New Pt^IIdiimine–dithiolate complexes containing a 1,2-dithiolate-1,2-closo-dicarbadodecarborane: an experimental and theoretical investigation

Abstract

Five new [Pt(N^N)(dtoc)] complexes (1-5; N^N = diimine: 2,2'-bipyridine and its 4,4'-alkyl/aryl-substituted derivatives or 1,10-phenanthroline; dtoc(2-) = 1,2-dithiolate-1,2-closo-dicarbadodecaborane) have been synthesized and characterized by spectroscopic and electrochemical methods, and by means of X-ray diffraction in the case of complexes 1 and 4. Hybrid DFT and time-dependent (TD) DFT calculations were performed on complexes 1-5 and the previously reported complex [Pt(Ph2phen)(dtoc)] (6; Ph2phen = 4,7-diphenyl-1,10-phenanthroline) both in the gas phase and in the presence of several solvents (CH2Cl2, CHCl3, CH3CN, acetone, THF, DMF, DMSO, and toluene) to gain an insight into the electronic structure of the complexes and explain their experimental features. Theoretical calculations allowed for the determination of structure-property relationships within the series of the six complexes considered, and the prediction of their second order nonlinear optical (SONLO) properties by evaluating their first static hyperpolarizabilities (βtot).

[AuIII(N^N)Br2](PF6): A Class of Antibacterial and Antibiofilm Complexes (N^N = 2,2′-Bipyridine and 1,10-Phenanthroline Derivatives)

“…The mechanism of action of Au III compounds is still a matter of debate and is under investigation . Some insights into the biological activity of the title compounds could be inferred from DFT calculations (Tables S4–S26 and Figures S9 and S10), carried out on the complex cations of compounds 1 – 10 based on previous studies on related systems. ,− Analysis of the eigenvalues of Kohn–Sham (KS) frontier molecular orbitals at the optimized geometry (Table S25) shows that the complex cations of compounds 1 , 4 , 6 , and 9 feature the most stable lowest unoccupied molecular orbitals (KS-LUMOs), which are antibonding in nature with respect to the gold–halogen bonds (Figure S10). Calculated KS-LUMO eigenvalues (ε LUMO ; Tables and S25) can be related to the experimental reduction potentials E pc 1 (Figure ), defining two groups of compounds: while the complex cations of compounds 3 , 7 , and 8 show the highest ε LUMO values, resulting in less positive E pc 1 values, the remaining complexes feature lower ε LUMO values, being therefore more prone to reduction.…”

“…The computational investigation on the complex cations of 1 – 10 was carried out at the DFT level by adopting the Gaussian 16 suite of programs. Following the results of previously reported calculations on related systems, ,− the PBE0 hybrid functional was adopted, along with the full-electron split valence basis sets (BSs) def2-SVP for light atomic species (C, H, N, Cl, and Br) and CRENBL basis sets with RECPs , for heavier gold species. BS data were extracted from the EMSL BS Library .…”

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.…”

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)

“…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 .…”