Luminescence properties of some monomeric and dimeric cycloplatinated(ii) complexes containing biphosphine ligands.

The starting complexes [PtCl(C^N)(dmso)], in which C^N is either ppy = 2-phenylpyridinate, , or bhq = 7,8-benzo[h]quinolinate, , were prepared by a known method using the reaction of [PtCl2(dmso)2] with ppyH or bhqH, respectively, in toluene under reflux conditions. The reaction of [PtCl(C^N)(dmso)], or , with 1 equiv. of a number of biphosphine ligands, P^P, gave the cationic monomeric complexes [Pt(ppy)(P^P)]Cl, for which P^P is either 1,2-bis(diphenylphosphino)ethane (dppe), , 1,3-bis(diphenylphosphino)propane (dppp), , or bis(diphenylphosphino)methane (dppm), ; the bhq analogous complex [Pt(bhq)(dppe)]Cl, , was prepared similarly. However, the complex [Pt(ppy)(dfppe)]Cl, , in which dfppe is 1,2-bis(dipentafluorophenylphosphino)ethane, was prepared by the reaction of with excess amount of dfppe. When each of the starting complexes [PtCl(C^N)(dmso)], or , were reacted with 0.5 equiv. of any of the P^P ligands, the dimeric complexes [Pt2Cl2(ppy)2(μ-P^P)], , or [Pt2Cl2(bhq)2(μ-P^P)], , were formed. The complexes were fully characterized using multinuclear ((1)H and (31)P) NMR spectroscopy and elemental analysis. The structures of typical complexes , , , and were also confirmed by X-ray crystallography. The effect of ligands on the luminescent properties of the complexes was investigated and DFT calculations were performed to confirm the assignments.