Structure And Properties Of Zn(?) And Cd(?) Coordination Polymers Based On 2,2?-Bipyridyl-3,3?-Dicarboxylate-1,1?-Dioxide Ligands

Coordination Polymers(CPs)are an emerging class of porous materials.Due to their structural and functional tunability as well as their ever-expanding application scope,coordination polymers have become one of the most interesting classes of materials for both scientists and engineers.They have been extensively studied for potential practical applications including gas storage and separation,luminescent and chemical sensing,biomedical applications and so on.Especially in catalysis,they are one of the earliest proven applications.The axial chiral(R,S)-2,2?-bipyridine-3,3?-dicarboxylic acid-1,1?-dioxide(H₂bpdado),as a new type of dipyridine dicarboxylic acid N-oxide ligand,has many advantages in the construction of coordination polymers.In the paper,9 coordination polymers are successfully constructed with 2,2'-bipyridine-3,3'-dicarboxylic acid-1,1'-dioxide(H₂bpdado)as the main ligand,different flexible auxiliary ligands and d¹⁰ transition metal(Zn^II/Cd^II)by solvent diffusion method,and their characterization and properties are tested in detail.Finally,the catalytic properties of these nine coordination polymers for the synthesis of 1,2,4,5-tetrazines are studied.The main research contents are as follows:(1)Nine coordination polymers 1-9,namely{[Zn(bpdado)(bpa)]·DMF·4H₂O}_n(1),{[Zn(bpdado)(bpa)]·DMA·4H₂O}_n(2),{[Zn₂(bpdado)₂(bpa)_0.5(H₂O)]·5H₂O}_n(3),{[Zn₂(bpdado)₂(bpa)₂]·8H₂O}_n(4),{[Zn₄(bpdado)₄(bpa)₄]·16H₂O}_n(5),{[Zn_2.5(bpdado)_2.5(bpp)(H₂O)₃]}_n(6),{[Zn(bpdado)(bpp)]·H₂O}_n(7),{[Cd(bpdado)(bpe)_0.5(H₂O)]·DMF·H₂O}_n(8)and{[Cd(bpdado)(bpe)_0.5(H₂O)]·DMA·H₂O}_n(9),are obtained by self-assembly of(R,S)-2,2'-bipyridine-3,3'-dicarboxylic acid-1,1'-dioxide(H₂bpdado)as the main ligand,1,2-bis(4-pyridine)-ethane(bpa),1,3-bis(4-pyridine)-propane(bpp),1,2-bis(4-pyridyl)-ethylene(bpe)as the auxiliary ligand and transition metal Zn^III and Cd^II.The characterization and properties of these coordination polymers are carried out.Among these coordination polymers,1 and 2 are isomorphic,and 8 and 9 are also isomorphic.Coordination polymers 1 and 2 have porous two-dimensional layered structure,so coordination polymers 1and 2 have adsorption properties and show good adsorption for CO₂.Coordination polymer 3is a double interpenetrating structure.Coordination polymers 4 and 5 have very similar structures,and they are complex three-dimensional structures.Coordination polymer 6 is a three-dimensional structure and coordination polymer 7 is a two-dimensional structure.Coordination polymers 8 and 9 are three-dimensional supramolecular structures with adsorption properties.Furthermore,coordination polymers 1-9 has good fluorescence properties,(2)The catalytic properties of these nine coordination polymers for the synthesis of1,2,4,5-tetrazines were studied.The experimental results showed that coordination polymer 5had better catalytic properties for the synthesis of tetrazine compounds than the other eight coordination polymers.Thirty 1,2,4,5-tetrazines were successfully synthesized under the optimal conditions,of which eight compounds were not reported.In addition,the crystal structures of nine compounds were obtained.And the crystal structures of nine compounds were analysis and discussion in detail.Seven of them were obtained for the first time.