New Versatile Strategy towards Zinc(II)‐, Copper(II)‐ and Cobalt(II)‐Metallated Thiophene/Porphyrin‐Hybrids

A series of linear and lateral functionalised porphyrin-thiophene hybrid molecules was synthesised. Directly linked metal-free conjugates were synthesised by a successive bromination/cross-coupling sequence and transformed subsequently into zinc, copper and cobalt porphyrins. In the lateral connection mode, diverse strategies were necessary to obtain zinc and cobalt porphyrins, whereas the synthesis of the copper derivative followed an established route. All compounds were investigated by cyclic voltammetry. Within the series, the cobalt derivatives were exceptional because the cobalt porphyrin oxidation proved to be in competition with the thiophene oxidation. These results lead to a better understanding of the redox behaviour because such hybrid molecules consist of two independent redox centres. Furthermore, in the linear case, the absorption spectra clearly indicated an electronic influence of the thiophene periphery on the porphyrin, although conjugation is hindered strongly.