Syntheses, structures and fluorescence of three novel 3D coordination polymers [Cd3(TMA)2(H-PRZ)(H2O)3(OH)] • H2O, Cd2Na2(TMA)2(H2O)4 and [Cd2Co(TMA)2(H2O)4]•2H2O (TMA = trimesic acid, PRZ = piperazine)

The hydrothermal reactions of H(3)TMA (or Na(3)TMA) with metal acetate yield three novel coordination polymers [Cd-3(TMA)(2)(H-PRZ)(H2O)(3)(OH)] (.) H2O (1), Cd2Na2(TMA)(2)(H2O)(4) (2) and [Cd2Co(TMA)(2)(H2O)(4)] (.) 2H(2)O (3) (TMA = trimesic acid, PRZ = piperazine). The three Cd(II) centers in 1 are bridged by TMA ligands and a mu(3)-O atom of coordinated hydroxide to generate a sandwich-liked tri-layer motif. These motifs with a Cd3O core are further interlinked by hydrogen bond interactions to stack in a 3D coordination framework with a porous dimension of ca. 7.5 x 5.5 A. Complex 2 is a three-dimensional polymer based on tetranuclear heterometallic clusters. The centrosymmetric tetranuclear heterometallic cluster contains a Cd2Na2 parallelogram cluster core. These clusters are connected through the coordination of carboxylate oxygen atoms of TMA ligands to form a 3D coordination framework. Complex 3 represents the first structural characterization of a trimesate complex containing two different transitional metals. Each TMA(3-) ligand in the Cd2CO(C9H3O6)(2)(H2O)(4) structure unit of 3 binds to other three structure units, resulting in a 3D coordination polymer. The three complexes exhibit strong fluorescent emission bands at 420 nm (lambda(ex) = 314 nm) for complex 1, 424 nm (lambda(ex) = 314 nm) for complex 2, and 419 nm (lambda(ex) = 308 nm) for complex 3 in the solid state at room temperature. The preliminary magnetic property of complex 3 has been investigated. (C) 2004 Elsevier Ltd. All rights reserved.