Heteroleptic Cu(I) complexes containing polypyridyl ligands and triphenylphosphine: Synthesis, structure, photophysical properties, DFT studies and applications in co-sensitized solar cells

Abstract

The synthesis and characterization by IR and 1H NMR spectroscopy, ESI-TOF+ mass spectrometry, cyclic voltammetry, single-crystal X-ray diffraction and thermal analysis of two novel heteroleptic Cu(I) complexes of general composition [CuI(L1)(PPh3)2]PF6·0.75CHCl3(1) and [CuI(L2)(PPh3)2]PF6·2.5CHCl3(2) PPh3=triphenylphosphine, L1=cis-(±)-2-(2,5-di(pyridin-2-yl)-4,5-dihydro-1H-imidazol-4-yl)pyridine and L2=2,4,6-tris(2-pyridyl)triazine) is reported. Both complexes show interesting photophysical properties, which were studied experimentally in solution and in the solid state by UV–Vis and fluorescence spectroscopy, and theoretically by using TD-DFT calculations. Additionally, their performance as co-sensitizer inDSSC was evaluated.