Molecular and Electronic Structures of Oxo-bis(benzene-1,2-dithiolato)chromate(V) Monoanions. A Combined Experimental and Density Functional Study

• Published in: Inorganic chemistry Vol. 45; no. 9; pp. 3499 - 3509
• Main Authors: Kapre, Ruta, Ray, Kallol, Sylvestre, Isabelle, Weyhermüller, Thomas, DeBeer George, Serena, Neese, Frank, Wieghardt, Karl
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01.05.2006
• Subjects: Anions; Benzene Derivatives; Chromates - chemical synthesis; Chromates - chemistry; Crystallography, X-Ray; Electron Spin Resonance Spectroscopy; Electrons; Magnetics; Molecular Structure; Spectrum Analysis; Temperature; Toluene - analogs & derivatives
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic051844s

Two oxo-bis(benzene-1,2-dithiolato)chromate(V) complexes, namely, [CrO(LBu)2]1- and [CrO(LMe)2]1-, have been synthesized and studied by UV−vis, EPR, magnetic circular dichroism (MCD), and X-ray absorption spectroscopy and by X-ray crystallography; their electro- and magnetochemistries are reported. H2LBu represents the pro-ligand 3,5-di-tert-butylbenzene-1,2-dithiol, and H2LMe is the corresponding 4-methyl-benzene-1,2-dithiol. A structural feature of interest for both the complexes is the folding of the dithiolate ligands about the S−S vector providing C s symmetry to the complexes. Geometry optimizations using all-electron density functional theory with scalar relativistic corrections at the second-order Douglas−Kroll−Hess (DKH2) and zeroth-order regular approximation (ZORA) levels result in excellent agreement with the experimentally determined structures and electronic and S K-edge X-ray absorption spectra. From DFT calculations, the C s instead of C 2 v symmetry for the complexes is attributed to the strong S(3p) → Cr(3d x 2 - y 2 ) π-donation in C s geometry providing additional stability to the complexes.