Self-Complexation of a Poly-Conjugated Donor Molecule with a Cyclic Acceptor

Abstract

Abstract The mixing of 2-benzylidene-4-phenyl-1,3-dithiole and cyclobis[4,4′-bipyridinium-1,1′-diyl-1,4-phenylenebis-(methylene)] as a cyclic acceptor in DMSO produced a green-brown solution, which showed a charge-transfer (CT) absorption band with a peak at 616 nm. The 1H NMR spectrum of the dithiole, after adding the cyclic acceptor in DMSO-d6, showed upfield shifts of the peaks for the dithiafulvene moiety. These facts indicated that an insertion of the dithiole into the cyclic acceptor by a CT interaction led to the formation of a pseudorotaxane. The self-assembly of π-conjugated dithiafulvene polymers and the cyclic acceptor by a CT interaction gave pseudopolyrotaxanes in DMSO. The UV-vis and 1H NMR spectra of the pseudopolyrotaxanes suggest that the incorporation ratio of the cyclic acceptors into the polymers depends on the molecular weights of the polymers. The polymers with lower molecular weights seem to be more favorable for polyrotaxane formation. After self-complexation of the polymer with the cyclic acceptor, an anodic shift of the oxidation potential of the dithiafulvene unit was observed in the cyclic voltammogram. In addition, the effective CT interaction between the dithiafulvene unit and the cyclic acceptor afforded a high conductivity of the pseudopolyrotaxane.