Enhancements in catalytic reactivity and selectivity of homobimetallic complexes containing heteroditopic ligandsElectronic supplementary information (ESI) available. CCDC 1497753. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7dt01294b

• Main Authors: Gatus, Mark R. D, McBurney, Roy T, Bhadbhade, Mohan, Messerle, Barbara A
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c7dt01294b

Rh( i ) and Ir( i ) homobimetallic complexes were synthesised using a heteroditopic ligand system on a xanthene scaffold containing a monodentate N-heterocyclic carbene ligand and a bidentate bis(pyrazol-1-yl)methane ligand. The complexes were tested as catalysts for the two-step dihydroalkoxylation and two-step hydroamination/hydrosilylation reactions. This is the first known report of an organometallic group 9 complex, Ir( i ) bimetallic complex, 13 , to selectively favour the opposite spirocyclisation product from that reported in the literature, 14c vs. 14b . The Ir( i ) homobimetallic complex catalyses the intramolecular hydroamination reaction of alkynamines efficiently and proved to be a highly active catalyst for promoting the subsequent hydrosilylation of the pyrrolines; completing the hydrosilylation reactions in less than 40 seconds. A chloro-bridged bimetallic species was observed in the solid state, revealing that the COD co-ligands present underwent an oxidation. Rh( i ) and Ir( i ) homobimetallic complexes coordinated to two characteristically different ligands on a xanthene scaffold showed enhanced reactivity and selectivity towards hydroelementation reactions.