Synthesis of some new tetra-aryl porphyrins for studies in solar energy conversion. Part 2. Asymmetric porphyrins

Abstract

The synthesis and characterisation of some asymmetrical meso-substituted porphyrins, for studies in solar energy conversion, are described. Isomeric porphyrins (5) and (6) could be cleanly separated and distinguished by the number of ¹³C n.m.r. resonances for the pyrrole α-carbon atoms. Similarly, ¹³C and ¹H n.m.r. spectrometry was used to characterise a porphyrin with n-pentadecyl and benzoqyinone meso-substituents, using the number of pyrrole α-carbon and β-hydrogen resonances. Thin films of porphyrin (11) coated onto glass slides fluoresced, indicating little or no concentration quenching in the coat.