Magnetic and optical characterization of one-dimensional isostructural σ-bonded tetracyanoquinodimethanido complexes of nickel(II) and copper(II)

Abstract

The complex [CuL(tcnq)₂][L = 3,10-bis(2-hydroxyethyl-1,3,5,8,10,12-hexaazacyclotetradecane); tcnq = 7,7,8,8-tetracyanoquinodimethane] has been prepared and crystallographically characterized. Its structure consists of linear chains of alternating copper–macrocycle and tetracyanoquinodimethanide dimers σ bonded to the copper atoms through a nitrile group. The compound is an insulator. The magnetic properties of both the copper and corresponding nickel compounds are the sums of the contributions arising from the transition-metal ion in octahedral symmetry and of (tcnq)₂^2– dimers. The magnetic data were fitted by a model which accounts for contributions from independent Curie spins for the cation and a thermally activated triplet state for the dimerized anions. No magnetic interactions between the metal ion and tcnq's have been observed, even at low temperatures.