The bulk electrochemical reduction of TCNQF2 (where TCNQF2 = 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane) in acetonitrile (0.1 M Bu4NPF6) in the presence of [Cu(CH3CN)4]+ leads to the electrocrystallisation of TCNQF2 1− and TCNQF2 2− materials, identified and proposed as CuITCNQF2 I− and CuI 2(TCNQF2 II−)(CH3CN)2, respectively. The existence of two forms of each solid was established by cyclic voltammetry. The low solubility of both CuITCNQF2 I− and CuI 2(TCNQF2 II−)(CH3CN)2 solids, facilitated detection of a solid-solid transformation in the presence of [Cu(CH3CN)4]+. CuITCNQF2 I− was synthesized chemically as a dark blue microcrystalline solid by reaction of TCNQF2 and CuI in CH3CN, as well as electrochemically. Electronic and vibrational spectroscopic methods confirmed the CuITCNQF2 I− product obtained by either method was structurally identical. Powder X-ray diffraction studies of CuITCNQF2 I− gave a closely related pattern to that for the thermodynamically stable CuITCNQI− phase II (a coordination polymer) rather than the kinetically favoured CuITCNQI− phase I. Scanning electron microscopy established the dominant morphology, derived from both electrocrystallized and chemically synthesised samples, were the same. The conductivity of CuITCNQF2 I− as a film on FTO glass was 6.0 × 10−6 S cm−1, which lies in the semiconducting range.
- Chemical synthesis of CuTCNQF
- Cyclic voltammetry
- Electrocrystallisation of CuTCNQF and Cu (TCNQF )(CHCN)
- Electronic and vibrational spectroscopy