Synthesis, spectroscopic and electrochemical characterization of different isomer types in tetrazolatoindium(III) porphyrins

Abstract

The synthesis and characterization of nine indium(III) porphyrin complexes with three types of σ-bonded tetrazolato axial ligands are reported. The investigated compounds In(por)(N₄CR) where R = CMe₃, CHCH₂ or CHCHCN and por = the dianion of 2,3,7,8,12,13,17,18-octaethylporphyrin (oep), 5,10,15,20-tetraphenylporphyrin (tpp) or 5,10,15,20-tetra-p-trifluoromethylphenylporphyrin (tfpp) were characterized by UV/VIS, IR and ¹H NMR spectroscopy as well as by electrochemistry. The N₄CR ligand of a given M(por)(N₄CR) complex can have the R group attached to either the 4 or 5 position of the tetrazolato ring and this is discussed in the present study with respect to the steric and electronic effects of the axial and equatorial ligands.