Electrochemically Directed Synthesis of Cu₂^I(TCNQF₄^II–)(MeCN)₂ (TCNQF₄ = 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane): Voltammetry, Simulations, Bulk Electrolysis, Spectroscopy, Photoactivity, and X‑ray Crystal Structure of

The new compound Cu2I(TCNQF4II–)­(MeCN)2 (TCNQF42– = 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– in acetonitrile containing [Cu­(MeCN)4]+(MeCN) and 0.1 M Bu4NPF6. In one scenario, TCNQF42– is quantitatively formed by reductive electrolysis of TCNQF4 followed by addition of [Cu­(MeCN)4]+ to form the Cu2I(TCNQF4II–)­(MeCN)2 coordination polymer. In a second scenario, TCNQF4 is reduced in situ at the electrode surface to TCNQF42–, followed by reaction with the [Cu­(MeCN)4]+ present in the solution, to electrocrystallize Cu2I(TCNQF4II–)­(MeCN)2. Two distinct phases of Cu2I(TCNQF4II–)­(MeCN)2 are formed in this scenario; the kinetically favored form being rapidly converted to the thermodynamically favored Cu2I(TCNQF4II–)­(MeCN)2. The postulated mechanism is supported by simulations. The known compound CuITCNQF4I– also has been isolated by one electron reduction of TCNQF4 and reaction with [Cu­(MeCN)4]+. The solubility of both TCNQF42–- and TCNQF4•–-derived solids indicates that the higher solubility of CuITCNQF4I– prevents its precipitation, and thus Cu2I(TCNQF4II–)­(MeCN)2 is formed. UV–visible and vibrational spectroscopies were used to characterize the materials. Cu2I(TCNQF4II–)­(MeCN)2 can be photochemically transformed to CuITCNQF4I– and Cu0. Scanning electron microscopy images reveal that CuITCNQF4I– and Cu2I(TCNQF4II–)­(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−)­(EtCN)2 analogue shows that this compound is structurally related to Cu2I(TCNQF4II–)­(MeCN)2.