Catalytic dehydrogenation of cyclooctane and triethylamine using aliphatic iridium pincer complexes

The majority of the known pincer iridium based catalysts for dehydrogenation of alkanes has arene-based backbones. Here, the catalytic activity of aliphatic iridium pincer complexes, viz, the cyclohexane-based phosphine complex (PCyP)IrHCl (4) (PCyP = {cis-1,3-bis-[(di-tert-butylphosphino)methyl]cyclohexane}(-)) and the 2-methylpropane-based phosphinite complex (POCOP)IrHCl (5) (POCOP = 1,3-bis-(di-tert-butyl-phosphinito)-2-methylpropane(-)), in dehydrogenation of cyclooctane and triethylamine was studied. They give TONs that are in the range of 0-200. In addition, improved procedures for synthesis and metallation of the PCyP ligand (3) are presented. (C) 2014 Elsevier Ltd. All rights reserved.