Ketone hydrosilylation by Cu(I) diphosphine complexes: A kinetic study

• A complete kinetic study of the diphosphine Cu(I) ketone hydrosilylation cycle.
• The proposed catalytic cycle is validated.
• Both cycle steps show similar rate constants.
• First order kinetics in silane and in ketone can be found, depending on process conditions.

Diphosphine ligands are commonly used for the catalytic hydrosilylation of ketones using Cu(I) complexes. While some DFT studies on the suggested catalytic cycle have been reported, we present herein a complete kinetic study of the copper(I) catalyzed reaction to verify the plausibility of the proposed catalytic cycle from an experimental point of view. The rate constants of the two consecutives steps are determined for BDP (BDP = 1,2-bis(diphenylphosphino)benzene) and rac-BINAP ligands. The two constants are found not to differ significantly, i.e. no rate limiting step is identified. Depending on operation conditions, a switch between rate limiting steps is observed leading to either first order kinetics in silane or ketone.

Kinetic studies of diphosphine copper(I) catalyzed ketone hydrosilylation confirm the plausibility of the proposed catalytic cycle. Both steps of the cycle show similar rate constants. Depending on operation conditions, a switch between rate limiting steps can be observed, leading to either first order kinetics in silane or ketone.Figure optionsDownload as PowerPoint slide