Cascade complexation: a single cyano bridge links a pair of Cu(ii) cations

Abstract

A series of structurally characterised μ-cyanodicopper(II) cryptates shows moderately strong antiferromagnetic interaction in the range −2J = 150–200 cm⁻¹, at the high end of the observed range for such assemblies. The lowest magnetic exchange coupling parameter is displayed where there is slight bending of the M–CN–M assembly, enforced by the constraints of cryptate encapsulation. Thermally accessible triplet EPR spectra are observed with zero-field splittings of the order of 0.13–0.14 cm⁻¹, confirming collinear ground-state d_z² orbitals for Cu(II), consistent with their trigonal-bipyramidal coordination geometries.