Bis(Thiosemicarbazone) and Other Nitrogen and Sulfur Ligated Complexes of Copper(II)

Abstract

We have measured the electron paramagnetic resonance and optical absorption properties of several complexes of copper(II) in which the ligands of the copper atom are two nitrogen and two sulfur atoms. Chelate structures varying from two saturated rings to a three‐condensed‐ring pseudoaromatic system have been explained. The effect of different degrees of protonation of the chelate rings has been investigated. The experiments show that, apart from varying the magnitude of the nitrogen superhyperfine interaction, these variables do not significantly affect the magnetic properties of the Cu(II), except for one case where protonation promotes dimerization. The relevance of these chelate structures to the unique Cu(II) sites in the copper‐containing proteins is discussed.