ELECTRONIC-STRUCTURE AND REACTIVITY OF DIOXYGEN PLATINUM COMPLEXES - AN AB-INITIO MO-LCAO STUDY

Ab initio Hartree Fock calculations have been carried out on the compl ex L2Pt(eta2-O2) and its derivatives L2Pt(OOH)X and L2Pt(OOH)(XY) obta ined by reaction with HX (HX = H2O, HCl, HOOCH, NH3) and HXYH (HXYH = oxalic acid, o-catechol, hydrazine, hydroxylamine, ethylendiamine, o-p henylendiamine). In addition also the reaction L2Pt(OOH)X + HX --> H2O 2 + L2PtX2 leading to the formation of hydrogen peroxide has been stud ied. The theoretical investigation gave, for all considered species, o ptimum complex geometry, charge distribution and reaction energies bei ng evaluated by means of a correlation energy density functional. The ability of the HX reagents to form hydrogen peroxide is discussed in t erms of absolute acidity and coordinating capability of the X-groups. This allows interpretation of the more peculiar aspects of the chemica l activation of dioxygen that leads to the coordinated hydroperoxide s pecies or hydrogen peroxide.