LUMINESCENT DONOR-ACCEPTOR PLATINUM(II) COMPLEXES

The emission properties of the complexes [Pt(dppm)(5,6-Me2phen)](ClO4) 2, [Pt(phen)(C=CPh)2], [P 5-Ph-phen)(CN)2] and [Pt(C(and)N(and)N-dpp)( NCCH3)](ClO4) have been studied. The large percentage of metal-ligand charge transfer character in the lowest excited states of these platin um(II) complexes has been demonstrated. Excited state oxidation and re duction potentials of [Pt(phen)(C=CPh)2] have been determined. The 3ML CT excited state of Pt(II) is highly electrophilic as suggested by the large kinetic isotope effect (k(H)/(k)D = 6.7) observed in the quench ing of the photoexcited [Pt(dppm)(5,6-Me2phen)](ClO4)2 complex by cycl ohexene and d10-cyclohexene. Facile replacement of the coordinated ace tonitrile in [Pt(C(and)N(and)N-dpp)(NCCH3)](ClO4) by pyridine ligands provides an entry to a new class of emissive donor-acceptor cyclometal lated platinum(II) complexes.