Magnetichyphen;Resonance Studies on Copper(II) Complex Ions in Solution. II. Oxygenminus;17 NMR and Copper(II) EPR in Aqueous Solutions of Cu(en)(H2O)42+and Cu(en)2(H2O)22+

摘要

The temperature dependences of the17O NMR and Cu(II) EPR spectra of solutions of the ethylenedihyphen;amine complex ions Cu(en)(H2O)42+and Cu(en)2(H2O)22+are analyzed in terms of an octahedrally coordinated structure with tetragonal distortion. It is found that the17O NMR spectrum is broadened and shifted by Cu(en)(H2O)42+through scalar hyperfine interaction with the copper (II) electron spin, while Cu(en)2(H2O)22+has no effect. The Cu(II) EPR spectra of both species have linewidth contributions from spinmdash;rotational relaxation, from tumbling of an ionic complex having an anisotropicgfactor and an anisotropic hyperfine coupling constant, and from63Cu isotropic hyperfine and14N isotropic extrahyperfine splitting. The results are discussed in terms of the antibonding molecularhyphen;orbital model for theB1gground state of Cu(II) and compared with the previous study on Cu(H2O)62+.