X-ray Crystal Structures of Discrete and Polymeric Silver Based Molecules Containing 4,4′-Dimethyl-2,2′-Bipyridine and 2,2′-Bipyridine

Abstract  The reaction of AgBF₄ with 4,4′-dimethyl-2,2′-bipyridine and 2,2′-bipyridine yields three previously unreported compounds. The molecular structures of these compounds were obtained by single-crystal X-ray diffraction. Crystallization of 1 occurs in the centrosymmetric monoclinic space group C2/c (No. 15) with a = 23.407(3), b = 10.7552(13), c = 13.9332(17); and β = 111.893(2) and Z = 8. Crystallization of 2 occurs in the centrosymmetric orthorhombic space group Pbca (No. 61) with a = 11.178(3), b = 23.590(6), c = 29.339(8) and Z = 8. Crystallization of 3 occurs in the centrosymmetric monoclinic space group P2₁/c (No. 14) with a = 11.2250(6), b = 8.7713(5), c = 15.4048(8), and β = 109.333(2) and Z = 4. Details of the synthesis and the structural characterization of the title compounds are presented and discussed. Index Abstract  The organic ligands 4,4′-dimethyl-2,2′-bipyridine and 2,2′-bipyridine, were used to synthesize three new complexes with AgBF₄, whose structures are dependent on the type of solvent used in the reaction as well as solvent of crystallization.      

A Cocrystal of Baicalein and 4,4′-Bipyridine with Zipper-Type Architecture

Journal of Chemical Crystallography - A new cocrystal of baicalein, possessing three A-ring-hydroxyl groups and without B-ring-hydroxyl groups and 4,4′-bipyridine (BE·2BPY·H2O) has...     

Syntheses,Structures and Optical Properties of a Series of Lanthanide Complexes with Chelidamic Acid and 4,4′-Bipyridyl

Abstract  

The title complexes, (C₁₀H₈N₂)·[Y(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·3H₂O (1), (C₁₀H₈N₂)·[Er(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·3H₂O (2), (C₁₀H₈N₂)·[La(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·4.5H₂O (3), (C₁₀H₈N₂)·[Sm(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·4.75H₂O (4), (C₁₀H₈N₂)·[Pr(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·4.75H₂O (5) were synthesized and characterized by X-ray single-crystal diffraction. The crystal structures of 1–2 reveal that they are isomorphous, among which the metal atoms are all eight-coordinate with a distorted dodecahedron coordination geometry. The structures of 3–5 are isomorphic, among which the metal atoms are all nine-coordinate with distorted tricapped trigonal prismatic coordination geometries by two chelidamic acid ligands. Complexes 1–5 are formed into 3D networks by H-bonds. The optical properties of 1–5 were investigated in terms of fluorescent spectra, which all exhibit strong luminescence.     

Solid State Intercalation of 4,4′-Bipyridine into the Interlayer Space of Montmorillonites

Abstract

Intercalation of 4,4′-bipyridine into the interlayer spaces of cobalt(II), nickel(II) and copper(II)-montmorillonites by solid-solid reactions was investigated. The successful intercalation of 4,4′-bipyridine and the complex formation in the interlayer spaces of montmorillonites was confirmed by powder XRD (the change in the basal spacings) as well as IR and the thermal analysis of the products.     

Synthesis and Crystal Structures of Ternary Copper(II) Complex Containing Salicylaldehyde Schiff Base and 4,4′-Bipyridine

Abstract  A new ternary mixed-ligand complex [Cu₂(sal-glu)₂(bipy)(H₂O)₂] · (H₂O) (bipy = 4,4′-bipyridine and sal-glu = salicylaldehyde l-glutamic Schiff base) has been synthesized and characterized by X-ray diffraction. It crystallizes in the triclinic system, space group P-1 with a = 9.6199(13) ?, b = 9.9111(13) ?, c = 9.9167(13) ?. The amino acid Schiff base coordinates to the Cu(II) ion in a tridentate mode including phenol-hydroxyl oxygen, carboxyl oxygen and amide nitrogen atom, while the bipy coordinates in bidentate bridging mode linking two Cu(II) ions. The [Cu₂(sal-glu)₂(bipy)(H₂O)₂] units are linked into 1-D chain structure and the bipy molecules are interspersed into parallel sheets via intermolecular hydrogen bonds. The carboxyl oxygen atoms, phenolic oxygen atoms and water oxygen atoms are involved in the extensive intermolecular hydrogen bond network between the water molecules and phenol-hydroxyl oxygen atoms from salicylaldehyde derived ligand. Graphical Abstract  A new ternary mixed-ligand complex [Cu₂(sal-glu)₂(bipy)(H₂O)₂]·(H₂O) (bipy = 4, 4′-bipyridine and sal-glu = salicylaldehyde l-glutamic Schiff base) crystallizes in the triclinic system, space group P-1 with a = 9.6199(13) ?, b = 9.9111(13) ?, c = 9.9167(13) ?. The amino acid Schiff base coordinates to the Cu(II) ion in a tridentate mode including phenol-hydroxyl oxygen, carboxyl oxygen and amide nitrogen atom, while the bipy coordinates in bidentate bridging mode linking two Cu(II) ions. The [Cu₂(sal-glu)₂(bipy)(H₂O)₂] units are linked into 1-D chain structure and the bipy molecules are interspersed into parallel sheets via intermolecular hydrogen bonds. The carboxyl oxygen atoms, phenolic oxygen atoms and water oxygen atoms are involved in the extensive intermolecular hydrogen bond network between the water molecules and phenol-hydroxyl oxygen atoms from salicylaldehyde derived ligand.      

Synthesis and Characterization of Two Pb(II) Complexes of 2,2′-dihydroxy,Dimethoxy-1,1′-binaphthyl-3,3′-dicarboxylic Acid

Two new complexes {[Pb(L¹)(DMSO)₂(H₂O)]·DMF}_n (1, L¹ = 2,2′-dihydroxy-l,l′-dinaphthyl-3,3′-dicarboxylate) and {[Pb(L²)(DMS O)·DMSO}_n (2, L² = 2,2′-dimethoxy-l,l′-dinaphthyl-3,3′-dicarboxylate) have been synthesized under mild conditions and structurally characterized. Crystal structural analysis reveals that complex 1 adopts a 1D infinite chain structure which forms 2D sheet by hydrogen bonds interactions. Complex 2 possesses a 2D sheet structure, which was further assembled into a 3D supramolecular network through the π-π weak interactions. IR spectra indicates the carboxyl group coordinates with the Pb²⁺ ion. TGA shows that complex 2 is highly thermally stable up to 120°C.     

Crystal and Molecular Structures of 2-Amino-4-Nitrobenzoic Acid and Its Cocrystals with 2,2′-Bipyridine (2/1) and Bis(pyridin-2-yl)ketone (1/1)

Abstract  

The eight-membered {···HOC=O}₂ synthon featured in the crystal structure of 2-amino-4-nitrobenzoic acid (1) is replaced by carboxylic acid···N-pyridine hydrogen bonds in its cocrystals with 2,2′-bipyridine (2/1; 2) and bis(pyridin-2-yl)ketone (1/1; 3) indicating the robust nature of the latter synthon. Disruption of the three-dimensional architecture based on O–H···O and N–H···O(nitro) hydrogen bonds in (1) is evident in the cocrystals which form supramolecular tubes (2) and chains (3) based on O–H···N and N–H···O hydrogen bonding. Compound (1) crystallizes in the monoclinic space group P2₁/n with a = 3.6291(1) ?, b = 7.7339(3) ?, c = 26.561(1) ?, β = 91.385(2)°, and Z = 4. Compound (2) crystallizes in the monoclinic space group C2/c with a = 27.562(3) ?, b = 6.8300(6) ?, c = 12.923(1) ?, β = 110.593(5)°, and Z = 4. Compound (3) crystallizes in the monoclinic space group P2₁/c with a = 3.795(3) ?, b = 12.024(8) ?, c = 35.65(2) ?, β = 92.131(6)°, and Z = 4 (determined from synchrotron data).     

The Preparation and Properties of the α,ω-bis(4,4′-Cyanobiphenyloxy)Alkanes: Nematogenic Molecules with a Flexible Core

The first twelve members of the homologous series of α,ω-bis(4,4′-cyanobiphenyloxy) alkanes have been synthesised. The compounds are nematogenic, although the mesophases for the first and third members of the series are monotropic. Both the nematic-isotropic transition temperature and the entropy of transition exhibit a pronounced dependence on the length of the flexible core; this is analogous to that found for main chain thermotropic liquid crystal polymers.     

Influence of Changes in Central Core on the Mesomorphic Properties of 4,4′-Dialkoxy-2,2′-Dihydroxybenzalazine and Derivatives

Two new series of compounds that have mesomorphic properties were synthesized: the 4,4′-dialkoxy-2,2′-dihydroxy-a-methylbenzalazines and the 4,4′-dialkoxy-2,2′-dihy-droxybenzalazines. The first series shows crystalline and smectic polymorphism.

A comparative study of the mesomorphic properties of these series with those of the 4,4′-dialkoxy-2,2′-dihydroxy-α,α'-dimethylbenzalazines was carried out to establish the influence of the central groups on the mesomorphic properties.     

4,4′-Di(N)Hexoxybenzalazine: Crystal and Molecular Structure and Phase Characterization of the Liquid Crystalline Compound

Abstract

The crystal and molecular structure of the mesogenic title compound (HBA) is described. Lattice parameters are: space group P1, a = 9.003(2) Å, b = 8.850(2) Å, c = 8.510(2) Å, α = 79.63(1)°, β = 65.04(1)°, γ = 87.41(1)° (at T = 299 K). The molecules contain a centre of symmetry and the phenyl rings are coplanar. In order to obtain better structural data for a comparison with its methoxy derivative (MBA) a redetermination of this structure was carried out using a new data set. The melting enthalpy of HBA is 45(2) kJmol^?1 (127.8(5)°C) its clearing enthalpy is 1.5(4) kJmol^?1 (153.2(5) °C). The fluctuation wave-length 2π/q_‖ of 27(2) Å in the nematic state can be compared with the molecular length of 31.63 Å.     

X-ray Crystal Structures of Silver Based Molecules Containing 5,5′-Dimethyl-2,2′-bipyridine and 2,2′-bipyridine

Abstract  

The reaction of AgBF₄ with 5,5′-dimethy-2,2′-bipyridine and 2,2′-bipyridine yields three previously unreported compounds. The molecular structures of these compounds were obtained by single-crystal X-ray diffraction. Crystallization of 1 occurs in the centrosymmetric triclinic space group P-1 (No. 2) with a = 13.0069(6), b = 13.5903(6), c = 13.9489(6); and α = 95.677(2), β = 98.995(2), γ = 101.716(2) and Z = 6. Crystallization of 2 occurs in the centrosymmetric monoclinic space group C2/c (No. 15) with a = 23.413(3), b = 11.2116(13), c = 13.0653(13) and β = 123.074(3), and Z = 4. Crystallization of 3 occurs in the centrosymmetric triclinic space group P-1 (No. 2) with a = 12.6843(12), b = 12.8834(13), c = 12.9887(13), and α = 96.172(5), β = 95.149(5), γ = 98.051(6) and Z = 2. Details of the synthesis and the structural characterization of the title compounds are presented and discussed.     

Synthesis and Crystal Structure of Nickel(II) Complex with 2,2′-Biimidazole and 4-Aminobenzoic Acid

Abstract  The Ni(II) complex, [Ni(H₂biim)₂(PABA)₂]Cl₂·2H₂O, H₂biim being 2,2′-biimidazole, PABA being 4-aminobenzoic acid has been synthesized and the crystal structure determined using X-ray crystallography. The complex crystallizes in triclinic system, space group P − 1 with unit cell parameters a = 8.3920(9) ?, b = 9.8436(11) ?, c = 9.8874(11) ?, α = 94.862(2)°, β = 109.142(2)°, γ = 90.992(2)°, V = 767.95(15) ?³ and Z = 1. The molecules of the complex in the crystal assemble by way of N–H⋯Cl, O–H⋯Cl, O–H⋯O hydrogen bonds as well as π–π stacking interactions to provide a two-dimensional supramolecular structure. Index Abstract  Synthesis and Crystal Structure of Nickel(II) Complex with 2,2′-Biimidazole and 4-Aminobenzoic Acid Yanping Li and Pin Yang* The molecules of the title complex [Ni(H₂biim)₂(PABA)₂]Cl₂·2H₂O in the crystal assemble by way of N–H⋯Cl, O–H⋯Cl, O–H⋯O hydrogen bonds as well as π–π stacking interactions to provide a two-dimensional supramolecular structure.      

A New Lanthanide Coordination Polymer with 4,4′-Oxybis (Benzoic Acid) Ligand: Hydrothermal Synthesis, Crystal Structure and Photoluminescence

Abstract  

Self-assemblies of the organic ligand 4,4′-oxybis(benzoic acid) with metal salt (Eu³⁺) have led to one new complex, namely, Eu(oba)₂(phen) (1) (oba = 4,4′-oxybis (benzoic acid), phen = 1,10-phenanthroline). The structure was determined by single crystal X-ray crystallography and further characterized by elemental analysis and IR spectra. X-ray diffraction analysis reveals that it crystallizes in the monoclinic C2/c space group with a = 13.4943(12) ?, b = 19.3737(18) ?, c = 27.359(2) ?, β = 99.539°, V = 7053.7(1) ?³, Z = 8, μ = 1.862, F(000) = 3376. The Eu(III) ions along the a-axis are bridged by oba ligand into infinite oval-like one-dimensional chain. Interestingly, because of the existing of hydrogen bonging (O5–H5···O6), the title complex further formed a 2D layer structure with an interlayer separation of ca. 19.3737(18) ?. The complex exhibits excellent fluorescence property.     

Molecular and crystal structure of 4′-cyanobenzo-15-crown-5

The crystal structure of 4′-cyanobenzo-15-crown-5 is determined by X-ray diffraction. The crystallographic parameters of single crystals are as follows: a = 40.479(6) Å, b = 8.821(2) Å, c = 8.484(2) Å, β = 93.94(2)°, V = 3022.2 ų, Z = 8, d _calcd = 1.27 g/cm³, and space group C2/c. The structure is solved by the direct method and refined by the least-squares procedure to R = 0.068. The conformation of the macrocycle in 4′-cyano-B15C5 is described by the a-a-g ^? -a-a-g-g ^? -a-a-g-a-g-a-a-s sequence of torsion angles.     

Syntheses and Crystal Structures of Two New Cadmium(II) and Nickel(II) Complexes with 1,4-Phenylenediacetate and 2,2′-Bipyridyl-Like Ligands

Abstract  

Two new complexes, namely [Cd(PDA)_0.5(2,2′-bpy)Cl](H₂PDA) (1) and [Ni(PDA)(phen)(H₂O)]₂ (2) (H₂PDA = 1,4-phenylenediacetic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline), have been synthesized and characterized by elemental analysis, IR spectra and X-ray crystal diffraction. Single-crystal X-ray diffraction analysis shows that complex 1 crystallizes in the triclinic space group P-1 with unit cell dimensions a = 8.760 (4) ?, b = 11.190 (5) ?, c = 13.917 (7) ?, α = 110.383 (5)°, β = 101.736 (5)°, γ = 100.612 (5)°, V = 1202.8 (10) ?³, Z = 2, R ₁ = 0.0314 and wR ₂ = 0.0898. Complex 2 crystallizes in the monoclinic space group P2(1)/n with unit cell dimensions a = 9.911 (3) ?, b = 17.924 (6) ?, c = 10.638 (4) ?, β = 94.998 (5)°, V = 1882.7 (11) ?³, Z = 2, R ₁ = 0.0397 and wR ₂ = 0.1150. In complex 1, Cd(II) ions are alternately bridged by PDA ligands and chloride ions into 1D chains and the PDA ligands display trans-configuration. Complex 2 is a dimer and two Ni(II) ions are linked by two PDA ligands with cis-configuration, resulting in a cyclic structure. In spite of these differences, both in complexes 1 and 2 there are π–π stacking interactions and hydrogen bonding to make them 3D supramolecular frameworks.     

Complexes of 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (4,13-diaza-18-crown-6) with 2,5-pyridinedicarboxylic and 2,2′-dithiosalicylic acids

A 1:2:2 complex of 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane with 2,5-pyridinedicarboxylic acid and water (1) and its 1:1:1.75 complex with 2,2-dithiosalicylic acid and water (2) have been obtained and characterized by x-ray diffraction. C₂₆H₄₀N₄O₁₄ (1), triclinic, , a = 9.574(1) Å, b = 9.632(1) Å, c = 9.723(1) Å, = 112.70(1)°, = 91.07(1)°, = 115.45(1)°, V = 728.35(13) ų, Z = 1. C₂₆H_39.5N₂O_9.75S₂ (2), M = 600.22, triclinic, , a = 10.492(1) Å, b = 10.945(1) Å, c = 14.535(2) Å, = 102.74(1)°, = 109.08(1)°, = 90.68(1)°, V = 1532.2(3) ų, Z = 2. In complex 1, both N-atoms of the macrocyclic ring are protonated. The following types of H-bonding have been found: (1) between protonated aza groups of the macrocycle and ionized carboxylic groups; (2) between the protonated aza groups and N-atoms of the pyridine nuclei (D–A distance slightly exceeds 3 Å); (3) between water molecules and C=O groups of the non-ionized carboxylic groups; and (4) between the nonionized and ionized groups of the carboxylic acid. The above interactions give rise to the formation of a developed supramolecular network in the crystals of 1. In complex 2, despite the presence of several types of hydrogen bonds involving the aza crown, 2,2-dithiosalicylic acid and water, the aromatic anions are H-bound only to the two other components, and not to each other. The H-bonds found in complex 2 are between (1) one of the protonated aza groups and water, (2) protonated aza groups and O-atoms of the ionized carboxylic groups, (3) water molecule and carboxylic O-atom, (4) water molecule and sulfur atom, and (5) water molecule and O-atom of diaza-18-crown-6.