A theoretical study of a model oxymyoglobin has been performed at the INDO level. The geometrical structure of the Fe-O2 subunit has been analysed by making a complete geometry optimization of the dioxygen molecular coordinates in both an isolated system and a system interacting with a model environment. In the case of the isolated system, the most interesting result is the evidencing of two minima corresponding to bent end-on and perpendicular side-on structures. The transfer of charge from iron to dioxygen has been shown to be very sensitive to the dioxygen orientation and the variation of this charge transfer as a function of some interatomic distances has been interpreted in terms of the d and π* orbital interactions. The study of the environment effect shows that, although electrostatic interactions do not play a major role in the dioxygen position, hydrogen-bond formation between O2 and vicinal ligands substantially favours a bent end-on conformation. © 1991.
|Journal||Journal of Molecular Structure: THEOCHEM|
|Publication status||Published - 26 Jul 1991|