Substituent Effect on the Thermodynamics and Kinetics of Carbyne Complex [(η5-C5H5)(CO)(COMe)Re≡CC6H4X] Isomerization to Carbene Complex [(η5-C5H5)(CO)2Re=C(Me)(para-C6H4X]: A Theoretical Study

Abstract

This study investigates the effect of different substituents on the isomerization reaction of the [(η5‑C5H5)(CO)(Me)Re≡CC6H5] carbyne complex to the [(η5-C5H5)(CO)2Re=C(Me)(C6H5)] carbene complex using MPW1PW91-based quantum mechanical calculations. In this respect, the study evaluates the influence of electron withdrawing groups (EWGs) and electron donating groups (EDGs) groups on the relative energies, thermodynamics parameters and the rate constant of this reaction and correlates the calculated parameters with the Hammett and Brown’s constants for the para-substituted functional groups (σp and $$\sigma _{{\text{p}}}^{ + }$$, respectively). Also, the calculated Wiberg indices of the Re–C bond values were used to illustrate the cleavage and formation of π-bonds along with the Re–C bonds in the isomerization transition state. The rate constants of the isomerization reaction were computed from 300 to 1200 K, in gas phase.