| Design and construction of coordination polymers with their intriguingtopological structures and potential applications as functional solid materials havearoused great interest in chemists. In order to get such materials, the most effectiveand facile method is to employ the well-designed organic ligands as well asappropriate metal ions. However, it is still challenging to target structures with desiredproperties because many factors affect the result, such as the subtle interplay of metalcoordination preferences, connection modes of organic ligands, reaction temperature,the ratio of reagents, solvents, pH value, anions, and so on. The rational design andsynthesis of compounds with desired architectures and promising properties seems tobe a great challenge for chemists. However, it also provides an opportunity tounderstand the relationships between these influence factors and the diverse structuresthey produce.Recently, flexible multi-carboxylate ligands have become attractive as buildingelements in the synthesis of multidimensional networks because their conformationalfreedom can be affected easily by external influencing factors, and may provide morepossibility for the construction of structures with unusual topologies. In order to getmore useful information in this field, we chose the flexible5,5’-（1,4-phenylenebis-（methylene））bis（oxy）diisophthalic acid （H4L） as a functional ligand, changing thesolvents, reaction pH and using auxiliary ligands, a series of coordination compoundshave been assembled successfully, namely {[Zn3（L）（OH）2（H2O）3]·2H2O}n（1）,{[Zn（H2L）（H2O）2]·H2O}n（2）,[Zn2（L）（H2O）4]n（3）,{[Zn2（H3L）2（H2L）（H2O）2（MeCN）2]}n（4）,{[Co2（H3L）2（H2L）（H2O）2（MeCN）2]}n（5）,[Zn2（H3L）2（H2L）（2,2’-bipy）2]n（6）,[Zn2（H3L）2（H2L）（phen）2]n（7）,{[Zn2（L）（4,4’-bipy）2]·4H2O}n（8）,{[Zn2（L）（bpe）2]·4H2O}n（9）,{[Zn2（L）（pdp）2]·4H2O}n（10）,{[Zn2（L）（bpmp）2]·6H2O}n（11）,{[Zn7（L）4（bpp）2（H2O）2（DMF）2][（CH3）2NH2]}n（12）,[CuII2CuI2（H2L）3（bpp）2]n（13）,{[Zn2（L）（pbtmb）2]·4H2O}n（14）,{[Zn2（L）（mbtmb）2]·4H2O}n（15）,[Zn2（L）（obtmb）2]n（16）,[Zn2（L）（btmbp）2]n（17）,{[Zn2（L）（btmbp）（H2O）4]·2H2O}n（18）,{[Co2（L）（btmbp）（H2O）4]·2H2O}n（19）,{[Cd2（L）（btmbp）（H2O）4]·2H2O}n（20）. All thecomplexes were characterized by X-ray crystallography, IR, elemental, thermalstability, and powder X-ray diffraction analyses. The photochemical properties ofcompounds1-4,6-12,14-18and20were also tested in the solid state at roomtemperature. Compounds1-5are constructed of only metal atoms with H4L ligands.Compound1features a3D architecture constructed of a linear Zn3cluster with H4Lligands. Compound2is a2D waved layer structure with （4,4） grid as sql topology.Compound3displays a3D network simplified by a （3,6）-connected2-nodal net withant topology. Compounds4and5both exhibit1D infinite chains coordinationstructure, in which the H4L ligand is displayed as two kinds of deprotonated forms.Compounds6-13are constructed of metal atoms and H4L ligands with variouspyridines N-donor ligands. Compounds6and7also exhibit1D infinite chainscoordination structure. Compounds8,9,10and11are similar and possess （4,4）-connected3D frameworks with bbf topology, while also exhibiting an intriguingthree-fold interpenetrated structure. Compound13is a3D framework withmixed-valence, exhibiting the first reported7-fold interpenetrated pcu network.Compounds14-20are constructed of metal atoms and H4L ligands with variousflexible bis（triazole） ligands. Compound14shows a4-fold interpenetrating3Darchitecture with4-connected mog topology. Compound15displays a2D+2Dâ†'3Dpolycatenation network simplified as new4-connected topology with the Schlaflinotation of {4,64;8}2{42,64}. Compounds16and17are the2D polythreadingstructure, in which two layed networks interpenetrate in a （2D/2D） parallel fashion.Compounds18and19show （3,4）-connected2D frameworks with ABCDABCDstacking mode. Compounds20shows similar structure with Compounds18and19,while with ABAB stacking mode.Their structural diversities show that the solvents, pH value of the reaction systemand auxiliary ligand all play significant roles in affecting the coordinationconformations and deprotonation of the H4L ligand during the structural self-assemblyprocess. The research further enriches the crystal engineering strategy and offers newpossibilities for controlling the formation of desired metal-organic frameworks.Furthermore, luminescent measurements reveal that complexes1-4,6-12,14-18and20are good candidates for photoactive materials, owing to their strong luminescentemissions. The successful syntheses of compounds14-17provide new perspectives todesign different kinds of entangled networks. |
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