NUCLEAR QUADRUPOLE COUPLING IN THE TRIS (TRIMETHYLPHOSPHINESULFIDE )-COPPER (I) ION

Partial support of this research by the National Science Foundation is acknowledged.Author Institution: Department of Chemistry, Virginia Polytechnic Institute and State University BlacksburgThe crystal structure determination of $Cu[(CH_{3})_{3}PS]_{3}[ClO_{4}]$ and $Cu[(CH_{3})_{3}PS]_{3}[BF_{4}]$ have shown that the ligands from an almost perfect trigonal planar configuration about the copper atom and that the anion is quite far removed from the cation site. These two conditions make this cation system ideal as a model compound for the study of copper nuclear quadrupole coupling and for the comparison of experimental and calculated electric field gradient parameters. Both compounds were investigated using a conventional superregenerative spectrometer and the following resonances were observed. \begin {tabular}{cccc} Compound &$v(^{63}Cu)$(MHz) &$v(^{65}Cu)$(MHz) &$v(^{63}Cu)/v(^{65}Cu)$\\ $Cu[(CH_{3})_{3}PS]_{3}[C10_{4}]$ &24 815.1 &12 968.2 &1.0804\\ $Cu[(CH_{3})_{3}PS]_{3}[BF_{4}]$ &24 837.8 &22 985.6 &1.0806\\ \end {tabular} The nuclear quadrupole coupling constant at the copper atom site has been calculated by using an extended Huckel molecular orbital method to obtain the electron densities of the copper valence orbitals and the partial charges on the ligand atoms and by using published values for the Sternheimer factors. Calculations have been made for several different combinations of possible valence orbitals and atomic basis sets. The results give reasonable (order of magnitude) agreement with the experimental results. A discussion of the calculations and the approximations involved will be presented