Conformational dynamicity in a copper(II) coordination complex

Dalton Trans. 2023 Jun 20;52(24):8376-8383. doi: 10.1039/d3dt01213a.

Abstract

The geometries of copper coordination complexes are intricately related to their electron transfer capabilities, but the role of dynamics in these processes are not fully understood. We have previously reported CuCl(dpaOMe), a complex exhibiting conformational fluxionality in its CuI state and rigidity upon oxidation to CuII. Here, we report the synthesis and characterization of [CuCl(dpaSMe)]+/0, a complex exhibiting relative rigidity in its CuI state and structural dynamics upon oxidation to CuII. The dynamics of [CuCl(dpaSMe)]+ were characterized via X-ray diffraction, cyclic voltammetry, and EPR spectroscopy, where temperature-dependent interconversion between trigonal bipyramidal and square pyramidal geometries is observed. Coupling these solid and solution-state characterization data enabled assignment of the coordination geometries involved. Factors impacting these dynamics and their potential implications for electron transfer are discussed.