Electrochemically Directed Synthesis of Cu2I(TCNQF4II鈥?/sup>)(MeCN)2 (TCNQF4 = 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane): Voltam

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• 作者：Thanh H. Le ; Ayman Nafady ; Nguyen T. Vo ; Robert W. Elliott ; Timothy A. Hudson ; Richard Robson ; Brendan F. Abrahams ; Lisandra L. Martin ; Alan M. Bond
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：March 17, 2014
• 年：2014
• 卷：53
• 期：6
• 页码：3230-3242
• 全文大小：751K
• 年卷期：v.53,no.6(March 17, 2014)
• ISSN：1520-510X

文摘

The new compound Cu₂^I(TCNQF₄^{II鈥?/sup>)(MeCN)₂ (TCNQF₄2鈥?/sup> = dianion of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) has been synthesized by electrochemically directed synthesis involving reduction of TCNQF₄ to TCNQF₄2鈥?/sup> in acetonitrile containing [Cu(MeCN)₄]+_(MeCN) and 0.1 M Bu₄NPF₆. In one scenario, TCNQF₄2鈥?/sup> is quantitatively formed by reductive electrolysis of TCNQF₄ followed by addition of [Cu(MeCN)₄]+ to form the Cu₂I(TCNQF₄II鈥?/sup>)(MeCN)₂ coordination polymer. In a second scenario, TCNQF₄ is reduced in situ at the electrode surface to TCNQF₄2鈥?/sup>, followed by reaction with the [Cu(MeCN)₄]+ present in the solution, to electrocrystallize Cu₂I(TCNQF₄II鈥?/sup>)(MeCN)₂. Two distinct phases of Cu₂I(TCNQF₄II鈥?/sup>)(MeCN)₂ are formed in this scenario; the kinetically favored form being rapidly converted to the thermodynamically favored Cu₂I(TCNQF₄II鈥?/sup>)(MeCN)₂. The postulated mechanism is supported by simulations. The known compound CuITCNQF₄I鈥?/sup> also has been isolated by one electron reduction of TCNQF₄ and reaction with [Cu(MeCN)₄]+. The solubility of both TCNQF₄2鈥?/sup>- and TCNQF₄鈥⑩€?/sup>-derived solids indicates that the higher solubility of CuITCNQF₄I鈥?/sup> prevents its precipitation, and thus Cu₂I(TCNQF₄II鈥?/sup>)(MeCN)₂ is formed. UV鈥搗isible and vibrational spectroscopies were used to characterize the materials. Cu₂I(TCNQF₄II鈥?/sup>)(MeCN)₂ can be photochemically transformed to CuITCNQF₄I鈥?/sup> and Cu0. Scanning electron microscopy images reveal that CuITCNQF₄I鈥?/sup> and Cu₂I(TCNQF₄II鈥?/sup>)(MeCN)₂ are electrocrystallized with distinctly different morphologies. Thermogravimetric and elemental analysis data confirm the presence of CH₃CN, and single-crystal X-ray diffraction data for the Cu₂I(TCNQF₄II鈭?/sup>)(EtCN)₂ analogue shows that this compound is structurally related to Cu₂I(TCNQF₄II鈥?/sup>)(MeCN)₂.}