نتایج جستجو برای: nhc

تعداد نتایج: 1697  

Journal: :Organometallics 2022

Thanks to the +PCy3 substituents which are unlikely undergo intramolecular C–H activation, Pd(II) complex [(C,C,C)PdCl](OTf) having a neutral LX2-type NHC, diphosphonium bis(ylide) pincer ligand was selectively prepared by double deprotonation of [(NHC)PdCl2(Py)] precursor with tBuOK. The influence on overall electronic properties this scaffold evaluated IR spectroscopy data corresponding Pd–CO...

2013
Miguel A. Huertos Julio Pérez Lucía Riera Jesús Díaz Ramón López

The current importance of nitrogen heterocyclic carbene (NHC) ligands in several areas of coordination chemistry and catalysis can hardly be overemphasized. The deprotonation of imidazolium salts is the prime route to NHCs; however, the study of the transformations relating imidazole and NHC ligands is still an emerging area of research. The thermodynamic preference for Nor C-coordination in im...

Journal: :Chemistry: A European Journal 2023

Oxidative N-heterocyclic carbene (NHC) catalysis offers the chance to perform oxidative and oxygenative transformations which give rise various NHC-bound intermediates, paving way non-umpolung processes through activation of carbon atoms heteroatoms. The aim this review is discuss developments literature in field NHC-catalysis since 2014, with particular focus pivotal intermediates their mechan...

Journal: :Discrete Mathematics 2008
Juan José Montellano-Ballesteros Victor Neumann-Lara Eduardo Rivera-Campo

The neighbourhood heterochromatic number nhc(G) of a non-empty graphG is the smallest integer l such that for every colouring of G with exactly l colours, G contains a vertex all of whose neighbours have different colours. We prove that limn→∞(nhc(Gn)− 1)/|V (Gn)| = 1 for any connected graph G with at least two vertices. We also give upper and lower bounds for the neighbourhood heterochromatic ...

Journal: :Dalton transactions 2010
Giacomo L Petretto Miao Wang Antonio Zucca Jonathan P Rourke

Four different NHC ligands have been coordinated to Pt(II) centres; for the first time cyclometallation of the NHC ligand was observed, but only when the platinum centre had a DMSO and two methyl co-ligands. Cyclometallation resulted in the exclusive formation of five-membered rings, and the absence of any double cyclometallation reactions with appropriate ligands rules out the possibility of a...

2011
Lian-jun Liu Feijun Wang Wenfeng Wang Mei-xin Zhao Min Shi

Axially chiral mono(NHC)-Pd(II) and mono(NHC)-Au(I) complexes with one side shaped 1,1'-biphenyl backbone have been prepared from chiral 6,6'-dimethoxybiphenyl-2,2'-diamine. The complexes were characterized by X-ray crystal structure diffraction. The Pd(II) complex showed good catalytic activities in the Suzuki-Miyaura and Heck-Mizoroki coupling reactions, and the (S)-Au(I) complexes also showe...

Journal: :Chemical science 2012
Eirik Lyngvi Jeffrey W Bode Franziska Schoenebeck

The origin of stereoselectivity of NHC-catalyzed annulation reactions of ynals and stable enols was studied with Density Functional Theory. The data suggest that the C-C bond formation is the stereo-determining step. Only the deprotonated pathway (containing an oxy anion and overall neutral species) was found to give rise to discrimination of the competing stereoisomers. This is due predominant...

Journal: :Dalton transactions 2013
Wioletta Kośnik Karol Grela

A synthetic route to backbone functionalised imidazolinium salts-NHC ligand precursors has been developed. These tagged NHC ligands can be used to obtain a homogeneous Hoveyda-type catalyst (19) containing a quaternary ammonium group on a C-8 long spacer. Products of olefin metathesis reactions promoted by complex 19 can be readily purified from Ru-residues by filtration of the reaction mixture...

2012
Amit Pratap Singh Rajendra S. Ghadwal Herbert W. Roesky Julian J. Holstein Birger Dittrich Jean-Philippe Demers Veniamin Chevelkov Adam Lange

An abnormal N-heterocyclic carbene (aNHC) has been used as a Lewis base to initiate dismutation of trichlorosilane. This report presents the reactivity differences of a normal N-heterocyclic carbene (NHC) versus aNHCwith heavier group 14 elements. Three novel compounds (NHC)2 SiCl2H2 (2), aNHC SiCl2H2 (3), and aNHC GeCl2 (4) have been synthesized and characterized by single crystal X-ray analys...

2014
Shohei Sase Yuriko Ikehara Kei Goto

The title compound, [Ru(C47H43N2)Cl(C10H14)]·2C6H6, crystallized with two independent mol-ecules of benzene. One of the N-aryl moieties of the N-heterocyclic carbene (NHC) ligand underwent cyclo-metallation to form a five-membered ruthenacycle. The complex has a three-legged piano-stool structure with two C atoms incorporated in the five-membered ruthenacycle and a Cl atom as legs. The ruthenac...

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