Bis N-heterocyclic chelate ligand

The synthesis of a chlorosilyliumylidene [(bNHC)SiCl] Cl from the his N-heterocyclic chelate ligand (bNHC) precursor is described. A straight forward reaction of equimolar amoimts of bis N-heterocyclic chelate ligand (bNHC) with NHC-SiCl2 (NHC = l,3-his(2,6-diisopropylphenyl)imidazol-2-ylidene) (3) in THF at room temperature leads to the formation of chlorosilyliumylidene [(hNHC)SiCl]+Cl- (Scheme 6.3.3.1). 

The synthesis of bis N-heterocyclic chelate ligand (bNHC) namely l,l -methylene-3,3 -di-2,6-diisopropylphenylimidazole-2,2 -diyli-dene is carried out by modification of the literature procedures (4,5). 

Morgan BP, Galdamez GA, GiUiard RJ, Smith RC. Canopied fram-chelating bis(N-heterocyclic carbene) ligand synthesis, structure and catalysis. Dalton Trans. 2009 2020-2028. 

Sluijter SN, Warsink S, Lutz M, Elsevier CJ. Synthesis ofpaUadium(0) and -(II) complexes with chelating bis (N-heterocyclic carbene) ligands and their application in semi hydrogenation. Dalton Trans. 2013 42 7365-7372. 

Zanardi A, MataJA, Peris E. A simple route to chelating, structurally different triazole-based bis(N-heterocyclic carbene) ligands and their coordination to Pt . Eur J Inorg Chem. 2011 2011 416-421. 

In a manner similar to platinum ones, rhodium—carbene complexes have been recently tested in the hydrosilylation of alkenes and alkynes (3). Especially, rhodium complexes with N-heterocyclic carbene (NHC) ligands have attracted considerable attention. Their performance is comparable with that of phosphine complexes. The following exemplary ligands were used 1,3-imidazoylidene chelate bis(imidazolinum-carbene) phosphine-functionalized NHC alkylammonium-imidazolium chloride salts NHC pincer complexes, pyridine-functionalized N-heterocyclic carbenes (also with iridium), and bis(dichloroimidazolylidene) (also with iridium). 

The neutral radical 11.12 is an interesting heterocyclic analogue of 2,2 -bipyridyl. This paramagnetic (spin-bearing) ligand forms an N, -chelated complex with bis(hexafluoroacetylacetonato)cobalt(ir). ... 

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