SYNTHESIS, CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF THE FIRST SINGLE AZIDO-BRIDGED COPPER(II) CHAIN [CU(BPYM)(N-3)(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-ra y diffraction methods. The structure consists of neutral chains of cop per( II) ions bridged by a single azide group exhibiting the asymmetri c end-to-end coordination mode. A terminally bound azide ligand and a didentate bpym group complete the square pyramidal geometry of the met al atom. The intrachain copper-copper separation is 5.063(1) A. The ma gnetic behaviour was investigated in the temperature range 2.0-290 K. The susceptibility curve exhibits a maximum at 4.9 ii showing the occu rrence of a weak intrachain antiferromagnetic coupling. Analysis of th e magnetic data using the Heisenberg uniform linear chain model ((H) o ver 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-b ridged dinuclear copper(ll) complexes. (C) 1998 Elsevier Science S.A. All rights reserved.