Conformational dynamicity in a copper(ii) coordination complex

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(dpa^OMe), a complex exhibiting conformational fluxionality in its Cu^I state and rigidity upon oxidation to Cu^II. Here, we report the synthesis and characterization of [CuCl(dpa^SMe)]^+/0, a complex exhibiting relative rigidity in its Cu^I state and structural dynamics upon oxidation to Cu^II. The dynamics of [CuCl(dpa^SMe)]⁺ 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.