Displaying publications 281 - 300 of 396 in total

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  1. Fulltext Dichloridobis(2-{1-[2-(1H-indol-3-yl)ethyl-iminio]eth-yl}phenolate-κO)zinc(II)-2-{1-[2-(1H-indol-3-yl)ethyl-iminio]eth-yl}phenolate (1/2)
    Ali HM, Mohamed Mustafa MI, Rizal MR, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 5):m718-9.
    PMID: 21202245 DOI: 10.1107/S1600536808011161
    In the mononuclear complex mol-ecule of the title compond, [ZnCl(2)(C(18)H(18)N(2)O)(2)]·2C(18)H(18)N(2)O, the Zn atom, which lies on a twofold rotation axis, is coordinated by phenolate O atoms in a tetra-hedral coordination geometry. The coordinated Schiff base uses its indole NH donor site to form a hydrogen bond to the negatively charged phenolate O atom of the uncoordinated zwitterionic Schiff base. There is an intra-molecular N-H⋯O hydrogen bond in the coordinated and uncoordinated Schiff bases. The indole NH site of the uncoordinated Schiff base does not engage in a hydrogen-bond inter-action. The CH(2)-CH(2) group in the uncoordinated Schiff base is disordered equally over two positions.
  2. Fulltext (μ-4-Methyl-benzene-thiol-ato-κS:S)bis-[carbon-yl(η-cyclo-penta-dien-yl)molybdenum(II)]
    Wong RC, Ooi ML, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 5):m695.
    PMID: 21202229 DOI: 10.1107/S1600536808010751
    The asymmetric unit of the title compound, [Mo(2)(C(5)H(5))(2)(C(7)H(7)S)(2)(CO)(2)], consists of two half-mol-ecules, each molecule lying on a centre of symmetry. The thiol-ate groups function as bridges between the Mo(II) atoms, which adopt a quasi-octa-hedral geometry. In the octa-hedral environment the two ligating S atoms are in a cis arrangement.
  3. Fulltext Quinoxalin-2-yl p-tolyl ether
    Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 9):o1823.
    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)°.
  4. Fulltext Phenyl quinoxalin-2-yl ether
    Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 9):o1820.
    PMID: 21201795 DOI: 10.1107/S1600536808026809
    The aromatic ring systems in the title compound, C(14)H(10)N(2)O, form a dihedral angle of 63.8 (1)°, resulting in an opening up of the ether-O atom angle to 118.2 (1)°.
  5. Fulltext 2-(4-Chloro-anilino)pyridine
    Fairuz MZ, Aiyub Z, Abdullah Z, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 9):o1800.
    PMID: 21201779 DOI: 10.1107/S1600536808026317
    The two aromatic rings of each of the four independent molecules in the asymmetric unit of the title compound, C(11)H(9)ClN(2), are approximately coplanar; the four mol-ecules are arranged into two amino-pyridyl N-H⋯N hydrogen-bonded pairs. The structure has a 15% twin component related by a twofold rotation about [100].
  6. Fulltext Quinoxalin-2-yl m-tolyl ether
    Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 9):o1822.
    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)°.
  7. Fulltext Quinoxalin-2-yl o-tolyl ether
    Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 9):o1821.
    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.
  8. Fulltext 6-[(E)-3,7-Dimethyl-octa-2,6-dien-yl]-5,7-dihydr-oxy-8-(2-methyl-butano-yl)-4-phenyl-2H-chromen-2-one from Mesua kunstleri King (Kosterm)
    Chan G, Awang K, A Hadi AH, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 7):o1332.
    PMID: 21202956 DOI: 10.1107/S1600536808018151
    The title compound, C(30)H(34)O(5), crystallizes with two symmetry-independent mol-ecules in the asymmetric unit. In the crystal structure, the two independent mol-ecules are disposed about a pseudo-center of inversion. An intra-molecular O-H⋯O hydrogen bond is observed in each independent mol-ecule. The crystal structure is stabilized by C-H⋯O hydrogen bonds.
  9. Bis(dicyclohexylammonium 3-thienylacetate)
    Ng SW, Chantrapromma S, Razak IA, Fun HK
    Acta Crystallogr C, 2001 Mar;57(Pt 3):291-2.
    PMID: 11250582
    The triclinic cell of the title compound contains 2C(12)H(24)N(+) x 2C(6)H(5)O(2)S(-) ion pairs that are linked by four hydrogen bonds [N...O = 2.728 (3) and 2.758 (3) A] across a centre of inversion.
  10. Red-green-blue laser emissions from dye-doped poly(vinyl alcohol) films
    Yap SS, Siew WO, Tou TY, Ng SW
    Appl Opt, 2002 Mar 20;41(9):1725-8.
    PMID: 11921803
    A microscope slide acting as a passive waveguide was coated by three separate poly(vinyl alcohol) films that were doped with Coumarin 460, Disodium Fluorescein, and Rhodamine 640 perchlorate. On collinear pumping by a nitrogen laser, these dyes furnished primary red-green-blue laser emissions that were collected and waveguided by the microscope slide but exited from both ends. Frosting the waveguide exit introduced light scattering at the glass-air interface and spatially overlaid the red-green-blue laser emissions that emerged as a uniform white-light beam.
  11. Luminescent polymorphic aggregates of trinuclear Cu(I)-pyrazolate tuned by intertrimeric CuNPy weak coordination bonds
    Zhan SZ, Chen W, Zheng J, Ng SW, Li D
    Dalton Trans, 2021 Jan 18.
    PMID: 33459321 DOI: 10.1039/d0dt03661g
    Five luminescent polymorphic aggregates of trinuclear Cu(i)-pyrazolate, namely [anti-Cu3L3]2 (1), [syn-Cu3L3·C2H5OH]2 (2), [anti-Cu3L3·C2H5OH]n (3), [anti-Cu3L3·0.5C7H8]n (4) and [syn-Cu3L3·C8H10]n (5) (HL = 4-(pyridin-4-ylthio)-3,5-dimethyl-1H-pyrazole), were reported. The trimeric Cu3L3 fragments present syn- and anti-conformations dependent on the dangled direction of 4-pyridyl groups on the two sides of the Cu3Pz3 plane (Pz = pyrazolate). Intertrimeric NPyCu weak coordination bonds associate these Cu3L3 fragments together to form dimeric or polymeric structures, which are further stabilized by crystallized solvent molecules or intertrimeric CuCu interactions. The solvated complexes (3-5) may be transformed into the unsolvated complex 1 by evacuation of the crystallized solvents upon heating. All these complexes emit from green to yellow under UV irradiation, which originated from the triplet excited states of metal to ligand charge transfer (3MLCT) mixed with intertrimeric CuCu interactions. This work provides a novel kind of supramolecular aggregate based on Cu3Pz3 beyond the classical π-acidbase adducts and metallophilicity-dependent dimers/oligomers.
  12. Thiosemicarbazone Derivative Induces in vitro Apoptosis in Metastatic PC-3 Cells via Activation of Mitochondrial Pathway
    Sinniah SK, Tan KW, Ng SW, Sim KS
    Anticancer Agents Med Chem, 2017;17(5):741-753.
    PMID: 27671302 DOI: 10.2174/1871520616666160926110929
    BACKGROUND: Thiosemicarbazone (TSC) is a Schiff base that has been receiving considerable attention owing to its promising biological implication and remarkable pharmacological properties. The most promising drug candidate of this class would be Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone) which has entered phase II clinical trials as a potent anti-cancer chemotherapeutic agent.

    OBJECTIVE: The current research aimed to synthesize several Schiff base ligands from (3-formyl-4-hydroxyphenyl) methyltriphenylphosphonium (T). Additionally, the current research aimed to study the growth inhibitory effect of triphenylphosphonium containing thiosemicarbazone derivatives on PC-3 cells by deciphering the mechanisms involved in cell death.

    METHOD: The compounds were characterized by various spectroscopic methods (infrared spectra, 1H NMR, 13C NMR, HRESIMS and X-ray crystallography) and the results were in conformity with the structure of the targeted compounds. Growth inhibitory effect of the compounds were performed against six human cell lines.

    RESULTS: DM(tsc)T displayed most potent activity against PC-3 cells with IC50 value of 2.64 ± 0.33 μM, surpassing that of the positive control cisplatin (5.47 ± 0.06 μM). There were marked morphological changes observed in DM(tsc)T treated cells stained with acridine orange and ethidium bromide which were indicative of cell apoptosis. Treatment with DM(tsc)T showed that the cell cycle is arrested in the G0/G1 phase after 72 hours. Mitochondrial membrane potential loss was observed in cells treated with DM(tsc)T, indicating the apoptosis could be due to mitochondria mediated pathway.

    CONCLUSION: This study indicates that DM(tsc)T would serve as a lead scaffold for rational anticancer agent development.

  13. Fulltext (E)-4-Hydr-oxy-N'-(2-hydr-oxy-4-methoxy-benzyl-idene)benzohydrazide N,N-dimethyl-formamide solvate
    Mohd Lair N, Mohd Ali H, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008 Dec 20;65(Pt 1):o190.
    PMID: 21581645 DOI: 10.1107/S160053680804289X
    The Schiff base mol-ecule of the title compound, C(15)H(14)N(2)O(4)·C(3)H(7)NO, adopts a trans configuration with respect to the C=N double bond; the Schiff base itself is nearly planar (r.m.s. deviation 0.20 Å). The amido N atom is a hydrogen-bond donor to the dimethyl-formamide solvate mol-ecule. One of the hydr-oxy groups forms an intra-molecular hydrogen bond to the N atom of the C=N double bond, whereas the other forms an inter-molecular hydrogen bond to the carbonyl group.
  14. Langerhans Cell Histiocytosis in Paediatric Zygoma Swelling
    Ng SW, Zakawi FA, Shanmuganathan J, Al-Yahya SN
    Indian J Otolaryngol Head Neck Surg, 2022 Dec;74(Suppl 3):5905-5909.
    PMID: 36742809 DOI: 10.1007/s12070-021-02480-5
    Langerhans cell histiocytosis (LCH) is a rare neoplasm characterized by accumulation of histiocytes in various tissues. It has a wide clinical spectrum and its presentation may mimic clinical features of common diseases. High level of suspicion is required for early diagnosis. Here is a rare case of a rapidly aggressive LCH which first presented with right zygomatic swelling.
  15. Fulltext N-Acetyl-2-hydroxy-N'-[methoxy(1-methylindol-2-yl)methyl]benzohydrazide
    Yehye WA, Rahman NA, Ariffin A, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008 Aug 23;64(Pt 9):o1824.
    PMID: 21201799 DOI: 10.1107/S1600536808026846
    In the crystal structure of the title Schiff-base, C(20)H(21)N(3)O(4), the amino group forms an N-H⋯O hydrogen bond to the acetyl group of an adjacent mol-ecule, forming a zigzag chain. The 2-hydr-oxy group is inter-nally hydrogen bonded to the amido group though an O-H⋯O hydrogen bond.
  16. Fulltext 4-Nitro-phthalo-nitrile
    Jan CY, Shamsudin NB, Tan AL, Young DJ, Ng SW, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2014 Mar 1;70(Pt 3):o323.
    PMID: 24765021 DOI: 10.1107/S1600536814003468
    In the title compound, C8H3N3O2 (systematic name: 4-nitro-benzene-1,2-dicarbo-nitrile), the nitro group is twisted out of the plane of the benzene ring to which it is attached [O-N-Cring-Cring torsion angle = 9.80 (13)°]. In the crystal packing, supra-molecular layers with a zigzag topology in the ac plane are sustained by C-H⋯N inter-actions.
  17. Fulltext 4-Nitro-phthalamide
    Jan CY, Shamsudin NB, Tan AL, Young DJ, Ng SW, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2014 Mar 1;70(Pt 3):o293.
    PMID: 24765000 DOI: 10.1107/S1600536814002955
    In the title compound, C8H7N3O4 (systematic name: 4-nitro-benzene-1,2-dicarboxamide), each of the substituents is twisted out of the plane of the benzene ring to which it is attached [dihedral angles of 11.36 (2)° for the nitro group, and 60.89 (6) and 34.39 (6)° for the amide groups]. The amide groups are orientated to either side of the least-squares plane through the benzene ring with the amine groups being directed furthest apart. In the crystal, a three-dimensional architecture is established by a network of N-H⋯O hydrogen bonds.
  18. 1,1'-Diethyl-4,4'-bipyridine-1,1'-diium bis(1,1,3,3-tetracyano-2-ethoxypropenide): multiple C-H...N hydrogen bonds form a complex sheet structure
    Setifi Z, Lehchili F, Setifi F, Beghidja A, Ng SW, Glidewell C
    Acta Crystallogr C Struct Chem, 2014 Mar;70(Pt 3):338-41.
    PMID: 24594730 DOI: 10.1107/S2053229614004379
    In the title salt, C14H18N2(2+) · 2C9H5N4O(-), the 1,1'-diethyl-4,4'-bipyridine-1,1'-diium dication lies across a centre of inversion in the space group P21/c. In the 1,1,3,3-tetracyano-2-ethoxypropenide anion, the two independent -C(CN)2 units are rotated, in conrotatory fashion, out of the plane of the central propenide unit, making dihedral angles with the central unit of 16.0(2) and 23.0(2)°. The ionic components are linked by C-H...N hydrogen bonds to form a complex sheet structure, within which each cation acts as a sixfold donor of hydrogen bonds and each anion acts as a threefold acceptor of hydrogen bonds.
  19. Fulltext Ethyl (2Z)-3-oxo-2-(3,4,5-tri-meth-oxy-benzyl-idene)butano-ate
    Zukerman-Schpector J, Hino CL, Moran PJ, de Paula BR, Ng SW, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2013;69(Pt 9):o1474.
    PMID: 24427096 DOI: 10.1107/S1600536813023374
    In the title compound, C16H20O6, the conformation about the C=C double bond [1.344 (2) Å] is Z. With respect to this bond, the ketone is almost coplanar [C-C-C-O torsion angle = -179.60 (10)°] and the ester is almost perpendicular [C-C-C-O = 78.42 (13)°]. The meth-oxy substituents of the central benzene ring are either almost coplanar [C-C-O-C = 3.54 (15) and 177.70 (9)°] or perpendicular [C-C-O-C = 80.08 12)° for the central substituent]. In the crystal, the three-dimensional architecture features C-H⋯O and π-π [inter-centroid distance = 3.6283 (6) Å] inter-actions.
  20. Zinc (II) complex with a cationic Schiff base ligand: synthesis, characterization, and biological studies
    Lee SK, Tan KW, Ng SW, Ooi KK, Ang KP, Abdah MA
    Spectrochim Acta A Mol Biomol Spectrosc, 2014;121:101-8.
    PMID: 24231745 DOI: 10.1016/j.saa.2013.10.084
    A cationic Schiff base ligand, TSB (L) and its Zn (II) complex (1) were synthesized and characterized by using CHN, (1)H-NMR, FT-IR, UV, LC-MS, and X-ray methods. Their ability to inhibit topoisomerase I, DNA cleavage activities, and cytotoxicity were studied. X-ray diffraction study shows that the mononuclear complex 1 is four coordinated with distorted tetrahedral geometry. The singly deprotonated Schiff base ligand L acts as a bidentate ON-donor ligand. Complexation of L increases the inhibitory strength on topoisomerase I activity. Complex 1 could fully inhibit topoisomerase I activity at 250 μM, while L did not show any inhibitory effect on topoisomerase I activity. In addition, L and complex 1 could cleave pBR322 DNA in a concentration and time dependent profile. Surprisingly, L has better DNA cleavage activity than complex 1. The cleavage of DNA by complex 1 is altered in the presence of hydrogen peroxide. Furthermore, L and complex 1 are mildly cytotoxic towards human ovarian cancer A2780 and hepatocellular carcinoma HepG2.
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