Synthesis and light-absorption characteristics of thiophene derivatives bearing ferrocenylthiocarbonyl groups

Thiophene-based dyes bearing two ferrocenylcarbonyl groups were obtained from a short synthesis involving direct arylations of the thiophene rings. A subsequent thionation of the carbonyl groups resulted in the formation of new thiophene-based dyes bearing two ferrocenylthiocarbonyl groups. These dyes absorb in a wide range of the visible spectrum due to their π-π∗ and d-π∗ transitions, and show a remarkable red-shift of the absorption band relative to their carbonyl analogues without increasing the molecular size.