A Ge-bridged methylviologen derivative (
GMV2+2I
−) was synthesized by dimethylation of dipyridinogermole (
DPyG). Viologen
GMV2+2I
− showed a UV absorption band at 270 nm, similar to
DPyG and longer than the corresponding bridge-free methylviologen (
MV2+2I
−). Electrochemical properties of
GMV2+2I
− were investigated with respect to cyclic voltammograms, showing highly reversible two step reduction, like
MV2+2I
−. Interestingly,
GMV2+2I
− exhibited enhanced electron-affinity with higher 1
st reduction potential by approximately 0.08 V than that of
MV2+2I
−, likely due to the effects Ge-bridge lowering the LUMO energy level. However, the 2
nd potential was little affected by the bridge. Clear electrochromic colour changes based on the reversible electrochemical interconversion among
GMV2+/
GMV+/
GMV were observed in acetonitrile. Monomethylated
DPyG (
GMV′+I
−) was also prepared, whose properties are discussed in comparison with those of
DPyG and
GMV2+2I
−.
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