Abstract

Two series of bis[1,2-bis(4-n-alkylphenyl)ethane-1,2-dithiolene]nickel, C_n–Ni (n = 1–12), and bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel, C_nO–Ni(n = 1–12, 14, 16, 18), have been synthesized. Their mesomorphism, thermochromism, supramolecular structures and π-acceptor property have been investigated by using different scanning calorimetry, polarizing microscopy, temperature-dependent X-ray diffraction technique, electronic spectroscopy and cyclic voltammetry. From the X-ray diffraction and electronic spectral results, it was established that the C_nO–Ni complexes for n≤10 exhibit two differently colored discotic lamellar (D_L) mesophases whereas none of the C_n–Ni complexes has a mesophase, and that the thermochromism (brown → green) is attributable to a slow transformation from the Ni–Ni bonded dimers to the Ni–S bonded dimers.