| The rational design and controlled synthesis of the coordination polymers with novel topologies and special function represent the central interests of contemporary coordination and supramolecular chemistry. However, because the factors influencing the construction of metal-organic frameworks include not only the inherence of metal ion and ligand, but also the effects of reaction conditions, such as solvent, counterion, temperature and even stoichiometry, so to premeditatedly make the CPs with desired structures is still beyond reaching.In order to explore the effect of anions, as auxiliary ligands, and the geometry of primary ligands on the formation of metal-organic frameworks (MOFs), we designed and synthesized three bipyrazole ligands, specifically bis-(pyrazo-4-yl)methane (L1), 3,3',5,5'-tetramethyl-4,4'-bipyrazole (L2) and 1,3,3',5,5'-pentamethyl-4,4'-bipyrazole (L3), from which twelve CPs were obtained from their reactions with Cu(I) or Ag(I) in the presence of different anions. Assembly of these CPs reveals that the features of anions, such as charges, sizes, hydrophilicity / hydrophobicity, and the geometry of ligands significantly affect the assemblies of CPs. In addition, comparing the emissions of 10-12 reveals that the CPs based on different ligands are photochemically different though they similarly possess the Cu-pyrazolate coordination. In such a sense, the outcomes of this effort provide a new sight into the design of functional coordination compounds.The dissertation is divided into four chapters. The first chapter briefly introduces the concept and latent applications of MOFs and the construction and practical instances of coordination helicates. And then we review the coordination chemistry of CuCN incorporating with azo-donating ligands, and finally give the justification to choosing this area as topic.The second chapter describes the syntheses and crystal structures of four CPs, e.g. {[Cu2(L1)2(Hbtc)]·2H2O}n (1), [Cu2(L1)2(SO4)]n (2), [Cu2(L1)2(CuCl3)]n (3), [Cu2 (L1)2(Tta)]n (4) (where the Hbtc2- = benzenetricaroxylate, Tta2- = tartarate), which are comparably assembled from Cu(I), L1 and linking divalent anions. X-Ray structural analysis reveals that the sulfate-bearing 2 is uniquely three-dimensional (3D), while 1, 3 and 4 are 2D, in a way, suggesting the effect of counter anions. Comparing the structure of three compounds (1,3,4) , we conclude that: (1) The helix of the same layer whether are homochiral or not does not matter with the bridging anions whether are chiral or not; (2) In the same layer, it prefers the same chiral helix to assemble in the circumstances of steric hindrance.In chapter three, the syntheses and structures of five CPs based on L1, Cu(I) ion and univalent organic anions (namely benzenesulfonate (Bs-), toluenesulfonate (Ts-), hydroxybenzenesulfonate (HBs-) and trifluoromethylsulfonate (FMs-)) were described. The polymers are [Cu(L1)(Bs)]n (5), [Cu(L1)(Ts)]n (6), [Cu(L1)(HBs)]n (7), [Ag(L1)(Ts)]n (8), [Ag(L1)(Fs)]n (9), all of which are 1D and in all which the L1 adopts an endo-trans conformation, combining with coinage metal ions, to furnish the 21 symmetric helices and the anions act as the terminal ligands attaching to the helical chains. Especially 8 exhibits an argenophilic interaction and so assembles into a 2D network. In 5, 7, 8 and 9 the [M(L1)] helices appear in pairs of P and M forms and so the CPs are crystallized in centrosymmetric space groups. But, in the measured crystal of 6 the helices uniformly exist in a P form and so it gives a chiral space group. It is expectable that the bulk of 6 is a conglomerate of M and P enantiomers. In this sense, the isolation of 6 exemplifies a spontaneous resolution of two optical isomers.Chapter four describe the structures and luminescence of three CPs obtained from reactions of CuCN with L1, L2 and L3 respectively. Of the CPs, {[Cu2(CN)2L1]}n(10) is 2D, consisting of [CuCN] chains and L1s, {[Cu(CH3CN)4]@[Cu7(CN)8(L2)2]}n (11) is 3D, composed of a 3D [Cu-7(CN)8(L2)2] MOF encapsulating [Cu(CH3CN)4] motifs as guests, and {CH3CN@[Cu2(CN)2L3]}n (12) is 3D, made of a [Cu2(CN)2L3] MOF allowing residence of CH'-3CN molecules. The CPs are photoemissive; when irradiated, 10 emits blue light, and 11 and 12 emits yellow. |
PDF Full Text Request