Exchange interaction in oxygenhyphen;bridged dimers of copper (II) with aromaticNhyphen;oxides. I. Method of calculation and application to dihyphen;mgr;hyphen;(pyridineNhyphen;oxide)hyphen;bis lsqb;dichlorocopper(II)rsqb;

摘要

A method, based on the Diracndash;Van Vleckndash;Serber permutation degeneracy model, for the estimation of the exchange integralJin oxygenhyphen;bridged dimers of copper (II) with aromaticNhyphen;oxides is demonstrated for the case of the dimer dihyphen;mgr;hyphen;(pyridineNhyphen;oxide)hyphen;bis (dichlorocopper II), lsqb;(C6H5NO)CuCl2rsqb;2. The calculations are limited to the planar threehyphen;center, fourhyphen;electron system Cu(uarr;)ndash;O(uarr;darr;)ndash;Cu(uarr;), with due account of the second bridging oxygen and all omitted atoms or electrons. The computational details and approximations are discussed. It is found thatJis sensitive to the structural data, the atomic orbitals and functions used, the ionic state of copper, and configuration interaction (inclusion of excited, chargehyphen;transfer configurations). The exchange interaction is mediated by a sgr; superexchange pathway, all pgr; pathways being excluded. Finally, both the oxygen 2sand 2porbitals contribute toJ.