Synthesis, Structure And Properties Of 5 - Substituted Trimellitic Acid Coordination Polymers

Coordination Polymers （CPs）, a kind of attractive material, is developing at very fast speed which can be confirmed from the sharp growth in volume of CPs publications and CPs structures in the past few decades. The research on CPs is growing vigorously due to their novel framework structures, topologies and potential applications containing gas adsorption, separation and storage, magnetism, catalysis, ion exchange, luminescence, proton-conducting etc.Using three 5-substituted-1,2,3-benzenetricarboxylic acids:5-amino-benzenetricarboxylic acid （H₃ATBC）,5-azido-benzenetricarboxylic acid （H₃N₃TBC） and 5-（nicotinamido） benzenetricarboxylic acid （H₃NATP） as the primary ligands, combination of three bispyridyl ancillary ligands:4,4’-bipyridine （4,4’-bpy）,1,2-di（pyridin-4-yl）diazene （4-DiPyDz） 1,2-bis（pyridin-4-ylmethylene）hydrazine （4-BPyMHz） and metal ions (Zn²⁺/Cd²⁺/Cu²⁺/Co²⁺/Ni²⁺/Mn²⁺/Ba²⁺/Na⁺/Cs⁺), sixteen coordination polymers were synthesized. All the complexes were characterized by elemental analysis, X-ray crystallography, IR spectra, and thermal analysis. Fluorescent properties of complexes 1-16 and gas-adsorption properties, proton conductivity of some coordination polymers have also been investigated. In addition, we also explore the influence of bispyridyl auxiliary ligands, metal ions and solvent on structures and properties.1. The solvothermal reactions of 5-amino-benzenetricarboxylic acid （H₃ATBC） as primary ligands, bipyridyl auxiliary ligands:4,4’-bipyridine （4,4’-bpy）,1,2-di（pyridin-4-yl）diazene （4-DiPyDz）, and Zn²⁺, Cd²⁺, Cu²⁺, Ni²⁺give rise to seven novel coordination polymers. In {[Zi₄（ATBC）₂（OH）₂（H₂O）₂]-H₂O}_n （1）, two reverse ATBC^3- connecting zinc ions through N atom and carboxyl oxygen form a three dimensional （3D） structure. For {[Cd₅Na（ATBC）3Cu₃-OH)₂（H₂O）₅]-H₂O}_n （2）, four cadmium ions tightly linked by//3-oxygen atoms, carboxyl oxygen atoms and oxygen atoms in water form a tera-clusters. Then combine ATBC^3- which connected by a sodium ion and another cadmium ion to form a 3D structure In complex{[Cd₃（ATBC）₂（H₂O）₂]-H₂O}_n （3）, inverted and staggered ATBC^3- ligands expand into a 3D framework via carboxyl atoms and ammo nitrogen atoms. Coordination polymers {[Cu₃（ATBC）₂（H₂O）₄]-10H₂O}_n （4）,{[Ni₃（ATBC）₂（4,4’-bpy）₂（H₂O）₂]-10H₂O}n （5） and {[Ni₃（ATBC）₂（4-DiPyDz）₂（H₂O）₂]-13H₂O}n （6） are all microporous 3D structures. Comparing 4, 5, and 6, we can conclude that the length of auxiliary ligands affects the pore size of the coordination polymer. The methane and nitrogen adsorption experiments were conducted for complex 6.{[Cu14（4,4’-bpy）₄（SO₄）（H₂O）₂][Cu₂（ATBC）₂]-H₂O}_n （7） is a two-dimensional staggered structure interspersed with zero-dimensional sheet-like network. Hydrogen bonding and π…π stacking interactions form a three dimensional supramolecular network. Coordination polymers 1-7 have good fluorescence properties.2. Three heterometallic complexes and three mixed ligands coordination polymers have been synthesized by reactions of 5-azido-benzenetricarboxylic acid （H₃N₃TBC） and metal Zn²⁺/Cd²⁺/Cu²⁺/Co²⁺/Ba²⁺/Na+/Cs+ions and bispyridyl ancillary ligands:4,4’-bipyridine （4,4’-bpy） and 1,2-bis（pyridin-4-ylmethylene）hydrazine （4-BPyMHz） under three common synthetic methods:volatilization, diffusion method and solvothermal method. In {[CdNa（N₃TBC）（H₂O）₂]-H₂O}n （8）, two inverted N₃TBC^3-ligands connect sodium ions and cadmium ions, then form a 3D structure through oxygen atoms and nitrogen atoms from ligands. {[CdCs（N₃TBC）（H₂O）]-H₂O}_n （9） is a mixed metal three-dimensional framework with Cd²⁺and Cs+connected alternately. In{BaNa₂（HN₃TBC）₂（H₂O）₃}_n （10）, Since binding capacity of Ba²⁺ ion and HNsTBC₂’is weaker, only a two-dimensional layered structure is formed. For {[Cui.5（N₃TBC）（4,4’-bpy）（H₂O）]-H₂O}n （11）, two inverted N₃TBC3-ligand connected with copper ions form a ID chain, then change to a 3D structure through 4,4’-bpy. In {[Coi.5（N₃TBC）（4,4’-bpy）i.5（H₂O）₂]-2H₂O}n （12）, the connection with N₃TBC₃’and cobalt ions forms a one-dimensional curve which expands to a 2D structure by 4,4’-bpy. The other 4,4’-bpy and cobalt ions are connected into a one-dimensional chain structure which interspersed in the 2D structure.{Zn（H₄-BPyMHz）（N₃TBC）}n （13） The connection between Znl with the carboxyl oxygen atoms of N₃TBC₃’, a nitrogen atom from H₄-BPyMHz+ion forms a Z-type chain structure. Complexes 8-13 show excellent fluorescence properties.3. Three new coordination polymers based on 5-（nicotinamido） benzenetricarboxylic acid （H₃NATP） under solvothermal condition have been synthesized with Zn（NO₃）₂-6H₂O and Mn（OAc）₂-4H₂O. Compound 14-16 have good fluorescence properties. In {[Zn₈（NATP）₄（OH）₄（H₂O）₅]-7H₂O}n （14）, Eight nuclear clusters extend through NATP₃" to form a 3D structure with channels. Compound 14 contains channels with large amount of free water. Proton conduction experiments demonstrate that 14 can draw an excellent conductivity, and the conductivity increases by temperature.{[Mn₃（NATP）₂（H₂O）n]-10H₂O}n （15） is a two-dimensional layered structure. Layers stacking form a 3D supramolecular structure through hydrogen bonds and π…π stacking interactions.{[Mni.s（NATP）（H₂O）₃]-2H₂O}n（16） Complexes 15 and 16 is substantially the same synthesis conditions, by increasing the pH of the solvent,,16 turns into a three-dimensional framework.