Yugen Zhang

Structural, spectral and thermal properties of a new anion zinc(II) hexamethylenetetramine complex

Abstract The structure of complex [Hhmt]2[Zn2(hmt)(NCS)6], where hmt=hexamethylenetetramine, is reported. Crystal data: Fw 901.80, a=13.87(1), b=17.18(1), c=9.125(7) A , α=67.11(3), V=1900(1) A 3 , Z=2, space group =P-1, T=173 K , λ( Mo-Kα )=0.71070 A , ρ calc =1.576 g cm −1 , μ=16.73 cm −1 , R=0.073, Rw=0.110. The ligand hmt is bridged by two Zn ions, forming a novel structure motif. Two protonated hmt groups per formula unit act as counter ions. The IR spectrum and the GT curve of the complex are also measured and clearly reflect its structural properties.

Synthesis and crystal structure of a complex bearing interesting structural motifs: [Cu (C4H7N3) H2O (4,4′-Hbpy)]·SO4·NO3

Abstract A new complex [Cu (C4H7N3) H2O (4,4′-Hbpy)]·SO4·NO3 was synthesized and X-ray characterized. Elemental analysis, X-ray diffraction and infrared spectroscopy of the complex were performed. The crystal system is orthorhombic. Crystal data: Fw=498.98, spacegroup: P212121. Z=4, a=14.952(3), b=20.491(4), c=6.713 A . V=2056.7(9) A . λ( Mo-Kα )=0.71070 A . μ=12.18 cm −1 , D calc =1.66 g/cm 3 , F000=1032.00, R=0.062, Rw=0.087. X-ray analysis illustrated that 4,4′-bpy is mono-protonated and that there are two kinds of anions in one molecule, which give rise to the hydrogen interaction between the molecules in the crystal. Then an extended three-dimensional network is formed along the hydrogen bonds and π–π bonds between the pyridine rings.

Thermodynamically controlled products: novel motif of metallohelicates stabilized by inter- and intra-helix hydrogen bonds

Two temperature and/or time dependent self-assembly processes of maleic dianion (male), thiourea and zinc(II) or cadmium(II) ions have been studied. By prolonging the reaction time and heating, the kinetic product [{Zn(male)(tu)(H2O)}2]·4H2O 1 can be converted into the thermodynamic product [{Zn(male)(tu)2}n] 2. In the case of the Cd–maleate–tu system, the thermodynamic product with helical formation [{(male)Cd(tu)2}2(male)Cd(tu)(H2O)2]n4 was obtained from the kinetically controlled product [Cd(Hmale)2(tu)2(H2O)2] 3 by prolonging the reaction time. The thermodynamic helicate 2 bears a new metallohelicate motif in which the helical structure is induced and stabilized by interhelix hydrogen bonding. On the contrary, 4 also bears an infinite metallohelicate motif where the helix is induced and stabilized by intrahelix hydrogen bonding and a 3-D network is formed through hydrogen bonds and short S⋯S contacts among neighboring helixes. All the complexes were characterized by X-ray crystallography.