Synthesis, Structure and Properties of Donor-acceptor-type [4]Dendralenes

[4]Dendralene and its analogs possessing both strongly electron-donating 1,3-dithiol-2-ylidenes and electron-accepting dicyanomethylidenes (2b-4b) were successfully synthesized. X-ray structure analysis revealed that 2b adopts a nonplanar structure, in which half units of 2b are significantly inclined to each other. Cyclic voltammograms of 2b-4b consisted of one pair of two-electron oxidation waves and one pair of one-electron reduction waves.