Displaying publications 61 - 80 of 692 in total

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  1. Fairuz ZA, Aiyub Z, Abdullah Z, Ng SW
    PMID: 21578695 DOI: 10.1107/S1600536809050041
    In the crystal structure of the title compound, [Cu(2)(C(2)H(3)O(2))(4)(C(12)H(12)N(2))(2)], the binuclear mol-ecule lies about a center of inversion; the four acetate groups each bridge a pair of Cu(II) atoms. The coordination of the metal atom is distorted square-pyramidal, with the bonding O atoms comprising a square basal plane and the coordinating N atom of the N-heterocycle occupying the apical position. The pyridine ring is twisted with respect to the benzene ring at a dihedral angle of 45.68 (16)°. Intra-molecular N-H⋯O hydrogen bonding is present between the imino and carb-oxy groups.
  2. Aiyub Z, Badaruddin E, Abdullah Z, Fairuz ZA, Ng SW, Tiekink ER
    PMID: 21588567 DOI: 10.1107/S1600536810034033
    In the centrosymmetric title mol-ecule, [Cu(2)(CH(3)COO)(4)(C(6)H(9)N(3))(2)], each of the four acetate groups bridges a pair of Cu(II) atoms [Cu-Cu = 2.6540 (4) Å]. The distorted octa-hedral geometry of the metal atom is completed by an N-donor atom of the N-ethyl-pyrimidin-2-amine ligand: an intra-molecular N-H⋯O hydrogen links its N-H group to an acetate carboxyl-ate O atom. In the crystal, C-H⋯O inter-actions link the mol-ecules into a supra-molecular chain along the b axis.
  3. Mohd Lair N, Mohd Ali H, Ng SW
    PMID: 21583308 DOI: 10.1107/S1600536809029171
    The central Cd(II) atom in the trinuclear title compound, [Cd(3)(C(14)H(19)N(2)O(3))(2)(CH(3)COO)(4)], lies on a center of inversion and is bonded to the O atoms of four acetate groups as well as to the phenolate O atoms of the mono-deprotonated Schiff base ligands in a distorted all-trans octa-hedral geometry. Two of the acetate groups function in a μ(2)-bridging mode, while the other two each chelate to the terminal Cd(II) atom and simultaneously bind to the central metal atom in a κ(3)-bonding mode. The Schiff base anions N,O-chelate to the terminal metal atoms. The morpholine ring assumes a chair conformation.
  4. Ozair LN, Abdullah N, Khaledi H, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2010 Apr 30;66(Pt 5):m589-90.
    PMID: 21579064 DOI: 10.1107/S1600536810015060
    The structure of the dinuclear title complex, [Cu(2)(C(5)H(9)O(2))(4)(C(5)H(5)N)(2)], represents a monoclinic polymorph of the previously reported triclinic form [Blewett et al. (2006 ▶). Acta Cryst. E62, m420-m422]. Each carboxyl-ate group is bidentate bridging and the distorted octa-hedral geometry about each Cu(II) atom is completed by a pyridine N atom and the other Cu atom [Cu⋯Cu = 2.6139 (7) Å]. In the crystal, mol-ecules are connected into supra-molecular chains via π-π inter-actions formed by the pyridine rings [centroid-centroid distance = 3.552 (3) Å] and these are connected into a two-dimensional array in the ac plane by C-H⋯π contacts. One of the tert-butyl groups is disordered over two orientations in a 0.734 (6):0.266 (6) ratio.
  5. Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2012 Dec 1;68(Pt 12):m1536.
    PMID: 23468744 DOI: 10.1107/S1600536812045060
    In the title solvated salt, [Ag(C18H15P)4](CF3CO2)·C2H5OH, the Ag(I) atom is coordinated by four P atoms from triphenyl-phosphane ligands in a distorted tetra-hedral geometry. The anion and solvent are engaged in weak O-H⋯O hydrogen bonds. Of the four triphenyl-phosphane ligands, two each have an equally disordered phenyl ring while the Ag(I) atom is disordered over two positions in a 0.9595 (15):0.0405 (15) ratio and the trifluoro-acetate anion is equally disordered over two positions with respect to the lattice ethanol mol-ecule.
  6. Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2012 Dec 1;68(Pt 12):m1537.
    PMID: 23468745 DOI: 10.1107/S1600536812045072
    The Ag(I) atom in the title hydrated solvated salt, [Ag(C18H15As)4](CF3CO2)·0.5CH3OH·0.5H2O, is coordinated by four As atoms from triphenyl-arsane ligands in a distorted tetra-hedral geometry. In the crystal, O-H⋯O hydrogen bonding occurs between carboxyl-ate groups of anions and lattice solvent mol-ecules. Of the four triphenyl-arsane ligands in the Ag complex cation, two each have an equally disordered phenyl ring while the trifluoro-acetate anion is disordered over two positions with respect to the lattice methanol and water mol-ecules which both show half-occupyncy. The crystal studied was a non-merohedral twin with a 13.6 (1)% contribution of the minor twin component.
  7. Yap QL, Lo KM, Ng SW
    PMID: 21580859 DOI: 10.1107/S1600536808032790
    The mol-ecule of the title compound, [Sn(C(5)H(5)S)(4)], lies on a special position of site symmetry. The Sn(IV) atom shows a slightly distorted tetra-hedral coordination.
  8. Keng TC, Lo KM, Ng SW
    PMID: 21754572 DOI: 10.1107/S1600536811015704
    The six-coordinate Sn(IV) atom in the title compound, [SnCl(4)(C(14)H(14)OS)(2)], exists in a cis-SnCl(4)O(2) octa-hedral geometry. Of the four Cl atoms, two are close to adjacent S atoms [Cl⋯S = 3.320 (1) and 3.376 (1) Å]; the Sn-Cl bonds involving these two Cl atoms are longer than the other two Sn-Cl bonds.
  9. Ng SW
    PMID: 21588594 DOI: 10.1107/S1600536810030369
    In the title salt, C(7)H(11)N(2) (+)·Br(3) (-), the essentially planar cation (r.m.s. deviation = 0.006 Å) forms an N-H⋯Br hydrogen bond to one of the Br atoms of the almost linear anion [Br-Br-Br = 179.31 (2)°]. The crystal studied was found to be a racemic twin. The whole-mol-ecule disorder of the cation and anion about a twofold rotation axis described earlier [Ng (2009). Acta Cryst. E65, o1276] is an artifact of halving one of the axes of the ortho-rhom-bic unit cell.
  10. Boonnak N, Chantrapromma S, Fun HK
    PMID: 24427082 DOI: 10.1107/S1600536813021223
    3,6,11-trihy-droxy-1,1-dimethyl-2,3-di-hydro-chromeno[2,3-f]chromen-7-one monohydrate), known as pruniflorone N, crystallized as a monohydrate, C18H16O6·H2O. The three ring systems of the xanthone skeleton are approximately coplanar, with an r.m.s. deviation of 0.0270 (1) Å from the plane through the 14 non-H atoms. The O atoms of the two hy-droxy substituents on the benzene rings also lie close to this plane, with deviations of 0.019 (1) and 0.070 (1) Å. The 2'-hy-droxy-4',4'-di-methyl-pyran ring is disordered over two positions with a 0.798 (3):0.202 (3) site-occupancy ratio. An intra-molecular O-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, the xanthone and water mol-ecules are linked into a three-dimensional network by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions. π-π inter-actions, with centroid-centroid distances of 3.5982 (7), 3.6081 (7) and 3.6456 (7) Å, are also observed.
  11. Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    PMID: 21201798 DOI: 10.1107/S1600536808026834
    The dihedral angle between the two aromatic ring systems in the title compound, C(15)H(12)N(2)O, is 42.6 (1)°. The angle at the O atom is widened to 117.7 (1)°.
  12. Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    PMID: 21201796 DOI: 10.1107/S1600536808026810
    The dihedral angle between the two aromatic ring systems in the title compound, C(15)H(12)N(2)O, is 85.9 (1)°; The angle at the O atom is widened to 118.2 (2)°. The quinoxalin-yloxy part of the mol-ecule lies on a mirror plane and the tolyl group is disordered over two positions about the mirror plane.
  13. Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    PMID: 21201797 DOI: 10.1107/S1600536808026822
    The dihedral angle between the two aromatic ring systems in the title compound, C(15)H(12)N(2)O, is 79.4 (1)°. The angle at the O atom is widened to 116.93 (9)°.
  14. Loh WS, Quah CK, Hemamalini M, Fun HK
    PMID: 21588699 DOI: 10.1107/S1600536810032745
    The asymmetric unit of the title compound, C(10)H(6)N(2)·0.5C(4)H(4)O(4), consists of one quinoline-2-carbonitrile mol-ecule and a half-mol-ecule of fumaric acid, which lies on an inversion center. The quinoline-2-carbonitrile mol-ecule is almost planar, with an r.m.s. deviation of 0.008 (1) Å. The acid and base are linked together via pairs of inter-molecular C-H⋯O and O-H⋯N hydrogen bonds, forming R(2) (2)(8) ring motifs. In the crystal, the carbonitrile mol-ecules are further linked by inter-molecular C-H⋯N hydrogen bonds, generating R(2) (2)(10) ring motifs, resulting in zigzag chains running along the c axis.
  15. Loh WS, Quah CK, Hemamalini M, Fun HK
    PMID: 21588729 DOI: 10.1107/S1600536810033118
    In the title compound, C(10)H(6)N(2), the mol-ecule is almost planar, with an r.m.s. deviation of 0.014 Å. The dihedral angle between the aromatic rings is 1.28 (16)°. In the crystal, mol-ecules are stacked along the a axis by way of weak aromatic π-π stacking inter-actions between the benzene and pyridine rings of adjacent mol-ecules [centroid-centroid separation = 3.7943 (19) Å].
  16. Hassan IN, Yamin BM, Kassim MB
    PMID: 21580948 DOI: 10.1107/S1600536808030596
    The title compound, C(13)H(16)N(2)O(3)S, is a thio-urea derivative with benzoyl and propoxycarbonyl-methyl groups attached to the two terminal N atoms. These groups adopt trans and cis configurations, respectively, with respect to the S atom across the thio-urea C-N bonds. The compound crystallizes in the P2(1)/c space group with Z = 8, resulting in two unique molecules in the asymmetric unit linked by C-H⋯S and C-H⋯O hydrogen bonds, forming a one-dimensional zigzag chain along the c axis.
  17. Wong HW, Lo KM, Ng SW
    PMID: 21754676 DOI: 10.1107/S1600536811019106
    The V(V) atom in the polymeric title compound, [NaV(C(15)H(13)N(3)O(3))O(2)(H(2)O)(2)](n), is O,N,O'-chelated by the Schiff base dianion and is five-coordinated in a trigonal-bipramidal coordination geometry. The oxide O atoms occupy the equatorial sites and one oxide O atom is connected to the Na(I) atom. The ligand simultaneously O,O'-chelates to the water-coordinated Na(I) atom; its coordination number is seven owing to an Na⋯N(pyrid-yl) bond. The two independent formula units, which are disposed about a false center of inversion, are connected into a layer. Adjacent layers are consolidated into a three-dimensional network by O-H⋯O and O-H⋯N hydrogen bonds.
  18. Sinha B, Dey GC, Sarkar B, Roy A, Ng SW, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2014 Mar 1;70(Pt 3):m112-3.
    PMID: 24764942 DOI: 10.1107/S1600536814004280
    The title complex, [Cu{μ3-O2CC6H3(NO2)2-3,5}(μ-OH)] n , features zigzag chains in which successive pairs of Cu(II) atoms are connected by OH bridges and bidentate carboxyl-ate ligands, leading to six-membered Cu(O)(OCO)Cu rings. The zigzag chains are connected into a three-dimensional architecture by Cu-O(nitro) bonds. The coordination geometry of the Cu(II) atom is square-pyramidal, with the axial position occupied by the nitro O atom, which forms the longer Cu-O bond. Bifurcated hy-droxy-nitro O-H⋯O hydrogen bonds contribute to the stability of the crystal structure.
  19. Ng SW
    PMID: 21202251 DOI: 10.1107/S1600536808011045
    In the crystal structure of the title compound, [Fe(C(6)H(4)NO(2))(2)](n), one nicotinate group O,O'-chelates one Fe atom and binds through the N atom to the other Fe atom; the second nicotinate group bridges three Fe atoms through the N and two O atoms. The μ(2)- and μ(3)-bridging modes of the two nicotinate groups result in a polymeric three-dimensional network structure. The Fe atom shows octa-hedral coordination geometry but one of the Fe-O bonds is somewhat long [2.522 (2) Å].
  20. Rizal MR, Ng SW
    PMID: 21577714 DOI: 10.1107/S1600536809035168
    The cyclo-hexane-1,3-dicarboxyl-ate dianion in the title three-dimensional coordination polymer, [Zn(2)(C(8)H(10)O(4))(2)(C(10)H(8)N(2))](n), has one carboxyl-ate group in an equatorial position and the other in an axial position of the cyclo-hexane ring, which adopts a chair conformation. The carboxyl-ate groups function as bridges to two adjacent Zn(II) atoms, generating a layer motif. Adjacent layers are linked through the 4,4'-bipyridine N-heterocycle, forming a three-dimensional network; the geometry of Zn(II) is square-pyramidal with the N atom of the N-heterocycle occupying the apical position. The N-heterocycle lies about a center of inversion and is disordered in a 1:1 ratio with respect to the C atoms bearing H atoms.
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