Design, Synthesis And Crystal Structures Of Coordination Polymers Derived From N-heterocyclic Ligands

This thesis consists of four chapters. In chapterâ… , the history and progress of crystal engineering, the design strategies of coordination polymer and subtle factors influencing the self-assembly system are briefly introduced. The backgroud of our research work and main conclusions of this thesis are summarized.In chapterâ…¡, the preparation and crystal structures of seven new complexes [Cu（HIzA）₂（H₂O）₂] （1）, [M（HIzA）₂（EG）₂] [M = Cu for 2, Co for 4, and Zn for 5] {[Cu（IzA）]·H₂O}_n （3）, [Co（IzA）（bipy）₂]·6H₂O （6）, and [Cd（HIzA）（bipy）（NO₃）]_n （7） （H₂IzA = indazole-3-carboxylic acid, EG = ethylene glycol, and bipy = 2,2’-bipyridine） are de-scribed. Among them, complexes 1-3, Cu^â…¡-H₂IzA system, are generated from different re-action conditions with the same Cu^â…¡source. Mononuclear complex 1 exhibits a 2-D hydro-gen bonding layer while complex 2 shows 3-D supramolecular network. In complex 3, the penta-coordinated Cu^â…¡centres are linked by IzA^2- anions resulting in a 3-D array with the lvt-a topology. Complexes 4 and 5 are isostructural with 2. Adding auxiliary ligand bipy to the system, we obtained complexes 6 and 7. The 1-D guest water chains are intercalated between the 2-D weak hydrogen bonding layers in mononuclear complex 6, leading to a 3-D network via weak hydrogen bonds. Complex 7 displays a 2-D layer constructed by aromatic interactions between the adjacent 1-D polymeric chains. The influence of reaction condi-tions, auxiliary ligands, and hydrogen bonding functionality on the final structures is dis-cussed.In chapterâ…¢, the reaction of different metal sources with ImA ligands affords twelve complexes [Mn（ImA）₂（Cl）₂]_n （8）, [M（ImA）₂（Cl）₂] （M = Co for 9, and Zn for 11）,{[Cu（ImA）₂（H₂O）]·H₂O·2Cl}_n （10）, {[Cd（ImA）₂（Cl）₂]·2H₂O}_n （12）, [M（ImA）₂（NCS）₂（H₂O）₂]（M = Mn for 13, and Co for 14）, [Ni（ImA）₄（NCS）₂] （15）, [Cu₂（ImA）₄（NCS）₄] （16）,[Zn（ImA）₂（NCS）₂] （17）, [Ni₂（ImA）₈（H₂O）₂]·4ClO₄·4H₂O （18）, and {[Ag（ImA）₂]·NO₃}_n （19） （ImA = 4-（1H-imidazol-1-yl）aniline）. The structures include various coordination motifs, ranging from mononuclear unit （as in 9, 11, 13, 14, 15 and 17）, to dinuclear unit （as in 16 and 18）, to 1-D chain （as in 10,12 and 19）, and then to 2-D layer （as in 8）. In the cases of 13, 14, 15, and 17, the finally strutures display the 2-D supramolecular networks via multiple hydrogen bonds, while the other complexes exhibit the 3-D architectures via intermolecular interactions. The research result demonstrates that the nature of metal ions, counterions, and the conformational nature of ImA ligands influence the final solid-state structures.In chapterâ…£, self-assembly of positional isomers, the flexible di-carboxylic ligands 3-and 4-H₂ccmp·Cl [3- and 4-H₂ccmp·Cl = 3- and 4-carboxy-l-carboxymethyl-pyridinium chloride], with transitional metal salts, yields six new complexes [Zn（3-ccmp）₂]_n （20）, [Pb（3-ccmp）（Cl）]_n （21）, [M（4-ccmp）₂（H₂O）₂] （M = Mn for 22, and Co for 23）, {[Zn（4-ccmp）₂]·2H₂O}_n （24）, and [Pb₃（4-ccmp）₄（Cl）₂]_n （25）. Complex 20 includes simple ribbon-like chains with no interchain interactions. Complex 21 exhibits a 2-D metallacyclic layer with the hetero-chiral helical chains. Mononuclear complexes 22 and 23 are isostruc-tural displaying 3-D networks via versatile hydrogen bonds. Remarkably, complex 24 pre-sents the 2-D+2-Dâ†'2-D polythreading array. In complex 25, the two crystallographically independent Pb^â…¡centers are linked by the 4-ccmp^- anions to result in a 3-D noninterpene-trating network. Among them, the 3- and 4-ccmp^- anions present various coordination fash-ions. The crystal structures reveal that the 3-ccmp^- anions may exhibit gauche- or anti-configuration upon metal complexation, whereas the 4-ccmp^- anions have no such con-formation adjusting. The structural difference indicates that the flexiblity of 3- and 4-ccmp^-anions facilitate the adjustment of the conformations and binding fashions to meet the coor-dination requirement.