(C5Me5)2Y(μ-H)(μ-CH2C5Me4)Y(C5Me5) as a reservoir of electrons for the reduction of PhSSPh and CO2: A theoretical study

Abstract

Reaction mechanisms for the reduction of PhSSPh and CO2 by the trivalent yttrium tuck-over hydride complex (C5Me5)2Y(μ-H)(μ-CH2C5Me4)Y(C5Me5) (1) have been investigated by means of DFT methods. Complex 1 can be seen as a reservoir of electrons able to deliver two electrons to a substrate by combining its hydride ligand with its tuck-over methylene moiety to form a (C5Me5)- ligand. The study shows that CO2 should be effectively reduced by complex 1. A two-steps metathesis process is found as the likely mechanism for the synthesis of both [(C5Me5)2Y(μ-SPh)]2 and [(C5Me5)2Y]2 (μ-CO2). The latter complex can further react with another CO2 molecule to generate either a carbonate or an oxalate sandwiched complex. However, the high thermodynamic stability of the latter should favor its exclusive formation.