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

Abstract

This paper presents the syntheses, the 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 is 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 µβ 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 µβ value of the series of complexes, twice as high as that of the linear complex 9.

Exploration of Photophysical and Nonlinear Properties of Salicylaldehyde-Based Functionalized Materials: A Facile Synthetic and DFT Approach

“… 60 − 62 For explaining the structure–property of a molecule concerning the NLO characters, the concepts of polarizability and hyperpolarizability are helpful. 63 In addition to the NLO response, the properties of organic compounds offer a crucial role in the internal charge-transfer process and extended π-conjugated systems. 64 …”

Twisted One-Dimensional Charge Transfer and Related Y-Shaped Chromophores with a 4H-Pyranylidene Donor: Synthesis and Optical Properties

“…All voltammograms show three redox processes corresponding to one irreversible reduction peak (implicating the acceptor end) and two reversible oxidation steps, related to the two one-electron oxidations of the pyranylidene unit, as previously described for other chromophores with a similar design 13b and D−π–A platinum complexes with this donor end. 21 …”

A review of functional linear carbon chains (oligoynes, polyynes, cumulenes) and their applications as molecular wires in molecular electronics and optoelectronics

“…Gauthier et al reported a series of linear mono-and di-platinum complexes end-capped with diphenylpyranylidene (donor) and pentafluorophenyl (acceptor) moieties, including 45 which gave a low second-order NLO response in chloroform solution. 142 The length of the oligoyne linkers, and the number of platinum centres, did not significantly affect the NLO responses of these complexes. Their structural configuration plays a significant role, as a related V-shaped complex exhibited an NLO response twice as high as that of the linear counterpart.…”