Spectral Luminescent Properties of Metal Chelates on the Basis of Aminomethylene Derivatives of 5-Pyrazolethione

The absorption and luminescence of bisbidentate complexes of aminomethylene derivatives of 5-pyrazolethione with Zn²⁺, Cd²⁺, Hg²⁺, and Pb²⁺ in dilute solutions in hydrocarbons and 95% ethanol are determined by the structure of the ligand in the complexes. In the Zn²⁺, Cd²⁺, and Hg²⁺ complexes, N···M coordination is realized, whereas in the Pb²⁺ complexes, S··· M. In the Zn-Cd-Hg series, a heavy-atom effect is revealed, which stimulates exclusively radiationless transitions involving the S ₁ and T states.