Bibliographies thématiques / Cavitandi

Littérature scientifique sur le sujet « Cavitandi »

Auteur : Grafiati
Publié le 11 mars 2023

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Articles de revues sur le sujet "Cavitandi"

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Shi, Qixun, Matthew P. Mower, Donna G. Blackmond et Julius Rebek. « Water-soluble cavitands promote hydrolyses of long-chain diesters ». Proceedings of the National Academy of Sciences 113, no 33 (1 août 2016) : 9199–203. http://dx.doi.org/10.1073/pnas.1610006113.

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Water-soluble, deep cavitands serve as chaperones of long-chain diesters for their selective hydrolysis in aqueous solution. The cavitands bind the diesters in rapidly exchanging, folded J-shape conformations that bury the hydrocarbon chain and expose each ester group in turn to the aqueous medium. The acid hydrolyses in the presence of the cavitand result in enhanced yields of monoacid monoester products. Product distributions indicate a two- to fourfold relative decrease in the hydrolysis rate constant of the second ester caused by the confined space in the cavitand. The rate constant for the first acid hydrolysis step is enhanced approximately 10-fold in the presence of the cavitand, compared with control reactions of the molecules in bulk solution. Hydrolysis under basic conditions (saponification) with the cavitand gave >90% yields of the corresponding monoesters. Under basic conditions the cavitand complex of the monoanion precipitates from solution and prevents further reaction.
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Turunen, Lotta, Fangfang Pan, Ngong Kodiah Beyeh, Mario Cetina, John F. Trant, Robin H. A. Ras et Kari Rissanen. « Halogen-bonded solvates of tetrahaloethynyl cavitands ». CrystEngComm 19, no 35 (2017) : 5223–29. http://dx.doi.org/10.1039/c7ce01118k.

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Tetrahaloethynyl cavitands as multitopic halogen bond donors form a multitude of solvate structures with halogen bond acceptor solvents, such as DMF and DMSO, depending on the structure of the cavitand and the nucleophilicity of the solvent used.
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Brekalo, Deliz, Kane, Friščić et Holman. « Exploring the Scope of Macrocyclic “Shoe-last” Templates in the Mechanochemical Synthesis of RHO Topology Zeolitic Imidazolate Frameworks (ZIFs) ». Molecules 25, no 3 (1 février 2020) : 633. http://dx.doi.org/10.3390/molecules25030633.

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The macrocyclic cavitand MeMeCH2 is used as a template for the mechanochemical synthesis of 0.2MeMeCH2@RHO-Zn16(Cl2Im)32 (0.2MeMeCH2@ZIF-71) and RHO-ZnBIm2 (ZIF-11) zeolitic imidazolate frameworks (ZIFs). It is shown that MeMeCH2 significantly accelerates the mechanochemical synthesis, providing high porosity products (BET surface areas of 1140 m2/g and 869 m2/g, respectively). Templation of RHO-topology ZIF frameworks constructed of linkers larger than benzimidazole (HBIm) was unsuccessful. It is also shown that cavitands other than MeMeCH2—namely MeHCH2, MeiBuCH2, HPhCH2, MePhCH2, BrPhCH2, BrC5CH2—can serve as effective templates for the synthesis of x(cavitand)@RHO-ZnIm2 products. The limitations on cavitand size and shape are explored in terms of their effectiveness as templates.
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Pedrini, Alessandro, Federico Bertani et Enrico Dalcanale. « Fluorinated Tetraphosphonate Cavitands ». Molecules 23, no 10 (17 octobre 2018) : 2670. http://dx.doi.org/10.3390/molecules23102670.

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Two synthetic protocols for the introduction of fluorine atoms into resorcinarene-based cavitands, at the lower and upper rim, respectively, are reported. Cavitand 1, bearing four fluorocarbon tails, and cavitand 2, which presents a fluorine atom on the para position of a diester phosphonate phenyl substituent, were synthesized and their complexation abilities toward the model guest sarcosine methyl ester hydrochloride were evaluated via NMR titration experiments. The effect of complexation on the 19F NMR resonance of the probe is evident only in the case of cavitand 2, where the inset of the cation-dipole and H-bonding interactions between the P=O bridges and the guest is reflected in a sizable downfield shift of the fluorine probe.
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Turunen, L., N. K. Beyeh, F. Pan, A. Valkonen et K. Rissanen. « Tetraiodoethynyl resorcinarene cavitands as multivalent halogen bond donors ». Chem. Commun. 50, no 100 (2014) : 15920–23. http://dx.doi.org/10.1039/c4cc07771g.

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The first examples of iodoethynyl resorcinarene cavitands as rigid 3D halogen bond (XB) donor molecules are presented. These concave macrocycles form strong, RXB = 0.78–0.83, halogen bonds with dioxane oxygen, pyridine nitrogen and a bromide anion in tetraproropyl ammonium bromide resulting in deep cavity cavitand structures.
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Dalcanale, E., M. Torelli, I. Domenichelli, A. Pedrini, F. Guagnini, R. Pinalli, F. Terenziani, F. Artoni et R. Brighenti. « pH-Driven Conformational Switching of Quinoxaline Cavitands in Polymer Matrices ». Synlett 29, no 19 (24 juillet 2018) : 2503–8. http://dx.doi.org/10.1055/s-0037-1610219.

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While pH-driven interconversion of tetraquinoxaline cavitands (QxCav) from vase to kite conformation has been extensively studied both in solution and at interfaces, cavitands behavior in solid matrices is still unexplored. Therefore, the synthesis of a new class of quinoxaline cavitand based copolymers is here reported; a soluble linear poly(butyl methacrylate) (PBMA) and an insoluble cross-linked polydimethylsiloxane (PDMS), ensuring a convenient incorporation of the switchable unit, were chosen as polymer matrices. Conformational studies, performed both in solution and at the solid state, confirmed the retention of vase → kite switching behavior when moving from monomeric units to polymeric structures.
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Pinalli, Roberta, et Chiara Massera. « Nitrosonium complexation by the tetraphosphonate cavitand 5,11,17,23-tetramethyl-6,10:12,16:18,22:24,4-tetrakis(phenylphosphonato-κ2O,O)resorcin(4)arene ». Acta Crystallographica Section E Crystallographic Communications 73, no 12 (3 novembre 2017) : 1801–5. http://dx.doi.org/10.1107/s2056989017015857.

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The crystal structure of a new supramolecular complex between the tetraphosphonate cavitand 5,11,17,23-tetramethyl-6,10:12,16:18,22:24,4-tetrakis(phenylphosphonato-κ2O,O′)resorcin(4)arene and the nitrosyl cation NO+, as the BF4−salt, is reported. The complex, of general formula [(C56H44P4O12)(NO)]BF4·CH2Cl2or NO@Tiiii[H, CH3, C6H5] BF4·CH2Cl2, crystallizes in the space groupP-1. The nitrosyl cation is disordered over two equivalent positions, with occupancies of 0.503 (2) and 0.497 (2), and interacts with two adjacent P=O groups at the upper rim of the cavitand through dipole–charge interactions. In the lattice, the cavitands are connected through a series of C—H...π interactions involving the methyl and methylenic H atoms and the aromatic rings of the macrocycle. The structure is further stabilized by the presence of C—H...F interactions between the hydrogen atoms of the cavitands and the F atoms of the tetrafluoridoborate anion. As a result of the disorder, the lattice dichloromethane molecules could not be modelled in terms of atomic sites, and were treated using thePLATONSQUEEZE procedure [Spek (2015).Acta Cryst.C71, 9–18]. The complexation process has also been studied in solution through NMR titrations.
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Rahman, Faiz-Ur, Yong-sheng Li, Ioannis D. Petsalakis, Giannoula Theodorakopoulos, Julius Rebek et Yang Yu. « Recognition with metallo cavitands ». Proceedings of the National Academy of Sciences 116, no 36 (19 août 2019) : 17648–53. http://dx.doi.org/10.1073/pnas.1909154116.

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We describe here the effects of metal complexation on the molecular recognition behavior of cavitands with quinoxaline walls. The nitrogen atoms of the quinoxalines are near the upper rim of the vase-like shape and treatment with Pd(II) gave 2:1 metal:cavitand derivatives. Characterization by 1H, 13C NMR spectroscopy, HR ESI-MS, and computations showed that the metals bridged adjacent quinoxaline panels and gave cavitands with C2v symmetry. Both water-soluble and organic-soluble versions were prepared and their host/guest complexes with alkanes, alcohols, acids, and diols (up to C12) were studied by 1H NMR spectroscopy. Analysis of the binding behavior indicated that the metals rigidified the walls of the receptive vase conformation and enhanced the binding of hydrophobic and even water-soluble guests, compared to related cavitands reported previously. The results demonstrated that the conformational dynamics of the cavitand were slowed by the coordination of Pd(II) and stabilized the host’s complexes.
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Biavardi, Elisa, et Chiara Massera. « Crystal structure of a host–guest complex between mephedrone hydrochloride and a tetraphosphonate cavitand ». Acta Crystallographica Section E Crystallographic Communications 75, no 2 (29 janvier 2019) : 277–83. http://dx.doi.org/10.1107/s2056989019001464.

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A new supramolecular complex (I) between the tetraphosphonate cavitand Tiiii[C3H7,CH3,C6H5] [systematic name: 2,8,14,20-tetrapropyl-5,11,17,23-tetramethyl-6,10:12,16:18,22:24,4-tetrakis(phenylphosphonato-O,O′)resorcin[4]arene] and mephedrone hydrochoride {C11H16NO+·Cl−; systematic name: methyl[1-(4-methylphenyl)-1-oxopropan-2-yl]azanium chloride} has been obtained and characterized both in solution and in the solid state. The complex of general formula (C11H16NO)@Tiiii[C3H7,CH3,C6H5]Cl·CH3OH or C11H16NO+·Cl−·C68H68O12P4·CH3OH, crystallizes in the monoclinic space group P21/c with one lattice methanol molecule per cavitand, disordered over two positions with occupancy factors of 0.665 (6) and 0.335 (6). The mephedrone guest interacts with the P=O groups at the upper rim of the cavitand through two charge-assisted N—H...O hydrogen bonds, while the methyl group directly bound to the amino moiety is stabilized inside the π basic cavity via cation...π interactions. The chloride counter-anion is located between the alkyl legs of the cavitand, forming C—H...Cl interactions with the aromatic and methylenic H atoms of the lower rim. The chloride anion is also responsible for the formation of a supramolecular chain along the b-axis direction through C—H...Cl interactions involving the phenyl substituent of one phosphonate group. C—H...O and C—H...π interactions between the guest and adjacent cavitands contribute to the formation of the crystal structure.
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Pedrini, Alessandro. « Host–guest supramolecular interactions between a resorcinarene-based cavitand bearing a –COOH moiety and acetic acid ». Acta Crystallographica Section E Crystallographic Communications 75, no 3 (22 février 2019) : 397–401. http://dx.doi.org/10.1107/s2056989019002512.

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The cavitand 5,11,17,23-tetramethyl-4,24:6,10:12,16:18,22-tetrakis(methylenedioxy)resorcin[4]arene functionalized at the upper rim with a carboxylic acid group, CavCOOH-in, of chemical formula C37H32O10, was synthesized in order to study its supramolecular interactions with acetic acid in the solid state. Crystals suitable for X-ray diffraction analysis were obtained by slow evaporation of a dichloromethane–acetone solution of CavCOOH-in, to which glacial acetic acid had been added. The resulting compound, C37H32O10·2C2H4O2 (1) crystallizes in the space group P\overline{1} and its asymmetric unit consists of one molecule of cavitand and two molecules of acetic acid, one of which is encapsulated inside the aromatic cavity and disordered over two positions with a refined occupancy ratio of 0.344 (4):0.656 (4). The guest interacts with the host primarily through its methyl group, which (in both orientations) forms C—H...π interactions with the benzene rings of the cavitand. The crystal structure of 1 is dominated by O—H...O and C—H...O hydrogen bonding due to the presence of acetic acid and of the carboxylic group functionalizing the upper rim. Further stabilization is provided by offset π–π stacking interactions between the aromatic walls of adjacent cavitands [intercentroid distance = 3.573 (1) Å].
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Thèses sur le sujet "Cavitandi"

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Trusso, Sfrazzetto Giuseppe. « Progettazione e sintesi di nuovi cavitandi macrociclici ». Thesis, Università degli Studi di Catania, 2011. http://hdl.handle.net/10761/122.

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I cavitandi chinossalinici sono recettori molecolari sintetici aventi una cavita' idrofobica il cui diametro medio raggiunge gli 8 à . Questa cavita' e' in grado di inglobare al suo interno vari guest, stabilizzandoli mediante interazioni idrofobiche. Sono numerosi in letteratura gli esempi in cui questi cavitandi vengono utilizzati come host nei confronti di guest achirali. Sono pochi invece gli esempi in cui i cavitandi vengono utilizzati come recettori di guest chirali. In questo lavoro di tesi sono stati sintetizzati nuovi cavitandi chinossalinici chirali in grado di svolgere riconoscimento enantiomerico nei confronti di vari amminoacidi chirali opportunamente modificati. Questi cavitandi sono stati funzionalizzati con una unita'à à  salen chirale in grado di coordinare un catione metallico. L'introduzione di un catione uranile ha permesso di ottenere dei recettori eteroditopici, in grado di riconoscere coppie ioniche chirali (il catione viene riconosciuto dalla cavita' chinossalinica, mentre l'anione viene coordinato dal centro metallico che agisce come acido di Lewis). E' stato sintetizzato successivamente un recettore salen-uranile strutturalmente piu' semplice, da utilizzare come sistema modello per chiarire il meccanismo di riconoscimento di questi sistemi eteroditopici. Al fine di realizzare nuovi materiali chirali a base di silice, e' stato sintetizzato un cavitando chirale funzionalizzato con una catena alifatica contenente un doppio legame terminale. La superficie cosi' realizzata e' stata caratterizzata mediante tecniche XPS, SEM e IR. Infine e' stato funzionalizzato un cavitando con una unita' fullerenica ottenendo un fotosensibilizzatore per la produzione di ossigeno singoletto in grado di ossidare, e quindi tagliare, con alta efficienza residui di DNA. Grazie alle sue caratteristiche fotochimiche, questo composto puo' trovare applicazione in terapie fotodinamiche contro alcune forme di carcinoma.
Quinoxaline cavitands are synthetic molecular receptors with an hydrophobic cavity; these compounds are able to recognize several guests via hydrophobic interactions. Many examples of achiral recognition using these cavitands are reported in literature; at the best of our knowledge there are few reports about efficient chiral recognition. In this work new chiral quinoxaline based cavitands for enantiomeric recognition of functionalized aminoacids were synthesized. We introduced a chiral salen unit in the cavitand scaffold to allow the coordination of a metal cation and in particular an uranyl site, that permits the realization of an heteroditopic receptor, able to bind chiral ion pair of aminoacid salts. After this work we synthesized as a heteroditopic model a chiral uranyl salen complex containing two pyrenil arms, in order to elucidate the recognition mechanism of the hosts. To obtain new chiral materials silica based, we designed a new chiral cavitand functionalized with an aliphatic chain double bond terminated. This new surface was characterized by XPS, SEM and IR. Moreover we synthesized a cavitand with a fullerene unit, allow a new photosensitizer that generates singlet oxygen. This compound is able to perform an efficient DNA cleavage and should be applied in photodynamic therapy.
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De, Zorzi Rita. « Structural studies on molecular recognition in protein complexes and supramolecular systems ». Doctoral thesis, Università degli studi di Trieste, 2009. http://hdl.handle.net/10077/3082.

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2007/2008
Il riconoscimento molecolare tra due o più specie chimiche mediante interazioni non covalenti è il principale argomento di studio della chimica supramolecolare. Individuare i fini meccanismi di complementarietà che presiedono il processo di associazione molecolare è di fondamentale importanza sia per la comprensione di come funzionano i sistemi biologici naturali sia per lo sviluppo di nuovi sistemi supramolecolari artificiali. Nel presente lavoro di tesi, l’analisi delle interazioni che governano il riconoscimento molecolare sia in sistemi supramolecolari artificiali che in complessi proteici naturali è stata condotta attraverso la tecnica di diffrazione di raggi X da cristallo singolo, che consente la precisa identificazione delle interazioni coinvolte e dei gruppi funzionali responsabili del riconoscimento molecolare. In particolare, sono state analizzate le differenze tra due forme cristalline del citocromo c da Cuore di Cavallo, ottenute rispettivamente in ambiente ossidante e riducente in presenza di ioni nitrato. Lo ione nitrato è stato utilizzato in questo lavoro biocristallografico come sonda ionica per analizzare le variazioni della superficie elettrostatica connesse con il processo ossidoriduttivo del citocromo e per individuare i principali passaggi del meccanismo di riconoscimento molecolare in cui è coinvolto questo trasportatore di elettroni. Nell’ambito dello studio di sistemi in grado di mimare i sistemi biologici, sono stati analizzati anche complessi supramolecolari artificiali contenenti porfirine. Un nuovo versatile materiale nanoporoso è stato ottenuto attraverso utilizzo di interazioni non covalenti sinergiche tra calixareni e porfirine. Questa struttura supramolecolare che ricorda le zeoliti è stata successivamente funzionalizzata attraverso la diffusione di ioni metallici nei canali della struttura. Il materiale nanoporoso così ottenuto, contenente un pigmento porfirinico assieme ad uno ione metallico, è molto promettente per il successivo sviluppo di sistemi artificiali che coniugano la capacità di raccogliere la radiazione elettromagnetica nel campo del visibile con centri catalitici in grado di immagazzinare tale energia in legami chimici. In questo lavoro di tesi, un complesso, costituito da un nucleo formato da 4 ioni rutenio legati da ponti ossigeno, che ha dimostrato elevate capacità catalitiche nella reazione di produzione di ossigeno a partire dall’acqua in presenza di cerio (IV), è stato caratterizzato strutturalmente. Lo studio cristallografico ha permesso di ottenere dettagli strutturali importanti per la comprensione del meccanismo di reazione di tale complesso. Sensori che si avvalgono delle caratteristiche di reversibilità dell’interazione e di specificità del substrato tipiche della chimica supramolecolare possono essere ottenuti mediante la progettazione razionale di opportuni recettori molecolari. In questa tesi, cristalli isomorfi di un cavitando tetrafosfonato sono stati ottenuti in presenza di diversi alcoli guest, permettendo il confronto delle interazioni che determinano la formazione del complesso. Successivamente, sono stati portati a termine esperimenti di cocristallizzazione in presenza di coppie alcoliche, al fine di studiare la competizione tra queste specie per il sito del cavitando. Molecole a cavità che presentano funzionalità di host possono essere utilizzate anche nella progettazione di polimeri supramolecolari. Questo tipo di sistemi è particolarmente interessante per la possibilità di attivare o disattivare la polimerizzazione in risposta ad uno stimolo esterno. In questa tesi, un approccio di questo tipo è stato applicato alla sintesi di un omopolimero e di un eteropolimero.
Molecular recognition of two or more molecules through non covalent interactions is the field of supramolecular chemistry. The evaluation of the subtle mechanisms of complementarity inducing the molecular association has a fundamental importance in order to both elucidate biological processes and develop new artificial supramolecular systems. In the present thesis, analyses on various, artificial and natural, supramolecular systems, have been carried out using X-ray diffractions techniques on single crystals, that allow the precise determination of interaction geometries of the functional groups involved. In particular, structural differences between two crystal forms of Horse Heart cytochrome c, obtained in presence of nitrate ions, in an oxidizing and in a reducing environment, respectively, have been analysed. In this biocrystallographic work, nitrate ions have been used as ionic probes to analyse variations on the electrostatic surface due to the oxidoreductive processes of cytochrome and to identify the main steps of the molecular recognition mechanism, involving this electron transport protein. In order to develop systems able to mimicking biological processes, supramolecular complexes containing porphyrins have been analysed. A highly flexible nanoporous material has been obtained by synergistic non-covalent interactions of calixarene and porphyrin building blocks. This supramolecular zeolite-like structure has been easily functionalized by diffusion and coordination of metal ions in the large void channels of the crystals. This new nanoporous material, containing a porphyrinic dye together with a metal ion, is very promising for the development of artificial systems combining visible light harvesting properties and catalytic centres, able to store energy in chemical bonds. In this thesis, a complex constituted by a core of four ruthenium atoms bound through oxygen bridges, that demonstrated catalytic properties in oxygen evolving reactions from water oxidation in presence of Ce (IV), has been characterized through X-ray diffraction. The crystallographic analysis has allowed the determination of important structural details in order to understand the reaction mechanism of this complex. Sensing systems, that exploit the characteristics of reversibility of interactions and specificity of the substrate, typical of supramolecular chemistry, can be achieved with a rational design of suitable molecular receptors. In this thesis, isomorphic crystals of a tetraphosphonato cavitand have been obtained in presence of different alcoholic guests, allowing the comparison of interactions responsible for the complex formation. Afterwards, cocrystallizzation experiments in presence of two alcoholic species have been carried out in order to investigate the competition of these molecules for the cavitand site. Hollow molecules with host functionalities can also be exploited in the design of supramolecular polymers. These systems have attracted particular interest for the possibility of switch on/off the polymerisation after an external stimuli. In this thesis, a supramolecular approach has been applied in order to synthesize a homopolymer and a heteropolymer.
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Martínez, Rodríguez Luis. « Molecule and catalyst design for recognition and activation of small molecules ». Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/398693.

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Engeldinger, Eric. « Cyclodextrin-derived metallo-cavitands ». Université Louis Pasteur (Strasbourg) (1971-2008), 2003. https://publication-theses.unistra.fr/public/theses_doctorat/2003/ENGELDINGER_Eric_2003.pdf.

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Cette thèse est consacrée à la synthèse multi-étapes d'une série de ligands basés sur une plateforme de type a-cyclodextrine ainsi qu'à l'étude de leurs propriétés complexantes et catalytiques. Deux des cyclodextrines, L1 et L2, sont substituées par deux bras phosphites, -C6H4-o-OP(OPh)2, greffés respectivement sur les positions A,D et A,C. Quatre autres CD comportent des entités PPh2 directement ancrées sur le bord primaire: L3 (disubstitution A,D), L4 (disubstitution A,C), L5 (trisubstitution A,C,E) et L8 (monosubstitution). Enfin, deux monophosphines, L6 et L7, très encombrées, ont été obtenues par pontage des unités AB et AC, respectivement, par le dianion PPh2-. Malgré leur longueur importante, les deux diphosphites L1 et L2 forment facilement avec [Rh(NBD)(THF)2]BF4 des complexes chélate où l'atome métallique fait partie d'un très grand macrocycle (29 ou 24 chaînons, respectivement). Le complexe rhodié obtenu avec L2 catalyse l'hydrogénation asymétrique du diméthylitaconate avec un excès énantiomérique remarquable (83. 6%). La phosphine L3, de symétrie C2, forme avec Ag+ un complexe chélate (P,P,OMe). Ce dernier présente un comportement hémilabile en solution caractérisé par une coordination alternée de chacun des 4 groupes MeO du bord supérieur. L'addition de divers nitriles provoque la formation d'espèces où le (ou les) nitrile(s) coordiné(s) sont piégés à l'intérieur de la cavité. Cette dernière contribue de façon remarquable à la stabilité du complexe [AgP2(CH3CN)2]+, un type de complexe dont l'existence n'avait pas encore été démontrée. Autre propriété inattendue: lorsqu'on fait réagir les diphosphines L3 ou L4 avec des entités chlorées, LnMCl, on obtient systématiquement des chélates trans où l'entité M-Cl pointe vers l'intérieur de la cavité. Cette orientation particulière résulte d'une interaction faible entre le chlore coordiné et deux protons H-5 de la cavité, une interaction encore jamais observée à l'intérieur d'une cyclodextrine. Dans les monophosphines L6 et L7, obtenues par pontage diastéréospécifique, le doublet libre du phosphore est dirigé vers l'axe de la CD. Cette propriété permet de synthétiser des complexes auto-inclus
The present thesis deals with the multi-step synthesis of a series of ligands based on an a-cyclodextrin platform as well as the study of their coordination and catalytic properties. Two of the cyclodextrins, L1 and L2, are functionalised with two phosphite sidearms, -C6H4-o-OP(OPh)2, tethered to the A,D and A,C positions, respectively. Four other CDs bear PPh2 entities which have been directly anchored to the primary face: L3 (AD-disubstitution), L4 (AC-disubstitution), L5 (ACE-trisubstitution) and L8 (monosubstitution). Finally, two sterically hindered monophosphines, L6 and L7, have been obtained by bridging units AB and AC, respectively, with the PPh2- dianion. Despite their length, both diphosphites L1 and L2 readily form cationic chelate complexes with [Rh(NBD)(THF)2]BF4, in which the metal is part of a large macrocyle (29 and 24 members, respectively). The rhodium complex obtained with L2 catalyses the asymmetric hydrogenation of dimethylitaconate with a remarkable enantiomeric excess (83. 6%). The C2-symmetrical diphosphine L3 forms a (P,P,OMe) chelate complex with Ag+ which displays hemilabile behaviour, the four primary MeO groups alternatively binding the metal centre. Addition of various nitriles affords complexes in which the coordinated nitrile(s) is (are) always trapped inside the cavity. The latter highly contributes to the stability of the [AgP2(CH3CN)2]+ complex, a type of complex that had so far never been detected. Another unexpected property was uncovered when reacting diphosphines L3 and L4 with chloro complexes, LnMCl, which gave rise systematically to trans chelates, in which the M-Cl fragment is directed towards the cavity interior. The particular orientation of the M-Cl bond results from weak interactions between the coordinated chloride and two inner-cavity H-5 protons. Such interactions inside a CD are unprecedented. In both monophosphines, L6 and L7, synthesised by diastereospecific capping, the phosphorus lone pair is pointing towards the CD axis. This feature allows formation of self-inclusion complexes
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Berghaus, Carsten. « Tetrapeptido-Methylendioxyresorc[4]arene chirale Cavitanden / ». [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968375375.

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El, Moll Hani. « Synthèses et propriétés catalytiques de cavitands résorcinaréniques ». Strasbourg, 2009. http://www.theses.fr/2009STRA6118.

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Franc, Jean-Pierre. « Etude physique d'écoulements cavitants ». Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37598038p.

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Scott, Michael P. « Synthesis and Properties of Conformationally Restricted Cavitand Systems ». Phd thesis, Canberra, ACT : The Australian National University, 2017. http://hdl.handle.net/1885/154341.

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The work described in this thesis is focused on the synthesis, functionalisation and study of conformationally restricted cavitand systems. Cavitands are rigid molecules with a concave π-basic surface, which bind a variety of guests. Larger supramolecular systems have been synthesised by covalently connecting several cavitands together. Two such multi-cavitand arrays are presented in this thesis, namely superbowls and cyclotetra-cavitands. Chapter 1 is a review of resorcinarenes and pyrogallolarenes. The configurational and conformational possibilities of these molecules is discussed, along with the various synthetic methods developed for their preparation and derivatisation. The reported types of hydrogen-bonded, metal coordinated and covalently-linked multi-resorcinarene and multi-pyrogallolarene structures are described. The host-guest chemistry of these structures is described, as is their use as a catalyst for chemical transformations. Chapter 2 is an introduction to the chemistry of superbowls and related deep-cavity cavitands. The synthesis of superbowls by the reaction of four ‘wall’ cavitands with one ‘base’ cavitand is described, followed by the methods developed for their derivatisation. The ability of superbowls to act as hosts to tetra-alkyl ammonium salts and aspirin is discussed. Finally, the chemistry of deep-cavity cavitands with introverted functionality is surveyed. Chapter 3 describes the synthesis of new ortho-functionalised, arylated cavitands. These arylated cavitands exist as two atropisomers due to restricted rotation of the biaryl bond. The two atropisomers are described as either ‘inside’ or ‘outside’, depending on whether the ortho-functionality resides inside or outside of the cavity of the cavitand. Methods for the synthesis and interconversion of these two atropisomers are investigated. By varying the temperature and solvent, either the inside or outside atropisomer could be made the predominant species in solution. The addition of acids to the solution of a cavitand with an amine substituent resulted in significant changes to atropisomer equilibrium ratios. Chapter 4 describes the synthesis of new superbowls by a novel synthetic route. This route first combines one functionalised ‘wall’ cavitand with the ‘base’ cavitand, followed by the incorporation of three unfunctionalised wall cavitands. This novel approach permits the synthesis of sizeable amounts of previously difficult-to-obtain mono-functionalised superbowls. The first superbowl with introverted functionality is reported. A preliminary study of this superbowl’s inside/outside atropisomerism and host-guest chemistry is described. Chapter 5 describes how cavitand bowls carrying two distally-positioned terminal alkyne substituents generate cyclotetramers from Glaser coupling reactions. The 1,3-butadiynyl-linked cyclotetra-cavitand exists predominantly in two equivalent saddle shaped conformations. Interchange is rapid on the human timescale at ambient temperature but is modulated through manipulation of bowl rim substituents. Conversion of the four 1,3-butadiynyl-linkers into 2,5-thiophenylene-linkers causes a switch to a square-shaped cyclotetra-cavitand with the four sulfurs directed outside of the newly-formed macrocycle.
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Delannoy, Yves. « Modélisation d'écoulements instationnaires et cavitants ». Grenoble INPG, 1989. http://www.theses.fr/1989INPG0070.

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Les performances croissantes des turbomachines hydrauliques necessitent une modelisation des ecoulements instationnaires, subcavitants et cavitants, abordee ici en bidimensionnel par une discretisation volumes finis des equations d'euler, sur un maillage curviligne orthogonal. Un modele diphasique 2d-1fl de poches de cavitation a ete developpe, ainsi qu'un algorithme implicite pour un ecoulement allant de l'incompressible au supersonique. Les resultats subcavitants ont ete compares a des experiences de profil oscillant: la confrontation est satisfaisante dans le cas ou les effets visqueux sont negligeables, et souligne l'interet des schemas de discretisation du second ordre (quick, smart. . . ), par rapport au schema amont. Les calculs de cavitation instationnaire menent, sans apport emirique, a des poches pulsantes et des structures diphasiques tourbillonnaires entrainees, qui ont ete observees experimentalement dans d'autres etudes
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Marie-Magdeleine, Artem. « Caractérisation des fonctions de transfert d'organes hydrauliques en régimes cavitant et non-cavitant ». Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-01011968.

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Dans le cadre de l'amélioration des méthodes de modélisation du comportement hydraulique des moteurs à ergols liquides, il est important de disposer des méthodes d'identification expérimentale adaptées au besoin de caractérisation des fonctions de transfert des pompes en régime cavitant, notamment pour prédire les risques d'occurrence des phénomènes de couplage fluide-structure comme le Pogo. La matrice de transfert dynamique d'une pompe relie dans le domaine fréquentiel les fluctuations complexes (module + phase) de débit et de pression à l'entrée avec celles de sortie de la pompe. Par ailleurs, les mécanismes physiques qui régissent la réponse d'une pompe soumise à des fluctuations de pression et/ou de débit restent méconnus, ce qui rend aujourd'hui très difficile les prévisions théoriques. Dans le cadre des travaux développés, une nouvelle boucle d'essais a été mise en place permettant la mesure de la pression fluctuante et l'évaluation du débit fluctuant par une approche d'intensimétrie hydroacoustique. Une méthodologie d'essais a été mise en place sur le banc de test pour caractériser les fonctions de transfert de différents organes hydrauliques, notamment en régime cavitant, comme une pompe centrifuge. Ces travaux expérimentaux ont permis également d'alimenter et de valider les modèles de type " système " RLC utilisés pour la simulation du comportement acoustique du circuit. Les méthodologies d'essais, de post-traitement et de modélisation développés dans le cadre de cette thèse seront appliquées par l'industriel lors des essais dédiés sur le banc de test à des composants moteur.
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Chapitres de livres sur le sujet "Cavitandi"

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Korotcenkov, Ghenadii. « Cavitands ». Dans Integrated Analytical Systems, 147–53. New York, NY : Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-7388-6_9.

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Wishard, Anthony, et Bruce C. Gibb. « A Chronology of Cavitands ». Dans Calixarenes and Beyond, 195–234. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-31867-7_9.

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Bailey, P. D., S. R. Carter, D. G. W. Clarke et G. A. Crofts. « Polycyclic peptides as novel cavitands ». Dans Peptides 1990, 225–26. Dordrecht : Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3034-9_94.

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Tancini, Francesca, et Enrico Dalcanale. « Polymerization with Ditopic Cavitand Monomers ». Dans Supramolecular Polymer Chemistry, 71–93. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2012. http://dx.doi.org/10.1002/9783527639786.ch4.

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Azov, Vladimir A., et François Diederich. « Switching Processes in Cavitands, Containers and Capsules ». Dans Molecular Switches, 257–300. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2011. http://dx.doi.org/10.1002/9783527634408.ch8.

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Delangle, Pascale, Jean-Christophe Mulatier et Jean-Pierre Dutasta. « Phosphorylated Cavitands : Encapsulation of Hard Cationic Guests ». Dans Molecular Recognition and Inclusion, 321–24. Dordrecht : Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5288-4_49.

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Tonezzer, M., E. Menin, S. Carturan, G. Maggioni, A. Quaranta, R. Pinalli et E. Dalcanale. « Luminescent Cavitands as Novel Optically Active Materials ». Dans Lecture Notes in Electrical Engineering, 411–15. New York, NY : Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-3860-1_73.

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Bailey, P. D., S. R. Carter, D. G. W. Clarke, G. A. Crofts et J. H. M. Tyszka. « Polycyclic peptides : A new type of cavitand ». Dans Peptides, 373–75. Dordrecht : Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2264-1_138.

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Borsato, Giuseppe, Julius Rebek et Alessandro Scarso. « Capsules and Cavitands : Synthetic Catalysts of Nanometric Dimension ». Dans Selective Nanocatalysts and Nanoscience, 105–68. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2011. http://dx.doi.org/10.1002/9783527635689.ch4.

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Timmerman, Peter, Harold Boerrigter, Willem Verboom, Gerrit J. Van Hummel, Sybolt Harkema et David N. Reinhoudt. « Proximally Functionalized Cavitands and Synthesis of a Flexible Hemicarcerand ». Dans Calixarenes 50th Anniversary : Commemorative Issue, 167–91. Dordrecht : Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0267-4_11.

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Actes de conférences sur le sujet "Cavitandi"

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Bardet, A., F. Parret, M. Guillemot, S. Besnard, P. Montméat, C. Barthet, P. Prené, Matteo Pardo et Giorgio Sberveglieri. « Cavitands thin films as sensitive coating for explosives sensors ». Dans OLFACTION AND ELECTRONIC NOSE : Proceedings of the 13th International Symposium on Olfaction and Electronic Nose. AIP, 2009. http://dx.doi.org/10.1063/1.3156569.

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Altamore, Timothy M., Elizabeth S. Barrett, Peter J. Duggan, Peter J. Nichols, Michael S. Sherburn et Melanie L. Szydzik. « HIGHLY SELECTIVE FRUCTOSE TRANSPORT MEDIATED BY CAVITAND BORONIC ACIDS ». Dans XXIst International Carbohydrate Symposium 2002. TheScientificWorld Ltd, 2002. http://dx.doi.org/10.1100/tsw.2002.559.

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Sgreccia, E., A. Macagnano, E. Dalcanale, C. Di Natale et R. Paolesse. « A study of mass effect in a cavitand supramolecular sensor ». Dans Proceedings of the 11th Italian Conference. WORLD SCIENTIFIC, 2008. http://dx.doi.org/10.1142/9789812793393_0004.

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Gilberto Dalfre Filho, Jose, et Thais Vieira Omido. « EFICIÊNCIA ÓTIMA DO EQUIPAMENTO TIPO JATO CAVITANTE COM MÚLTIPLOS JATOS ». Dans XXIII Congresso de Iniciação Científica da Unicamp. Campinas - SP, Brazil : Galoá, 2015. http://dx.doi.org/10.19146/pibic-2015-37870.

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Zampolli, S., I. Elmi, G. C. Cardinali, M. Severi, E. Dalcanale et P. Betti. « Use of Cavitands as Selective Adsorbing Materials in GC-like Air Quality Monitoring Microsystems ». Dans Proceedings of the 11th Italian Conference. WORLD SCIENTIFIC, 2008. http://dx.doi.org/10.1142/9789812793393_0044.

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Domingo, C., E. del Puerto, S. Sánchez-Cortés, J. V. García-Ramos, P. M. Champion et L. D. Ziegler. « SERS of Insoluble Synthetic Organic Pigments Employing Calixarenes as Dispersive Cavitands : Application to Quinacridone Quinone ». Dans XXII INTERNATIONAL CONFERENCE ON RAMAN SPECTROSCOPY. AIP, 2010. http://dx.doi.org/10.1063/1.3482430.

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FERRARI, M., V. FERRARI, D. MARIOLI, A. TARONI, M. SUMAN et E. DALCANALE. « COMPARATIVE EXPERIMENTS ON CAVITAND-COATED PZT RESONANT PIEZO-LAYER AND QCM SENSORS EXPOSED TO ORGANIC VAPORS ». Dans Proceedings of the 8th Italian Conference. WORLD SCIENTIFIC, 2004. http://dx.doi.org/10.1142/9789812702944_0013.

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Gilberto Dalfre Filho, Jose, et Heitor Da Costa Moreira. « Avaliação de desgaste de materiais por cavitação com o equipamento tipo jato cavitante ». Dans XXIII Congresso de Iniciação Científica da Unicamp. Campinas - SP, Brazil : Galoá, 2015. http://dx.doi.org/10.19146/pibic-2015-37348.

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Gilberto Dalfre Filho, Jose, et Huang Taosheng. « O equipamento tipo jato cavitante e a sua eficiência por análises de imagens ». Dans XXIII Congresso de Iniciação Científica da Unicamp. Campinas - SP, Brazil : Galoá, 2015. http://dx.doi.org/10.19146/pibic-2015-37365.

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PEREIRA, F. F., L. D. C. PINEDA et A. C. HABERT. « NOVAS MEMBRANAS POLIMÉRICAS DE MATRIZ MISTA CONTENDO CAVITANDOS ORGÂNICOS E NANOPARTÍCULAS DE CARBONO PARA SEPARAÇÃO DE GASES ». Dans Congresso Brasileiro de Engenharia Química em Iniciação Científica. São Paulo : Editora Blucher, 2017. http://dx.doi.org/10.5151/chemeng-cobeqic2017-449.

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