On the Role of Chalcogen Donor Atoms in Diimine‐Dichalcogenolate Pt^II SONLO Chromophores: Is It Worth Replacing Sulfur with Selenium?

Abstract

Two new diimine‐diselenolate PtII chromophores [Pt(bipy)(Me‐dset)] (1) and [Pt(phen)(Me‐dset)] (2) (Me‐dset2– = N‐methyl‐2‐thioxothiazoline‐4,5‐diselenolate) were synthesized and characterized. The effect of replacing sulfur with selenium was investigated by comparing the UV/Vis spectroscopic and electrochemical properties of 1 and 2 with those of the corresponding sulfur analogues, [Pt(bipy)(Me‐dmet)] (3) and [Pt(phen)(Me‐dmet)] (4), with a particular focus on their linear and nonlinear optical properties.

Diradical Character of Neutral Heteroleptic Bis(1,2-dithiolene) Metal Complexes: Case Study of [Pd(Me2timdt)(mnt)] (Me2timdt = 1,3-Dimethyl-2,4,5-trithioxoimidazolidine; mnt2– = 1,2-Dicyano-1,2-ethylenedithiolate)

“…During the past few decades, DFT calculations have been used successfully to investigate the structural features and the redox and spectroscopic properties of homoleptic and heteroleptic complexes containing 1,2-dithiolene ligands. − ,,,,,, DFT calculations were applied here on Me 2 timdt q – , mnt q – ( q = 0, 1, 2), and related compounds and the relevant neutral, monoanionic, and dianionic homoleptic and heteroleptic Pd complexes.…”

“…In these complexes, most often containing a Ni II ion, ,− the most electron withdrawing “pull” ligand L tends to assume the ene-1,2-dithiolate form L 2– (d in Scheme ), with shorter C–C and longer C–S bond distances, while the other “push” ligand ( L′ ) assumes a 1,2-dithione form (b in Scheme ), with longer C–C and shorter C–S distances, so that the complex is generally described as the dithione-dithiolato species [M II ( L 2– )­( L′ )]. The electronic structure of these complexes in their neutral state, reminiscent of that of diimine-dichalcogenolato complexes, − shows the HOMO featuring a larger contribution from the “pull” ligand L 2– and the LUMO from the “push” ligand L′ . The peculiar visible–near-IR (vis–NIR) electron transition of the neutral species assumes a partial charge-transfer (CT) character from the 1,2-dithiolato L 2– ligand to the 1,2-dithione L′ (LL′CT), testified by a remarkable negative solvatochromism of the resulting absorption band .…”

Photoconducting Devices with Response in the Visible–Near-Infrared Region Based on Neutral Ni Complexes of Aryl-1,2-dithiolene Ligands

“…Aimed at elucidating both the redox and optical properties of 1 x – – 2 x – , as well as their electronic structure and cis / trans isomerism, DFT calculations were carried out on the title bis­(1,2-dithiolene) Ni neutral and monoanionic complexes. In agreement with previously established approaches on related systems, ,,− the mPW1PW hybrid functional was used in combination with full-electron split-valence basis sets, including polarization functions from Schäfer, Horn, and Ahlrichs in the Weigend formulation (def2-SVP) for light atomic species (C, H, S) and the LanL08­(d) BS with effective core potentials for nickel.…”

High Photothermal Activity within Neutral Nickel Dithiolene Complexes Derived from Imidazolium-Based Ionic Liquids

“…Seeking a more efficient alternative, we adapted the metalation/chalcogenation procedure used earlier with 1,3-dithiole-2-thione or 1,3-thiazoline-2-thione . The successive reaction of these heterocycles with lithium diisopropylamine (LDA) and elemental sulfur (or selenium) is known indeed to afford the corresponding dithiolate (or diselenolate) derivatives in good yield.…”