Perimidin-2-ylidene rhodium(I) complexes; unexpected halogen exchange and catalytic activities in transfer hydrogenation reaction
Articles > Article · 2014
Authors: P. Arzu AKINCI, Süleyman GÜLCEMAL, Olga N. KAZHEVA, Grigorii G. ALEXANDROV, Oleg A. DYACHENKO, Engin CETINKAYA, BEKİR ÇETİNKAYA
Journal of Organometallic Chemistry, Journal Indexed in SCI Expanded, International, WoS, 2014, vol 765, pp 23-30
DOI: 10.1016/j.jorganchem.2014.04.033
Summary
Four new [(NHC)RhCl(COD)] (NHC = perimidin-2-ylidene; COD = 1,5-cyclooctadiene) rhodium complexes (4a-c and 5a) have been prepared by the reaction of [Rh(mu-OMe)(COD)](2) with perimidinium bromides (2a-c and 3a). The halogen exchange, abstracted from 1,2-dichloroethane was observed during the reaction and [(NHC)RhCl(COD)] complexes were obtained instead of [(NHC)RhBr(COD)]. All ligand precursors and complexes have been fully characterized by H-1, C-13 NMR, IR spectroscopy, elemental analysis and mass spectroscopy. X-ray diffraction studies on single crystals of 4a and 5a confirm the square planar geometry. The nu((CO)) values of [(NHC)RhCl(CO)(2)] complexes (6a-c and 7a) revealed that the NHC ligands are not good sigma-donors. Transfer hydrogenation (TH) reaction of aliphatic and aromatic ketones has been comparatively studied by using complexes 4a-c and 5a as catalysts. (C) 2014 Elsevier B.V. All rights reserved.