A New Way to both Oligothiophene-Spaced Bimetallic Complexes and Functionalized Oligothiophenes

Mono- and binuclear oligothiophene rhodium complexes are obtained by single and double C-S bond cleavage of 2,2¢:5¢,2¢¢:5¢¢,2¢¢¢-quaterthiophene, respectively. S-Methylation of the C-S insertion products, followed by carbonylation of the resulting thioether complexes give the functionalized oligothiophenes 5-[1-(methylthio)- buta-1,3-diene]-2,2¢:5¢,2¢¢-terthiophene and 5,5¢-bis[1- (methylthio)-buta-1,3-diene]-2,2¢-bithiophene. The rhodium metal is recovered as a bis(carbonyl) complex.