Mono- and Diplatinum Polyynediyl Complexes as Potential Push-Pull Chromophores: Synthesis, Characterization, TD-DFT Modeling, and Photophysical and NLO Properties

This paper presents the syntheses and photophysical and the electrochemical characterizations of four new mono- and diplatinum polyynediyl complex chromophores end-capped with diphenylpyranylidene and pentafluorophenyl moieties. The nonlinear optical properties (NLO) of these compounds are investigated using the electric-field-induced second harmonic generation (EFISH) technique, and their experimental optical properties are confirmed by time-dependent density functional theory (TD-DFT) with a range-separated hybrid. All complexes show positive mu beta values. While the inductive electron-withdrawing pentafluorophenyl ligand, the length of the polyyne linkers, and the number of platinum centers do not seem to significantly affect the NLO responses of these complexes, their structural configuration plays a significant role, as shown by the V-shaped complex 10 exhibiting the highest mu beta value of the series of complexes, twice as high as that of the linear complex 9.