Syntheses, Structures And Properties Of Coordination Polymers Constructed By The Flexible Tripodal N-heterocyclic Ligand, Aromatic Carboxylic Acids And Transition Metals

Recently, the rational design and synthesis of ligands with N-donors present quite an active area, not only because of their strong coordination capacity and can provide more potential coordination sites but also coordination polymers’constructed by these groups potential applications.In order to obtain these coordination polymers, we choose a flexible ligand with an arene core and N-donors to as the functional ligand. Then, ten coordination polymers with unique structures and topologies,namely,{[Zn1.5(tttmb)(Hbptc)]·H2O}n (1),{[Cd(tttmb)(Hbtc)]·5H2O}n (2),[Cd(tttmb)(btec)0.5]·(H2O)}n (3),{[Cd2(tttmb)2(btec)(H2O)3]·H2O}n (4),{[Cd(tttmb)(o-cpla)]·(CH3CN)·(H2O)2}n (5),{[Cd(tttmb)(m-phda)(H2O)]·2H2O}n (6),{[Cd(tttmb)(Hada)2]·6H2O}n (7),{[Co2(tttmb)(m-bdc)2](CH3CN)}n (8),{[Ni(tttmb)(oba)]·2H2O}n (9) and [Ni3(tttmb)2(p-Hbdc)6(H2O)6]n (10) have been successfully synthesized under hydro(solvo)thermally condition based on a flexible N-contained ligand1,3,5-tris(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene (tttmb) and aromatic polycarboxylate acids. Coordination polymers1-10were characterized by elemental analysis, IR spectroscopy, X-ray single-crystal diffraction and thermogravimetric analyses.Single crystal X-ray diffraction analysis shows that coordination polymers1-5and8-9are3D networks,6-7are2D structures while10presents a1D chain. Coordination polymers1,2and3crystallize in the chiral space group P43212, P21212and P43212, respectively. Interestingly, by controlling the hydrothermal reaction temperature of3, a new achiral coordination polymer4is synthesized.5exhibits a3D net with (63)(66)(7·82) topology.6reveals a2D ladder-like structure with (4,4) topology containing alternating Cd11//m-phda2-left-and right-handed helical motifs.7presents a2D structure with (4-82)2.8shows a fascinating three-dimensional polymeric architecture with the point of (8·102)(44·62·84)2(42·6)2(4·102).9exhibits a3D2-fold interpenetrating structure containing left-and right-handed helical chains.The structural and dimensional diversity of these coordination polymers not only indicates that the flexible ligand tttmb exhibits strong coordination ability and diverse coordination modes, but also shows that aromatic polycarboxylate coligands can effectively tune the final structural features and maneuver much more complicated and fascinating topologies. Moreover, our research demonstrates that the temperature can affect the structures of coordination polymers. The different photoluminescence behaviors of2-6, tttmb and part of aromatic polycarboxylate coligands have been studied in the solid state at room temperture. The result shows that2-6exhibit intense fluorescence and are promising candidates for photoactive materials with potential applications.