Synthesis, crystal structure, and charge-transfer complexes of TTF derivatives having two imidazole hydrogen-bonding units

New hydrogen-bond functionalized tetrathiafulvalene (TTF) derivatives (1 and 2) having two imidazole moieties, which are attached to TTF at the 2- and 4-positions in the imidazole ring, respectively, were synthesized. Electrochemical measurements indicated that the introduction of imidazole moieties at 2- or 4-positions slightly reduced or enhanced the electron-donating ability of TTF. In the crystal structure of 1, N–H⋯N hydrogen-bonds of the imidazole ring formed a two-dimensional sheet, and further π-stacks on the TTF skeleton built up a one-dimensional column. Mixing 1 with electron-acceptors afforded fully ionic charge-transfer complexes having a 1:1 donor–acceptor ratio, while complex formation of 2 with tetracyanoquinodimethane and p-chloranil yielded partial charge-transfer complexes showing semiconducting behaviors (room temperature conductivities=10−3–10−2 S cm−1).