5,15-bis(4′-methoxyphenyl)-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphin axial complexes of rhenium: Synthesis and reactions in protic solvents

Abstract

The spectral (UV–Vis, IR, and NMR ¹H) properties and the state of oxorhenium(V) complexes with 5,15-bis(4′-methoxyphenyl)-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphin H₂P (O=Re(X)P) in protic solvents have been studied depending on the axial trans-ligand X^– (X = Cl, OPh, or OH). The O=Re(Cl)P, O=Re(OPh)P, and O=Re(OH)P in AcOH and CF3COOH are subjected to reaction of substitution their axial ligands with solvent molecules or anions, while remaining stable to the dissociation of M–N bonds and to oxidation both to the macrocyclic ligand and to the central metal cation. Quantitative parameters of the coordination of molecular oxygen by O=Re(Cl)P in 17.4–18.2 M H₂SO₄ to form O=Re(O₂)P⁺ · Cl^– have been obtained, these parameters being independent of the initial H₂SO₄ concentration. The character of peripheral functional substituents in H₂P has been shown to be responsible for the stability of the studied oxo complexes to chemical oxidation in aerated acids.