Synthesis, crystal structure, magnetic properties and theoretical studies on a one-dimensional polynuclear copper(ii) complex [Cu2(μ1,3-SCN)2(μ′1,3-SCN)2(MPyO)2]n

Abstract

A new one-dimensional polynuclear copper(II) complex [Cu₂(μ_1,3-SCN)₂(μ′_1,3-SCN)₂(MPyO)₂]_n (where MPyO = 4-methylpyridine N-oxide) has been synthesized and its crystal structure determined by X-ray crystallography. In the complex there exist two kinds of bridging coordination modes, namely, μ_1,3-SCN⁻ equatorial–equatorial (EE) bridging ligand and μ′_1,3-SCN⁻ equatorial–axial (EA) bridging ligand. Two μ_1,3-SCN⁻ EE bridging ligands coordinate two copper(II) ions in a binuclear unit, and the S atoms from the μ′_1,3-SCN⁻ EA bridging ligands as axial coordinated atoms link the binuclear units into one-dimensional chains. The ESR spectra have been investigated, and variable temperature (4–300 K) magnetic measurements were analyzed using a binuclear Cu(II) magnetic interaction formula and indicate the existence of strong antiferromagnetic coupling with 2J = − 216.00 cm⁻¹ between bridged copper(II) ions. Density functional calculations have been carried out on this binuclear unit, yielding a similar singlet–triplet splitting. The mechanism of strong antiferromangetic interaction is revealed according to the calculations.