Synthesis,crystal structures and magnetic properties of three Ni(II) complexes having NiN4 core with argentocyanide,terephthalate and dicyanamide ions: From discrete molecule to a helical network

This work describes the synthesis and X-ray crystallographic characterization of three nickel(II) complexes [Ni(3,2,3-tet){Ag(CN)₂}₂] (1), [Ni(3,2,3-tet)(μ-tp)]_n · 1.5nH₂O (2) and {[Ni(3,2,3-tet)(μ_1,5-dca)](ClO₄)}_n (3) where 3,2,3-tet = N,N′-bis(3-aminopropyl)-1,2-ethylenediamine, tp = terephthalate and dca = dicyanamide. Compound 1 is a heterotrinuclear discrete distorted octahedral molecule whereas compound 2 forms a 1D polymeric network and an extended 2D network is formed by intermolecular hydrogen bonding. Interestingly, two adjacent 1D chains execute a novel double-helical network constructed by Ni(II) and the bridging dca ligand in compound 3. The variable temperature magnetic susceptibility measurements for compounds 2 and 3 were also carried out.