Theoretical study on intermediate in oxygen transfer reaction in molybdoenzyme model system

Calculations on the [MoO(OPh)(OPMe3)T] (T=hydrotris(1-pyrazolyl)borate) model system show that the calculated OMoOP dihedral angle is in good agreement with the experimental value found in the crystal structure of [MoO(OPh)(OPEt3) T3Pr] (T3Pr=hydrotris(3-isopropyl-1-pyrazolyl)borate) and very different than the calculated value for the [MoO(SH)2(NH3)2(OPMe3)] model system. This indicates that the types of ligands coordinated to the molybdenum atom are responsible for the value of the dihedral angle and not the crystal packing forces in the crystal structure.