Bis(3-pyridyl)-substituted TTF as a Donor–Acceptor System: Synthesis, Crystal Structures, and Properties

A triad compound, bis(3-py)-substituted TTF (L2) (py = pyridine; TTF = tetrathiafulvalene) was synthesized and characterized. The absorption spectroscopy and electrochemical properties of L2, and its protonated products were studied. The results of electronic absorption spectroscopy and cyclic voltammetry confirm that the mono- and di-protonated species of L2 are successively generated with the protonation processes. A unique N+H⋯N hydrogen-bonded (H-bonded) trimer motif based on the L2 was constructed in the protonated complex. This result is very different from that of an analog triad compound, bis(4-py)-substituted TTF (L1).