Pyridine-containing Amide Assembly Supramolecular Structure Of The Ligand Group

Coordination supramolecular structure describes the ordered infinite network coming from metal-ligand coordination and intermolecular interactions (hydrogen bonds, #- # contacts,efc.) among ligands. The compounds with such supramolecular structures have been playing an important role in the research of material and biological field. It has always been the researcher's goal to synthesize predetermined supramolecular and crystal structure, to reach the goal we need to know various reaction conditions that decide the final structure.Recently, supramolecules with"zero-",one-,two- or three- dimensional frameworks have been prepared by using metal-directed self-assembly and simple rigid ligands (4,4'-bipyridine, multi-cyano, 1,4-benzenedicarboxylic acid, 1,3,5- benzenetricarboxylic acid, etc.). These rigid organic ligands allow for a relatively easy acquirement of the desired structure for their simple coordination organic groups and fixed connection type to metal (size and angle). Because of their multiple types and changeable structural topologies, the ligands with multi-function parts and certain flexibility are more easily to be affected by environments and reaction conditions to form various supramolecular structure and thus are good candidates for research that probes into the environment and condition's influence on supermoleular structures. For this purpose five monodentate or bidentate amide-containing pyridyl-type ligands (N-phenyl-4-pyridinecarboxamide, ppca; N-(methylphenyl)-4-pyridinecarboxamide, mppca; N-(4-nitrophenyl}-4-pyridinecarboxamide,nppca; N,N'-bis(3-pyridinylmethyl)-1,4-benzenedi-carboxamide,bpmb;l,2-bis(4-pyridinecarboxamide)ethane,bpce) had been synthesized from isonicotinic acid or 3-aminomethylpyridine.The common characters of these ligands are that they all contain pyridyl group which can form coordination bond with metal, the amide group that can form hydrogen bond, pyridyl or phenyl ring that can form #- # stacking interactions and all those ligands have flexibility. Crystals of sixteencoordination supramolecular compounds were successfully obtained by using the ligands and divalent first transition metal cations.The composition and crystal structure of the compounds had been determined. The influence of the counter anions and solvent on supermolecular structure and the structural features presented by flexible ligands are discussed in details.The whole thesis consists of seven chapters. Chapter 1 is about the literature review and the significance of the paper. Chapters 2-6 are about the main research content of this text. Chapter 7 is conclusions.The main research in this paper is divided into four major parts:The first part (chapter 2): anion-directed self-assembly of [Cu(ppca)2 (H20)2(N03)2], {[Cu2(/<-OH)2(ppca)2(H20)4] (C1O4)2}> [Cu2^-CH3COO)4 (ppca)2], the results indicated that different coordination ability of anions OJO3',OH~,ClO4~,CH3COO>/c.) led to different coordination structure which through the influence on hydrogen bond and x- x contacts and controlled the final structure.The second part (chapter 3): solvent-directed self-assembly of [Cu(mppca)2(CH3COO)2], {[Cu2(//-CH3COO)4(mppca)2]mppca} and {[Cu2( JJ -CH3COO)4(nppca)2]2C2HsOH},{[Cu2( n -CH3COO)4(nppca)4] -2DMF} indicated solvent is one of the other factors which decided the structure, although no solvent molecule was found in some complexes, solvent especially water took an important role in complex's structure and affected its final structure.The third part (chapter 4 and chapter 5): the influence of different flexibility on structure: hemi-rigid ligand bpmb formed a zigzag-like chain with first transition metal ions {[MffcpmbXTOHC^OHh] (NC^2}n(M=Zri,Cd,Co,)-As a derivative of ethane, bpce has an onrf-linear conformation in its free state. Bpce adopt gauche conformation to gave cyclic closed structure which formed one dimensional chain-like coordination polymers {[Cu(bpce)2(H2O)] (Xh6H20}n(X= N03", BF4", HCO3", C1O4'). In {[Cu(bpce)2(ClO4)] (ClO4)}n, each Cu center is linked to four adjacent Cu centers by an...