A survey on (azido)-, (triazolato)- and (tetrazolato) metal (III or IV) porphyrin complexes

This mini-review describes the work of our group in collaboration with Karl M. Kadish on nitrogen-bonded (tetrazolato) and (triazolato) metal(III or IV) porphyrin complexes obtained through the cycloaddition reaction between metalloporphyrin azides and various dipolarophiles such as nitriles or alkynes. The tetrazole or triazole linkage depends on the nature of the aryl or alkyl groups attached to the axial ligand. Different analytical techniques have been employed to determine the structure of these complexes, including electrochemistry, which helps elucidate the reaction mechanism that proceeds through an intermediate three-centered activated complex.