MnBr(CO)5: a commercially available highly active catalyst for olefin hydrosilylation under ambient air and green conditions

Abstract

The catalytic hydrosilylation of alkenes is a major industrial reaction and a very efficient and atom-economical way to obtain functional organosilane compounds and cross-linked materials. Platinum-based catalysts are currently preferred in the industry despite the low availability and high cost of platinum but considerable efforts are being directed to replace Pt with non-noble metals. In this context, we developed a robust and highly active non-noble metal catalytic system using commercially available MnBr(CO)₅. It was successfully employed in olefin hydrosilylation reactions using various functional olefins and industrially relevant silanes such as 1,1,1,3,5,5,5-heptamethyltrisiloxane (MD^HM) and polymethylhydrosiloxanes (PMHS). This system tolerates unpurified substrates and can be used in green solvents (H₂O, anisole) under ambient air, selectively yielding the anti-Markovnikov hydrosilylated products (yields up to >99%) at 70 °C using 2 mol% catalyst. MnBr(CO)₅ was also successfully employed for the synthesis of cross-linked materials using dienes, carbonyl and epoxide containing substrates with low Mn loadings (0.3 mol%) at 70 °C under ambient air.