Cyanato—copper(II) complexes with organic ligands. IX. ESR spectra and magnetic susceptibilities of cyanato-copper(II) complexes with ligands of the aniline group

Abstract

The ESR spectra of complexes of formula Cu-(NCO) 2L 2 where L = aniline, p-chloroaniline, p-bromoaniline, p-iodoaniline, o-, m-, and p-toluidine were recorded and their magnetic susceptibilities were measured at different temperatures. Cu(NCO) 2(an) 2 shows a normal orthorhombic, while Cu(NCO) 2 (o-tol) 2 exhibits a normal axial ESR spectrum (for abbreviations see note 2). Complexes with L = p-chloroan, p-bromoan, m-, and p-tol give “reversed” orthorhombic spectra and Cu(NCO) 2(p-iodoan) 2 displays a “reverse” axial spectrum; these results are interpreted as due to the presence of exchange interaction. The susceptibilities of all these complexes obey the Curie-Weiss law χ M corr α(T + Θ) − with the values of Θ in the range of +2− +41 K. The temperature dependence of the susceptibility of Cu(NCO) 2(o-tol) 2 conforms with a one-dimensional Ising model for g = 2.12 and 2J = −20 cm −.