Structural Distortions upon Oxidation in Heteroleptic [Cp2W(dmit)] Tungsten Dithiolene Complex: Combined Structural, Spectroscopic, and Magnetic Studies

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• 作者：Eric W. Reinheimer ; Iwona Olejniczak ; Andrzej Ł ; apiski ; Roman wietlik ; Olivier Jeannin ; Marc Fourmigu
• 刊名：Inorganic Chemistry
• 出版年：2010
• 出版时间：November 1, 2010
• 年：2010
• 卷：49
• 期：21
• 页码：9777-9787
• 全文大小：1053K
• 年卷期：v.49,no.21(November 1, 2010)
• ISSN：1520-510X

文摘

Four different cation radical salts are obtained upon electrocrystallization of [Cp₂W(dmit)] (dmit = 1,3-dithiole-2-thione-4,5-dithiolato) in the presence of the BF₄⁻, PF₆⁻, Br⁻, and [Au(CN)₂]⁻ anions. In these formally d¹ cations, the WS₂C₂ metallacycle is folded along the S···S hinge to different extents in the four salts, an illustration of the noninnocent character of the dithiolate ligand. Structural characteristics and the charge distribution on atoms, for neutral and ionized complexes with various folding angles, were calculated using DFT methods, together with the normal vibrational modes and theoretical Raman spectra. Raman spectra of neutral complex [Cp₂W(dmit)] and its salts formed with BF₄⁻, AsF₆⁻, PF₆⁻, Br⁻, and [Au(CN)₂]⁻ anions were measured using the red excitation (λ = 632.8 nm). A correlation between the folding angle of the metallacycle and the Raman spectroscopic properties is analyzed. The bands attributed to the C═C and C−S stretching modes shift toward higher and lower frequencies by about 0.3−0.4 cm⁻¹ deg⁻¹, respectively. The solid state structural and magnetic properties of the three salts are analyzed and compared with those of the corresponding molybdenum complexes. Temperature dependence of the magnetic susceptibility shows the presence of one-dimensional antiferromagnetic interactions in the BF₄⁻, PF₆⁻, and [Au(CN)₂]⁻ salts, while an antiferromagnetic ground state is identified in the Br⁻ salt below T_Nel = 7 K. Interactions are systematically weaker in the tungsten salts than in the isostructural molybdenum analogs, a consequence of the decreased spin density on the dithiolene ligand in the tungsten complexes.