Novel alternating ferro-ferromagnetic two-dimensional (4,4) and photoluminescent three-dimensional interpenetrating PtS-type coordination networks constructed from a new flexible tripodal ligand as a four-connected node

Two novel two-dimensional (2D) and one three-dimensional (3D) coordination polymers[Ni(HTTG)(H2O)(2)](n) (1), [Co(HTTG)(H2O)(2)](n) (2), and [Cd(HTTG)](n) (3) have been hydrothermally synthesized by self-assembly of an unexplored tripodal ligand H(3)TTG (N,N',N' '-1,3,5-triazine-2,4,6-triyltris-glycine) and corresponding metal salts. X-ray diffraction analysis reveals that the three polymers exhibit novel frameworks due to diverse coordination conformations and different acid forms of the flexible tricaboxylate ligands. The isostructural complexes 1 and 2 possess 2D frameworks with M(H2O)(2)(CO2)(2) chains bridged by the ligands, and the resulting 3D networks were extended through R-2(2)(8) hydrogen bonds between the undeprotonated carboxylate groups and the triazine rings as well as pi center dot center dot center dot pi interactions between the triazine rings. Complex 3 shows a 3D interpenetrating compact network with inorganic Cd2O2 chains interconnected by the flexible organic ligands. Topological analysis indicates that in all three complexes the tripodal ligand acts as a four-connected square-planar node, linking four-connected square-planar or tetrahedral-connected metal centers to form interesting two-dimensional (2D) (4,4) (in 1 and 2) and three-dimensional (3D) 2-fold interpenetrating PtS topologies (in 3), respectively. Interestingly, both 1 and 2 exhibit ferromagnetic interactions within the chains bridged by the syn-anti carboxylate groups and the water molecules alternately, and complex 3 displays strong photoluminescent properties at 413 nm due to the coordination of the ligands with the metal centers.