B-Tetrasubstituted meso-tetra(4'-n-butylphenyl)porphyrins and their metal complexes: Synthesis and structural properties

A new family of ß-tetrasubstituted porphyrins, 2,3,12,13-tetra[ phenylethynyl (PE)/4-methoxyphenyl (4''-CH3OPh)/4- carboxy methylesterphenyl (4''-CH3CO2Ph)]-5,10,15,20- tetrakis(4'-n-butylphenyl)porphyrin, H2T(4'-BuPh)P(R)4 and their metal (CoII, CuII and ZnII) complexes were synthesized using H2T(4'-BuPh)PBr4 as the precursor. These porphyrins show red-shifted absorption bands and follow the nature of the ß-pyrrole substituent, R: PE < Br < 4''-CO2CH3Ph 4''- OCH3Ph. Crystal structures of MT(4'-BuPh)P(PE)4 (M = 2H, CoII, CuII and ZnII) derivatives were determined by singlecrystal XRD and they are isomorphous. The normal coordinate structure decomposition analysis of these structures reveal a slight wave-type of distortion of the macrocycle. Electrochemical redox properties of these derivatives show an anodic shift in potentials relative to their metallotetraphenylporphyrins (MTPPs), and this has been ascribed mainly to the electronic effect of the substituents.