Molecular tectonics: structural and magnetic properties of a discrete copper binuclear complex and a 1-D coordination network

Abstract

Two new copper complexes 2 ([Cu₂(pyS₄)Cl₄]·2CHCl₃) and 3 ([Cu₂(pyS₄)Cl₂]²⁺·2BF₄⁻) have been prepared, their crystal structures elucidated and their magnetic properties studied. Compound 2 is a discrete binuclear copper (II) complex. The geometry around the metal centre is a distorted square pyramid. Compound 3, in contrast, is an infinite coordination network formed upon mutual bridging of binuclear species through chloride atoms. Again, the geometry around each copper atom is closed to a square pyramid. The packing of the 1-D coordination networks generates channels which are occupied by BF₄⁻ anions. The magnetic behaviour observed for the 1-D network is comparable to the one corresponding to a discrete chloro-bridged copper (II) binuclear complex. In terms of magnetic coupling, whereas a strong ferromagnetic coupling is observed between the two spin bearers within the dimer (d = 3.467 Å) (J/k_B = 337 K), a weak interdimer antiferromagnetic interaction is measured (zJ′/k_B = −1.6 K).