Clathration of Two-Dimensional Coordination Polymers:  Synthesis and Structures of [M(4,4‘-bpy)₂(H₂O)₂](ClO₄)₂·(2,4‘-bpy)₂·H₂O and [Cu(4,4‘-bpy)₂(H₂O)₂](ClO₄)₄·(4,4‘-H₂Bpy) (M = Cd^II, Zn^II and bpy = Bipyridine)

Abstract

In the presence of guest 2,4'-bpy molecules or under acidic conditions, three compounds, [Cd(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(2).(2,4'-bpy)(2).H(2)O (1), [Zn(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(2).(2,4'-bpy)(2).H(2)O (2), and [Cu(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(4).(4,4'-H(2)bpy) (3), were obtained from the reactions of the metal salts and 4,4'-bpy in an EtOH-H(2)O mixture. 1 has a 2-D square-grid network structure, crystallizing in the monoclinic space group P2/n, with a = 13.231(3) Å, b = 11.669(2) Å, c = 15.019(3) Å, beta = 112.82(3) degrees, Z = 2; 2 is isomorphous with 1, crystallizing in the monoclinic space group P2/n, with a = 13.150(3) Å, b = 11.368(2) Å, c = 14.745(3) Å, beta = 110.60(3) degrees, Z = 2. The square grids superpose on each other into a channel structure, in which each layer consists of two pairs of shared edges, perfectly square-planar with an M(II) ion and a 4,4'-bpy at each corner and side, respectively. The square cavity has dimensions of 11.669(2) x 11.788(2) and 11.368(2) x 11.488(2) Å for 1 and 2, respectively. Every two guest 2,4'-bpy molecules are clathrated in each hydrophobic host cavity and are further stabilized by pi-pi stacking and hydrogen bonding interactions. The NMR spectra clearly confirm that both 1 and 2 contain 4,4'-bpy and 2,4'-bpy molecules in a 1:1 ratio, which have stacking interaction with each other in the solution. 3 crystallizes in the orthorhombic space group Ibam, with a = 11.1283(5) Å, b = 15.5927(8) Å, c = 22.3178(11) Å, Z = 4. 3 is made up of two-dimensional square [Cu(4)(4,4'-bpy)(4)] grids, where the square cavity has dimensions of 11.13 x 11.16 Å. Each [4,4'-H(2)bpy](2+) cation is clathrated in a square cavity and stacks with one pair of opposite edges of the host square cavity in an offset fashion with the face-to-face distance of ca. 3.95 Å. Within each cavity, the [4,4'-H(2)bpy](2+) cation forms twin three-center hydrogen bonds with two pairs of ClO(4)(-) anions. The results suggest that the guest 2,4'-bpy molecules and protonated [4,4'-H(2)bpy](2+) cations present in the reaction systems serve as structure-directing templates in the formation of the crystal structures and exclude self-inclusion of the networks having larger square cavities.

Supramolecular self-assembly of nucleotide–metal coordination complexes: From simple molecules to nanomaterials

“…This research domain addresses two main areas: (i) the deliberate construction of molecular interlocked/intertwined species and polymers, such as catenanes, knots, molecular cages, circular helicates, 1D helical chains and ladders, 2D grids, 3D porous motifs, and the interpenetration mode; and (ii) the crystal design and engineering of various topologies with interesting properties in materials science. The selfassembly of metal-organic frameworks is affected greatly by factors such as the solvent system, template, pH of the solution, geometric requirements of metal ions, and counter ions [178][179][180][181].…”

Crystal structure of(μ-4,4'-bipyridine-N,N')bis(N,N'-ethylene-bis(salicylaldiminato))dizinc(II)methanol disolvate,Zn2(C10H8N2)(C16H14N2O2)2·2CH3OH

“…Zinc is an essential element for human, which plays a central, if still only dimly understood, role in a number of healing processes probably acting as a convenient source of bioactive Zn 2+ (aq). 4,4'-bipyridine is an excellent rodlike bifunctional ligand and has been extensively employed as the rigid organic building block for the construction of infinite ID, 2D, 3D coordination polymeric frameworks [5][6][7]. The study of zinc(II) complex involving an aromatic Schiff base as the primary ligand, 4,4'-bipyridine as the secondary ligand acting as a bridging mode can serve as useful models for gaining a better understanding of enzyme-metal ion-substrate complexes that play an important role in metalloenzyme-catalyzed biochemical reactions.…”

Supramolecular assembly of three d10 metal coordination polymers based on the naphthalene-1,8-dicarboxylate ligand: Syntheses, structures and luminescent properties

“…Generally, the selection of metal ions and organic ligands is critical for the construction of supramolecular structures [19][20][21][22]. We chose 1,8-nap and 2,2′-bipy on the basis of the following considerations: (1) the CH groups from 2,2′-bipy can act as H donors and the carboxylate group O atoms from 1,8-nap ligand can act as hydrogen bond acceptors, which can form CH···O hydrogen bond; (2) it is probably that naphthalene ring from the 1,8-nap and pyridine ring from the 2,2′-bipy can form - stacking interactions.…”