Syntheses, Structures And Properties Of Novel Coordination Polymers Based On Sulfonate/Nitrogen Heterocyclic Ring With Rigid Frameworks

A large number of miracles and achievements have been made possible by the design and syntheses of discrete or extended metal-organic architectures because they have a vast range of applications, ranging from molecular absorption, catalysis, ion-exchange to non-linear optical devices. Though considerable progress has been obtained on the theoretical forecast and practical approaches, the control of the configuration of MOFs is still a major challenge in many cases due to the coordination geometry of the central metal ion, the flexibility and shape of the organic ligand, the ratio of metal/ligand, pH value, etc. Among these factors, the rational choice of organic ligands plays a crucial role in deciding the structures of the metal-organic complexes. Generally speaking, rigid organic ligands have more priority on the controllable growth of crystal structure than the flexible organic ligands.In this article we selected three rigid organic ligands, we selected three rigid ligands,namely,4,4'-Dinitrostilbene-2,2'-disulfonate(L1),2-(5-{6-[5-(Pyrazin-2-yl)-1H-1,2,4-triazol-3-yl]pyridin-2-yl}-1H-1,2,4-triazol-3-yl)pyrazine(L2)and2,6-bis.(3-(pyrid-3-yl)-1,2,4-triazolyl) pyridine(L3). In L1, the two functional groups of sulfnate at2(2') position can afford multi-oxygen coordination modes; L2and L3can afford nitrogen atoms. The rich electronic phenyl units containing π-conjugated system in these ligands and the hydrogen-bonding sites can enhance the stability of MOFs. Through the introduction of four subsidiary ligands:phen,4,4'-bipy, imidazole and1,4-Phenylenediacetic acid, we have obtained eleven new coordination polymers {[Ni(4,4-bipy)(H2O)4]·L1·4H2O}n (1),{[Co(4,4-bipy)(H2O)4]·L1·4H2O}n (2),[Cd(phen)2(L1)n·H2O]n (3),{[Pb(phen)2(L1)]n (4),{[Cu(dazo)4]·L1·H2O}n (5),{[Zn(phen)2(H2O)2]n·L1·5H2O}n (6),[Pb(4,4'-bipy)(L1)]n (7),[Cd2(L2)2(H2pdac)2](8),{[Zn(L2)(H2O)2]·(H2O)1.5}n(9),[CdI2(L3)]·H2O (10),(11).1and2are layered-hydrotalcite materials with cationic-planes, sandwiched-anions and sandwiched-waters.3,4,5,9and11are one-dimensional coordination polymers.6,10are mononuclears,8is dinuclear, these three compounds are further connected to supramolecular complexes via intermolecular hydrogen bonds and π-πstacking interactions.7is a three dimensional framework with (4~4·6~10·8)(3·4~3·5~2)(4~3·6~3) topology.Compounds1-7are characterized by IR, elementalanalysis and thermogravimetry. We also study the Photoluminescence Properties of the polymers3,4,6,7. Methylene blue is a cationic dye and is unfriendliness to environment, we found that compounds1-7exhibits the good property of adsorption to methylene blue in water solution. Furthermore, we also found that the desorption of methylene blue can be occurred in methanol, acetonitrile, DMSO, etc.