Synthesis, X-ray crystal structure and magnetic study of the 1D {[Cu2(N,N,N′,N′-tetramethyl-ethylenediamine)2(μ-1,5-dca)2(dca)2]}n complex

Abstract Reaction of Cu(NO 3 ) 2  · 3H 2 O, N , N , N ′, N ′-tetramethyl-ethylenediamine (L) and sodium dicyanamide (Nadca) in aqueous medium yields a complex the {[Cu 2 L 2 (μ-1,5-dca) 2 (dca) 2 ]} n complex, 1 . Single crystal X-ray analysis reveals that complex 1 has a 1D infinite chain structure in which copper(II) ions are bridged by single dicyanamide anions in an end-to-end fashion. The coordination environment around copper(II) is distorted square pyramidal. Two among the four coordination sites of the basal plane are occupied by the nitrogen atoms of the diamine and two remaining sites are occupied by the terminal nitrogen atom of a bridging and of a monodentate dca anions. The fifth coordination site (apical) is occupied by a nitrogen atom from a bridging dca anion of an adjacent CuL(dca) 2 moiety, yielding the [Cu 2 L 2 (μ-1,5-dca) 2 (dca) 2 ] dinuclear unit. Dimeric units are connected to each other by single μ-1,5-dicyanamido group to form infinite 1D chains which propagate parallel to the crystallographic c -axis. The variable temperature magnetic susceptibility measurements evidenced weakly antiferromagnetic interactions ( J  = −0.26 cm −1 ) in {[Cu 2 L 2 (μ-1,5-dca) 2 (dca) 2 ]} n , 1 .