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 2 O)(saldmen)Cu}{(NC)Ag(CN)}] 1, 1 ∞ [{Cu 2 (salaepipH) 2 (μ-CN)}{μ-[Ag(CN) 2 ]}](ClO 4 ) 2 ·4H 2 O 2, 1 ∞ [{(salaepy)Cu}{μ-[Ag(CN) 2 ]}] 3, 1 ∞ [{(salaepy)Cu}{μ-[Cu(CN) 2 ]}] 4, [(salaepy)Zn-NCAuCN] 2 ·H 2 O 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 2 n +, 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 = – J S 1 S 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).