A New Synthetic Approach to Thiophene-Nickel(II)porphyrin Hybrid Molecules and their Electrochemical and Computational Investigation

New synthetic strategies for thiophene-nickel(II)porphyrin hybrid molecules are described. Three principles-linear direct, linear spacer and lateral spacer connectivities-were realised and compared with respect to their electrochemical behaviour. Computational investigations by DFT methods confirm experimental data and explain cylic voltammetric oxidations. For the linear direct connectivity, the number of thiophene units per substituted position must be at least two, since the porphyrin core acts as conjugation breaker and hinders the formation of higher oligomers. Alternatively an ethynylene spacer can be introduced to increase conjugation and to optimise the conducting properties. The lateral spacer connection mode proved to be best suited to the electrochemical formation of hybrid compounds.