding together the organic ligands in specific orientations. Thus, appropriate combinations of metal ions and ligands lead to the controlled self-assembly of interesting one-, two- and three-dimensional molecular aggregates. This thesis details the preparation of a range of novel flexible bridging heterocyclic ligands using conventional organic synthesis, and then explores their reactions with a variety of transition metal precursors. By varying the nature of the organic ligand and the transition metal precursor, new and exciting supramolecular topologies and architectures can be formed. A total of forty-eight ligands were synthesised in this work, forty-seven of which are new compounds. The majority of the ligands synthesised were based around commercially available bisphenol cores. All forty-eight of the ligands had nitrogen heterocyclic groups as coordinating units. The ligands discussed in this thesis can be divided into three main sections. The first involves the synthesis and coordination chemistry of two-armed ligands based around the Bisphenol A, Bisphenol Z and Bisphenol AP cores. The second section describes the synthesis and coordination chemistry of the larger Bisphenol P and Bisphenol M based two-armed bridging ligands. The third section describes the synthesis and coordination chemistry of various multi-substituted ligands, including tripodal ligands based around a trisphenol core, four-armed ligands and six-armed ligands. The two-armed bisphenol based ligands proved very successful as synthons in metallosupramolecular chemistry and produced many products with a variety of different metal atoms. The complexes characterised included discrete dimeric products, coordination polymers and a number of helicates, including a dinuclear quadruply-stranded helicate. Multi-armed ligands are topical, because they have multiple coordination sites that are capable of binding and bridging multiple metal atoms. Such coordination can lead to the construction of cage-like species and complicated networks. A series of three-armed ligands based around a trisphenol core were synthesised with the intention to use these to form such species on coordination with appropriate metal salts. Indeed, one of the products of self-assembly was an interesting M₃L₂ cage. Various other multi-armed ligands were also investigated. The ligands and complexes in this thesis were characterised by a variety of structural techniques, such as ¹H NMR, ¹³C NMR, mass spectrometry, elemental analysis and X-ray crystallography when crystals were obtained. The crystal structures of twenty-seven ligands and forty-three complexes are described.

Die vorliegende Arbeit hat neben der Untersuchung der Synthese über den Controlled SBU-Approach von HKUST-1, ein poröses Kupfertrimesat, die Abscheidung dieses Metal-Organic Frameworks in dünnen Quarzglaskapillaren mit einer Länge von 10 bis 30 m und Innendurchmessern zwischen 0,53 und 0,25 mm zum Thema. Diese Säulen werden zur gaschromatographischen Trennung wie auch zur Bestimmung physikochemischer Kenngrößen, die den Adsorptionsvorgang verschiedener Analyten auf der HKUST-1 Oberfläche beschreiben, verwendet. Zu den untersuchten Stoffen gehören neben unpolaren n-Alkanen, unterschiedlich substituierte Phenylaromaten und starke Lewisbasen, wie Alkoxyalkane. Bei diesen kann der Einfluss der Gestalt und Länge der an den Sauerstoffatomen befindlichen Alkylgruppen auf die Adsorption an HKUST-1 in Form von spezifischen und unspezifischen Wechselwirkungsenthalpien, bestimmt aus gaschromatographischen Messungen, und infrarotspektroskopischen Auswertungen untersucht werden. Abschließend wird eine quantitative Aussage über das Verhältnis von Acidität und Basizität der HKUST-1 Oberfläche getroffen.

Metal-organic frameworks (MOFs) have been intensely researched over the past 20 years. In this dissertation, metal-inorganic frameworks (MIFs), a new class of porous and nonporous materials using inorganic complexes as linkers, in lieu of traditional organic linkers in MOFs is reported. Besides novel MIF regimes, the previously described fluorous MOF "FMOF-1", is re-categorized herein as "F-MIF1". F-MIF-1 is comprised of [Ag4Tz6]2- (Tz = 3,5-bis-trifluoromethyl-1,2,4-triazolate) inorganic clusters connected by 3-coordinate Ag+ metal centers. Chapter 2 describes isosteric heat of adsorption studies of F-MIF1 for CO2 at near ambient temperatures, suggesting promise for carbon capture and storage. We then successfully exchanged some of these Ag(I) centers with Au(I) to form an isostructural Au/F-MIF1. Other, nonporous MIFs have been synthesized using Ag2Tz2 clusters with bridging diamine linkers 4,4'-bipyridine, pyrazine, and a Pt(II) complex containing two oppositely-situated non-coordinating pyridines. This strategy attained luminescent products better-positioned for photonic devices than porous materials due to greater exciton density. Chapter 3 overviews work using an entirely inorganic luminescent complex, [Pt2(P2O5)4]4- (a.k.a. "PtPOP") to form new carbon-free MIFs. PtPOP is highly luminescent in solution, but as a solid shows poor quantum yield (QY ~0.02) and poor stability under ambient conditions. By complexing PtPOP to various metals, we have shown a dramatic enhancement in its solid-state luminescence (by an order of magnitude) and stability (from day to year scale). One embodiment (MIF-1) demonstrates microporous character. Chapter 4 overviews the design and application of new MIF linkers. Pt complexes based upon (pyridyl)azolates, functionalized with carboxylic acid groups, have been synthesized. These complexes, and their esterized precursors, show strong luminescence on their own. They have been used to generate new luminescent MIFs. Such new MIFs may be useful toward future inorganic (LEDs) or organic (OLEDs) light-emitting diodes, respectively. The electronic communication along their infinite coordination structures is desirable for color tuning and enhanced conductivity functions, compared to the small molecules used in such technologies, which rely on intermolecular interactions for these functions.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Este trabalho consistiu na síntese e caracterização de complexos de metais de transição, especialmente os íons metálicos da primeira série de transição, Cu2+, Co2+ e Zn2+, contendo o ânion dicarboxilato 2,6-piridinodicarboxilato bem como os ligantes nitrogenados rígido e flexível: 4,4’-bipiridina (BIPY) e 1,3-bis(4-piridil)propano (BPP). Todos os compostos sintetizados foram caracterizados por análise elementar (CHN), análise termogravimétrica (TG), espectroscopia vibracional na região do infravermelho (IV) e difração de raios X de monocristal. O capítulo 1 abrange uma breve introdução sobre Polímeros de Coordenação. Adicionalmente, incluiu-se uma apresentação sobre Química Supramolecular seguido de uma apresentação sobre o ligante carboxilato e os ligantes nitrogenados utilizados neste trabalho, destacando a intensa pesquisa na área. No capítulo 2 descreve-se a síntese do sal de sódio derivado do ácido dicarboxílico, bem como dos seis complexos contendo o ligante nitrogenado 1,3-bis(4-piridil)propano e o ligante nitrogenado BIPY. Estes complexos foram formulados como [Cu(2,6-PDC)(2,6-PDCH2)].3H2O (1), [Cu2 (μ-BPP) (2,6-PDC)2(H2O)2]. 2H2O (2), {[Co(H2O)4 (BPP)] [Co(2,6-PDC)2]. H2O}n (3) e (H2BPP) [Zn(2,6-PDC)2].4H2O (4), [ Co2 (μ-BIPY) (2,6-PDC)2(H2O)4]. 2H2O (5) e [Cu2(μ-O2CCH2C4H3S)4(Bipy)]n (6). O capítulo 3 relaciona-se com a caracterização dos complexos contendo o ligante nitrogenado 1,3-bis(4-piridil)propano. Os complexos (2) e (3) tiveram suas estruturas determinadas por difração de raios X de monocristal. O complexo (2) é homobimetálico com dois centros de Cu(II) em geometria pirâmide de base quadrada distorcida conectados através do ligante BPP em ponte. Por outro lado, o composto (3) apresenta uma porção complexa aniônica formada por um centro de Co(II) e dois ânions piridinodicarboxilatos e uma cadeia polimérica catiônica, constituída por íons Co(II) e ligantes BPP em ponte. Em ambos os casos um sistema supramolecular 3-D é gerado através de ligações de hidrogênio. Os dados analíticos e espectroscópicos para o composto (4) sugerem a formação de um complexo formado por duas porções. A porção aniônica é formada por dois ligantes 2,6-piridinodicarboxilatos coordenados de forma tridentada através da coordenação (O-N-O) ao centro de Zn(II) e estabilizando a carga um ligante nitrogenado BPP duplamente protonado. Esse tipo de estrutura é bem suportado por vários exemplos da literatura. O capítulo 4 engloba a caracterização dos complexos contendo o ligante nitrogenado rígido 4,4’-bipiridina (BIPY). Os complexos (5) e (6) tiveram suas estruturas determinadas por difração de raios X de monocristal. No complexo (5) temos a formação de um composto binuclear onde o ligante nitrogenado BIPY atua em ponte entre os sítios metálicos de Co(II) que por sua vez se encontram coordenados de modo tridentado ao ânion 2,6-piridinodicarboxilato e duas moléculas de água culminando em uma geometria octaédrica para o centro metálico. A natureza 3-D é evidenciada através de ligações de hidrogênio do tipo O – H...O. No composto (6) verifica-se que cada centro metálico adota uma geometria pirâmide de base quadrada na qual a base é formada pelos oxigênio do grupos carboxilato e a posição apical ocupada por um átomo de nitrogênio proveniente do ligante BIPY, que atua em ponte entre os sítios de Cu(II), originando uma cadeia polimérica unidimensional. O presente trabalho revela um grande interesse no estudo da Química Supramolecular, abrangendo importantes conteúdos em Química Inorgânica Supramolecular propondo-se diferentes rotas sintéticas para obtenção das estruturas supramoleculares.
This work describes the synthesis and characterization of transition metal complexes, especially the metallic ions from the first row, Cu2+, Co2+ and Zn2+, containing the 2,6-pyridinedicarboxylate anion as well as the rigid and the flexible nitrogen ligands, 4,4’-bipyridine (BIPY) and 1,3-bis(4-pyridil)propane (BPP). All the compounds were characterized by means of elemental analysis (CHN), thermal analysis (TG), infrared spectroscopy (IR) and single crystal X-ray diffraction analysis. Chapter 1 involves a brief introduction about Coordination Polymers. In addition a presentation about Supramolecular Chemistry, carboxylate anions and nitrogen ligands used in this work, is include enphatizing the intensive research in this area. In chapter 2, the synthesis of the sodium salt derived from the dicarboxylic acid, as well as of the six complexes containing the nitrogen ligands 1,3-bis(4-pyridil)propane and 4,4’-bipyridine are described. These complexes were named [Cu(2,6-PDC)(2,6-PDCH2)].3H2O (1), [Cu2 (μ-BPP) (2,6-PDC)2(H2O)2]. 2H2O (2), {[Co(H2O)4 (BPP)] [Co(2,6-PDC)2]. H2O}n (3) e (H2BPP) [Zn(2,6-PDC)2].4H2O (4), [ Co2 (μ-BIPY) (2,6-PDC)2(H2O)4]. 2H2O (5) e [Cu2(μ-O2CCH2C4H3S)4(Bipy)]n (6). Chapter 3 presents the characterization of the complexes containing the nitrogen ligand 1,3-bis(4-pyridil)propane. Complexes (2) and (3) had their structures determined by single crystal X-ray analysis. Complex (2) is homobimetallic were two Cu(II) centers in a distorted square-piramide geometry, connected by a BPP ligand in the bridging mode. On the other hand, compound (3) presents an anionic moiety, formed by a Co(II) center and two pyridinedicarboxylate anions and a cationic polymeric chain, formed by Co(II) ions and bridging BPP ligands. In both cases, a 3-D supramolecular array is generated through hydrogen bondings. The analytical and spectroscopic data for compound (4) suggest the formation of an ionic complex, in which the anionic moiety contains two 2,6-pyridinedicarboxylate anions coordinated to the Zn(II) center in the tridentate (ONO) fashion. The nitrogen ligand BPP is protonated, (H2BPP2+) estabilizing the anionic unit. This type of structure is well supported by several examples from literature. Chapter 4 describes the characterization of the complexes containing the rigid nitrogen ligand 4,4’-bipyridine (BIPY). Complexes (5) and (6) have had their structures determined by single crystal X-ray diffraction analysis. Complex (5) is homobinuclear in which the nitrogen ligand BIPY bridges two Co(II) sites that are also coordinated by 2,6-pyridinedicarboxylate anion in the tridentate mode as well as by two water molecules, in an distorted octahedral geometry. The 3-D supramolecular nature of the system is achievied through O – H…O hydrogen bondings. In compound (6) it can be noticed that each metal center adopts the distorted square-pyramide geometry in which the base is formed by the oxygen atoms from the carboxylate groups and the apical positions is occupied by nitrogen atom from BIPY ligand. The BIPY ligands bridge the Cu(II) sites, generating a one-dimensional polymeric chain. This work shows a great interest in the study of Supramolecular Chemistry, covering important content in Supramolecular Inorganic Chemistry proposing different synthetic routes to obtain of the supramolecular structures.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Este trabalho descreve a síntese e caracterização de oito compostos de coordenação, [Zn(PYA)2(H2O)2]n (1), [Mn(PYA)2(H2O)2]n (2), {[Co(2,5PDC)(H2O)2] .H2O}n (3), [Mn(2,5HPDC)2(H2O)2] (4), [Ni(2,3HPDC)2(H2O)2] (5), {[Cu(3,4HPDC)2(H2O)2] .DMSO}n (6), {[Co(3,4HPDC)2(H2O)2](H2O)(DMSO)}n (7) e {[Cu2(3,4HPDC)2(H2O)5]}n (8) contendo ligantes da família dos ácidos piridinodicarboxílicos, que são N-, O- doadores e podem proporcionar modos de coordenação interessantes frente aos íons metálicos da 1º série de transição selecionados para o trabalho (Mn2+, Co2+, Ni2+, Cu2+ e Zn2+). Os ligantes utilizados foram os ácidos 2,3 piridinodicarboxílico (2,3H2PDC), 2,5 piridinodicarboxílico (2,5H2PDC), 3,4 piridinodicarboxílico (3,4H2PDC), trans-3-(piridil)-acrílico (HPYA) e 3-(2-tienil)acrílico (HTA). Dos oito compostos descritos neste trabalho, apenas três são inéditos. Os compostos inéditos, (6), (7) e (8) foram caracterizados por análise elementar, análise térmica (TG e DTA), espectroscopia vibracional na região do infravermelho, e difração de raios X por monocristal. Nesses três compostos, em acordo com os dados espectroscópicos, a difração de raios X por monocristal mostrou que os ligantes se apresentam na forma parcialmente desprotonada e além disso, observou-se a formação de redes poliméricas. Em todos os casos, os arranjos supramoleculares são formados por ligações de hidrogênio. Todos os compostos apresentam o metal central em geometria octaédrica, com excessão do composto (8) que mostra dois centros de Cu(II), sendo um em geometria octaédrica e outro como pirâmide de base quadrada. Foi feita também a descrição topológica das redes poliméricas formadas, com auxilio do programa TOPOS. Dentre os compostos apresentados neste trabalho, apenas os compostos (4) e (5) não formam cadeias ou redes poliméricas. O teste de capacidade de adsorção de gás para o composto polimérico (6) foi feito através das isotermas de N2, utilizando o método BET.
This work describes the synthesis and characterization of eight coordination compounds, [Zn(PYA)2(H2O)2]n (1), [Mn(PYA)2(H2O)2]n (2), {[Co(2,5PDC)(H2O)2] .H2O}n (3), [Mn(2,5HPDC)2(H2O)2] (4), [Ni(2,3HPDC)2(H2O)2] (5), {[Cu(3,4HPDC)2(H2O)2] .DMSO}n (6), {[Co(3,4HPDC)2(H2O)2](H2O)(DMSO)}n (7) and {[Cu2(3,4HPDC)2(H2O)5]}n (8) containing N-,O-donor ligands from pyridinedicarboxylic acids family that can provide interesting coordination modes toward the first row transition metal ions (Mn2+, Co2+, Ni2+, Cu2+ e Zn2+). 2,3 pyridinedicarboxylic (2,3H2PDC), 2,5 pyridinedicarboxylic (2,5H2PDC), 3,4 pyridinedicarboxylic (3,4H2PDC), trans-3-(pyridyl)-acrylic (HPYA) and 3-(2-thienyl)acrylic acid (HTA) were used as ligands. Among the eight compounds described in this work, only three are unpublished. The novel compounds, (6), (7) and (8) were characterized by elemental analysis, thermal analysis (TG and DTA), infrared vibrational spectroscopy, and single crystal X-ray diffraction analysis. In these three compounds, in accordance with the spectroscopic data, single crystal X-ray diffraction analysis showed that the ligands are present in partially deprotonated form and furthermore, the formation of polymeric networks was observed. In all cases, supramolecular arrangements are formed by hydrogen bonds. All compounds show the metal center in octahedral geometry, except compound (8) that has two Cu (II) centers; one in octahedral geometry and other in a square pyramidal geometry. A topological description was also made for the polymeric networks formed, supported by the software TOPOS. Among all compounds presented in this work, only compounds (4) and (5) do not form polymeric chains or networks. The gas adsorption capacity test was realized for the polymeric compound (6), through N2 isothermal, using BET method.

Dans ce travail, l’approche de la tectonique moléculaire, basée à la fois sur la reconnaissance moléculaire et le processus itératif d’auto-assemblage à l’état cristallin, a été utilisée pour la formation de réseaux moléculaires de coordination, ainsi que de réseaux moléculaires à base de liaisons hydrogène. La synthèse de nouveaux tectons à base de dérivés de TCA (p-tert-butylthiacalix[4]arene et p-H-thiacalix[4]arene) offrant des groupements coordinants de type pyridine (avec différentes positions de l’azote sur les noyaux pyridiniques) et de dérivés de TMTCA (tetramercaptothiacalix[4]arene) portant aussi des groupement de type pyridine (avec différentes positions de l’azote sur les noyaux pyridiniques) mais aussi cyano, carboxylates, pyrazole et imidazole a été mise au point. Tous les tectons adoptent la conformation 1,3-alternée, permettant l'obtention de réseaux moléculaire de dimensionalité élevée. Les composés obtenus ont été caractérisés à la fois en solution et à l'état cristallin. Leur aptitude à former des réseaux de coordination en présence de métaux de transition (tels que Ag(I), Hg(II), Cd(II), Cu(II), Co(II), Fe(II)) a été explorée. La possibilité de formation de réseaux à base de liaison hydrogènes a été également testée en utilisant le carboxylate-bisamidinium type de reconnaissance. Beaucoup de nouveaux polymères de coordinations possédant diverses dimensionnalités, en particulier, 3D de type diamant, et certaines réseaux à base de liaisons hydrogènes ont été obtenus. La différence de la connectivité entre TCA et TMTCA vis-à-vis des cations métalliques a été étudiée et discutée
In this work, the molecular tectonic strategy, based on the molecular recognition together with the iterative self-assembly process in the crystalline phase, has been used for the formation of molecular networks (coordination polymer and H-bonded networks). The synthesis of new tectons based on the TCA derivatives (p-tert-butylthiacalix[4]arene et p-H-thiacalix[4]arene) offering pyridyl binding sites with different position of N atom in the rings, as well as the TMTCA derivatives (tetramercaptothiacalix[4]arene) bearing pyridyl (also with different position of N atom in the rings), cyano, carboxylate, pyrazolyl, imidazolyl coordinating groups has been achieved. All tectons were fixed in 1,3-alternate conformation, allowing the formation of high dimensionality networks. The structures of obtained tectons were characterized in solution, as well as in the solid state. The propensity of these tectons to form coordination polymers upon the combination with different transition metal cations such as Ag(I), Hg(II), Cd(II), Cu(II), Co(II), Fe(II) has been expoled. The possibility to form the H-bonded networks has also been investigated using the carboxylate-bisamidinium type of recognition pair. New coordination polymers possessing different dimensionalities (especially 3D diamond like) and some H-bonded networks have been obtained. The differences in the connectivity of TCA and TMTCA towards the metal cations have been studied and discussed

博士
國立臺北科技大學
工程科技研究所
95
In recent years, the design, self-assembly, and application of supramolecular coordination polymers have been extensively studied. The organic ligands with different geometry shape and angle have been designed and synthesized. The reactions of these organic ligands with the metallic ions form the corresponding functional coordination polymers. In this dissertation, the metallic ions were chosen from Co+2, Ni+2, Cu+2, Zn+2 and Cd+2. Two types of the organic ligands were selected for self-assembly. One type of ligand was based on literature synthesized, the other type of ligand was designed and synthesized. We synthesized five new pyrazine-modulated ligands, [(N-Pyrazin-2-yl)(N''-pyridin-2-yl)pyridine-2,6-diamine (H2pzpypy), N,N''-bis(pyridin- 2-yl)pyrazine-2,6-diamine (H2pypypz), (N-Pyrazin-2-yl)-(N''-pyridin-2-yl)pyrazine- 2,6-diamine (H2pzpypz), N,N''–bis(pyrazin-2-yl)-pyridine-2,6-diamine (H2pzpzpy) and N,N''–bis(pyrazin-2-yl)pyrazine-2,6-diamine (H2pzpzpz). By coordinating with metal ions Cu+2 and Ni+2, several 1-D, 2-D and 3-D supramolecular coordination polymers determined by X-ray single crystal diffraction have been obtained. Another new ligand, trans-4,4''-azo-1,2,4-triazole (atr) was also synthesized for the construction of coordination polymers. The ligand is a planar molecule with two triazoles linked by an azo group. It could be served as a multi-dentate ligand or a good linkage ligand. A series of Co(II) polymeric compounds with 1-D, 2-D and 3-D frameworks have been successfully synthesized and characterized structurally. The ligand, 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (3-bpd), has also been used for the synthesis of three novel coordination polymers. Two novel coordination polymers have the same chemical composition, [ZnCl2(3-bpd)]n and they show different structural conformations with one forming a helical chain and the other a square-wave chain. The intermolecular C−H•••Cl hydrogen bonds in both structures play important roles in the formation of 3-D framework. The coordination polymer [Ni2(NO3)4(3-bpd)3]n•nEtOH, with all the bridging ligands in a bis-monodentate mode connecting to the Ni(II) ions, formed a 3-D metal-organic polymeric framework that shows a 1-D microporous channel with dimensions of ca. 6.7 x 8.5 Å2 along the a-axis. The EtOH guest molecules are intercalated into these channels. The reaction of N,N''-bis(4-pyridylmethyl)oxalamide (4py-ox) with Co+2 and Cd+2 formed two novel supramolecular coordination compounds, [CoCl2(4py-ox)]n•0.5nH2O, and [Cd(NO3)2(4py-ox)1.5]n, respectively. The structure of [CoCl2(4py-ox)]n•0.5nH2O features a 1-D zigzag chain. Two interwoven chains create a cavity of ca 8.6 x 8.6 Å2, which produces a 3-D channel and water molecules are held in the channel by hydrogen bonds. The structure of [Cd(NO3)2(4py-ox)1.5]n shows a 2-D sheet polymeric framework and the neighboring sheets are interlaced, and the 3-D structure of this compound is microporous.

This thesis provides an account of the synthesis and study of fifteen amide-containing polypyridyl ligands, eleven of which are new compounds. These ligands all possess at least one amide moiety, potentially capable of anion binding and one or more pendant pyridyl donor groups as the metal coordinating sites. A further evolution over previously reported compounds is that a majority of the amide compounds incorporate a pre-organised amide component that will constitute the anion binding region. The alkyl and phenyl spacers were utilised to confer flexibility to these compounds and to extend the spacing between the anion binding moiety and the pendant metal complexing groups. The compounds investigated in this work are divided into three categories; (i) unsymmetrical monoamide ligands that possess one amide functional group, one ester protected carboxylate and one external donor pyridyl moiety; (ii) symmetrical flexible amide ligands that possess two or more internal amide groups and two external pyridyl metal coordinating sites, and; (iii) symmetrical amide bridging ligands that incorporate two di-2-pyridylmethylamine chelating motifs. The coordination chemistry and metallo-supramolecular chemistry of these ligands was investigated with a range of late transition metals including cadmium(II), copper(II), cobalt(II), silver(I), zinc(II) and palladium(II). Palladium(II) precursors, with a selection of monodentate or bidentate chelating ancillary blocking ligands, were utilised to form discrete mono- and dinuclear assemblies with a view to investigating anion complexation in solution. Other transition metal precursors were studied with a focus on the synthesis of coordination polymers that display anion coordinating pockets. Reaction of the monoamide ligands containing a pendant 3-pyridyl group with copper salts led to the formation of five very similar discrete planar and cleft-containing [Cu₂L₂] dinuclear metallo-macrocyclic complexes. The monoamide compounds, lacking a methylene spacer between the amide and the pendant pyridyl ring, form near planar [Cu₂L₂] dinuclear metallo-macrocyclic complexes; meanwhile introduction of a CH₂ spacer, by using a more flexible ligand, results in the formation of cleft-containing complexes. Reaction of the more flexible ligand with copper perchlorate results in a cleft-containing complex whereby encapsulation of a perchlorate anion in the cavity is stabilised by anion-π interactions. The flexible monoamide ligand with a pendant 4-pyridyl group forms 1-D coordination polymers based on a similar dinuclear metallo-macrocycle building block motif. Reaction of a related ligand with cadmium(II) nitrate and copper(II) acetate led to a formation of two 2-D coordination polymers, both prepared via a solvothermal approach. The 2-D coordination polymer obtained with cadmium(II) nitrate has small oval channels with the oxygen atoms of the nitrate anions and ligands lining the channels. This contrasts with the 2-D coordination polymer obtained with copper(II) acetate which is close-packed in the solid-state. In a similar manner to studies on the monoamide ligands, the symmetrical flexible diamide ligands and tetraamide ligands were used to form discrete complexes and metallo-macrocyclic containing coordination polymers. Two mononuclear Pd(II) supramolecular cages were obtained from the reaction of flexible diamide ligand with pendant 3-pyridyl groups, while a mixture of Pd(II) supramolecular isomers was obtained with the analogue of this ligand. A crystal structure of a mononuclear palladium(II) complex showed specific anion interactions between the pre-organised NH donors and hexafluorophosphate anions in the solid-state. Similar interactions were observed in the majority of the coordination polymers obtained with the flexible diamide and tetraamide ligands. In the crystal structures of three isostructural dinuclear metallo-macrocycle based coordination polymers containing the diamide ligand with pendant 3-pyridyl groups, the pre-organised NH donors are hydrogen bonded to the counterions, including nitrate and perchlorate. In addition to this interaction, the structures were stabilised by π-stacking interactions between the pendant pyridine groups and pyridyl cores. Reaction of the flexible diamide ligand containing pendant 4-pyridyl groups with cadmium(II) and zinc(II) nitrate provided access to two isostructural and isomorphous 1-D coordination polymers, while slow evaporation with cadmium(II) perchlorate gave 2-D coordination polymer. Reaction of the set of flexible tetraamide ligands containing pendant 4-pyridyl groups gave two coordination polymers that adopt semi-helical and close-packed structures in the solid-state. Only one coordination polymer was able to be obtained with the tetraamide ligands with pendant 3-pyridyl groups. The coordination chemistry of the chelating amide ligands with silver(I), cadmium(II) and palladium(II) salts were also studied and these ligands found to act as a bis(bidentate) ditopic bridge to connect two metal ions. This study has revealed that the monoamide or unsymmetrical amide ligands in combination with copper(II) salts can form discrete anion cages potentially capable of interacting with anions via hydrogen bonding and anion-π interactions. The symmetrical and flexible diamide ligands also show potential to interact with anions in the solid-state and may be used for the development of materials suitable for anion separation or sequestration and also as design elements of anion binding moieties for sensors. Unfortunately, the incorporation of more flexible amide ligands into metallo-supramolecular assemblies was not shown to increase the ‘size’ of the anion pocket of the assemblies but, due to the additional flexibility, results in the formation of more close-packed structures. It is also shown that self-association may limit the applicability of the tetraamide ligands to bind with either cations or anions in solution. The preliminary anion competition studies have shown that the coordination compounds derived from L5 and L6 tend to precipitate salts of either sulfate or, more likely based on the Hofmeister series, perchlorate anions under competitive conditions. All compounds obtained in this work were characterised by a combination of ¹H and ¹³C NMR spectroscopy, IR spectroscopy, mass spectrometry, elemental analysis and X-ray crystallography. Simultaneous Thermal Analysis (STA) and Powder Diffraction X-ray Diffraction (PXRD) results for selected compounds are also described. In this thesis, crystal structures of seven ligands and twenty nine novel coordination compounds are described.
Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2012

碩士
國立中正大學
化學所
93
The research focus in this thesis is classified into two parts. In the first part, we synthesize a series of dipyridyl dialkyl amides (1,4-bis[(3-pyridyl)ethynyl]benzene (L23’), 4,4’-diethynyl-4’’,4’’’- dipyridylbiphenyl (L24), 3,3’-diethynyl-4’’,4’’’-dipyridylbiphenyl (L24’)) and tripyridyl amides (N1,N3,N5-tri(pyridin-3-yl)benzene-1,3,5- tricarboxamide (L12’) ) as bridging ligands for the supramolecular synthesis. The long and rigid ligands L23’, L24, and L24’ are used in the construction of six molecular triangles via self-assembly with Pd(II) and Pt(II) ions as corners and d-t-bpy (4,4’-tert-butyl bipyridine) as ancillary ligands, [Pd(d-t-bpy)(L23’)]3(OTf)6 (1), [Pt(d-t-bpy)(L23’)]3(OTf)6 (2), [Pd(d-t-bpy)(L24)]3(OTf)6 (3), [Pt(d-t-bpy)(L24)](OTf)6 (4), [Pd(d-t-bpy) (L24’)]3(OTf)6 (5), and [Pt(d-t-bpy)(L24’)]3(OTf)6 (6). In addition, molecular cages, {[Pd(d-t-bpy)]3(L12’)2}(OTf)6 (7) and {[Pt(d-t-bpy)]3 (L12’)2}(OTf)6 (8), are constructed from the tripyridyl amide ligand L12’. Complexes 1-8 are isolated and characterized by electrospray ionization mass spectrometry, 1H NMR, and elemental analysis. In the second part, we design and synthesize a new tetrapyridyl amide ligand (1,4,7,10-tetraaza-cyclododecane-1,4,7,10-tetrakis-pyridin- 4-yl-amide (L13) ) as a bridging ligand for the synthesis of a series of cadmium(II) and zinc(II) coordination polymers, {[Cd(L13)(DMSO)2] Br2}n (9), {[Cd(L13)(DMSO)2]I2}n (10), {[Cd(L13) (DMSO)2](NO3)2}n (11), and {[Zn(L13)1/2(DMSO)]Br2}n (12). The X-ray diffraction analysis confirms that 9-11 are three-dimensional frameworks, and 12 two-dimensional one, where these four coordination polymers all show interesting one-dimension channels in the solid state. Finally, absorption and luminescence properties of 1-12 are also investigated in this thesis.

Nature has always remained a constant source of inspiration for chemists for synthesizing natural products, mimicking enzymatic reactions or to construct molecular architectures resembling biological assemblies. With the rapid growth of ‘Supramolecular Chemistry’ along with the advancement of the synthetic methodologies, molecular systems with brand new complexities have been synthesized, alongside the efficacy of weak, reversible non-covalent interactions have also been extensively explored. A number of such forces including hydrogen bonding, solvophobic effect, dynamic covalent interactions and metal-ligand coordination have been exploited to assemble the molecular building blocks and stitch them together to construct discrete ‘self-assembled’ architectures integrated with desired functionalities. Metal-ligand coordination driven self-assembly certainly evolved as one of the most successful approaches for the construction of discrete supramolecular architectures during last two and half decades. The high directionality and reversible nature of certain metal-ligand bonds allow the pre-designing of sophisticated architectures which can be successfully obtained by ‘error corrections’ via a thermodynamically controlled self-assembly process. Numerous aesthetically elegant two dimensional (2D) and three dimensional (3D) metallosupramolecular architectures have been constructed which have been studied for various potential applications including guest encapsulation, catalysis, sensing, optoelectronics, drug delivery, protection of reactive species etc. Construction of such molecular architectures uses symmetric and rigid building blocks which strictly preserves their geometrical coding and thus finally determines the fate of the self-assembly. Pyridyl-based donors have been extensively used due to their well-behaved coordination with transition metal ions. Interestingly, imidazole based donors remained almost unexplored for such purpose mainly due to the rotational flexibility of imidazole moieties owing to the lack of -electron delocalization with the aromatic backbone, which makes pre-designing an architecture extremely difficult. However, this unpredictability can lead to the formation of unprecedented molecular architectures. Furthermore, the conventional rigid ‘acceptors’ used in the ‘directional bonding approach’ always results in the formation of rigid assemblies, which cannot be utilized for the construction of smart molecular machine based applications. In this context, incorporation of restricted rigidity in the building blocks can be a convenient approach to construct versatile and flexible supramolecular architectures. Although flexible donors are quite common in coordination-driven self-assembly, the use of flexible metal acceptor is scarcely Highly symmetric spherical assemblies of square planer Pd(II) and Pt(II) ions are one of the most extensively studied metallosupramolecular architectures owing to their topological similarity with the spherical virus capsids. Unfortunately, none of the reported molecular spheres are soluble in water which restricts their applications in aqueous media. On the other hand, most of the metallosupramolecular architectures cannot be used for redox based applications as the oxidation state of the associated metal ions must be kept unaltered. Although, assemblies constructed mainly by the ferrocene containing acceptors are shown to be exhibiting redox property, the donor inherited redox active metallosupramolecular systems are extremely rare. Discrete 3D metallosupramolecular cages have been extensively studied as synthetic hosts where the hydrophobic pockets have been utilized as safe shelter for reactive species, for catalyzing chemical transformations, tuning electronic and optical properties of guest molecules, as delivery vehicle for drug molecules etc. However, a major drawback of many such 3D cages is associated with their closed-shell topology, where the large cavities are accessible though relatively much smaller apertures which prevent larger guest molecules to enter inside. So, an interesting finding in this field would be to construct molecular hosts with larger apertures. Picric acid (PA) is a strong organic acid and like many other polynitroaromatic compounds, it is a powerful explosive. In addition, it has large scale industrial application for the synthesis of dyes and pharmaceuticals. However, PA has potential health hazards and it is a water pollutant owing to its high aqueous solubility. Thus, the development of selective receptors which can efficiently interact with PA and detect it at very lower concentration is an appealing field of research. Chapter 1 briefly discusses the history of supramolecular chemistry and the concept of ‘self-assembly’ along with the several synthetic methodologies for the construction of discrete supramolecular architectures. It also includes a brief discussion on the various design approaches to construct 2D and 3D molecular architectures by metal-ligand coordination which is followed by an account on some of the important applications of such metallosupramolecular architectures. At the end, a small introduction on the fluorescence-based detection techniques for PA has also been included. Chapter 2A accounts for the exploration of two linearly substituted benzene bisimidazole donors L1 and L2 for coordination-driven self-assembly. L1 and L2 possesses different ‘natural’ donor angles as the imidazole moieties in L2 are twisted heavily with respect to the phenyl plane due to the steric hindrance exerted by the methyl groups. Interestingly, while the self-assembly of L1 with [cis-(tmeda)Pd(NO3)2] (tmeda = N,N,Nꞌ,Nꞌ-tetramethylethane-1,2-diamine) exclusively formed a [3+3] molecular triangle, the self-assembly of L2 yielded a [4+4] molecular square as the major product with the same acceptor. In addition, similar treatment with the analogous Pt(II) acceptor resulted mixtures of [3+3] and [4+4] assemblies in both cases; however, the [3+3] assembly was the major product in case of L2. These contradictory product distributions in case of L2 with analogous Pd(II) and Pt(II) acceptors could be corroborated by the delicate balance between the entropic and enthalpic contributions. Scheme 1. Self-assembly of L1/L2 with [cis-(tmeda)Pd(NO3)2] and [cis-(tmeda)Pt(NO3)2], respectively. Furthermore, the reactions of L1 and L2 with a 0º bisplatinum acceptor, viz. AntPt yielded the expected [2+2] macrocycles (8 and 9), respectively. However, the interesting observations Scheme 2. Self-assemblies of L1 and L2 with the 0º bisplatinum acceptor AntPt. obtained from the variable temperature NMR studies suggested the existence of a mixture of inter-convertible conformational isomeric structures of 9. Chapter 2B describes the synthesis of a novel semi-rigid bisplatinum acceptor bisPt-NO3 based on benzil backbone for the construction of flexible metallamacrocycles. The benzil group was selected due to its unique rotational flexibility along the benzyl C-C bond which can generate a wide range of bite angles to make it compatible with the variety of donors of diverse shapes and sizes. The acceptor was successfully self-assembled with four different bisimidazole donors (L1-L4) to yield corresponding [2+2] metallamacrocycles (M1-M4) which were characterized by multinuclear NMR and ESI-MS spectrometry; and their structures were elucidated by semi-empirical geometry optimizations. Scheme 3. Self-assembly of [2+2] metallamacrocycles M1-M4 by a semi-rigid bisplatinum acceptor bisPt-NO3. Chapter 3 discusses the synthesis of the very first example of a water soluble molecular sphere MC-1 by the self-assembly of square planar Pd(II) ions with a flexible cationic tritopic donor La(NO3)3 containing 4,4-bispyridyl arms. The structural flexibility of La(NO3)3 makes it capable of binding with metal ions in its syn- or anti-conformations which was also experimentally observed in the structures of the three newly synthesized coordination polymers, viz. Ag-CP, Zn-CP and Cd-CP constructed by using La(NO3)3 as (co)ligand. Finally, the 4:3 self-assembly of [La(NO3)3] and Pd(NO3)2 in aqueous media produced the desired M6L8 type Scheme 4. Self-assembly of the water soluble molecular dice MC-1 from the tricationic tritopic donor La(NO3)3. molecular sphere- MC-1, which contain 36+ overall charges. The compound could be easily solubilized in water after isolation as solid by simple stirring at room temperature. Single crystal X-ray diffraction analysis (SCXRD) revealed the ‘dice’-shaped architecture of MC-1 where the eight faces are occupied by the coordinated Pd2+ ions and the bispyridyl arms and the vertices are occupied by mesityl moieties. MC-1 is stable in aqueous media, however disintegrates in DMSO, as observed by variable temperature NMR experiments. In addition, MC-1 also produced ligand inherited redox signals in cyclic voltammetry experiments. Chapter 4 describes the synthesis of a novel non-symmetric tetraimidazole donor L based on carbazole backbone. The complexity of the donor is associated with the allowed free rotation of the imidazole moieties along with the non-symmetric nature of the carbazole backbone which make L a very unusual donor for coordination-driven self-assembly. The crystal structure of L showed that the presence of the N-Me group caused a greater twisting of the nearby imidazole moieties with respect to the other set of imidazole moieties. The self-assembly of L with [cis-(en)Pd(NO3)2] (en = ethane-1,2-diamine) yielded a mixture of M4L8 and M6L12 type self-assembled products, as evidenced from the ESI-MS spectrometry. However, the DOSY NMR spectra of the product showed a single diffusion coefficient for all the peaks, indicating that both type of assemblies have similar size and hence suggested the formation of a tetrafacial barrel and a cubic architecture. A similar self-assembly of L with [cis-(tmeda)Pd(NO3)2] also produced a water soluble product. ESI-MS spectra in this case only confirmed the formation of a M4L8 assembly- MB-1. SCXRD analysis of the coronene encapsulated complex of MB-1 gave more insights on the sophisticated non-symmetric tetrafacial barrel architecture of MB-1 with large Scheme 5. Construction of the water soluble molecular barrel MB-1 by the self-assembly of a non-symmetric tetraimidazole donor L. rectangular apertures. The centrosymmetric molecule can encapsulate two aromatic guest molecules inside its hydrophobic cavity and was found to be efficiently encapsulating polyaromatic hydrocarbons (PAHs) in aqueous media. In addition, MB-1 has been successfully exploited to carry water insoluble perylene molecule inside HeLa cells for fluorescence imaging purpose without showing significant toxicity. L also formed a water insoluble tetrafacial barrel (MB-2) by self-assembly with [cis-(dppf)Pd(OTf)] (dppf=diphenylphosphino ferrocene) which interestingly has a symmetrical architecture, as evidenced from the SCXRD analysis. The formation of the symmetrical barrel is driven by the steric hindrance between the bulky phenyl groups of the nearby dppf moieties. Chapter 5 reports the study of interactions between picric acid (PA) with a few newly synthesized fluorescent imidazolium salts (S1-S3). The fluorescence titration study of the positively charged receptors with PA showed rapid decrease of the corresponding fluorescence intensities upon gradual addition of PA. The Stern-Volmer plots suggested the involvement of both static and dynamic quenching mechanisms which was further supported by fluorescence lifetime measurements, NMR and UV-Vis spectroscopic analyses. The values of the Stern-Volmer constants (Ksv) reflected strong receptor-PA binding. The quenching efficiency calculations in the presence of several other analytes proved that the receptors are highly selective for PA in both aqueous and non-aqueous media. The mode of interactions in solid state was investigated by the crystal structure analysis of the [S1PA] complex. 1H NMR spectra of the same complex indicated strong interaction between the imidazolium moieties of the receptor Scheme 6. The fluorescent imidazolium salts based receptors S1-S3 and the florescence titration plot for S1 with PA. Inset: the solutions of S1 and (S1+PA) in DMSO under UV light. with PA in solution; however, no significant interaction of PA with the anthracene moieties was observed in solution as we well as in the solid state. Also the quenching efficiencies and the Ksv values were correlated with the positive charge(s) present on the receptors with the help of two newly synthesized mono-positive receptors S4 and S5.

Over the past few decades, supramolecular self-assembly has become an alternative synthetic tool for constructing targeted discrete molecular architectures. Among various interactions, metal-ligand coordination has attracted great attention owing to high bond enthalpy (15−50 Kcal/mol) and predictable directionality. The basic principle of metal-ligand directed self-assembly relies on the proper designing of information encoded rigid complementary building units (a transition metal based acceptor and a multidentate organic donor) that self-recognize themselves in a chemically reasonable way (depends on their bite angle and symmetry) during self-assembly process. As far as acceptor units are concerned, Pd(II) and Pt(II) metal-based cis-blocked 90° acceptors have so far been used greatly for the construction of a library of 2D/3D discrete supramolecular architectures due to their rigid square planar geometry and kinetic lability. However, in some cases the efforts to design finite supramolecular architectures using a cis-blocked 90° acceptor in combination with a bulky donor ligand were unsuccessful, which may be due to the steric demands of donor ligand. Moreover, the resulted assemblies from such cis-blocked 90° building unit are mostly non-fluorescent in nature and limit the possibility of using them as chemosensors for various practical applications. Unlike that of rigid square-planar Pt(II) and Pd(II)-metal based building blocks, the use of other transition metal-based building units for the construction of discrete nanoscopic molecular architectures are known to lesser extent, mainly because of their versatile coordination geometries. However, some of the half-sandwiched piano-stool complexes of late transition metals like Ru, Os, Ir and Rh are known to maintain the stable octahedral geometry under various reaction conditions. Moreover, the self-assembly using redox active transition metal-based building units may lead to redox active assemblies. On the other hand, symmetrical rigid donors have been widely used as the favorite choices for the purpose of constructing desired product mainly due to their predictable directionality. Flexible linkers are not predictable in their directionality during self-assembly process and thus results mostly in undesired polymeric products. Furthermore, metal-ligand directed self-assembly provides opportunity to introduce multifunctionality in a single step within/onto the final supramolecular architectures. Among various functional groups, the incorporation of unsaturated ethynyl functionality is expected to enrich the final assemblies to be π-electron-rich and the attachment of ethynyl functionality with heavy transition metal ions are known to be luminescent in nature due to the facile metal to ligand charge transfer (MLCT). Hence, the final supramolecular complexes can be used as potential fluorescence sensors for electron-deficient nitroaromatics, which are the chemical signature of most of the commercially available explosives. The main thrust of the present investigation is focused on the judicious design and syntheses of multifaceted 2D/3D supramolecular architectures of finite shapes, sizes and functionality using Pt(II)/Ru(II) based “shape-selective” organometallic building blocks and investigation of their application as chemosensors. CHAPTER 1 of the thesis presents a general review on the core concepts of self-assembly and supramolecular chemistry. In particular, it underlines the importance of metal-ligand directional bonding approach for designing a vast plethora of discrete 2D/3D supramolecular architectures with tremendous variation in topology. CHAPTER 2 describes the design and syntheses of a series of 2D metallamacrocycles using carbazole-functionalized shape-selective 90° building units. A new Pt2II organometallic 90° acceptor 3,6-bis[trans-Pt(PEt3)2(NO3)(ethynyl)]carbazole (M1) containing ethynyl functionality is synthesized via Sonagashira coupling reaction and characterized. The combination of M1 with three different flexible ditopic donors (L1−L3) afforded [2 + 2] self-assembled molecular squares (1−3), respectively [where L1 = 1,3-bis(4-pyridyl)isophthalamide; L2 = 1,3-bis(3-pyridyl)isophthalamide; L3 = 1,2-bis(4-pyridyl)ethane] (Scheme 1). Scheme 1: Schematic presentation of the formation of a series of [2 + 2] self-assembled molecular squares. An equimolar (1:1) combination of same acceptor M1 with rigid linear ditopic donors (L4-L5) yielded [4 + 4] self-assembled octanuclear molecular squares 4 and 5, respectively [L4 = 4,4’-bipyridine; L5 = trans-1,2-bis(4-pyridyl)ethylene]. Conversely, a similar reaction of M1 with an amide-based unsymmetrical linear flexible ditopic donor L6 resulted in the formation a [2 + 2] self-sorted molecular rhomboid (6a) as a single product [L6 = N-(4-pyridyl)isonicotinamide]. Despite the possibility of several linkage isomeric macrocycles (rhomboids, triangles and squares) due to different connectivity of the ambidentate linker, the formation of a single and symmetrical molecular rhomboid 6a as an exclusive product is an interesting observation. This chapter also presents the synthesis and characterization of a complementary 90° dipyridyl donor 3,6-bis(4-pyridylethynyl)carbazole (L7). Stoichiometric combination of L7 with several PdII/PtII-based 90° acceptors (M2−M4) yielded [2 + 2] self-assembled molecular “bowl” shaped macrocycles (7−9) respectively, in good yields [M2 = cis-(dppf)Pd(CF3SO3)2; M3 = cis-(dppf)Pt(CF3SO3)2; M4 = cis-(tmen)Pd(NO3)2]. All these newly synthesized macrocycles were characterized by various spectroscopic techniques and molecular structures of some of them were confirmed by single crystal X-ray diffraction analysis. In addition to their syntheses and characterization, fluorescence chemosensing ability for various analytes was investigated. Macrocycle 1 is a system composed of amide-based receptor units and carbazole-based fluorophore moieties. The fluorescence study of 1 elicited a dramatic enhancement in the fluorescence intensity upon gradual addition of P2O74- anion in DMF/H2O solvent mixture, whereas similar titration under identical condition with other anions like F-, ClO4-, and H2PO4- did not show such change. Hence, molecular square 1 can be used as selective fluorescence sensor for pyrophosphate (P2O74-) anion. Due to their extended π-conjugation, macrocycles 3-4 were used as fluorescence sensors for electron-deficient nitroaromatics, which are the chemical signatures of many commercially available explosives. The fluorescence study showed a marked quenching of initial fluorescence intensity of the macrocycles(3-4) upon gradual addition of picric acid (PA) and they exhibited large fluorescence quenching responses with high selectivity for nitroaromatics among various other electron deficient aromatic compounds tested. As macrocycle 7 has large concave aromatic surface, it was utilized as a suitable host for large convex guest such as fullerene C60. The fluorescence quenching titration study suggested that macrocycle 7 forms a stable ~1:1 host-guest complex with C60 and the calculated association constant (KSV) is 1.0 × 105 M-1. CHAPTER 3 presents two-component coordination-driven self-assembly of a series of [2 + 2] molecular rectangles and a [2 + 4] self-assembled molecular tetragonal prism. An equimolar combination of pre-designed linear PtII2-acceptors M5−M6 separately with three different “clip” donors (L2, L8−L9) led to the formation of [2 + 2] self-assembled tetranuclear cationic molecular rectangles (10−15), respectively [M5 = 1,4-bis[trans-Pt(PEt3)2(NO3)(ethynyl)] benzene; M6 = 4,4’-bis[trans-Pt(PEt3)2(CF3SO3)(ethynyl)]biphenyl; L8 = 1,3-bis(3-pyridyl)ethynylbenzene; L9 = 1,8-bis(4-pyridyl)ethynylanthracene]. Rectangles 10-15 showed strong fluorescence in solution owing to their extended π-conjugation. Amide-functionalized rectangle 10 was used as a macrocyclic receptor for dicarboxylic acids. Solution state fluorescence study showed that rectangle 10 selectively binds (KSV = 1.4 × 104 M-1) with maleic acid by subsequent enhancement in emission intensity and addition of other analogous aliphatic dicarboxylic acids such as fumaric, succinic, adipic, mesaconic and itaconic acids causes no change in the emission spectra; thereby demonstrated its potential use as macrocyclic receptor in sensor applications. Since rectangle 15 is enriched with π-conjugation, it was examined as a fluorescence sensor for electron-deficient nitroaromatics such as picric acid, which is often considered as a secondary chemical explosive. The fluorescence study of 15 showed a significant quenching of initial emission intensity upon titrating with picric acid (PA) and it exhibited the largest fluorescence quenching response with high selectivity for picric acid. Scheme 2: Schematic representation of formation of [2 + 4] self-assembled of molecular tetragonal prism. This chapter also describes two-component coordination [2 + 4] self-assembly of a pyrene-based PtII8 tetragonal prism (16) as shown in Scheme 2, using a newly designed tetratopic organometallic acceptor (M7; 1,3,6,8-tetrakis[trans-Pt(PEt3)2(NO3)(ethynyl)]pyrene) in combination with an amide-based “clip” donor (L2) and propensity of this prism (16) as a selective fluorescence sensor for nitroaromatic explosives has been examined both in solution as well as in thin-film. CHAPTER 4 reports the synthesis and structural characterization of a series of Ru(II)-based bi-and tetra-nuclear metallamacrocycles and hexanuclear trigonal prismatic cages. In principle, the self-assembly of a “clip” acceptor with an asymmetrical ditopic donor is expected to give two different linkage isomeric (head-to-tail and head-to-head) molecular rectangles because of different bond connectivity of the donor. However, the equimolar combination of half-sandwiched p-cymene binuclear Ru(II)-based “clip” acceptors (M8−M9) and an amide-based ambidentate donor (L6) resulted in the self-sorting of single linkage (head-to-tail) isomeric rectangles 17−18 as only products, respectively [M8 = [Ru2(μ-η4-C2O4)(MeOH)2(η 6-p-cymene)2](CF3SO3)2; M9 = [Ru2(μ- η4-C6H2O4)(MeOH)2(η 6-p-cymene)2](CF3SO3)2]. Molecular structures of these head-to-tail linkage isomeric rectangles were unambiguously proved by single crystal X-ray diffraction analysis. Likewise, the self-assembly of oxalato-bridged Ru(II) acceptor M8 with a rigid dipyridyl “clip” donor L8 yielded a tetranuclear cationic pincer complex 19, while a similar reaction of M8 with an anthracene-functionalized “clip” donor L9 having shorter distance (between their reactive sites) compared to L8 led to the formation of [1 + 1] self-assembled macrocycle 20. This chapter also represents the design and synthesis of two hexanuclear trigonal prismatic cages (21−22) from the self-assembly of a π-electron rich tripyridyl donor (L10; 1,3,5-tris(4-pyridylethynyl)benzene) in combination with binuclear acceptors M8 and M9, respectively (Scheme 3). Formation of these prismatic cages was initially characterized using various spectroscopic techniques and the molecular structure of oxalato-bridged prism 21 was confirmed by single crystal X-ray diffraction analysis. In addition to the structural characterization, the pincer complex 19 and trigonal prismatic cages 21−22 were used as fluorescence sensors for nitroaromatic explosives owing to their large internal porosity and their π-electron rich nature. Scheme 3: Schematic representation of the formation of [3 + 2] self-assembled trigonal prismatic cage. CHAPTER 5 covers the syntheses of a few discrete metallamacrocycles using flexible imidazole/carboxylate based donors instead of much widely employed polypyridyl donors. The metal-ligand directed self-assembly of oxalato-bridged acceptor M8 and an imidazole-based tetratopic donor (L11; 1,2,4,5-tetrakis(imidazol-1-yl)benzene) in methanol afforded [2 + 1] self-assembled tetranuclear macrocycle 23. Conversely, the similar combination of L11 with 2,5-dihydroxy-1,4-benzoquinonato-bridged binuclear complex (M9) in 1:2 molar ratio in methanol resulted in an octanuclear cage 24. Both the complexes (23−24) were isolated as their triflate salts in high yields and were characterized by various spectroscopic methods including single crystal X-ray diffraction analysis. Scheme 4: Schematic representation of formation of an octanuclear incomplete Ru(II) open prism via ruthenium-oxygen coordination driven self-assembly. This chapter also explains the self-sorting of an unusual octanuclear incomplete prism [Ru8(η6-p-cymene)8(tma)2(μ-η4-C2O4)2(OMe)4](CF3SO3)2 (25) via ruthenium-oxygen coordination driven self-assembly of building block M8 and sodium benzene-1,3,5-tricarboxylate (L12) (Scheme 4). Electronic absorption study indicated that prism 25 exhibited a remarkable shape-selective binding affinity for 1,3,5-trihydroxybenzene (phluoroglucinol) via multiple hydrogen bonding interactions and such shape-selective binding was confirmed by single crystal X-ray diffraction analysis. (For figures pl see the abstract file)

Doctor of Philosophy
Department of Chemistry
Christer B. Aakeröy
A set of multifunctional molecules [isomeric forms of 1-(pyridylmethyl)-2,2'-biimidazole] was synthesized and subjected to systematic co-crystallizations with selected hydrogen- and halogen-bond donors in order to explore the impact of interaction type, geometry and electrostatics on the resulting supramolecular architectures. The structural outcome with hydrogen-bond donors (carboxylic acids) is somewhat unpredictable because of the presence of the acid···biimidazole heterosynthon that can compete with biimidazole···biimidazole homosynthon. In contrast, the solid-state supramolecular behavior of those probe molecules is largely unchanged in halogen-bonded co-crystals. Only two types of primary interactions, the two-point hydrogen bonds responsible for pairing biimidazole moieties, and the single-point halogen bonds responsible for the co-crystal formation and structure extension, are present in these systems. The results highlight that, by incorporating geometric biases along with orthogonal interactions, one can effectively prevent synthon crossover which is of paramount importance in complex crystal engineering endeavors. Heterobifunctional ligands pave the way for elaborate metallo-supramolecular systems, and are also useful for combining metal-ligand bonding with other types of non-covalent interactions. Nine new acetylacetonate ligands featuring either pyridyl- or thiophenyl-heterocycles were successfully prepared, and their metal binding abilities were studied with selected di- and tri-valent transition metal ions. As expected, the acetylacetonate ligation to metal dications remains consistent. In each case, the metal is four-coordinate and resides in a square planar environment. Differences in the overall architectures arise from the role played by the terminal heterocycles and the solvent. In seven (out of nine) structures, the heterocyclic end is involved in a structure-directing interaction and it is more prevalent in ligands bearing 4-pyridinyl unit. Divergent molecules containing bulky substituents tend to produce porous materials via frustrated packing. Two rigid tetrahedral cores, tetraphenylmethane and 1,3,5,7-tetraphenyladamantane, grafted peripherally with four (trimethylsilyl)ethynyl moieties were found to have only isolated voids in their crystal structures. Hence, they were modified into tecton-like entities, tetrakis(4-(iodoethynyl)phenyl)methane [I₄TEPM] and 1,3,5,7-tetrakis(4-(iodoethynyl)phenyl)adamantane [I₄TEPA], and the effect of motif-forming characteristics of iodoethynyl units on molecular arrangement and crystal porosity was analyzed. I₄TEPM not only holds increased free volume compared to its precursor, but also forms one-dimensional channels. Furthermore, it readily co-crystallizes with Lewis basic solvents to afford two-component porous materials even though they suffer from stability issues. As the binding sites in I₄TEPM and I₄TEPA are tetrahedrally-predisposed, they can be further utilized for the modular assembly of highly symmetric, three-dimensional extended architectures. With that in mind, these two building blocks were subsequently allowed to react with various halide salts, and it was found that the reactions between I₄TEPM and tetraphenylphosphonium halides readily yield four-fold interpenetrated diamondoid networks sustained by C–I⋯X⁻ (X⁻ = chloride, bromide, iodide) halogen-bonding interactions. The halide anions exhibit mutual-induced fitting of their coordination and act as four-connecting tetrahedral nodes, while the tetraphenylphosphonium cations render essential templating information and structural support.