Cationic Rh and Ir complexes containing bidentate imidazolylidene–1,2,3-triazole donor ligands: synthesis and preliminary catalytic studies

Abstract

A series of new cationic Rh(I), Rh(III) and Ir(III) complexes containing hybrid bidentate N-heterocyclic carbene–1,2,3-triazolyl donor of general formulae [Rh(CaT)(COD)]BPh4 (2a–d), [Rh(CaT)(CO)2]BPh4 (3a–d) and [M(CaT)(Cp*)Cl]BPh4 (M = Rh, 4a–d; M = Ir, 5a–c), where CaT = bidentate N-heterocyclic carbene–triazolyl ligands, COD = 1,5-cyclooctadiene and Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl, were synthesised. The imidazolium–1,2,3-triazolyl pre-ligands (1a–c and 1e–i) were readily prepared using the Cu(I) catalysed ‘click reaction’ between phenyl azide or benzyl azides with propargyl functionalised imidazolium salts. The single crystal solid state structures of complexes 2a–d; 3a–b; 4a–d and 5a–b confirm the bidentate coordination of the NHC–1,2,3-triazolyl ligand with the NHC coordinating via the ‘normal’ C2-carbon and the 1,2,3-triazolyl donor coordinating via the N3′ atom to form six membered metallocycles. These complexes are the first examples of Rh and Ir complexes containing the hybrid NHC–1,2,3-triazolyl ligands which exhibit a bidentate coordination mode. A number of these complexes showed limited efficiency as catalysts for the intramolecular hydroamination of 4-pentyn-1-amine to 2-methylpyrroline.

Thiourea-Derived Chelating Ligands and Their Organometallic Compounds: Investigations into Their Anticancer Activity

“…1-[(1-Benzyl-1,2,3-triazol-4-yl)methyl]-3-methylimidazolium bromide and 1-[(1-benzyl-1,2,3-triazol-4-yl)methyl]-3-methylbenzimidazolium bromide were prepared according to ref. [ 50 ] using THF: H 2 O = 1:1 as the solvent instead of DMSO.…”

A versatile method for the preparation of carbon–rhodium hybrid catalysts on graphene and carbon black

“…Nitrogen gas for Schlenk line operation comes from in-house liquid nitrogen boil-off. 1-Azido-4-nitrobenzene, 47 [Rh(COD)Cl] 2 , 48 1-mesityl-3-(prop-2-yn-1-yl)-1 H -imidazol-3-ium bromide 49 and 1-mesityl-3-((1-phenyl-1 H -1,2,3-triazol-4-yl)methyl)-1 H -imidazol-3-ium tetraphenylborate 49 were synthesized using literature procedures. 1 H and 13 C{ 1 H} NMR spectra were recorded on Bruker DMX400, DMX500 and DMX600 spectrometers operating at 400, 500 and 600 MHz ( 1 H) respectively and 100, 125 and 150 MHz ( 13 C) respectively.…”

Synthesis and Characterization of Benzimidazolium Salts Bearing Triazole Groups

“…They exhibit activities in the transfer semihydrogenation of alkynes to Z-alkenes. In another study, cationic rodium and iridium complexes were prepared [20]. Gu et al synthesized palladium, platinum and copper complexes [21,22].…”