Volume of reaction, energetics, and kinetics of tetrahydrothiophene displacement of solvent from Mo(CO)5(alkane)

Abstract

Laser-induced optoacoustic spectroscopy (LIOAS) was used to determine the enthalpies and volumes of reactions for each step in ligand substitution of molybdenum hexacarbonyl with tetrahydrothiophene (THT). The enthalpy for substitution of CO on Mo(CO)₆ by an alkane and of coordinated alkane on Mo(CO)₅(alkane) by THT are 114 and −99 kJ mol⁻¹, respectively. Likewise, the volumes of reaction are 13 and −16 ml mol⁻¹. These results allow the calculation of the bond energies for Mo–alkane (56 kJ mol⁻¹) and Mo–THT (155 kJ mol⁻¹). Furthers studies should reveal that, for certain cases, the volume of reaction can be neglected in the determination of enthalpies of ligand substitution by LIOAS.