Synthesis, Structural Characterization, and Photophysical Study of Luminescent Face-to-Face Dinuclear Platinum(II) Alkynyl Phosphine Complexes and Their Tetranuclear Mixed-Metal Platinum(II)-Silver(I) and -Copper(I) Complexes

A series of luminescent face-to-face dinuclear platinum(II) alkynyl phosphine complexes with trimethoxyphenyl and carbazole moieties have been synthesized by phosphine exchange reaction. Two mixed-metal tetranuclear platinum(II)-silver(I) and -copper(I) complexes have also been synthesized. The complexes are well characterized by H-1, C-13, and P-31 NMR spectroscopy; positive ion FAB mass spectrometry, IR spectroscopy, and elemental analysis. Most of them have been structurally characterized by X-ray crystallography. All the complexes are found to show emissive behavior. Correlations of the emissive property with the Pt center dot center dot center dot Pt distance, the nature of the alkynyl and bridging phosphine ligands, and the nature of the encapsulated metal ions on the alkynyl ligands have been made. TDDFT/CPCM calculations have been performed to provide further insight into the origin of the absorption and emission properties.