Structurally alternating copper(II) chains from oxalate and azide bridging ligands: Syntheses and crystal structure of [Cu-2(mu-ox)-(deen)(2)(H2O)2(ClO4)(2)] and [{Cu-2(mu-N-3)(mu-ox)(deen)(2)}(n)][ClO4](n) (deen equals Et(2)NCH(2)CH(2)NH(2))

The mu-oxalato dinuclear compound [Cu-2(mu-ox)(deen)(2)(H2O)(2)(ClO4)(2)] 1 and the derived alternating mu-oxalato-mu-azido chain [{Cu-2(mu-N-3)(mu-ox)(deen)(2)}(n)][ClO4](n) 2, where deen = N,N-diethylethane-1,2-diamine, have been synthesized and characterised. The crystal structures of 1 and 2 have been determined by single-crystal X-ray analysis. Their magnetic behaviour has been recorded between 300 and 4 K, showing strong antiferromagnetic coupling in each case. The data were fitted by the expression for a dinuclear copper(II) compound giving the parameters J = -300(3) cm(-1), g = 2.15(1) for 1 and J = -287(1) cm(-1), g = 2.28(1) for 2.