Efficient Transfer Hydrogenation Using Iridium and Rhodium Complexes of Benzannulated N‐Heterocyclic Carbenes
Articles > Article · 2008
Authors: Hayati TÜRKMEN, Tania PAPE, F. Ekkehardt HAHN, BEKİR ÇETİNKAYA
European Journal of Inorganic Chemistry, Journal Indexed in SCI Expanded, International, WoS, 2008, vol 2008, pp 5418-5423
Summary
Abstract Benzimidazol‐2‐ylidene(NHC) derivatives of iridium(I) and rhodium(I) bearing electron‐rich and/or functional substituents R and R′ at the nitrogen atoms of the heterocycle [IrBr(cod)(NHC)] (a) or [RhBr(cod)(NHC)] (b) (R = 2,3,5,6‐tetramethylbenzyl; R′ = methoxyethyl, 1a,b; R = R′ = 2,3,5,6‐tetramethylbenzyl, 2a,b; R = pentamethylbenzyl, R′ =methoxyethyl, 3a,b; R = R′ = pentamethylbenzyl, 4a,b) were prepared. All compounds were fully characterized by 1H and 13C NMR spectroscopy, mass spectrometry (MALDI), and elemental analysis. In addition, the molecular structures of 1a, 2a, and 3a were determined by single‐crystal X‐ray diffraction studies. All of the new benzimidazol‐2‐ylidene iridium(I) and rhodium(I) complexes were found to be effective catalysts for transfer hydrogenation with iridium(I) derivative 1a showing the highest catalytic activity.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)