UV–vis
absorption and magnetic circular dichroism (MCD)
spectra of octakis thioethyl “free base” porphyrazine
H
2
OESPz and its metal complexes MOESPz (M = Mg, Zn, Ni,
Pd, Cu), as well as of [MnOESPz(SH)] were recorded. In the last case,
MCD proved to have quite good sensitivity to the coordination of this
complex with 1-methylimidazole (1-mim) in benzene. Time-dependent
density functional theory (TDDFT) calculations were carried out for
the considered porphyrazine complexes and showed good performance
on comparing with MCD and UV–vis experimental spectra, even
in the open-shell Cu and Mn cases. Calculations accounted for the
red shift observed in the thioalkyl compounds and allowed us to reveal
the role of sulfur atoms in spectroscopically relevant molecular orbitals
and to highlight the importance of the conformations of the thioethyl
external groups. Calculated MCD spectra of [MnOESPz(SH)] confirm the
Mn(III) → Mn(II) redox process, which leads to the [Mn(OESPz)(1-mim)
2
] species, and the relevance of the spin state for MCD is
revealed.