Intramolecular and reorientation dynamics of bis(triphenylphosphine)-3,6-di-tert-butyl-4,5-dimethoxy-o-semiquinone complex of copper(I) in viscous media

Two simultaneous dynamical processes are studied in solutions of varying viscosity by using the EPR linewidth data of a Cu(I) o-semiquinone complex with two triphenylphosphine ligands (PPh3), i.e. the overall reorientation (tumbling) of the complex and intramolecular exchange of the PPh3 ligands in the coordination sphere of the complex. It is shown that for fast motion the line broadening of the hyperfine components is due to both modulation of the anisotropic magnetic parameters by rotational diffusion and to modulation of the isotropic part of the 31P hyperfine interaction by intramolecular exchange. The intramolecular dynamics of the coordination sphere appears to be dependent on the solvent dynamics.