Synthesis and properties of oxygen-, methylene-, and alkylene- bridged poly(dithiafulvene)s

Polymerization by cycloaddition between aldothioketene and its alkyne-thiol tautomer (derived in situ from a diyne) leading to the formation of dithia fulvene unit-linked polymers has been studied. Two aromatic diynes [bis(4-e thynyldiphenyl)methane (1a) and 4,4'-diethynyldiphenyl ether) (1b)] were us ed as starting materials with the aim of obtaining non-pi -conjugated methy lene- and oxygen-bridged aromatic poly(dithiafulvene)s. The poly(dithiafulv ene) derived from bis(4-ethynyldiphenyl)methane can be considered as an int eresting precursor to a small band-gap polymer having alternating aromatic and quinonoid moieties, Further, two aliphatic diynes [1,7-octadiyne (3a) a nd 1,9-decadiyne (3b)] were subjected to cycloaddition polymerization to ob tain aliphatic poly(dithiafulvene)s containing localized electron-rich dith iafulvene units. The polymers obtained were characterized by IR, H-1 NMR, g el permeation chromatography, and cyclic voltammetry. The electron-donating property of the polymers was evident from the charge-transfer (CT) complex formation with an electron acceptor 7,7,8,8-teracyanoquinodimethane. The C T complexes were characterized by IR, H-1 NMR, and ultraviolet-visible spec troscopies. (C) 2001 John Wiley & Sons, Inc.