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 1H, 13C, and 31P 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···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.