Synthesis, crystal structure and magnetic properties of the first single azido-bridged copper(II) chain [Cu(bpym)(N3)2]n (bpym = 2,2′-bipyrimidine)

Single crystals of the copper(II) chain of formula [Cu(bpym) (N-3)(2)](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) A. The magnetic behaviour was investigated in the temperature range 2.0-290 K. The susceptibility curve exhibits a maximum at 4.9 ii showing the occurrence of a weak intrachain antiferromagnetic coupling. Analysis of the magnetic data using the Heisenberg uniform linear chain model ((H) over cap= -J Sigma (S) over cap(i) .(S) over cap(i+1) ) leads to J= -3.8 cm(-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(ll) complexes. (C) 1998 Elsevier Science S.A. All rights reserved.