| Metal organic framework?MOF?,also known as porous coordination polymer?PCP?,is formed by the assembly of metal ions or metal clusters with inorganic/organic ligands by coordination bonds.Due to their potential structural and functional diversity,such compounds have attracted a wide range of chemists.For more than two decades,a large number of novel coordination polymers have been synthetized and widely applied to optical sensing,gas adsorption and separation,and heterogeneous catalysis.In this article,by controlling the reaction conditions?changing the reaction solvent,regulating the reaction temperature,adjusting the pH?,twenty-one complexes have successfully been obtained by hydrothermal synthesis method using asymmetric carboxylic acid ligands.Structural characteristics,coordination methods and application properties have been studied.The paper consists of the following two parts:?1?Wedesignedandpreparedtheligand5-?3-lithium formate-1H-1,2,4-triazol-1-methyl?benzene-1,3-dicarboxylate?Li3ctbd?.Twelve compounds have been obtained by the combination of the ligand Li3ctbd and transition metal ions?Mn?II?,Zn?II?,Co?II?,Ni?II?,Cd?II?,Cu?II??and rare earth metalions?Yb?III?,Er?III??,namely,{[Mn3?ctbd?2]·2.75H2O}n?1?,[Zn2?ctbd??OH??H2O?2]n?2?,{[Zn?a-ctbd??H2O?]·H2O}n?3?,{[Zn2?b-ctbd??H2O?2]·H2O}n?4?,{[Co2?ctbd??H2O?]·3.5H2O}n?5?,{[Ni2?ctbd??OH??H2O?2]·5H2O}n?6?,[Cd?b-ctbd??H2O?2]n?7?,{[Cd?b-ctbd?2?H2O?]·H2O}n?8?,{[Yb?ctbd?2?H2O?3]·25/4H2O}n?9?,{[Er?ctbd?2?H2O?3]·25/4H2O}n?10?,[Cu?ctbd??phen?]·2H2O?11?,[Cu1.5?ctbd??2,2?-bipy?1.5]·0.75H2O?12?.The structures have been characterized by single crystal X-ray diffractometer,and the complex 1 and 2 are three-dimensional structures,3-7 are two-dimensional structures,8-10 are one-dimensional structures,11-12 are zero-dimensional structures.Elemental analysis,powder diffraction analysis and IR characterization were carried out.We also explored the solid fluorescence properties of ligands and complexes 3,8 at room temperature.Compared to ligands,complexes 3 and 8 have strong fluorescence emission intensity,probably because the stronger rigid structures of the complexes reduce the nonradiative decay of the intraligand excited state.We also studied the magnetic properties of complexes 1,5 and 6.The results show that there are antiferromagnetic interactions in 1 and 5;there is a weak ferromagnetic interaction in 6.Studies on the antibacterial activity of some complexes and ligands showed that complex 11exhibited great antibacterial effect against Bacillus subtilis.?ii?Seven compounds were obtained by self-assembly of the ligand1-?pyridin-2-methyl?-1H-pyrazole-3,5-dicarboxylate?Li2pypd?with six transition metal ions,[Mn?pypd??H2O?]n?13?,{[Pb2?pypd?2?H2O??phen?]·H2O}n?14?,[Cd?pypd??phen?]n?15?,[Cd?pypd??phen??H2O?2]?16?,[Co?pypd??H2O?]n?17?,{[Cu?c-pypd?]·2H2O}?18?,[Ni?pypd??H2O?3]·2H2O?19?.In addition,we also synthesizedtwonovelnickelcomplexeswith5-?pyridin-3-yl?-1H-pyrazole-3-carboxylicacid?H2ppc?ligand,namely{[Ni0.5?Hppc?]·H2O}n?20?and{[Ni?Hppc?2]·3H2O}n?21?.The structures have been characterized by single crystal X-ray diffractometer,elemental analysis,and infrared spectroscopy.The complex 13 is a three-dimensional frame structure,the complexes14-15,20-21 are two-dimensional planar structures,the complex 17 is a one-dimensional chain structure,and the complexes 16,18-19 are zero-dimensional structures.We further studied the solid fluorescence properties of the Li2pypd ligand and complexes 14,15 at room temperature.Fluorescence emission spectroscopy indicated that the maximum emission peak of 14 was attributed to the?-?*transition of the internal electrons of the ancillary ligand?phenanthroline?.The maximum emission peak of 15 can be attributed to the electronic transitions of the internal s and p orbital metal centers of lead ions.We also studied the magnetic properties of complexes 13 and 18,and the result showed that there is an antiferromagnetic interaction between metal ions in complexes 13 and 18. |
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