Base Metal‐terpyridine Complex Immobilized on Stationary Phase Aimed as Reusable Hydrosilylation Catalyst

Abstract

The catalytic activity of a base metal-terpyridine complex immobilized on silica gel ( M(tpy)X 2 @SiO 2 /H 2 O : M = Mn, Fe, Co, Ni, Cu; X = Cl, Br) for hydrosilylation was investigated. Co(tpy)Br 2 @SiO 2 /H 2 O in the presence of NaBHEt 3 exhibited the highest catalytic activity. The reusability of Co(tpy)Br 2 @SiO 2 /H 2 O activated by NaBHEt 3 was examined. It was found that the catalytic activity decreased with repeated use because of the peeling off of the Co complex anchor portion from the silica gel surface upon the attack of NaBHEt 3 . The introduction of Co(OAc) 2 instead of CoBr 2 to silica gel formed Co(tpy)(OAc) 2 - and Co(tpy)(OH) 2 -immobilized silica gel, which exhibited catalytic activity in the absence of an activator such as NaBHEt 3 . The glassware in which Co(tpy)(OH) 2 was immobilized on the inner wall was prepared. It was found that the hydrosilylation reaction catalytically occurred in the glassware and that the catalytic activity did not decrease even after 10 repeated uses.