Role of the imide axial ligand in the spin and oxidation state of Mn corrole and corrolazine complexes

Identifier:  PC:3124

Handle: https://hdl.handle.net/20.500.11797/PC3124

Authors:  Caballol, R.; Alcover-Fortuny, G.; Pierloot, K.; De Graaf, C.

Abstract:
Electronic structure calculations have been performed on four dierent Mn corrole and corrolazine complexes to clarify the role of the imide axial ligand on the relative stability of the dierent spin states and the stabilization of the high valent Mn ion in these complexes. Multicongurational perturbation theory energy calculations on the DFT optimized geometries shows that all complexes have a singlet ground state except the complex with the strongest electron with- drawal axial ligand, which is found to have a triplet ground state. The analysis of the sigma and pi interaction between metal and imide ligand shows that this spin crossover is caused by a subtle interplay of geometrical factors (Mn-N distance and coordination angle) and the electron withdrawal character of the imide. The analysis of the multicongurational wave functions reveals that the formally MnV ion is stabilized by an important electron transfer from both the equatorial cor-role/corrolazine ligand and the axial imide. The macrocycle donates roughly half an electron, being somewhere between the closed-shell trianionic and the dian-ionic radical form. The imide ligand transfers 2.5 electrons to the metal center, resulting in an eective d-electron count close to ve in all complexes.