Investigations on Water-Soluble Copper Complexes with the Sterically Demanding Triazacyclononane Derivative (tBu)2(nPrSO3)Htacn

Abstract

Related to environmentally friendly productions in the industry, the synthesis of catalysts with designed ligands for solubility in protic solvents and reactivity under mild conditions becomes important. Thus, copper complexes were synthesized with a ligand system that was designed for better solubility in protic solvents. The reactivity of copper complexes with hydrogen peroxide under ambient conditions was investigated in water and in methanol. The formation of a μ-η² : η²-peroxide copper complex with a stability of a few minutes was observed in contrast to most related complexes reported in the literature. A kinetic analysis was performed, leading to activation parameters of ΔH^≠: 66±4 kJ ⋅ mol⁻¹ and ΔS^≠: −5±12 J ⋅ K⁻¹ ⋅ mol⁻¹ (in water), a strong indication of an interchange mechanism.