Novel Electron Acceptors Bearing a Heteroquinonoid System. I. Synthesis and Conductive Complexes of 5,5'-Bis(dicyanomethylene)-5,5'-dihydro-Δ2,2'-bithiophene and Related Compounds

Article abstract of DOI:10.1246/bcsj.62.1539

Novel electron acceptors bearing a heteroquinonoid system, 5,5'-bis(dicyanomethylene)5,5'-dihydro-Δ^2,2'-bithiophene, its 3,3'-dichloro, 3,3'-dibromo, and 3,3',4,4'-tetrabromo derivatives, and 5,5''-bis(dicyanomethylene)-5,5''-dihydro-Δ^2,2':5',2''-tertiophene were synthesized by the action of tetracyanoethylene oxide or by Pd(0)-catalyzed substitution reactions with sodium dicyanomethanide on the corresponding α,α'-dihalogeno-heteroaromatics.They showed very small on-site Coulomb repulsion as expected, and afforded several highly conductive molecular complexes with electron donors such as hexamethylenetetratellurafulvalene.