E.S.R. study of copper and silver N,N-dialkyldiselenocarbamates

Abstract

The spin hamiltonian parameters of Cu(II) dialkyldiselenocarbamates, diluted in the corresponding Ni(II) complexes, have been calculated from the results of extended Hückel Molecular Orbital calculations and compared with the experimentally obtained values (Part I). Without the 4d functions of selenium, all calculated hyperfine couplings (those of copper as well as those of selenium, hence nine principal values) and two of the principal g values are found in very good agreement with the experimental ones. The third principal g value can be brought into agreement with the experimental value if the 4d functions of selenium are taken into account. In doing this also the rotation of the principal axes of g tensor relative to those of the copper hyperfine tensor can be understood. The results of the extended Hückel calculations show that the hyperfine couplings of the selenium atoms are determined almost completely by the molecular orbital of the unpaired electron. This enabled us to calculate the selenium part of this molecular orbital directly from the experimental splittings. From a comparison between the selenium hyperfine splittings in corresponding copper and silver compounds it could be concluded that the delocalization of the unpaired electron to the selenium atoms is much larger in the silver than in the copper compounds.