Design, Syntheses, Crystal Structures And Properties Of Coordination Polymers Based On 3-Hydroxycinnamic Ligands

As a newly-identified functional molecule-based material, metal-organic coordination polymer has been a focus of material chemistry due to their flexible tailoring structures, charming topological networks as well as their fascinating potential applications in functional solid materials adsorption, catalysis, ions exchange, and the development of optical, electronic and magnetic devices. Fourteen new coordination complexes have been synthesized based on 3-hydroxycinnamic acid (H2L1) and 3-carboxymethoxy phenyl acrylic acid (H2L2). All complexes have been determined by single-crystal X-ray diffraction, IR, thermal stabilities analyses and photoluminescence. The main results are as follows:Five transition metal complexes based on 3-hydroxycinnamic acid (H2L1) and 2,2'-bipy, phen or 4,4'-bipy, have been hydrothermal synthesized, namely [Cd(HL1)2(2,2'-bipy)2]n (1), [Cd(HL1)2(phen)2]n·2nH2O (2), [Cd(HL1)2(4,4'-bipy)(H2O)2]n-2n(4,4'-bipy) (3), [Zn(HL1)2(4,4'-bipy)(H2O)2]n·2n(4,4'-bipy)(4),[Co(HL1)2(4,4'-bipy)(H2O)2]n·2n(4,4'-bipy) (5). The complexes 1 and 2 have formed the distorted square antiprism geometry with Cd ions as the central ions.3-5 are isostructural with 1D chain structure. Complexes 1-4 exhibit the strong fluorescence in solid state at room temperature.Five new lanthanide coordination polymers based on 3-hydroxycinnamic acid (H2L1), namely, [Tb2(HL1)6(2,2'-bipy)2]n (6), [Sm2(HL1)6(2,2'-bipy)2]n (7), [Eu2(HL1)6(2,2'-bipy)2]n (8), [Nd2(HL1)6(2,2'-bipy)2]n·n(2,2'-bipy)-nH2O (9) and [Eu(HL1)3(H2O)]n·nH2O (10), have been hydrothermal synthesized. The complexes 6-8 are isostructural and isomorphous with dimeric structure. The complex 9 has the similar structure with 6-8 and contains 2,2'-bipy and H2O solvate molecules. The complex 10 is a 1D structure without secondary ligand. The ligand fluorescent emission is not observed among the luminescent of the complexes 6, 8 and 10, indicating an efficient energy transfer from the ligand to the Ln(III) ions.Four transition metal complexes based on 3-carboxymethoxy phenyl acrylic acid (H2L2), namely, [Zn(L2)(phen)]n (11), [Zn(L2)(4,4'-bipy)o.5]n (12), [Mn(L2)(4,4'-bipy)0.5(H20)2]n (13), [Mn(2,2'-bipy)2(H2O)2]n·n(L2)·8nH2O (14), have been synthesized by solution and hydrothermal methods. The complex 11 is 1D structure and complex 12 is a four-connected (4,4) network topology structure. The complex 13 is a 2D structure assembled by zigzag chains and linear 4,4'-bipyridine ligands. In complex 14, the free 3-carboxymethoxy phenyl acrylate anion does not coordinate to the metal cation. Complexes 11 and 12 exhibit the strong fluorescence in solid state at room temperature.