Coordination Booster-Catalyst Assembly: Remote Osmium Outperforming Ruthenium in Boosting Catalytic Activity.

Presented herein is a set of bimetallic and trimetallic "coordination booster-catalyst" assemblies in which the coordination complexes [RuII (terpy)2 ] and [OsII (terpy)2 ] acted as boosters for enhancement of the catalytic activity of [RuII (NHC)(para-cymene)]-based catalytic site. The boosters accelerated the oxidative loss of para-cymene from the catalytic site to generate the active catalyst during the oxidation of alkenes and alkynes into corresponding aldehydes, ketones and diketones. It was found that the boosting efficiency of the [OsII (terpy)2 ] units was considerably higher than its congener [RuII (terpy)2 ] unit in these assemblies. Mechanistic studies were conducted to understand this unique improvement.