Syntheses,Structures,Magnetism And Luminescence Of Coordination Polymers Constructed By Flexible Polycarboxylate Acid And Pseudohalide Ligands

In recent two decades,coordination polymer has attracted wide attention,owing to their intriguing crystal structures and potential applications such as luminescence,electricity,magnetism,absorption,catalysis,senor and medicine.Among the various methods to construct coordination polymers,the self-assembly of metal ions with polycarboxylic acid,N-heterocycles and pseudohaloid ligands is a very effective method.However,the formation of coordination polymers highly depends on synthesis conditions,such as temperature,pH,reactant molar ratio,solvent etc.,which bring a lot of uncertainty to the final complex structures.We need to further research the synthesis,crystal structures and functional properties of coordination polymers.This dissertation chose a flexible tetracarboxylic acid H₄L¹?5,5'-?1,2-phenylene-bis?methoxy??diisophthalic acid?,a semi-rigid tetracarboxylic acid H₄L²?2,5-bis??4-carboxylphenyl?amino?terephthalic acid?and two pseudohalides?CN^-,SCN^-?,as primary ligands.We harvested 15 cases of new transition-metal coordination polymers.The crystal structures were determined.Their luminescence,magnetism and thermal stability were studied.The main results are as follows.By using a flexible tetracarboxylic acid H₄L¹ primary ligand and different N-heterocyclic auxiliary ligands,we obtained six novel coordination polymers:[Zn?L¹?_0.5?bpe?_0.5?H₂O?]_n?1?,[Zn?L¹?_0.5?phen?]_n·nH₂O?2?,[Co_1.5?H₂L¹?_1.5?bpmp?_0.5?H₂O?]_n·nDMF·2nH₂O?3?,[Co_1.5?HL¹??2,2'-bpy?]_n·nH₂O?4?,[Ni?L¹?_0.5?bpmp??H₂O?]_n·2nH₂O?5?and[Co₂?L¹??bph?₂]_n·nDMF·0.5nH₂O?6?.Complex 1 is an interesting 3D MOF containing 1D nanotube-like tunnel.Complexes 2 and 4 are two2D coordination polymers.Complexes 3,5 and 6 were three 3D coordination polymers.Variable-temperature magnetic susceptibility and magneto-structural correlation studies indicates that complexes 3 and 4 are ferromagnetic,while complex6 is typically antiferromagnetic.All the complexes showed relatively high thermal stability.By using a semi-rigid tetracarboxylic acid H₄L² to react with Zn²⁺?Cd²⁺and Mn²⁺under the similar reaction condition,we obtained three new coordination polymers:[Zn₄?L²?₂?H₂O?₂]_n·2nH₂O?7?,[Cd₂?L²??DMF?₂?H₂O?]_n·2nH₂O?8?,and[Mn₂?L²??DMF?₃]_n·5nH₂O?9?.Three complexes have 3D polymeric structures.Complexes 7 and 8 show strong luminescence at 555 nm.Complex 9 has antiferromagnetic coupling.By the reactions of CuCN and CuSCN with four different N-heterocyclic ligands,we obtained six new coordination polymers:[Cu₈?CN?₈?btmb?₂]_n?10?,[Cu?CN??btmb?_0.5]_n?11?,[Cu?CN??btmbb?_0.5]_n?12?,[Cu₂?CN?₂?dpa?]_n?13?,[Cu₂?SCN?₂?bph?]_n?14?,and[Cu?SCN??btmb?_0.5]_n·nCH₃CN?15?.Complexes 10 and11 have the same Cu?I?ion and btmb ligand,but with/without K₃[Fe?CN?₆].The resulting complex structures are obviously different.Complex 10 has a porous 2D doule-layer polymeric structure,while 11 is a ladder-like double chain polymer.Complex 14 is a 3D coordination polymer,while 15 is 2D network.Their thermal stability is up to 270-300?.Cu?I?complexes 10-15 have similar ligand-centered luminescence.