Towards a better understanding of alkene metathesis: elucidating the properties of the major metal carbene catalyst types

Abstract

The difference in activity of metal carbene catalysts has a major influence on the efficiency and application of these metal carbenes as metathesis catalysts. The focus of this research is to examine the properties of the major metal carbene catalyst types to understand the general activity trend. A comparative investigation of the foremost Fischer-, Tebbe-, Grubbs-, and Schrock-type metal carbenes was done using a qualitative structure–activity type computational method via principal component analysis. The effect of the change in metal atom as well as the change in ligands was specifically considered. Four Fischer-, a Tebbe-, five Grubbs-, and a Schrock-type carbene were investigated in this regard. Geometry optimizations of all species were done at the GGA/PBE/ DNP level with Materials Studio DMol3 and subsequent single-point energy calculations were done with Gaussian at the PBEPBE level with the cc-pVQZ-type basis sets. Results showed that the descriptors extracted by the principal component analyses could successfully reproduce or match the generalized trend for metathesis activity, highlighting the importance of the frontier orbitals in the metathesis reaction