Synthesis, crystal structure and magnetic properties of the first single azido-bridged copper(II) chain [Cu(bpym) (N32]n (bpym + 2,2′-bipyrimidine)

Abstract

Single crystals of the copper(II) chain of formula [Cu(bpym) (N32]n (bpym = 2,2′-bipyrimidine) were prepared and characterized by X-ray diffraction methods. The structure consists of neutral chains of copper (II) ions bridged by a single azide group exhibiting the asymmetric end-to-end coordination mode. A terminally bound azide ligand and a didentate bpym group complete the square pyramidal geometry of the metal atom. The intrachain copper-copper separation is 5.063(1)Å. The magnetic behaviour was investigated in the temperature range 2.0–290 K. The susceptibility curve exhibits a maximum at .9 K showing the occurrence of a weak intrachain antiferromagnetic coupling. Analysis of the magnetic data using the Heisenberg uniform linear chain model (H^=−J∑S^i⋅S^i+1) leads to J = −3.8cm−1 and g = 2.12. The value of magnetic coupling of this compound is compared with that observed in the parent double end-to-end azido-bridged dinuclear copper(II) complexes.