Synthesis, structures and spectroscopic properties of platinum complexes containing orthometalated 2-phenylpyridine

The synthesis, structure and spectroscopy of a series of luminescent orthometalated square planar platinum(II) complexes are reported. Reaction of K2PtCl4 with one mole equivalent of 2-phenylpyridine (ppyH) in 2-ethoxyethanol and water (1:1 ratio) resulted in the formation of chloro-bridged dimeric precursor [Pt2(μ-Cl)2(ppy)2], which on further reactions with various anionic one-, two- and three-atom ancillary ligands, having O/N/S donors, yielded mono- and bi-nuclear platinum(II) complexes. Platinum(III) complexes of composition [Pt2Cl2(μ-Epy)2(ppy)2] have been isolated with pyE− (E = O or S) ligands. These complexes have been characterized by elemental analysis, NMR (1H, 31P, 195Pt) and absorption spectroscopy. The complexes [Pt2(μ-N∩N)2(ppy)2] (N∩N = pyrazole and 3,5-dimethylpyrazole); [Pt(S∩S)(ppy)] (S∩S = ethylxanthate and diisopropyldithiophosphate); [Pt2Cl2(μ-Epy)2(ppy)2] (Epy = 2-pyridinol {Opy} and 2-mercaptopyridine {Spy}) and [PtCl(ppy)(PhNC(Me)NHPh)] have been structurally characterized by X-ray crystallography.