Displaying publications 81 - 100 of 396 in total

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  1. Lo KM, Ng SW
    PMID: 21203314 DOI: 10.1107/S1600536808023155
    In the title compound, C(12)H(24)N(+)·Br(-), both cyclo-hexane rings adopt the usual chair conformation. The cation and anion are linked by N-H⋯Br hydrogen bonds into a linear chain running along the c axis.
  2. Lo KM, Ng SW
    PMID: 21581489 DOI: 10.1107/S1600536808040312
    The Pb(IV) atom of the plumbate dianion in the title compound, (C(7)H(11)N)(2)[Pb(Br(3.75)Cl(0.25))(C(6)H(5))(2)], lies on a centre of inversion in a tetra-gonally compressed octa-hedral geometry. One of the attached Br atoms is disordered with respect to a Cl atom in a 7:1 ratio. The disordered halogen atom is an N-H⋯(Br/Cl) hydrogen-bond acceptor for the cation.
  3. Lo KM, Ng SW
    PMID: 21202244 DOI: 10.1107/S1600536808011033
    The asymmetric unit of the title compound, [Ag(2)(C(2)ClF(2)O(2))(2)(C(25)H(22)P(2))(2)], consists of two half-mol-ecules, each Ag(I) ion lying on a center of symmetry. In each complete mol-ecule, two bis-(diphenyl-phosphino)methane ligands bridge two Ag(I) ions, which are further coordinated by one chloro-difluoro-acetate ligand, giving T-shaped geometries and short intra-molecular Ag⋯Ag distances of 3.1078 (6) and 2.9950 (6) Å. In one mol-ecule, the unique -CF(2)Cl group is rotationally disordered over two sites with approximate occupancies of 0.53 and 0.47 for the major and minor components, respectively.
  4. Lo KM, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008 Apr 23;64(Pt 5):m709.
    PMID: 21202239 DOI: 10.1107/S1600536808010829
    The chloride and chloro-difluoro-acetate anions occupy cis positions in the octa-hedral coordination geometry of the title compound, [Mn(C(2)ClF(2)O(2))Cl(C(12)H(8)N(2))(2)]. The two N-heterocycles both chelate the metal atom.
  5. Lo KM, Ng SW
    PMID: 21201777 DOI: 10.1107/S1600536808026214
    The imino-diacetic acid component of the title salt, C(4)H(8)NO(4) (+)·C(7)H(7)SO(3) (-), is protonated at the N atom. The cation uses the ammonium group to form hydrogen bonds to the O atoms of two adjacent sulfonate groups. In addition, the carboxylic acid portions of the cation form hydrogen bonds to the sulfonate groups. The hydrogen-bonding inter-actions give rise to a layer structure.
  6. Rizal MR, Ng SW
    PMID: 21202717 DOI: 10.1107/S1600536808012592
    The mol-ecule of the title compound, C(8)H(12)O(4), lies on a twofold rotation axis that passes through the mid-points of two opposite C-C bonds of the ring. Carboxyl groups of adjacent mol-ecules are linked by pairs of hydrogen bonds around a centre of inversion; this inter-action gives rise to a chain that runs along [101].
  7. Lo KM, Ng SW
    PMID: 21202515 DOI: 10.1107/S1600536808014669
    The Sn(IV) atom in the title salt, (C(7)H(11)N(2))(2)[SnBr(3)(CH(3))(2)Cl], lies on a center of inversion in a tetra-gonally compressed octa-hedron; two independent Br atoms share the same site as two independent chlorine atoms so that the anion effectively has one Cl and three Br atoms. The occupancies of the Br atoms are 0.721 (1) and 0.779 (1), and those of the Cl atoms are 0.279 (1) and 0.221 (1). The crystal structure involves N-H⋯halogen hydrogen bonds.
  8. Tou TY, Ng SW
    Acta Crystallogr C Struct Chem, 2021 Oct 01;77(Pt 10):586-590.
    PMID: 34607980 DOI: 10.1107/S2053229621009293
    The present report lists selected publications on centrosymmetric compounds that manifest second harmonic generation responses in a laser, along with a few publications that dispute the laser outcomes. Two studies provide a plausible explanation for this apparent contradiction between second-order nonlinear susceptibility and inversion symmetry: the crystals are noncentrosymmetric and are twinned by inversion. If crystal structures of SHG-active compounds are presented in centrosymmetric settings, the authors of the publications may consider stipulating that the true space group is likely to be one of the noncentrosymmetric sub-space groups.
  9. Lo KM, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2009 Apr 30;65(Pt 5):m593.
    PMID: 21583815 DOI: 10.1107/S1600536809015128
    The title stannoxane is a toluene-solvated dimer, [Sn(4)(C(7)H(6)Cl)(8)Cl(2)O(2)(OH)(2)]·C(7)H(8), the tetra-nuclear mol-ecule lying across a center of inversion. The Sn(4)O(4) framework, whose two independent Sn atoms show trigonal bipyramidal coordination, is essentially planar (r.m.s deviation = 0.02 Å). One of the two chloro-benzyl groups of the chloridodiorganyltin unit is disordered over two positions with the chloro-phenyl residue refined over two positions in a 50:50 ratio. The solvent mol-ecule is disordered about a twofold axis.
  10. Lo KM, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2009 Apr 08;65(Pt 5):o969.
    PMID: 21584011 DOI: 10.1107/S1600536809012136
    In the mol-ecule of the title compound, C(14)H(12)N(2)O(4), the two benzene rings make a dihedral angle of 84.53 (8)°. O-H⋯O and N-H⋯O hydrogen bonds link adjacent mol-ecules into a layer structure.
  11. Yue ZL, Feng YQ, Ng SW
    Acta Crystallogr C Struct Chem, 2015 Feb;71(Pt 2):100-2.
    PMID: 25652275 DOI: 10.1107/S2053229614028125
    In the linear coordination polymer catena-poly[[[aqua(1,10-phenanthroline-κ(2)N,N')copper(II)]-μ-pyridine-2,6-dicarboxylato-κ(4)O(2):O(2'),N,O(6)-[(nitrato-κ(2)O,O')bismuth(III)]-μ-pyridine-2,6-dicarboxylato-κ(4)O(2),N,O(6):O(6')] dihydrate], {[Bi(III)Cu(II)(C7H3NO4)2(NO3)(C12H8N2)(H2O)]·2H2O}n, the Bi(III) cation is O,N,O'-chelated by the two pyridine-2,6-dicarboxylate ligands and O,O'-chelated by the nitrate anion, the nine coordinating atoms conferring a tricapped trigonal prismatic environment on the metal centre. Each pyridine-2,6-dicarboxylate ligand uses one of its carboxylate O atoms to bind to an aqua(1,10-phenanthroline)copper(II) unit, the Cu-O dative bonds giving rise to the formation of a ribbon motif. The Cu(II) cation exhibits a square-pyramidal geometry. The ribbon motif propagates along the shortest axis of the triclinic unit cell and the solvent water molecules are hydrogen bonded to the same ribbon.
  12. Prasath R, Sarveswari S, Ng SW, Tiekink ER
    PMID: 24427050 DOI: 10.1107/S1600536813022022
    In the title ethanol solvate, C29H20Cl2N2O·C2H5OH, the quinolinyl residues form a dihedral angle of 46.41 (4)° with each other, and each is inclined [Cp-C-C=O and C=C-C-Cp (p = pyridyl) torsion angles = 54.8 (2) and 144.44 (19)°, respectively] with respect to the almost planar bridging prop-2-en-1-one residue [O=C-C=C torsion angle = -4.1 (3)°]. The ethanol solvent mol-ecule is disordered over two positions of equal occupancy and is located close to a centre of inversion. These mol-ecules reside in cavities defined by the organic mol-ecules, which are connected into a three-dimensional architecture by C-H⋯Cl, C-H⋯O and C-H⋯N inter-actions, as well as π-π contacts [inter-centroid distances = 3.5853 (10) and 3.8268 (11) Å], each involving pyridyl rings.
  13. Aiswarya N, Sithambaresan M, Kurup MR, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2013 Oct 9;69(Pt 11):m588-9.
    PMID: 24454026 DOI: 10.1107/S1600536813026883
    The title compound, [CuCl2(C19H16N4O)], contains a Cu(II) atom N,N',O-chelated by a neutral N-phenyl-hy-dra-zine-car-box-amide ligand and additionally coordinated by two Cl atoms, resulting in a distorted square-pyramidal geometry. The ligating atoms in the basal square plane of the complex comprise the azomethine N, the pyridine N, the amide O and one of the Cl atoms, whereas the other Cl atom occupies an apical position. The apical Cl atoms in adjacent layers function as hydrogen-bond acceptors to both NH groups. Intermolecular C-H⋯Cl and C-H⋯O interactions are also observed.
  14. Selvakumaran N, Karvembu R, Ng SW, Tiekink ER
    PMID: 24427014 DOI: 10.1107/S1600536813021053
    The title compound, C26H42N4O2S2, adopts a shallow U-shape as both pendant arms of the 1,3-substituted benzene ring are orientated in the same direction. The thione S atoms lie to the same side of the benzene ring and the carbonyl O atoms to the other. The most prominent feature of the crystal packing is the formation of inversion dimers mediated by N-H⋯S hydrogen bonds. One of the 2-methyl-propyl groups is statistically disordered over two positions.
  15. Prasath R, Sarveswari S, Ng SW, Tiekink ER
    PMID: 24427034 DOI: 10.1107/S1600536813021545
    In the title compound, C32H21ClN2O, an almost planar (r.m.s. deviation = 0.033 Å) prop-2-en-1-one bridge links quinolinyl and benzoquinolinyl residues; the latter are twisted out of the plane of the bridge [dihedral angles = 75.94 (5) and 20.20 (5)°, respectively]. In the crystal, a three-dimensional architecture arises as a result of C-H⋯O, C-H⋯π and π-π [centroid-centroid distances involving pyridine rings = 3.5806 (7)-3.7537 (7) Å] interactions.
  16. Pichika MR, Kang YB, Ng SW
    PMID: 24046652 DOI: 10.1107/S1600536813015675
    In the title compound, C17H14Cl2O3, the two benzene rings are twisted by 73.6 (2)°. The twist is similar to that found in the unsubstituted compound, viz. phenyl benzoate. In the crystal, inversion dimers are linked by pairs of C-H⋯O inter-actions.
  17. Pichika MR, Kang YB, Ng SW
    PMID: 24046651 DOI: 10.1107/S1600536813015791
    In the title compound, C17H16O3, the benzene rings are twisted by 63.54 (5)°. The twist is similar to that found in the unsubstituted compound, phenyl benzoate. The crystal packing features C-H⋯O hydrogen bonds.
  18. Pichika MR, Yew BK, Ng SW
    PMID: 23795011 DOI: 10.1107/S1600536813011458
    In the title compound, C18H18O4, the planes of the benzene rings are twisted by 81.60 (5)°. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into supra-molecular chains extending along the a axis.
  19. Keng TC, Lo KM, Ng SW
    PMID: 21836954 DOI: 10.1107/S1600536811023919
    In the title carboxyl-ate-bridged polymer, [Sn(C(7)H(7))(3)(C(7)H(5)O(3))](n), the Sn(IV) atom exists in a distorted trans-C(3)SnO(2) trigonal-bipyramidal geometry. The polymer propagates as a chain along the a axis. There are two independent formula units in the asymmetric unit; the furyl ring of one of the anions is disordered over two positions in a 0.630 (8):0.370 (8) ratio. The crystal studied was a non-merohedral twin with a minor twin domain of 37.3 (1)%.
  20. Keng TC, Lo KM, Ng SW
    PMID: 21754570 DOI: 10.1107/S1600536811015686
    The six-coordinate Sn(IV) atom in the title compound, [Sn(C(7)H(6)F)(2)Cl(2)(C(10)H(8)N(2))], shows a trans-C(2)SnN(2)Cl(2) octa-hedral coordination [C-Sn-C = 174.81 (10) and 176.71 (9)° in the two independent mol-ecules in the asymmetric unit]; the Cl atoms are cis to each other as are the N atoms of the chelating N-heterocycle.
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