Syntheses, Structures,and Properties Of Coordination Polymers Based On Tetrahedral Ligands

Seventeen new coordination polymers based on three kinds of tetrahedral ligands [TPOM=tetrakis(4-pyridyloxy-methylene)methane, TIYM=tetrakis(imidazol-1-ylmethyl)methane and H4TCOM=tetrakis[4-(carboxyphenyl)-oxamethyl]methane acid], different transition metals, the anions and the neutral ligands have been hydrothermally synthesized. Their structures have been determined by single crystal X-ray diffractions, IR, elemental analyses, TG and powder X-ray diffraction (PXRD). In addition, the UV-vis diffuse reflection spectra, luminescent properties and photocatalytic properties have been studied and the exploration of relationships between novel structures and properties are also carried out.1. Six structurally diverse coordination polymers based on TPOM, different transition metals and polycarboxylic acids [H2LI=1,3-benzenedicarboxylic acid, H2L2=5-hydroxyisophthalic acid, H3L3=1,3,5-benzenetricarboxylic acid and H4L4=1,2,4,5-benzenetetracarboxylic acid] have been hydrothermally synthesized. Compound1shows a3D4-connected framework with a rare (84-62) topology. Compounds2and3are isostructural and display3D2-fold interpenetrating frameworks with (64-82)(66)2topologies. Compound4exhibits a2-fold interpenetrating structure with a scarce trinodal (3,4,5)-connected (4-62)(4-69)66topology. Compound5possesses a3D4-connected net with the TPOM ligands located in the3D channels. Compound6features2D square layers (sql). The free TPOM ligands and L3anions form discrete fragments through hydrogen bonds and Ï€-Ï€ interactions. Interestingly, the fragments penetrate the2D networks above and below to yield a unique2Dâ†'3D polythreading framework. The structural differences among such compounds show the effects of the carboxylates and central metals on the complex structures. The UV-vis diffuse reflection spectra and luminescent properties were also investigated for the compounds.2. Five novel coordination polymers based on TIYM, different transition metals and the anions [H2L5=oxalic acid, NaWO4·2H2O and NaMoO4·2H2O] have been hydrothermally synthesized. Compound7shows a3D (4,5)-connected framework with (43·63)(43·66·8) topology. Compound8and9are isostructural and feature a scare3D (4,6)-connected net with (3·4·53·6)(32·4·54·67·7) topology. Compound10exhibits a (4,6)-connected (44·62)(44·610·8) topology. Compound11displays a trinodal (3,4)-connected (5·82)(54·6·8)2topology.3. Four unusual isomorphous coordination polymers based on H4TCOM,4-tolyl-2,2’:6’,2"-terpyridine (L6) and different transition metals have been hydrothermally synthesized. In compounds12-15, the metal atoms are linked by the TCOM anions to yield a chain with a loop. Every loop of each chain is penetrated by two L6ligand rods belonging to the two nearest chains, resulting in an unusual1Dâ†'2D inter digitated network. In the2D interdigitated network, there exist weak Ï€-Ï€ interactions between pyridyl groups of L6ligands. If the Ï€-Ï€ interactions are regarded as linkers, the2D interdigitated network belongs to an uneven (3,4)-connected layer. Furthermore, each individual (3,4)-connected layer is polycatenated with an infinite number of other perpendicular layers, yielding an unusual2Dâ†'3D polycatenane framework. The luminescent properties of compounds14and15have been studied. In addition, compounds12-15exhibit photocatalytic activities for MB degradation under UV irradiation. Submicrometer fiber12’ shows high photocatalytic effciency for MB degradation with respect to its corresponding macroscaled crystalline12.4. Two novel coordination polymers based on H4TCOM, TIYM and and different transition metals have been hydrothermally synthesized. In16, tetrahedral TCOM and TIYM ligands link neighboring Co(â…¡) atoms to generate a unique3D self-penetrating framework with a tetranodal4-connected (6·85)2(63·83)(86) topology. However, in17, Cd(â…¡) atoms are bridged by TCOM and TIYM ligands to furnish a3D framework with a highly rare (4,8)-connected (46)(44·62)(410·614·74) topology. In addition, compound16exhibits photocatalytic activity for dye degradation under UV light or visible-light and shows good stability toward photocatalysis.