Synthesis And Properties Study Of Phosphonic Acid Complexes

Coordination polymers(CPs),as one type of new functional material,have great potential in magnetism,proton conduction,fluorescence and catalysis.Coordination polymers can be classified into three categories:(1)organic carboxylic acids,(2)organic phosphonic acids,and(3)nitrogen heterocyclic acids.Organic phosphonic acid ligands have a variety of coordination modes,which can be chelated with metal ions to obtain CPs with different structures.Moreover,organic phosphonic acid CPs have high stability.Therefore,the design and synthesis of novel organic phosphonic acid CPs materials,and their structure and properties have been studied,which are of practical significance for the synthesis of new functional materials with practical application value.In this paper,three kinds of organic phosphonic acid ligands were designed and synthesized,(((4-methylbenzyl)azanediyl)bis(methylene))bis(phosphonic acid)(H4L1),(2-amino-1-hyd roxypropane-1,1-diyl)bis(phosphonic acid)(H5L2)and(((pyridin-3-ylm ethyl)azanediyl)bis(methylene))bis(phosphonic acid)(H4L3)(The ligand structure is shown in the figure).Ten new organic phosphonic acid CPs single crystals were cultured by hydrothermal method with these three ligands.The magnetic properties,proton conduction and fluorescence of the complexes were studied according to the structure of the complexes.The main research contents are as follows:1.Five organic phosphonic acid complexes,[Cu2L1(4,4'-bipy)0.5H2O]n(1),[Cu(H2L1)H2O](2),[Cd2(H2L1)2H2O](3),[Co2L1(H2O)2]·0.184H2O(4),[Fe3L12(OH)(H2O)3]·2H2O(5),have been synthesized by H4L1,four different metal salts and fauxiliary ligands(4,4'-bipyridine)under hydrothermal conditions and characterized by elemental analysis,IR,XRD and TGA.The structures of the five complexes were determined by X-ray single crystal diffraction.It was found that the complex 1 owes a three-dimensional structure,and the complexes 2-5 owe two-dimensional structures.The coordination modes of the ligands in the five complexes are different.Complexes 1 and 2 have the same metal ions,but complex 1 changes the dimension of complexes by adding 4,4'-bipyridine,so that the complex transforms from two-dimensional structure to three-dimensional structure.The magnetic properties of complexes 1-2 and 4-5 show that they have magnetic channels between metal ions,thus they have magnetic exchange.Complex 1 exhibits ferromagnetism,while complexes 2,4 and 5 exhibit antiferromagnetism.They are fitted with PHI and Curie-Weiss law.Further,the fluorescence properties of the complex 3 were investigated2.Three organic phosphonic acid complexes,[Co3(H2L2)2(H2O)6]3.28H2O(6),[Zn3(H2L2)2(H2O)6]3.27H2O(7),[Ni3(H2L2)2(H2O)6]3.13H2O(8),have been synthesized by H5L2 and three different metal salts under hydrothermal conditions and characterized by elemental analysis,IR,XRD and TGA.The structures of the three complexes were determined by X-ray single crystal diffraction,and the complexes 6-8 were one-dimensional structures.The one-dimensional chain structure in the complexes 6-8 are connected by a hydrogen bond into a three-dimensional structure,and there are infinitely extending water chains and water clusters.The hydrogen bonds of complexes 6 and 7 are the same,which are different from that of complexes 8.At room temperature(298K)and 98%RH,It was found that the proton conduction of complex 6 was 5.29 × 10-4S·cm-1,the proton conduction of complex 7 was 1.87 × 10-3S·cm-1,the proton conduction of complex 8 was 3.25×10-5S·cm-1?The proton conductivity of complex 7 is superior to the proton conductivity of most Cps materials.After soaking the complexes 6-8 for 7 days at room temperature,the mass of complex 6-8 did not decrease.And XRD characterization showed that complex 6-8 was stable in water.3.Two organic phosphonic acid complexes with 3D framework structure,[Co3(HL3)2(4,4'-bipy)2(H2O)2]2.77H2O(9),[Ni3(HL3)2(4,4'-bipy)2(H2O)2]2.53H2O(10),have been synthesized in the presence of H4L3 and two different metal salts under hydrothermal conditions and characterized by IR,XRD and TGA.The complexes 9 and 10 were determined to owe a three-dimensional structure by X-ray single crystal diffraction.