One Electron Reduced Square Planar Bis(benzene-1,2-dithiolato) Copper Dianionic Complex and Redox Switch by O2/HO鈥?/sup>

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• 作者：Biplab K. Maiti ; Luisa B. Maia ; Kuntal Pal ; Bholanath Pakhira ; Teresa Avil茅s ; Isabel Moura ; Sofia R. Pauleta ; Jos茅 L. Nu帽ez ; Alberto C. Rizzi ; Carlos D. Brondino ; Sabyasachi Sarkar ; Jos茅 J. G. Moura
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：December 15, 2014
• 年：2014
• 卷：53
• 期：24
• 页码：12799-12808
• 全文大小：590K
• ISSN：1520-510X

文摘

The complex [Ph₄P]₂[Cu(bdt)₂] (1^red) was synthesized by the reaction of [Ph₄P]₂[S₂MoS₂CuCl] with H₂bdt (bdt = benzene-1,2-dithiolate) in basic medium. 1^red is highly susceptible toward dioxygen, affording the one electron oxidized diamagnetic compound [Ph₄P][Cu(bdt)₂] (1^ox). The interconversion between these two oxidation states can be switched by addition of O₂ or base (Et₄NOH = tetraethylammonium hydroxide), as demonstrated by cyclic voltammetry and UV鈥搗isible and EPR spectroscopies. Thiomolybdates, in free or complex forms with copper ions, play an important role in the stability of 1^red during its synthesis, since in its absence, 1^ox is isolated. Both 1^red and 1^ox were structurally characterized by X-ray crystallography. EPR experiments showed that 1^red is a Cu(II)鈥搒ulfur complex and revealed strong covalency on the copper鈥搒ulfur bonds. DFT calculations confirmed the spin density delocalization over the four sulfur atoms (76%) and copper (24%) atom, suggesting that 1^red has a 鈥渢hiyl radical character鈥? Time dependent DFT calculations identified such ligand to ligand charge transfer transitions. Accordingly, 1^red is better described by the two isoelectronic structures [Cu^I(bdt₂, 4S^3鈥?*)]^{2鈥?/sup> 鈫?[CuII(bdt₂, 4S4鈥?/sup>)]2鈥?/sup>. On thermodynamic grounds, oxidation of 1red (doublet state) leads to 1ox singlet state, [CuIII(bdt₂, 4S4鈥?/sup>)]1鈥?/sup>.}