Formation of Tc(III)-EDTA complex

Abstract

Tc(III)-EDTA complex has been synthesized by the ligand substitution reaction of hexakis-(thiourea) technetium(III) ion with EDTA. The complex exhibits absorption maxima at 368 and 470 nm. The formation reaction proceeds predominantly as follows:

$$Tc(tu)_6^{3 + } + H_2 EDTA^{2 - } \to Tc(III) - EDTA$$

The rate constant k₂ was determined to be (2.1±0.2)×10⁻² M⁻¹.s⁻¹ at 25°C.