The heats of reaction of tolueneMo(CO)3 with a series of phosphines and phosphites have been measured by solution calorimetry. The order of stability toward formation of fac-(PR3)3Mo(CO)3 in THF solution is: P(OCH3)3s > PMe3 > PnBu3 > PMe2Ph > PEt3 > triphos > P(OPh)3 > PMePh2 > PPh3 > PCl3 and spans a range of 25 kcal/mol reflecting individual bond strength differences up to 8 kcal/mol. The bulky phosphines PCy3 and PtBu3 react with tolueneMo(CO)3 in THF, but 30-40 kcal/mol less heat is evolved in these reactions than with the other phosphines and phosphites. The coordinately unsaturated five-coordinate complexes (PR3)2Mo(CO)3 are proposed as the reaction products. The importance of both steric and electronic factors in the MoP bond is discussed.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry