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Matthew T. Zamora

Bio: Matthew T. Zamora is an academic researcher from University of Lethbridge. The author has contributed to research in topics: Carbene & Metalation. The author has an hindex of 7, co-authored 14 publications receiving 321 citations. Previous affiliations of Matthew T. Zamora include Queen's University & Tokyo University of Agriculture and Technology.
Topics: Carbene, Metalation, Mesoionic, Thio-, Proton NMR

Papers
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TL;DR: Bidentate N-heterocyclic carbene ligands are an important, and as yet unrecognized, step forward for the preparation of high stability nanomaterials.
Abstract: Highly stable gold nanoparticles (Au NPs) functionalized by bidentate N-heterocyclic carbene (NHC) ligands have been synthesized by top-down and bottom-up approaches. A detailed study of the effect of alkylation, denticity, and method of synthesis has led to the production of NHC-stabilized nanoparticles with higher thermal stability than bi- and tridentate thiol-protected Au NPs and than monodentate NHC-stabilized NPs. Importantly, bidentate NHC-protected NPs also displayed unprecedented stability to external thiol, which has been an unsolved problem to date with all nanoparticles. Thus, multidentate NHC ligands are an important, and as yet unrecognized, step forward for the preparation of high stability nanomaterials.

126 citations

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TL;DR: The pendent MIC(H)+ arm of the trans-triethylphosphine-functionalized Pd species can be metalated by [Rh(μ-OMe)(COD)]2, resulting in the generation of a hybrid NHC/MIC-bridgedmix.

71 citations

Journal ArticleDOI
TL;DR: In this paper, a meta-substituted benzene-bridged ditriazolium salt has been prepared using copper-catalyzed azide-alkyne cycloaddition (CuAAC) and methylation protocols.

52 citations

Journal ArticleDOI
TL;DR: Attempts to generate mixed Rh/Pd complexes using Pd(OAc)(2) to deprotonate the pendent arm of several of the above carbene-anchored/pendent-imidazolium complexes of Rh have proven unsuccessful, however, a targeted di-NHC-bridged heterobimetallic complex is proposed.
Abstract: Reaction of a series of linked diimidazolium dibromide salts with one-half equivalent of [Rh(μ-OAc)(COD)]2 under reflux conditions generates a series of carbene-anchored/pendent-imidazolium complexes, [RhBr(COD)(RC(H)-η1-Ceth)][Br] (MeC(H)-η1-Ceth = ethylene[(N-methyl)imidazolium][(N-methyl)imidazole-2-ylidene] and tBuC(H)-η1-Ceth = ethylene[(N-tert-butyl)imidazolium][(N-tert-butyl)imidazole-2-ylidene]) via deprotonation of one end of the diimidazolium salt and coordination of the resulting carbene to Rh. Reaction of these complexes with carbon monoxide or the appropriate diphosphine yields either [RhBr(CO)2(RC(H)-η1-Ceth)][Br] (R = Me, tBu) or [RhBr(P∩P)(MeC(H)-η1-Ceth)][Br] (P∩P = Ph2PCH2PPh2, Ph2PCH2CH2PPh2, Et2PCH2PEt2), respectively. The resulting diphosphine complexes readily decompose in solution. A series of palladium complexes [PdI3-n(PR3)n(L)][I]n (n = 1,2) and [PdI(P∩P)(L)][I]2 (L = tBuC(H)-η1-Cmeth, tBuC(H)-η1-Ceth; tBuC(H)-η1-Cmeth = methylene[(N-tert-butyl)imidazolium][(N-tert-butyl)imidazole-2-ylidene]), containing the linked NHC-imidazolium moiety, have also been prepared by reacting the triiodo complexes, [PdI3(tBuC(H)-η1-Cmeth)] and [PdI3(tBuC(H)-η1-Ceth)] with several mono- and diphosphines. Attempts to generate mixed Rh/Pd complexes using Pd(OAc)2 to deprotonate the pendent arm of several of the above carbene-anchored/pendent-imidazolium complexes of Rh have proven unsuccessful. However, a targeted di-NHC-bridged heterobimetallic complex [PdI2(PEt3)(μ-tBuCCmeth)RhI(COD)] (tBu CCmeth = 1,1′-methylene-3,3′-di-tert-butyldiimidazol-2,2′-diylidene) can be generated by deprotonation of the imidazolium group in [PdI2(PEt3)(tBuC(H)-η1-Cmeth)][I] using half an equivalent of [Rh(μ-OAc)(COD)]2. The X-ray structure determination of this Pd/Rh complex confirms the dicarbene-bridged formulation and shows a metal-metal separation of approximately 6.2 A. Reaction of this Rh/Pd complex with CO yields the corresponding dicarbonyl product [PdI2(PEt3)(μ-tBuCCmeth)RhI(CO)2] via replacement of the COD ligand. The related dicarbene-bridged Ir/Rh complex [IrBr(COD)(μ-tBuCCmeth)RhBr(COD)] can be generated by reaction of [IrBr(COD)(tBuC(H)-η1-Cmeth )][Br] with [Rh(μ-OAc)(COD)]2, while the Pd/Ir complexes [PdI2(PR3)(μ-tBuCCmeth)IrI(COD)] (PR3 = PPh3, PMe2Ph) can be generated by reaction of the monometallic [PdI2(PR3)(tBuC(H)-η1-Cmeth)][I] species with K[N(SiMe3)2] in the presence of [Ir(μ-Cl)(COD)]2. The carbonyl analogues, [PdI2(PR3)(μ-tBuCCmeth)IrI(CO)2], can be generated via a gentle purge of CO gas. These di-NHC-bridged heterobimetallic species represent some of the first examples of this class and are the first involving palladium.

45 citations

Journal ArticleDOI
TL;DR: The pyrrole-based ligand N,N'-((1H-pyr role-2,5-diyl)bis(diphenylphosphoranylylidene))bis(4-isopropylaniline) (HL(B)) can be deprotonated and coordinated to yttrium and samarium ions upon reaction with their respective trialkyl precursors.
Abstract: The pyrrole-based ligand N,N′-((1H-pyrrole-2,5-diyl)bis(diphenylphosphoranylylidene))bis(4-isopropylaniline) (HLB) can be deprotonated and coordinated to yttrium and samarium ions upon reaction with their respective trialkyl precursors. In the case of yttrium, the resulting complex [LBY(CH2SiMe3)2] (1) is a Lewis base-free monomer that is remarkably resistant to cyclometalation. Conversely, the analogous samarium complex [LBSm(CH2SiMe3)2] is dramatically more reactive and undergoes rapid orthometalation of one phosphinimine aryl substituent, generating an unusual 4-membered azasamaracyclic THF adduct [κ4-LBSm(CH2SiMe3)(THF)2] (2). This species undergoes further transformation in solution to generate a new dinuclear species that features unique carbon and nitrogen bridging units [κ1:κ2:μ2-LBSm(THF)]2 (3). Alternatively, if 2 is intercepted by a second equivalent of HLB, the doubly-ligated samarium complex [(κ4-LB)LBSm] (4) forms.

25 citations


Cited by
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Journal ArticleDOI
10 Mar 1970

8,159 citations

Journal ArticleDOI
TL;DR: The intention of this review is to provide a detailed analysis of the various supramolecular interactions of triazoles in comparison to established functional units, which may serve as guidelines for further applications.
Abstract: The research on 1,2,3-triazoles has been lively and ever-growing since its stimulation by the advent of click chemistry The attractiveness of 1H-1,2,3-triazoles and their derivatives originates from their unique combination of facile accessibility via click chemistry and truly diverse supramolecular interactions, which enabled myriads of applications in supramolecular and coordination chemistry The nitrogen-rich triazole features a highly polarized carbon atom allowing the complexation of anions by hydrogen and halogen bonding or, in the case of the triazolium salts, via charge-assisted hydrogen and halogen bonds On the other hand, the triazole offers several N-coordination modes including coordination via anionic and cationic nitrogen donors of triazolate and triazolium ions, respectively After CH-deprotonation of the triazole and the triazolium, powerful carbanionic and mesoionic carbene donors, respectively, are available The latter coordination mode even features non-innocent ligand behavior Moreover, these supramolecular interactions can be combined, eg, in ion-pair recognition, preorganization by intramolecular hydrogen bond donation and acceptance, and in bimetallic complexes Ultimately, by clicking two building blocks into place, the triazole emerges as a most versatile functional unit allowing very successful applications, eg, in anion recognition, catalysis, and photochemistry, thus going far beyond the original purpose of click chemistry It is the intention of this review to provide a detailed analysis of the various supramolecular interactions of triazoles in comparison to established functional units, which may serve as guidelines for further applications

626 citations

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TL;DR: This review provides an in-depth look at recent advances in the use of NHCs for the development of functional materials.
Abstract: N-Heterocyclic carbenes (NHCs) have become one of the most widely studied class of ligands in molecular chemistry and have found applications in fields as varied as catalysis, the stabilization of reactive molecular fragments, and biochemistry. More recently, NHCs have found applications in materials chemistry and have allowed for the functionalization of surfaces, polymers, nanoparticles, and discrete, well-defined clusters. In this review, we provide an in-depth look at recent advances in the use of NHCs for the development of functional materials.

335 citations

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TL;DR: Mesoionic carbenes as discussed by the authors are a subclass of the family of N-heterocyclic Carbenes that generally feature less heteroatom stabilization of the carbenic carbon and hence impart specific donor properties and
Abstract: Mesoionic carbenes are a subclass of the family of N-heterocyclic carbenes that generally feature less heteroatom stabilization of the carbenic carbon and hence impart specific donor properties and

316 citations