Bibliografie tematiche / N-Heterocyclic carbenes (NHC) complexes

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Letteratura scientifica selezionata sul tema "N-Heterocyclic carbenes (NHC) complexes"

Autore: Grafiati
Pubblicato: 11 gennaio 2025

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Articoli di riviste sul tema "N-Heterocyclic carbenes (NHC) complexes"

1

Longevial, Jean-François, Mamadou Lo, Aurélien Lebrun, Danielle Laurencin, Sébastien Clément e Sébastien Richeter. "Molecular complexes and main-chain organometallic polymers based on Janus bis(carbenes) fused to metalloporphyrins". Dalton Transactions 49, n. 21 (2020): 7005–14. http://dx.doi.org/10.1039/d0dt00594k.

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Abstract (sommario):
Janus bis(N-heterocyclic carbenes) composed of a porphyrin core with two N-heterocyclic carbene (NHC) heads fused to opposite pyrroles were used as bridging ligands for the preparation of metal complexes.
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2

Mokfi, Moloud, Jörg Rust, Christian W. Lehmann e Fabian Mohr. "Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for N-Heterocyclic Carbene Complexes". Molecules 26, n. 12 (17 giugno 2021): 3705. http://dx.doi.org/10.3390/molecules26123705.

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The xanthine-derivatives 1,3,7-trimethylxanthine, 1,3-dimethyl-7-benzylxanthine and 1,3-dimethyl-7-(4-chlorobenzyl)xanthine are readily ethylated at N9 using the cheap alkylating agents ethyl tosylate or diethyl sulfate. The resulting xanthinium tosylate or ethyl sulfate salts can be converted into the corresponding PF6- and chloride salts. The reaction of these xanthinium salts with silver(I) oxide results in the formation of different silver(I) carbene-complexes. In the presence of ammonia, ammine complexes [Ag(NHC)(NH3)]PF6 are formed, whilst with Et2NH, the bis(carbene) salts [Ag(NHC)2]PF6 were isolated. Using the xanthinium chloride salts neutral silver(I) carbenes [Ag(NHC)Cl] were prepared. These silver complexes were used in a variety of transmetallation reactions to give the corresponding gold(I), ruthenium(II) as well as rhodium(I) and rhodium(III) complexes. The compounds were characterized by various spectroscopic methods as well as X-ray diffraction.
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3

Buchspies, Jonathan, Md Mahbubur Rahman e Michal Szostak. "Suzuki–Miyaura Cross-Coupling of Amides Using Well-Defined, Air- and Moisture-Stable Nickel/NHC (NHC = N-Heterocyclic Carbene) Complexes". Catalysts 10, n. 4 (31 marzo 2020): 372. http://dx.doi.org/10.3390/catal10040372.

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Abstract (sommario):
In this Special Issue on N-Heterocyclic Carbenes and Their Complexes in Catalysis, we report the first example of Suzuki–Miyaura cross-coupling of amides catalyzed by well-defined, air- and moisture-stable nickel/NHC (NHC = N-heterocyclic carbene) complexes. The selective amide bond N–C(O) activation is achieved by half-sandwich, cyclopentadienyl [CpNi(NHC)Cl] complexes. The following order of reactivity of NHC ligands has been found: IPr > IMes > IPaul ≈ IPr*. Both the neutral and the cationic complexes are efficient catalysts for the Suzuki–Miyaura cross-coupling of amides. Kinetic studies demonstrate that the reactions are complete in < 1 h at 80 °C. Complete selectivity for the cleavage of exocyclic N-acyl bond has been observed under the experimental conditions. Given the utility of nickel catalysis in activating unreactive bonds, we believe that well-defined and bench-stable [CpNi(NHC)Cl] complexes will find broad application in amide bond and related cross-couplings of bench-stable acyl-electrophiles.
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4

Beig, Nosheen, Varsha Goyal, Raakhi Gupta e Raj K. Bansal. "N-Heterocyclic Carbenes–CuI Complexes as Catalysts: A Theoretical Insight". Australian Journal of Chemistry 74, n. 7 (2021): 503. http://dx.doi.org/10.1071/ch20332.

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Abstract (sommario):
The electronic structures of N-heterocyclic carbenes (NHC) imidazolinylidene, thiazolinylidene, imidazolylidene, thiazolylidene, and 1,2,4-triazolylidene and their complexes with cuprous halides (CuX, X=Cl, Br, I) were investigated theoretically at the B3LYP/def2-SVP level. In contrast to other NHCs, imidazolylidene and 1,2,4-triazolylidene do not dimerize owing to the negligible coefficient of the vacant p-orbital at the carbene centre in their respective LUMOs. This is further supported by their greater thermodynamic and kinetic stabilities revealed by greater activation free energies and smaller standard free energies for their dimerization. Second-order perturbation interactions in the natural bond orbital (NBO) analysis of the NHCs indicate that six π electrons are delocalized in imidazolylidene, thiazolylidene, and 1,2,4-triazolylidene, conferring aromatic character and thereby enhancing their thermodynamic stability. NBO analysis reveals the existence of effective back bonding from a d orbital of Cu to the NHC, increasing the Wiberg bond index of the C–Cu bond to ~1.5. Owing to the large electronic chemical potential (μ) and high nucleophilicity indices, NHCs are able to transfer their electron density effectively to the cuprous halides having low μ values and high electrophilicity indices to yield stable NHC–CuI complexes. Large values of the Fukui function f(r) at the carbene centre of the NHCs and Cu atom of the NHC–CuI complexes indicate their softness. Imidazolylidene was found to be the softest, rationalizing wide use of this class of NHCs as ligands. The coordination of the NHCs to cuprous halides is either barrierless or has a very low activation free energy barrier. In the A3 reaction wherein NHC–Cu(I) complexes are used as catalyst, the reaction of NHC–CuI with phenylacetylene changes the latter into acetylide accompanied by raising the energy level of its HOMO considerably compared with the level of the uncomplexed alkyne, making its reaction with benzaldehyde barrierless.
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5

Savka, Roman, Sabine Foro e Herbert Plenio. "Pentiptycene-based concave NHC–metal complexes". Dalton Transactions 45, n. 27 (2016): 11015–24. http://dx.doi.org/10.1039/c6dt01724j.

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6

Qie, Boyu, Ziyi Wang, Jingwei Jiang, Zisheng Zhang, Peter H. Jacobse, Jiaming Lu, Xinheng Li et al. "Synthesis and characterization of low-dimensional N-heterocyclic carbene lattices". Science 384, n. 6698 (24 maggio 2024): 895–901. http://dx.doi.org/10.1126/science.adm9814.

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Abstract (sommario):
The covalent interaction of N-heterocyclic carbenes (NHCs) with transition metal atoms gives rise to distinctive frontier molecular orbitals (FMOs). These emergent electronic states have spurred the widespread adoption of NHC ligands in chemical catalysis and functional materials. Although formation of carbene-metal complexes in self-assembled monolayers on surfaces has been explored, design and electronic structure characterization of extended low-dimensional NHC-metal lattices remains elusive. Here we demonstrate a modular approach to engineering one-dimensional (1D) metal-organic chains and two-dimensional (2D) Kagome lattices using the FMOs of NHC–Au–NHC junctions to create low-dimensional molecular networks exhibiting intrinsic metallicity. Scanning tunneling spectroscopy and first-principles density functional theory reveal the contribution of C–Au–C π-bonding states to dispersive bands that imbue 1D- and 2D-NHC lattices with exceptionally small work functions.
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Nonnenmacher, Michael, Dominik M. Buck e Doris Kunz. "Experimental and theoretical investigations on the high-electron donor character of pyrido-annelated N-heterocyclic carbenes". Beilstein Journal of Organic Chemistry 12 (23 agosto 2016): 1884–96. http://dx.doi.org/10.3762/bjoc.12.178.

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Abstract (sommario):
Rh(CO)2Cl(NHC) complexes of dipyrido-annelated N-heterocyclic carbenes were prepared. From the C–H coupling constant of the respective imidazolium salts and the N–C–N angle of the N-heterocyclic carbene (NHC), a weaker σ-donor character than that of typical unsaturated NHCs is expected. However, the IR stretching frequencies of their Rh(CO)2Cl complexes suggest an electron-donor character even stronger than that of saturated NHCs. We ascribe this to the extremely weak π-acceptor character of the dipyrido-annelated NHCs caused by the conjugated 14 πe− system that thus allows for an enhanced Rh–CO backbonding. This extremely low π-acceptor ability is also corroborated by the 77Se NMR chemical shift of −55.8 ppm for the respective selenourea, the lowest value ever measured for imidazole derived selenoureas. DFT-calculations of the free carbene confirm the low σ-donor character by the fact that the σ-orbital of the carbene is the HOMO−1 that lies 0.58 eV below the HOMO which is located at the π-system. Natural population analysis reveals the lowest occupation of the pπ-orbital for the saturated carbene carbon atom and the highest for the pyrido-annelated carbene. Going from the free carbene to the Rh(CO)2Cl(NHC) complexes, the increase in occupancy of the complete π-system of the carbene ligand upon coordination is lowest for the pyrido-annelated carbene and highest for the saturated carbene.
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Beig, Nosheen, Varsha Goyal e Raj Kumar Bansal. "Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review". Beilstein Journal of Organic Chemistry 19 (20 settembre 2023): 1408–42. http://dx.doi.org/10.3762/bjoc.19.102.

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Abstract (sommario):
N-Heterocyclic carbenes (NHCs) are a special type of carbenes in which the carbene carbon atom is part of the nitrogen heterocyclic ring. Due to the simplicity of their synthesis and the modularity of their stereoelectronic properties, NHCs have unquestionably emerged as one of the most fascinating and well-known species in chemical science. The remarkable stability of NHCs can be attributed to both kinetic as well as thermodynamic effects caused by its structural features. NHCs constitute a well-established class of new ligands in organometallic chemistry. Although initially NHCs were regarded as pure σ-donor ligands, later experimental and theoretical studies established the presence of a significant back donation from the d-orbital of the metal to the π* orbital of the NHC. Over the last two decades, NHC–metal complexes have been extensively used as efficient catalysts in different types of organic reactions. Of these, NHC–Cu(I) complexes found prominence for various reasons, such as ease of preparation, possibility of structural diversity, low cost, and versatile applications. This article overviews applications of NHC–Cu(I) complexes as catalysts in organic synthesis over the last 12 years, which include hydrosilylation reactions, conjugate addition, [3 + 2] cycloaddition, A3 reaction, boration and hydroboration, N–H and C(sp2)–H carboxylation, C(sp2)–H alkenylation and allylation, C(sp2)–H arylation, C(sp2)–H amidation, and C(sp2)–H thiolation. Preceding the section of applications, a brief description of the structure of NHCs, nature of NHC–metal bond, and methods of preparation of NHC–Cu complexes is provided.
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Ali, Hanan El-Sharkawy. "Bis-carbene metallic compounds: synthesis of imidazoline derivatives via cycloaddition reaction of isocyanides based on amidines". Journal of Scientific and Innovative Research 6, n. 2 (30 giugno 2017): 50–54. http://dx.doi.org/10.31254/jsir.2017.6202.

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Abstract (sommario):
In an effort to develop new classes of NHC (N-heterocyclic carbenes) complexes, two imidazoline-anchored ligand systems have been synthesized. The process is superior owing to two approaches: (i) a new synthesized phase transfer catalyst, namely, 1,1'-benzene-1,4-diyldipyridinium dibromide (BDPDB) used to catalyze the phase-transfer Hoffmann reaction of two structurally varied amines, dodecylamine and 1-amino-9,10- anthraquinone. The reaction successfully gave the corresponding isocyanides that display the highest reactivity in reasonable to good yields. (ii) A cycloaddition-rearrangement reaction between amidines and isocyanides gives easy access to a diverse range of highly substituted 5- and 2-imidazolines. Furthermore, imidazoline based bis-NHC (N-heterocyclic carbenes) precursors were prepared and complexed to copper cation (5-Z and 2-Z, Chart 1).
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Leitão, Maria Inês P. S., Giulia Francescato, Clara S. B. Gomes e Ana Petronilho. "Synthesis of Platinum(II) N-Heterocyclic Carbenes Based on Adenosine". Molecules 26, n. 17 (4 settembre 2021): 5384. http://dx.doi.org/10.3390/molecules26175384.

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Abstract (sommario):
Organometallic derivatization of nucleosides is a highly promising strategy for the improvement of the therapeutic profile of nucleosides. Herein, a methodology for the synthesis of metalated adenosine with a deprotected ribose moiety is described. Platinum(II) N-heterocyclic carbene complexes based on adenosine were synthesized, namely N-heterocyclic carbenes bearing a protected and unprotected ribose ring. Reaction of the 8-bromo-2′,3′,5′-tri-O-acetyladenosine with Pt(PPh3)4 by C8−Br oxidative addition yielded complex 1, with a PtII centre bonded to C-8 and an unprotonated N7. Complex 1 reacted at N7 with HBF4 or methyl iodide, yielding protic carbene 2 or methyl carbene 3, respectively. Deprotection of 1 to yield 4 was achieved with NH4OH. Deprotected compound 4 reacted at N7 with HCl solutions to yield protic NHC 5 or with methyl iodide yielding methyl carbene 6. Protic N-heterocyclic carbene 5 is not stable in DMSO solutions leading to the formation of compound 7, in which a bromide was replaced by chloride. The cis-influence of complexes 1–7 was examined by 31P{1H} and 195Pt NMR. Complexes 2, 3, 5, 6 and 7 induce a decrease of 1JPt,P of more than 300 Hz, as result of the higher cis-influence of the N-heterocyclic carbene when compared to the azolato ligand in 1 and 4.
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Più fonti

Tesi sul tema "N-Heterocyclic carbenes (NHC) complexes"

1

Durmus, Semih. "Silver(I) and Gold(I) N-Heterocyclic Carbene Complexes". University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1165247084.

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2

McMullon, Max William. "Exploiting anionically-tethered N-heterocyclic carbene complexes for small molecule activation". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31079.

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Abstract (sommario):
N-heterocyclic carbenes (NHCs) can be used as ligands for organometallics complexes, which can then facilitate numerous catalytic applications, such as, C-H activation, small molecule activation and numerous materials applications. The use of anionically-tethered NHCs for usage with electropositive metals has been pioneered by the Arnold group within the last decade. This thesis describes the synthesis of both aryloxide- and amide-tethered NHC organometallic complexes of s-, p-, d- and f-block metals to provide a platform for small molecule activation. Once synthesised, the reactivity of some of these complexes were tested by reaction with CO2 with the aim of turning a molecule considered a harmful (environmentally), waste product into value added products, potentially providing an alternative fuel source. Chapter One introduces the use of anionically-tethered NHCs for use in a number of organometallic complexes as well as their current potential as catalysts for a number of important small molecules. This chapter focuses upon the differences between complexes tethered with anionic O, N, P, S elements, f-element NHC complexes and the use of d-block NHC complexes for catalysis. Chapter Two contains the synthesis and characterisation of a number of aryloxy-tethered NHC p-, d- and f-block organometallic complexes using the ligand H2(LArO R)2. The synthesis of SnII complexes including the synthesis of new ‘normal’ ‘abnormal’ complexes given enough steric bulk around the Sn centre due to the lone pair present in Sn complexes, preventing one of the ligands binding through the classical carbene position and therefore binding through the backbone C4 carbon. The synthesis of MII (Zn, Co and Fe) complexes to compare the solid-state structure and binding mode of the carbenes. The synthesis and characterisation of MIII (Ce and Eu) complexes to assess the solid-state structure and binding modes within f-bock complexes. Chapter Three investigates the reactivity of the MII complexes (Sn, Zn, and Fe) with CO2. Successful reactions were characterised using NMR and further treated with alkynes to target catalytic reactions. Chapter Four contains reactions to target a number of amide-tethered bis (NHC) s-, p-, d- and f-block organometallic complexes using the proligand, H4(LN Mes)Cl3. Deprotonation studies undertaken with a number of bases to give the MI (Li and K) salts and MII (Mg) salts and proved to be unsuccessful upon isolation. Reactions to synthesise the p-, d- and f-block complexes were then undertaken using in situ free carbene production as well as the attempted isolation of the free carbene, both of which also proved unsuccessful. Chapter Five provides an overall conclusion to the work presented in Chapters Two, Three and Four within this thesis. Chapter Six gives the experimental and characterising data for the complexes and reactions.
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3

Ellul, Charles. "Trimetallic N-heterocyclic carbene complexes". Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538279.

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4

Gauthier, Étienne. "Chiral complexes based on helicenic N-heterocyclic carbenes : synthesis, structure, photophysical and chiroptical properties". Thesis, Rennes 1, 2020. http://www.theses.fr/2020REN1S083.

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Abstract (sommario):
Dans le cadre de ma thèse, de nouveaux complexes de métaux de transitions (rhénium, iridium, cuivre, or) chiraux possédant des ligands NHC-hélicéniques ont été synthétisés et les propriétés chiroptiques et photophysiques ont été étudiées. Le premier sujet d’étude s’est focalisé sur l’étude de complexes de rhénium(I) cyclométallés par des ligands hélicéniques-NHC de type (N^C:) émettant de la phosphorescence circulairement polarisée. Une influence du design du ligand, des ligands ancillaires et de la géométrie des complexes sur les propriétés chiroptiques et photophysiques a été observée. Le deuxième projet a été consacré à l’étude de nouveaux complexes chiraux d’iridium cyclométallés possédant un ou plusieurs ligands N-[6]helicenyl-benzimidazolylidène. L’attention s’est ensuite portée sur des complexes possédant des ligands monodentes. Ainsi, dans le cadre d’un troisième projet, un complexe de cuivre portant un ligand NHC-hélicénique démontrant des propriétés de fluorescence circulairement polarisée a pu être obtenu avec succès. Enfin, des complexes chiraux d’or coordinés par des ligands hélicéniques-NHC ont été préparés. Pendant ce projet, les propriétés électroniques (sigma-donatrice et pi-acceptrice) d’un carbène hélicénique ont été quantifiées
My PhD work was dedicated to the synthesis and the study of novel chiral transition metal complexes (rhenium, iridium, copper, gold) bearing NHC-helicenes ligands and to the study of their chiroptical and photophysical properties. The first subject focused on the preparation and the study of CP-phosphorescent complexes of cyclometalated rhenium(I) complexes bearing NHC-helicenic (N^C:) ligands. The influence of the ligand design, ancillary ligands and geometry of the complexes on the chiroptical and photophysical properties has been highlighted. In the second project, we have prepared novel chiral cyclometalated iridium complexes bearing one or multiple N-[6]helicenyl- benzimidazolylidene ligands.Then, the attention has been focused on monodentate complexes. Thus, in the third project, a chiral copper complex bearing a helicenic-NHC ligand which emits circularly polarized fluorescence was successfully obtained. Finally, chiral monodentate helicenic-NHC gold(I) complexes have been prepared. During this project, the electronic properties (sigma-donating et pi-accepting) of a helicenic-NHC were investigated
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5

Marr, Isobel Helen. "Synthesis and reactivity of scandium N-heterocyclic carbene complexes". Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/17970.

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Abstract (sommario):
Chapter one introduces N-heterocyclic carbenes (NHCs) and discusses their use as ligands for rare earth metal complexes, with particular emphasis upon compounds synthesised from 2009 until the present day. Chapter two details the synthesis and characterisation of the homoleptic scandium-NHC complex [Sc(L)3] (L = [OCMe2CH2(1-C{NCHCHNiPr})]). Reactions of [Sc(L)3] with boranes, CO2 and CS2 are described which exploit the relative lability of the Sc–Ccarbene bond and allow formation of [Sc(L)2(OCMe2CH2(1-B'C{NCHCHNiPr}))] (B' = 9-BBN, BPh3, B(C6F5)3, BH3), [Sc(OCMe2CH2(1-O2CC{NCHCHNiPr})3]n, [Sc(L)2(OCMe2CH2 (1-S2CC{NCHCHNiPr})] and [Sc(L)(OCMe2CH2(1-S2CC{NCHCHNiPr})2]2. The chapter also discusses the reactivity of [Sc(L)3] towards substrates containing acidic C–H and N–H bonds and substrates containing polar E–X bonds (where E = C, Si, B, P and X = Cl, I). Chapter three describes the synthesis and characterisation of the NHC substituted scandium benzyl complexes [Sc(Bn)2(L)]2 and [Sc(Bn)(L)2], and the attempted synthesis of NHC substituted scandium aminobenzyl complexes. The reactivity of [Sc(Bn)2(L)]2 with RX substrates (R = alkyl) is discussed in detail; depending on the nature of the alkyl group, these reactions can allow formation of R–Bn , the result of carbon-carbon coupling. The complex [Sc(Bn)(L)Cl]2 has been isolated from these reactions and is structurally characterised. The reactivity of [Sc(Bn)2(L)]2 towards C–H bonds is explored and attempts to prepare NHC substituted scandium hydrides are described. Comparisons of the relative stability and reactivity of [Sc(Bn)2(L)]2 and [Sc(Bn)3(thf)3] are drawn. Chapter four documents the synthesis and characterisation of [Sc(Odtbp)2(L)] (Odtbp = 2,6-di-tert-butylphenoxide), [Sc(Odtbp)(L)2], and the samarium analogue [Sm(Odtbp)(L)2]. The reactivity of these complexes towards various small molecules is described. The chapter also details attempts to prepare the cationic scandium complexes [Sc(L)2][Bort] (Bort = bis[3,3',5,5'-tetra-(tert-butyl)-2,2-diphenolato]borate) and [Sc(L)2][B(Ph)4]. Chapter five provides overall conclusions to the work presented in this thesis. Chapter six contains all experimental and characterising data for the complexes and reactions detailed in this work.
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6

Li, Kai, e 李凯. "Photoluminescent organoplatinum (II) complexes containing N-heterocyclic carbene (NHC) ligands". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50533915.

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Abstract (sommario):
The syntheses, structures, photophysical properties and applications of three types of photoluminescent organoplatinum(II) complexes containing N-heterocyclic carbene (NHC) ligands are described. The tetradentate dianionic bis(phenolate-NHC) type ligands provide a superior scaffold for constructing thermally stable and efficient deep-blue phosphorescent Pt(II) complexes with λmax of ~440-460 nm and solid-state emission quantum yields of ~30%. Highly efficient blue OLEDs with CIEx, y of (0.19, 0.21) were fabricated based on these emitters with maximum brightness, peak current efficiency and power efficiency of ~9500 cd m^(-2), 24 cd A^(-1) and 17 lm W^(-1), respectively. Structural modification by extending the π-conjugation of the tetradentate bis(phenolate-NHC) ligand leads to strongly phosphorescent platinum(II) complexes with long-lived emissive electronic states that can be used as a luminescent sensor for oxygen. DFT/TDDFT calculations and time-resolved spectroscopic characterizations were performed to gain insight into the structure-photophysics correlation. The N-heterocyclic carbene (NHC) ligand was incorporated into Pt(II) complexes containing tridentate deprotonated 1,3-bis(2-pyridyl)benzene (N^C^N) type ligand. In addition to the [(N^C^N)Pt(NHC)]PF6 type complexes with (N^C^N) in η3-tridentate coordination mode, Pt(II) complexes with η2-bidentate (N^CN) ligands, namely [(N^CN)Pt(NHC)2]PF6, have been isolated and structurally characterized. The highly phosphorescent [(N^C^N)Pt(NHC)]PF6 complexes were used for solution-processed green OLEDs fabrication. The peak current efficiency of 12.5 cd A^(-1) and maximum brightness higher than 2000 cd m^(-2) were achieved. The presence of the pendent pyridyl motif causes quenching of emission of the [(N^CN)Pt(NHC)2]PF6 complexes in solution at room temperature. Turning on solid-state emission of [(N^CN)Pt(nBu2Im)2]PF6 in the presence of an acidic vapor revealed its potential as a luminescent chemosensor. A class of dicationic platinum(II) terpyridyl complexes containing NHC ligand, namely [Pt(tpy)(NHC)](PF6)2, has been synthesized and structurally characterized. Even in the presence of the strong σ-donating NHC ligand, these complexes are non- or weakly emissive in solution at room temperature. However, this class of complexes displays intense emissions in solid state (298 K and 77 K), in glassy solution (77 K butyronitrile) and in PMMA (2 wt.%, 298 K). The ligand (terpyridine) displacement reaction arising from CN attack onto the Pt(II) center has been observed for [Pt(tpy)(nBu2Im)](PF6)2 leading to its application as a chemodosimeter for selective cyanide sensing in aqueous solution.
published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
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7

Santoro, Orlando. "Copper(I)-N-heterocyclic carbene (NHC) complexes : synthesis, characterisation and applications in synthesis and catalysis". Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/8409.

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Abstract (sommario):
The work described herein focuses on the synthesis and characterisation of copper(I) complexes bearing N-heterocyclic carbene (NHC) ligands, their use in catalysis as well as organometallic synthesis and related reaction mechanisms. Two classes of complexes were considered: neutral NHC-Cu(I) species and their cationic analogues. Concerning the former, initial efforts were focused on the development of a general and straightforward synthetic methodology towards complexes of the type [Cu(X)(NHC)] (X = Cl, Br, I). More than 10 NHC-Cu(I) species were synthesised in high yields under mild conditions, in air and using technical grade solvents. These complexes exhibited interesting activity in the catalytic dehydrogenation of formic acid/amine adducts proving in three times more efficiency than the copper salts previously employed in such a reaction. Hydroxide- and tert-butoxide analogues showed to be efficient catalysts in the N-methylation of amines with CO₂ as carbon source, and in the dehydrogenative coupling of silanes and carboxylic acids. Experimental and computational work were carried out in order to elucidate the mechanism of these transformations. Regarding the use of these species in organometallic synthesis, homo- and heteroleptic bis-NHC-Cu(I) complexes were employed as carbene transfer reagents to other transition metals. Aside from well-known cationic gold(I) species, two novel palladium(II) analogues were isolated and fully characterised.
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8

Saker, Oliver John. "Mono- and tri-nuclear ruthenium complexes incorporating N-heterocyclic carbene ligands". Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512305.

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9

Fantasia, S. M. "Synthesis and reactivity of Pt(2.) complexes bearing phosphines or N-heterocyclic carbenes (NHC) as ancillary ligands". Doctoral thesis, Università degli Studi di Milano, 2006. http://hdl.handle.net/2434/166365.

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10

Martin, Thomas Antony. "Unravelling the photochemistry of organometallic N-heterocyclic carbene complexes". Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547630.

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This thesis describes the synthesis, characterisation and reactivity of new manganese and rhenium(I) NHC complexes, which have been investigated both thermally and photochemically and the results contrasted with existing phosphine analogues in the literature. Cp’Mn(CO)2(NHC) (NHC = IEt2Me2 1, IMes 2, IiPr2Me2 3 and IPr 4) were synthesised and investigated by TRIR spectroscopy. Loss of CO was observed after 355 nm irradiation to form agostically stabilised intermediates, which reformed the parent species by recombination with CO on the nanosecond timescale. Loss of NHC was not observed, in contrast to Cp’Mn(CO)2(PPh3) which lost both CO and PPh3 upon photolysis. [Re(NHC)(Bpy)(CO)3]BAr4F (NHC = IEt2Me2 5, IMes 6) were synthesised and investigated by TRIR spectroscopy and UV/Vis absorption and emission spectrometry. Inclusion of an NHC altered the excited state manifold of the complexes, favouring population of the 3MLCT over the 3IL excited state. The lowest energy excited state for both 5 and 6 proved to be a 3MLCT excited state at 298 and 77 K. In contrast, [Re(PPh3)(Bpy)(CO)3]BAr4F exhibited 3MLCT at 298 K, but 3IL at 77 K. A series of complexes, M(NHC)(CO)4X and M(NHC)2(CO)3X (M = Re, X = Cl; M = Mn, X = Br) formed upon reaction of the corresponding M(CO)5X species and free NHC. The substitution pattern was dictated by the steric bulk of the NHC. Generation of the corresponding cations by halide abstraction was investigated. M(NHC)2(CO)3X was found to form agostic stabilised species upon halide abstraction by NaBAr4F in CH2Cl2. Under the same conditions, Re(IPr)(CO)4Cl was found to form the dichloromethane complex, [Re(IPr)(CO)4(η1-CH2Cl2)]BAr4F. In C6H5F solution under an atmosphere of dihydrogen, the CH2Cl2 ligand could be displaced by H2 to form the dihydrogen species, [Re(IPr)(CO)4(H2)]BAr4F.
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Libri sul tema "N-Heterocyclic carbenes (NHC) complexes"

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Fedorkiw, Terry William. Study of new ruthenium and iridium hydride complexes bearing N-heterocyclic carbenes as ligands. Ottawa: National Library of Canada, 2003.

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Fedorkiw, Terry William. Study of new ruthenium and iridium hydride complexes bearing N-heterocyclic carbenes as ligands. 2003, 2003.

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Zou, Taotao. Anti-Cancer N-Heterocyclic Carbene Complexes of Gold, Gold and Platinum: Thiol “Switch-on” Fluorescent Probes, Thioredoxin Reductase ... Reticulum Targeting Agents. Springer, 2018.

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Zou, Taotao. Anti-Cancer N-Heterocyclic Carbene Complexes of Gold, Gold and Platinum: Thiol “Switch-on” Fluorescent Probes, Thioredoxin Reductase ... Reticulum Targeting Agents. Springer, 2016.

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Zou, Taotao. Anti-Cancer N-Heterocyclic Carbene Complexes of Gold, Gold and Platinum: Thiol Switch-On Fluorescent Probes, Thioredoxin Reductase Inhibitors and Endoplasmic Reticulum Targeting Agents. Springer London, Limited, 2016.

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Capitoli di libri sul tema "N-Heterocyclic carbenes (NHC) complexes"

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Lazreg, Faïma, e Catherine S. J. Cazin. "NHC-Copper Complexes and their Applications". In N-Heterocyclic Carbenes, 199–242. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527671229.ch08.

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Lazreg, Faïma, e Catherine S. J. Cazin. "Medical Applications of NHC-Gold and -Copper Complexes". In N-Heterocyclic Carbenes, 173–98. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527671229.ch07.

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Wurm, Thomas, Abdullah Mohamed Asiri e A. Stephen K. Hashmi. "NHC-Au(I) Complexes: Synthesis, Activation, and Application". In N-Heterocyclic Carbenes, 243–70. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527671229.ch09.

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Wagers, Patrick O., Kerri L. Shelton, Matthew J. Panzner, Claire A. Tessier e Wiley J. Youngs. "Synthesis and Medicinal Properties of Silver-NHC Complexes and Imidazolium Salts". In N-Heterocyclic Carbenes, 151–72. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527671229.ch06.

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Murphy, Luke J., Katherine N. Robertson, Jason D. Masuda e Jason A. C. Clyburne. "NHC Complexes of Main Group Elements: Novel Structures, Reactivity, and Catalytic Behavior". In N-Heterocyclic Carbenes, 427–98. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527671229.ch15.

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Dierick, Steve, e István E. Markó. "NHC Platinum(0) Complexes: Unique Catalysts for the Hydrosilylation of Alkenes and Alkynes". In N-Heterocyclic Carbenes, 111–50. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527671229.ch05.

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Pérez, Pedro J., e M. Mar Díaz-Requejo. "Cu-, Ag-, and Au-NHC Complexes in Catalysis". In N-Heterocyclic Carbenes in Synthesis, 257–74. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/9783527609451.ch11.

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Nielsen, David J., e Kingsley J. Cavell. "Pd-NHC Complexes as Catalysts in Telomerization and Aryl Amination Reactions". In N-Heterocyclic Carbenes in Synthesis, 73–102. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/9783527609451.ch4.

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Hahn, F. Ekkehardt. "Complexes with Protic N-Heterocyclic Carbene (NR,NH-NHC) Ligands". In Advances in Organometallic Chemistry and Catalysis, 111–32. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118742952.ch9.

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Krylova, Valentina A., Peter I. Djurovich, Brian L. Conley, Ralf Haiges, Matthew T. Whited, Travis J. Williams e Mark E. Thompson. "Control of Emission Colour with N-Heterocyclic Carbene (NHC) Ligands in Phosphorescent Three-Coordinate Cu(I) Complexes†". In Electrophosphorescent Materials and Devices, 811–22. New York: Jenny Stanford Publishing, 2023. http://dx.doi.org/10.1201/9781003088721-45.

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Atti di convegni sul tema "N-Heterocyclic carbenes (NHC) complexes"

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Vo-Thanh, Giang, Audrey Aupoix e Chloée Bournaud. "Asymmetric transfer hydrogenation of aromatic ketones using rhodium complexes of chiral N-heterocyclic carbenes derived from (S)-pyroglutamic acid." In The 17th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2013. http://dx.doi.org/10.3390/ecsoc-17-a005.

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