Cationic platinum(II) complexes bearing Aryl-BIAN ligands : synthesis, structural and optoelectronic characterization

Abstract

Five cationic platinum(II) complexes bearing a 2-(3’-substituted-aryl)pyridine cyclometalating ligand (C^N) and a neutral Ar-BIAN ligand have been synthesized: [Pt(ppy)(PhBIAN)]PF6, 1, [Pt(3Fppy)(PhBIAN)]PF6, 2, [Pt(3MeOppy)(PhBIAN)]PF6, 3, [Pt(3MeOppy)( 4-FPhBIAN)]PF6, 4, [Pt(ppy)(4-MeOPhBIAN)]PF6, 5. All complexes have been characterized by NMR spectroscopy and mass spectrometry. Complexes 2 and 3 have been characterized by X-Ray crystallography. Structure-property relationships were established from UV-Visible spectroscopy and cyclic voltammetry studies. Interestingly, we found that when both the C^N and the Aryl-BIAN ligands contained electron-donating MeO groups the absorption spectrum for the platinum complex extended out to 650 nm. The electrochemical studies of these complexes established that they are electronically compatible dye-molecules for dye-sensitized solar cells.