Syntheses And Properties Of Coordinaion Polymers Based On 2,3,3’,4’-Biphenyltetracarboxylic Acid By Hydrothermal In Situ Method

In this research,seven complexes,[Co5(μ3-OH)2(as-bptc)2(H2O)6]n(1),{(H3O)2[Co4(μ3-O)(as-bptc)2(H20)]·4H2O}n(2),{K[Zn2(μ3-OH)(as-bptc)(H2O)2]}n(3),[Zn4(as-bptc)2(H2O)3]n(4),{[Zn2(as-bptc)(H2O)4]·(pra)}n(5),{[Cu2(as-bptc)(4,4’-bpy)(H2O)4]·H2O}n(6)and[Ni3(μ3-O)(as-H2bptc)2(4,4’-bpy)2(H2O)4]n(7),have been obtained by hydrothermal in situ reactions.FT-IR,single crystal X-ray diffractions,elemental analyses and powder X-ray diffractions were applied to determine their structures and check their purity.Moreover,thermal stabilities,luminescence and magnetism properties have also been measured.Four following results were obtained.1、There are seven new coordination modes of as-H4bptc in complexes 1-7.The as-H4bptc ligands are completely deprotonated and connect with several metal ions in complexes 1-5,which make the structure of 1-5 based on clusters or chain units except complex 5.Though the as-H4bptc is completely deprotonated in complex 6,the 3’-COO-does not coordinate to any metal ions.The as-H4bptc is partially deprotonated and only 2,4’-COO-participated in cooridnation in complex 7.Owing to the strut role of 4,4’-bpy,the number of metal ions connecting with as-H4bptc in complexes 6 and 7 is less than that in complexes 1-5.2.Two complexes based on porous structures were obtained.Complex 2 displays a porous 3D anion framework accommodating counter ions in its channels with the porosity of 27.2%.Complex 5 shows a porous 3D structure with the porosity of 25.3%,and the guest molecules,2-hydroxylpyrazine,exsit in its channels.Due to their high thermostabilities and porosity,complex 2 and 5 have the potential application values as porous material.3.Magnetic studies reveal that complex 1 shows an antiferromagnetic exchange between the five Co(Ⅱ)ions;While complex 2 displays a ferrimagnetic coupling or spin canting within the Co-O chains.Complex 6 shows a ferromagnetic coupling between two neighbouring Cu(Ⅱ)ions,and complex 7 exhibits an antiferromagnetic interactions or spin canting between Ni(Ⅱ)ions in Ni3 clusters.4、Complexes 3-5 show luminescence emission features at room temperature which were assigned to the intra-ligandπ*-πorπ*-n charge transfer.