Synthesis,Structures,and Properties Of A Series Of Functional Coordination Compounds Constucted From Biphenyl-tricarboxylic Acid Ligands

Within the rapid development of coordination chemistry,the synthesis and properties of new functional coordination compounds have become a research hotspot forscientists.Inparticular,coordinationcompoundsbearingaromatic multicarboxylate ligands not only feature unique structures,but also display a wide range of applications in the areas of catalysis,luminescence,molecular magnetism,gas adsorption,selective sensing and separation.However,the self-assembly of such coordination compounds is affected by many factors,and the formation of products with specific structures and functions still represents a synthetic difficulty.Therefore,inthepresentwork,twonewbiphenyl-tricarboxylicacidligands,5-?3,4-dicarboxylphenyl?picolinicacid?H₃dppa?and3'-nitro-biphenyl-2,4,4'-tricarboxylic acid?H₃nbtc?,were selected as promising building blocks and tested in various hydrothermal self-assembly reactions with different metal salts.As a result,nineteen new coordination compounds with different structures and dimensionality,configuration of ligands,high thermal stability,and interesting fluorescent and magnetic properties were synthesized,isolated,and fully characterized.The solid-state characterization techniques included the single-crystal and powder X-ray diffraction,topological analysis,infrared spectroscopy,elemental,and thermal analyses.Furthermore,the optical and magnetic properties of the compounds were also discussed.This thesis contains three chapters that focus on the topics as described below.Chapter 1:This chapter briefly introduces the main concepts of coordination chemistry,supramolecular chemistry and crystal engineering.Various types of synthetic methods and the main factors affecting the structures of the selected types of coordination compounds are discussed,as well as the structural diversity and potential applications of the compounds bearing the aromatic polycarboxylate ligands.Chapter2:Thischapterdescribestheapplicationof5-?3,4-dicarboxyphenyl?pyridinecarboxylic acid?H₃dppa?as a main ligand in the hydrothermal reactions with Zn^II,Ni^II,Mn,^III or Cu^III ions and in the presence of ancillary ligands such as H₂biim?H₂biim=2,2'-biimidazole?,bpa?bpa=bis?4-pyridyl?amine?,phen?phen=1,10-phenanthroline?,or 4,4'-bipy?4,4'-bipy=4,4'-bipyridine?.Seven new coordination compounds?1–7?were isolated and fully characterized,their structures and thermal stability were also discussed.Magnetic properties of compounds 1,2,4,and 6 were studied,revealing the antiferromagnetic?for 1,2,and 6?or ferromagnetic?for 4?interaction between adjacent metal centers.The fluorescent properties of 7 were also investigated.In addition,the photocatalytic activity of 1–7 was studied in the degradation of methylene blue in water as a model organic dye pollutant,revealing that the compound 4 displays the best photocatalytic activity among the tested catalysts.Chapter 3:In this chapter,3'-nitro-biphenyl-2,4,4'-tricarboxylic acid?H₃nbtc?was applied as a main building block for the hydrothermal generation of coordination compounds,using Cd^II,Zn ^II,Ni^II,and Co^III ions and various ancillary ligands,namely1,10-phenanthroline?phen?,2,2'-bipyridyl?2,2'-bipy?,and 4,4'-bipyridyl?4,4'-bipy?.As a result,twelve new coordination compounds were synthesized and fully characterized by standard solid-state methods.The structures of compounds 8–19range from zero-dimensional dimers?9 and 12?or mononuclear complexes?10,11,and 15?,to one-dimensional coordination polymers?8,13,14,17,and 18?and three-dimensional metal-organic frameworks?16 and 19?.The luminescent behavior of the compounds 8–10,12–14,and 17–19 was investigated in the solid state,while the magnetic properties were explored for the compound 16.