Cyanido-bridged heterometallic oligonuclear complexes and coordination polymers constructed using tridentate schiff-base ligands: Synthesis, crystal structures, and magnetic and luminescence properties. A new trimeric water cluster

Five new Cu II-Ag I, Cu II-Cu I, and Zn II-Au I complexes have been obtained starting from copper(II) and, respectively, zinc(II) complexes with (NNO) Schiff-base ligands: [{(H 2O)(saldmen)Cu}{(NC)Ag(CN)}] 1, 1 ∞[{Cu 2(salaepipH) 2(μ-CN)}{μ-[Ag(CN) 2]}](ClO 4) 2•4H 2O 2, 1 ∞[{(salaepy)Cu}{μ-[Ag(CN) 2]}] 3, 1 ∞[{(salaepy)Cu}{μ-[Cu(CN) 2]}] 4, [(salaepy)Zn-NCAuCN] 2•H 2O 5. The Schiff-base ligands (Hsaldmen, Hsalaepip, Hsalaepy) have been obtained by reacting the salicylaldehyde with N,N-dimethyletylenediamine, N-(2-aminoethyl)piperazine, and, respectively, 2-(2-aminoethyl)-pyridine. The structures of compounds 1 and 5 consist of discrete bi- and, respectively, tetranuclear species. The analysis of the packing diagram for crystal 1 reveals the formation of supramolecular double chains sustained by hydrogen-bond interactions involving the aqua ligand. Compounds 2, 3, and 4 are one-dimensional coordination polymers. The structure of 2 consists of chains constructed from {Cu(salaepip)} nodes bridged alternatively by [Ag(CN) 2] - and CN - ions, resulted from the partial decomposition of the silver complex. The 3-D architecture of the crystal is constructed from 1-D coordination polymers, [{Cu 2(salaepipH) 2(μ-CN)}{μ-[Ag(CN) 2]}] n 2n+, which are connected by three water molecules that form a triangular water cluster, resulting in a scaffold-like structure with large channels. Compounds 3 and 4 are similar. Their structures can be described as resulting from zigzag anionic chains, [M(CN) 2] n n- (M = Ag I or Cu I), with three-coordinated silver(I) or copper(I) ions, to which monocationic complexes, {(salaepy)Cu}, are attached. The cryomagnetic properties of compounds 1 and 2 have been investigated. Weak antiferromagnetic interactions (J = -2.8 cm -1, H = -JS 1S 2) mediated by hydrogen bonds are observed for compound 1. The cyanido bridge connecting the basal coordination sites of two copper(II) ions in 2 mediates a moderate antiferromagnetic coupling (J = -55.2 cm -1). Compound 5 exhibits blue luminescence (λ = 464 nm, λ ex = 400 nm). © 2012 American Chemical Society.