Supramolecular Formation via Hydrogen Bonding in Copper and Nickel Complexes with 2-Hydroxynicotinic Acid

Two complexes, Cu（HnicO）2 1 and Ni（HnicO）2（H2O）2 2 （H2nicO = 2-hydroxynicolinic acid）, were synthesized by hydrothermal reactions and structurally characterized. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 8.314（7）, b = 6.275（4）, c = 11.283（7）A, β = 98.32（3）°, V = 582.5（7）A^3, Z = 2, Mr = 339.74, Dc = 1.937 g/cm3, F（000） = 342, μ = 1.908 mm^-1, S = 1.097, the final R = 0.0284 mad wR = 0.0781 for 1177 observed reflections with Ⅰ 〉 2σ（Ⅰ）. Complex 2 crystallizes in monoclinic, space group P21/c, with a = 7.438（5）, b = 12.22（1）, c = 7.537（5）A,β = 100.07（3）°, V= 674.3（8）A3, Z = 2, Mr = 370.95, Dc = 1.827 g/cm^3, F（000） = 380, = 1.487 mm^-1, S = 1.041, the final R = 0.0335 and wR = 0.0779 for 1202 observed reflections with I 〉 2σ（Ⅰ）. There are extended 3D framework structures in complexes 1 and 2 due to the N-H…O and C-H…O hydrogen bonds. The copper atom in 1 has square planar coordination, while the nickel atom in 2 adopts octahedral coordination geometry. The TG curve shows that complex 2 is stable in solid state to 150 ℃.

Syntheses and Crystal Structures of Complexes [Cu(C_(14)H_8N_3O_4Br)](C_4H_9NO) and [Ni(C_(14)H_9N_2O_3Br)](C_4H_9NO)

The title compounds, Cu（L1）（C4H8NHO） and Ni（L2）（C4H8NHO） （H2L1 = 5-bromosalicylaldehyde-p-nitrobenzoylhydrazone, H2L2 = 5-bromosalicylaldehyde-p-hydroxybenzoylhydrazone）, have been obtained and characterized by single-crystal X-ray diffraction. Complex 1 belongs to the triclinic system, space group P1 with a = 8.6960（2）, b = 9.957（2）, c = 11.878（2）A, α = 73.36（3）, β = 78.25（3）, γ = 82.64（3）°, V = 962.1（3） A^3, Mr= 512.81, Z = 2, F（000） = 514, Dc = 1.770 g/cm^3,μ（MoKα） = 3.251, R = 0.0337 and wR = 0.0846. Complex 2 is of monoclinic, space group P21/c with a = 13.313（2）, b = 8.2096（1）, c = 21.890（3） A,β = 125.737（3）°, V = 1941.9（4） A^3, Mr= 478.97, Z = 4, F（000） = 968, Dc = 1.638 g/cm^3,μ（MoKα） = 3.085, R = 0.0356 and wR = 0.0817. The ligands form a satisfactory N2O2 square plane around the metal centers in two compounds. Different patterns of hydrogen bonds are observed owing to the presence of different substituents on aromatic ring of the acylhydrazone Schiff bases. In complex 1, square-planar copper（Ⅱ） complexes are linked by intermolecular hydrogen bonds leading to zigzag infinite chains. In complex 2, the metal complexes are linked via hydrogen bonds to form corrugated sheets in a staggered fashion; 3D channels along the b axis are constructed through other non-covalent interactions between the neighboring layers.

POLYMER NETWORK-POLY(ETHYLENE GLYCOL)COMPLEXES WITH SHAPE MEMORY EFFECT

The complexes of poly(methacrylic acid-co-methyl methacrylate) network with poly(ethylene glycol) stabilized byhydrogen bonds were prepared. By introducing the poly(ethylene glycol), a large difference in storage modulus below andabove the glass transition temperature occurred and the complexes exhibited shape memory behaviors. The morphology ofcomplexes was studied by using DSC, WAXD, and DMA. The results indicate that the fixed phase of this kind of novelshape memory materials is the network, and the reversible phase is the amorphous state of PEG:PMAA complex phase. Theshape recoverability almost reaches 100%. This type of complexes can be regarded as a novel shape memory network.

DFT Study of Hydrogen-Bonded 1,3,5-Triazine-Water Complexes

The 1,3,5-triazine-water hydrogen bonding interactions have been investigated using the density functional theory B3LYP method and 6-31 ＋＋G^＊＊ basis, obtaining one, two and seven energy minima of the ground states for the 1,3,5-triazine-water, 1,3,5-triazine-（water）2 and 1,3,5-triazine-（water）3 complexes respectively. The fully optimized geometries and binding energies were reported for the various stationary points. The global minima of 1,3,5-triazine-（water）2 and 1,3,5-triazine-（water）3 complexes have a hydrogen bond N…H-O and a chain of water molecules, terminated by a hydrogen bond O…H-C. The binding energies are 13.38, 39.52 and 67.79 kJ/mol for the most stable 1,3,5-triazine-water, 1,3,5-triazine-（water）2 and 1,3,5-triazine-（water）3 complexes respectively, after the basis set superposition error and zero point energy corrections. The H-O symmetric stretching modes of water in the complexes are red-shifted relative to those of the monomer water. In addition, the NBO analysis indicates that inter-molecule charge transfer is 0.02145 e, 0.02501 e and 0.02777 e for the most stable 1 ： 1, 1 ： 2 and 1 ： 3 complexes between 1,3,5-triazine and water, respectively.

Crystal Structure of the Coordination Polymer of Sodium with Hydrazone Derivant of Acetoacetanilide

One new polymer, [Na（NPHSNPAB）（CH3OH）]n, where NPHSNPAB stands for Nphenyl-2-[2-hydroxy-3-sulfo-5-nitrophenylhydrazone]butadione-1,3, has been synthesized and characterized by ^1H NMR and FTIR spectroscopy and single-crystal X-ray diffraction. For this complex： C（17）H（17）N4NaO9S, Mr = 476.39, triclinic system, space group P1, a = 8.8741（18）, b = 10.942（2）, c = 12.039（2） A, α = 65.74（3）, β = 77.49（3）, γ = 84.30（3）o, V = 1040.3（4） A3, Z = 2, Dc = 1.521 g/cm^3, λ = 0.71073 A, F（000） = 492, S = 1.106, R = 0.0614 and w R = 0.1423 for 2945 observed reflections with I 〉 2（I）. X-ray structural analysis revealed that the structure of NPHSNPAB framework was almost planar by C–H···O, N–H···O, O–H···O, and O–H···S hydrogen bonds. Moreover, sodium（I） center was bound by six O and one N atoms, forming the coordination polymer. The molecular packing diagram showed complicated hydrogen bonds and π···π stacking interaction in the polymer. The average bond distance of the two dicyclic units（3.768 A） indicated strong π···π stacking interaction. The complex displays greenyellow emission at room temperature.