Displaying publications 1 - 20 of 21 in total

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  1. Usman A, Chantrapromma S, Fun HK
    Acta Crystallogr C, 2001 Dec;57(Pt 12):1443-6.
    PMID: 11740112
    The title compound, 3,5,7-triaza-1-azoniatricyclo[3.3.1.1(3,7)]decane 2,4-dinitrophenolate monohydrate, C6H13N4+*C6H3N2O5-*H2O, the 1:1 hydrate adduct of hexamethylenetetramine (HMT) and 2,4-dinitrophenol, undergoes a temperature phase transition. In the room-temperature phase, the adduct crystallizes in the monoclinic P2(1)/m space group, whereas in the low-temperature phase, the adduct crystallizes in the triclinic P1 space group. This phase transition is reversible, with the transition temperature at 273 K, and the phase transition is governed by hydrogen bonds and weak interactions. In both these temperature-dependent polymorphs, the crystal structure is alternately layered with sheets of hexamethylenetetramine and sheets of dinitrophenol stacked along the c axis. The hexamethylenetetramine and dinitrophenol moieties are linked by intermolecular hydrogen bonds. The water molecule in the adduct plays an important role, forming O-H...O hydrogen bonds which, together with C-H...O hydrogen bonds, bridge the adducts into molecular ribbons. Extra hydrogen bonds and weak interactions exist for the low-temperature polymorph and these interconnect the molecular ribbons into a three-dimensional packing structure. Also in these two temperature-dependent polymorphs, dinitrophenol acts as a hydrogen-bond acceptor and HMT acts as a hydrogen-bond donor.
  2. 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.
  3. Usman A, Razak IA, Fun HK, Chantrapromma S, Zhang Y, Xu JH
    Acta Crystallogr C, 2001 Dec;57(Pt 12):1438-40.
    PMID: 11740110
    In the title compound, C25H19NO4, the indole moiety is not completely planar, the heterocyclic ring being distorted very slightly towards a half-chair conformation. The benzoyl and 4-methoxyphenyl substituents are individually almost planar and are in a bisecting and nearly perpendicular configuration, respectively, with respect to the plane of the indole moiety. The molecular and packing structures in the crystal are stabilized by intramolecular and intermolecular C-H...O interactions.
  4. Chong CS, Chong HY, Fun HK, Leong LS
    Health Phys, 1985 Nov;49(5):1008-10.
    PMID: 4066326
  5. Shanmuga Sundara Raj S, Fun HK, Zhang J, Xiong RG, You XZ
    Acta Crystallogr C, 2000 Jun 1;56(Pt 6):E274-5.
    PMID: 15263128
    In the crystal structure of the title compound, C(12)H(10)N(4), the pyridine ring makes a dihedral angle of 1.12 (9) degrees with the mean plane of the complete almost planar and crystallographically centrosymmetric molecule. There are stacks of parallel molecules along the a-axis direction, with alternate stacks having a herring-bone arrangement relative to each other and an interplanar spacing of 3.551 A.
  6. Eltayeb NE, Teoh SG, Kusrini E, Adnan R, Fun HK
    PMID: 20004137 DOI: 10.1016/j.saa.2009.11.006
    A new Mn(III) complex, [MnCl(H(2)O)(L)].H(2)O.C(2)H(5)OH, where L=2,2'-[1,2-phenylenebis[nitrilomethylylidene]]bis(6-methoxyphenolate), has been synthesized and characterized by single-crystal X-ray diffraction. There is a good agreement between calculated and experimental structural data. The complex is crystallized in orthorhombic with space group Pbca. The Mn1 atom is coordinated with one Schiff base ligand, one water molecule and one chloride anion, forming a six-coordination number. The electronic and fluorescence spectra of the complex were also studied.
  7. Panicker CY, Varghese HT, Narayana B, Divya K, Sarojini BK, War JA, et al.
    PMID: 25863457 DOI: 10.1016/j.saa.2015.03.064
    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of Methyl N-({[2-(2-methoxyacetamido)-4-(phenylsulfanyl) phenyl]amino} [(methoxycarbonyl)imino]methyl)carbamate have been investigated using HF and DFT levels of calculations. The geometrical parameters are in agreement with XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential study was also performed. The first and second hyperpolarizability was calculated in order to find its role in nonlinear optics. Molecular docking studies are also reported. Prediction of Activity Spectra analysis of the title compound predicts anthelmintic and antiparasitic activity as the most probable activity with Pa (probability to be active) value of 0.808 and 0.797, respectively. Molecular docking studies show that both the phenyl groups and the carbonyl oxygens of the molecule are crucial for bonding and these results draw us to the conclusion that the compound might exhibit pteridine reductase inhibitory activity.
  8. Usman A, Razak IA, Chantrapromma S, Ghorai SK, Mal D, Fun HK, et al.
    Acta Crystallogr C, 2001 Sep;57(Pt 9):1118-9.
    PMID: 11588390
    The title compound, C(19)H(16)O, crystallizes with two molecules of opposite chirality in the asymmetric unit. In both molecules, the naphthalene and cyclopentanone moieties are individually planar. The two cyclopentane rings adopt envelope conformations, while the cyclohexane ring adopts a boat conformation.
  9. Usman A, Razak IA, Chantrapromma S, Fun HK, Sarkar TK, Basak S, et al.
    Acta Crystallogr C, 2001 Sep;57(Pt 9):1116-7.
    PMID: 11588389
    In the title compound, C(16)H(19)ClN(2)O(4), the pyridine ring is nearly planar, the piperidine ring is non-planar and the cyclohexane ring adopts a screw-boat conformation. The carboxylate group makes a dihedral angle of 80.9 (2) degrees with the least-squares plane through the cyclohexane ring.
  10. Usman A, Razak IA, Chantrapromma S, Fun HK, Ray JK, Das Adhikari S, et al.
    Acta Crystallogr C, 2001 Dec;57(Pt 12):1441-2.
    PMID: 11740111
    In the title compound, C20H20FNO5S, the pyrrolidine ring adopts an envelope conformation. The fluorophenyl and thiophene rings are individually planar. The molecular and crystal structures are stabilized by intra- and intermolecular C-H...O interactions.
  11. Raj SS, Fun HK, Zhao PS, Jian FF, Lu LD, Yang XJ, et al.
    Acta Crystallogr C, 2000 Jul;56 ( Pt 7):742-3.
    PMID: 10935066
  12. Shanmuga Sundara Raj S, Fun HK, Wu J, Tian YP, Xie FX, Shao ZH, et al.
    Acta Crystallogr C, 2000 Nov;56 Pt 11:1321-2.
    PMID: 11077284
    The title compound, [Ni(C(21)H(15)N(2)S(2))(2)], has a novel cis configuration with two fluorene moieties on the same side. The Ni atom is in a square-planar configuration. The molecular packing is stabilized by intramolecular stacking between the fluorene moieties and extensive C-H.pi interactions.
  13. Ng SW, Shanmuga Sundara Raj S, Fun HK, Razak IA, Hook JM
    Acta Crystallogr C, 2000 Aug;56 ( Pt 8):966-8.
    PMID: 10944291
    catena-Poly[dicyclohexylammonium [tributyltin-mu-(4-oxo-4H-pyran-2,6-dicarboxylato-O(2):O( 6))]], (C(12)H(24)N)[Sn(C(7)H(2)O(6))(C(4)H(9))(3)], consists of 4-oxo-4H-pyran-2,6-dicarboxylato groups that axially link adjacent tributyltin units into a linear polyanionic chain. The ammonium counter-ions surround the chain, and each cation forms a pair of hydrogen bonds to the double-bond carbonyl O atoms of the same dianionic group. The chain propagates in a zigzag manner along the c axis of the monoclinic cell. In catena-poly[methyl(phenyl)ammonium [tributyltin-mu-(pyridine-2,6-dicarboxylato-O(2):O(6))]], (C(7)H(10)N)[Sn(C(7)H(3)NO(4))(C(4)H(9))(3)], the pyridine-2, 6-dicarboxylato groups also link the tributyltin groups into a chain, but the hydrogen-bonded chain propagates linearly on the ac face of the monoclinic cell.
  14. Ng SW, Yang Farina AA, Othman AH, Baba I, Sivakumar K, Fun HK
    Acta Crystallogr C, 2000 Mar 15;56(Pt 3):E84-5.
    PMID: 15263206
    The title compound, [Sn(CH(3))(2)(C(5)H(10)NO(2)S(2))(2)], has crystallographic mirror symmetry (C-Sn-C on mirror plane) and the coordination polyhedron around the Sn atom is a tetrahedron [C-Sn-C 139.3 (2) degrees and S-Sn-S 82.3 (1) degrees ] distorted towards a skew-trapezoidal bipyramid owing to an intramolecular Sn.S contact [3.0427 (6) A]. The molecules are linked into a linear chain by intermolecular O-H.O hydrogen bonds [O.O 2.646 (3) A].
  15. Shanmuga Sundara Raj S, Razak IA, Fun HK, Zhao PS, Jian F, Yang X, et al.
    Acta Crystallogr C, 2000 Apr 15;56(Pt 4):E130-1.
    PMID: 15263175
    In the crystal of the title complex, [Co(C(9)H(6)NO)(3)].C(2)H(5)OH, the central Co atom has a distorted octahedral coordination comprised of three N atoms and three O atoms from the three 8-quinolinolato ligands. The three Co-O bond distances are in the range 1.887 (2)-1.910 (2) A, while the three Co-N bond distances range from 1.919 (2) to 1.934 (2) A. The solvent ethanol molecule forms an intermolecular O-H.O hydrogen bonding with a quinolinolato ligand.
  16. Low KS, Muniandy S, Naumov P, Shanmuga Sundara Raj S, Fun HK, Razak IA, et al.
    Acta Crystallogr C, 2000 Mar 15;56(Pt 3):E113-4.
    PMID: 15263222
    Bis(N,N-dimethylthiocarbamoylthio)acetic acid, [(CH(3))(2)NC(=S)S](2)CHC(=O)OH or C(8)H(14)N(2)O(2)S(4), exists as a centrosymmetric hydrogen-bonded dimer [O.O 2.661 (3) A].
  17. Mary YS, Panicker CY, Sapnakumari M, Narayana B, Sarojini BK, Al-Saadi AA, et al.
    Spectrochim Acta A Mol Biomol Spectrosc, 2015 Feb 5;136 Pt B:473-82.
    PMID: 25448948 DOI: 10.1016/j.saa.2014.09.060
    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 1-[5-(4-bromophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone have been investigated experimentally and theoretically using Gaussian09 software package. The title compound was optimized using the HF/6-31G(d) (6D, 7F), B3LYP/6-31G (6D, 7F) and B3LYP/6-311++G(d,p) (5D, 7F) calculations. The B3LYP/6-311++G(d,p) (5D, 7F) results and in agreement with experimental infrared bands. The geometrical parameters are in agreement with XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential was also performed. From the MEP it is evident that the negative charge covers the C=O group and the positive region is over the rings. First hyperpolarizability is calculated in order to find its role in nonlinear optics. Molecular docking studies suggest that the compound might exhibit inhibitory activity against TPII and may act as anti-neoplastic agent.
  18. Mary YS, Panicker CY, Sapnakumari M, Narayana B, Sarojini BK, Al-Saadi AA, et al.
    PMID: 25528512 DOI: 10.1016/j.saa.2014.11.041
    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbaldehyde have been investigated experimentally and theoretically. The title compound was optimized using at HF and DFT levels of calculations. The B3LYP/6-311++G(d,p) (5D,7F) results and in agreement with experimental infrared bands. The normal modes are assigned using potential energy distribution. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using natural bonding orbital analysis. The frontier molecular orbital analysis is used to determine the charge transfer within the molecule. From molecular electrostatic potential map, it is evident that the negative electrostatic potential regions are mainly localized over the carbonyl group and mono substituted phenyl ring and are possible sites for electrophilic attack and, positive regions are localized around all para substituted phenyl and pyrazole ring, indicating possible sites for nucleophilic attack. First hyperpolarizability is calculated in order to find its role in nonlinear optics. The geometrical parameters are in agreement with experimental data. From the molecular docking studies, it is evident that the fluorine atom attached to phenyl ring and the carbonyl group attached to pyrazole ring are crucial for binding and the results draw us to the conclusion that the compound might exhibit phosphodiesterase inhibitory activity.
  19. Panicker CY, Varghese HT, Nayak PS, Narayana B, Sarojini BK, Fun HK, et al.
    PMID: 25863456 DOI: 10.1016/j.saa.2015.03.065
    FT-IR spectrum of (2E)-3-(3-nitrophenyl)-1-[4-piperidin-1-yl]prop-2-en-1-one was recorded and analyzed. The vibrational wavenumbers were computed using HF and DFT quantum chemical calculations. The data obtained from wavenumber calculations are used to assign IR bands. Potential energy distribution was done using GAR2PED software. The geometrical parameters of the title compound are in agreement with the XRD results. NBO analysis, HOMO-LUMO, first and second hyperpolarizability and molecular electrostatic potential results are also reported. The possible electrophile attacking sites of the title molecule is identified using MEP surface plot study. Molecular docking results predicted the anti-leishmanic activity for the compound.
  20. Hamid AA, Joharry MK, Mun-Fun H, Hamzah SN, Rejali Z, Yazid MN, et al.
    Reprod Biol, 2017 Mar;17(1):9-18.
    PMID: 28262444 DOI: 10.1016/j.repbio.2017.02.001
    Amniotic fluid (AF) is now known to harbor highly potent stem cells, making it an excellent source for cell therapy. However, most of the stem cells isolated are from AF of mid-term pregnancies in which the collection procedure involves an invasive technique termed amniocentesis. This has limited the access in getting the fluid as the technique imposes certain level of risks to the mother as well as to the fetus. Alternatively, getting AF from full-term pregnancies or during deliveries would be a better resolution. Unfortunately, very few studies have isolated stem cells from AF at this stage of gestation, the fluid that is merely discarded. The question remains whether full-term AF harbors stem cells of similar potency as of the stem cells of mid-term AF. Here, we aim to review the prospect of having this type of stem cells by first looking at the origin and contents of AF particularly during different gestation period. We will then discuss the possibility that the AF, at full term, contains a population of highly potent stem cells. These stem cells are distinct from, and probably more potent than the AF mesenchymal stem cells (AF-MSCs) isolated from full-term AF. By comparing the studies on stem cells isolated from mid-term versus full-term AF from various species, we intend to address the prospect of having highly potent amniotic fluid stem cells from AF of full-term pregnancies in human and animals.
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