Half‐sandwich iridium complexes: Synthesis and catalytic activity in dehydrogenation of alcohols to carboxylic acids

Abstract

A series of N,N‐chelate half‐sandwich iridium complexes were synthesized by a simple method with good yields. The dehydrogenation of a series of aromatic and aliphatic primary alcohols to corresponding carboxylic acids has been successfully achieved by the prepared air stable iridium complexes under mild reaction conditions. Carboxylic acids were obtained in high yields under open flask condition with broad substrates and good tolerance to sensitive functional groups. Such a half‐sandwich iridium catalyst system showed desirable stability and catalytic activity, and the achievement of a high TOF of 372.0 h−1 could be observed with an extremely low catalyst loading of only 0.05 mol%. Furthermore, the sustainable catalyst could be reused for a minimum of five cycles without obviously losing its activity, highlighting its potential application in industry. Structure of N,N‐chelate iridium complexes 1 and 3 were determined by single‐crystal X‐ray analysis.