The Synthesis, Structure And Property Studies Of Mercury Compounds With Acylamide Ligands

In recent years, the coordination polymers has been developed rapidly, and alreadybecome a hot research in the field of supramolecular chemistry and crystal engineering. Asa branch of the coordination polymers, mercury complexes is one of the key directions oftoday’s research, due to its excellent optical properties and structural diversity. Therefore,the study of the mercury complexes matter has great significance. Herein, we synthesized aseries of novel structure and function of the application prospects complexes byhydrothermal （solvothermal）, and investigated the impact of solvent effects on thestructural diversity. Furthermore, their fluorescence and thermal stability properties werealso characterized. This work offers some new research ideas for the supramolecularself-assembly, molecular design and synthesis through the molecular structure andproperties study of this series mercury pyridine amides complexes.The study of full text includes the following three parts:Firstly, di-pyridine amide ligand L1was designed and synthesized, and fivecompounds were obtained by hydrothermal （solvent heat） method with L1ligand.Complex1was synthesized with HgI₂and mixed solvent（CH3CN: H2O=4:2,6mL）; onlychange the solvent obtained the different structures of the complexes （CH3CN,4mL）2,3（CH3CN: CHCl3=4:2,6mL） and4（CH3CN: CHCl3: H2O=4:1:1,6mL） were found,respectively. Clearly, complex1,2,3, and4are a solvent-induced isomer. In addition,1and2are isomers.1is28-membered metallomacrocycle zero-dimensional structures, thesemetallomacrocycles can display a two-dimensional supramolecular net govern byhydrogen bonds and stack into a three-dimensional structure. Different from thezero-dimensional metallomacrocycle structure in1, the overall structure of2is aone-dimensional saddle-like chain. The free volume estimated by Platon program is18.5%of the cell volume. During the reaction of3and4, this work present an precedent foracylamide ligand involving such kind of in situ reaction, which generated Cl-andCH3-L1-CH3]2+ion. Unexpectedly, in3the L ligand is not included, the combination ofHg1and Hg2govern by two μ2-Cl-bridges creates a inorganic dinuclear Hg（II） structurecontaining mixed halogen ions. The solvent-accessible volume is20.3%of cell volume,calculated by Platon program. Compound4is a zwitterionic compound. Two identicalhelical chains can be further associated together by hydrogen contacts （N-H…Cl）, where aoutstanding point is a three-fold hydrogen bonds for Cl-ion. In addition, by adding otherCo（NO3）2and KSCN prepared a3D Co （II）-Hg （II） nuclear coordination polymer5,molecular formula is Hg0.5Co（SCN）3L1（CH3CN）（H2O）, its three-dimensional framework can simplifies an unprecedented （4,6）-connected grid when the metal ion as anode, and topology symbol is （56）（42.55.64.72.82）2.Secondly, according to the guidance quality with the structure of the ligand forcoordination geometry, we designed and synthesized bipyridine amide ligands L2, L3, L4and three pyridine amide ligand L5, then through solvothermal method, L2, L3, L4andHgI₂self-assembly synthesis three different structures of mercury（II） complexes6,7and8,obtained two isomers9and10by ligand L5. Wherein, complexes6and7are the similarityzero-dimensional structure with S-shaped. And their both two-dimensional supramolecularstructure formed through hydrogen bonding and Ï€-Ï€ interactions, then with AA stackedmanner further into the three-dimensional structure.8is a one-dimensional spiral chainstructure. The left-handed and right-handed intertwined into a two-dimensional structureby Ï€-Ï€ interaction between the naphthalene ring, Through hydrogen bonds, thesetwo-dimensional chain are further ligated together to generate a windmill-like3D offour-leaf structure.9is a triangular one-dimensional layered structure, and thesupramolecular structure is a porous three-dimensional grid, each cell may be included inthe volume of the solvent molecules is17%; while10is an sawtooth one-dimensionalchain structure, through hydrogen and48-ring constituting an unlimited expansion of thetwo-dimensional grid. Since the complexes9Crystallization the polarity point group P21space group, so we tested its ferroelectric properties, the results show that it has goodferroelectric performance.Thirdly, in order to explore the effects on the structure of more flexible ligands, wedesigned and synthesized of two amino methylene-bis-pyridine amide ligands L6and L7,then through hydrothermal （solvothermal） method, with HgI₂self-assembled synthesisingof three mercury（II） complexes11,12,13, respectively. Wherein, the complexes11and12are isomers.11is a one-dimensional spiral chain structure formed by-HgI₂-L6-unit. Thetwo-dimensional grid structure is formed by hydrogen bonding between the helix, and thenobtained its three-dimensional supramolecular structure in the a-axis directionaccumulation by AABBAA. Complex12is also a one-dimensional chain structure andchain structure formed by hydrogen bonding interactions in the three-dimensionalsupramolecular structure. Complex13is a spiral linear one-dimensional structure, to forma three-dimensional structure by hydrogen bonding between the chains. Interestingly, thateach chain connected to four spiral chain structure through H-bonds. The fluorescencespectrum shows the excitation wavelength of313nm, at444nm present similar Blu-rayemission in compound13.