Displaying publications 1 - 20 of 220 in total

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  1. Muthukkumar M, Karthikeyan A, Poovarasan M, Ruckmani V, Rajaram D, Jegan Jennifer S, et al.
    Acta Crystallogr E Crystallogr Commun, 2019 Apr 01;75(Pt 4):443-446.
    PMID: 31161053 DOI: 10.1107/S2056989019003189
    In the redetermination of the title compound, C3H5N2OS+·CI-, the asymmetric unit consists of one independent 2-oxo-1,3-thia-zolidin-4-iminium cation and one independent chloride anion. The cation inter-acts with a chloride anion via N-H⋯Cl hydrogen bonds forming a supra-molecular chain along [010]. These supra-molecular chains are further extended by weak C-H⋯Cl and C-H⋯O inter-actions, forming a two-dimensional network parallel to (001). The crystal structure is further stabilized by weak C-O⋯π inter-actions, supporting a three-dimensional architecture. The structure was previously determined by Ananthamurthy & Murthy [Z. Kristallogr. (1975). 8, 356-367] but has been redetermined with higher precision to allow the hydrogen-bonding patterns and supra-molecular inter-actions to be investigated.
  2. Arafath MA, Kwong HC, Adam F
    Acta Crystallogr E Crystallogr Commun, 2019 May 01;75(Pt 5):571-575.
    PMID: 31110788 DOI: 10.1107/S2056989019004444
    In the title compound, C10H13N3OS, the azomethine C=N double bond has an E configuration. The phenyl ring and methyl-hydrazine carbo-thio-amide moiety [maximum deviation = 0.008 (2) Å] are twisted slightly with a dihedral angle of 14.88 (10)°. In the crystal, mol-ecules are linked into sheets parallel to the ab plane via N-H⋯S hydrogen bonds and C-H⋯π inter-actions.
  3. Arafath MA, Kwong HC, Adam F
    Acta Crystallogr E Crystallogr Commun, 2019 Jul 01;75(Pt 7):1065-1068.
    PMID: 31392026 DOI: 10.1107/S2056989019008946
    The asymmetric unit of the title compound, C15H21N3OS, comprises of two crystallographically independent mol-ecules (A and B). Each mol-ecule consists of a cyclo-hexane ring and a 2-hy-droxy-3-methyl-benzyl-idene ring bridged by a hydrazinecarbo-thio-amine unit. Both mol-ecules exhibit an E configuration with respect to the azomethine C=N bond. There is an intra-molecular O-H⋯N hydrogen bond in each mol-ecule forming an S(6) ring motif. The cyclo-hexane ring in each mol-ecule has a chair conformation. The benzene ring is inclined to the mean plane of the cyclo-hexane ring by 47.75 (9)° in mol-ecule A and 66.99 (9)° in mol-ecule B. The mean plane of the cyclo-hexane ring is inclined to the mean plane of the thio-urea moiety [N-C(=S)-N] by 55.69 (9) and 58.50 (8)° in mol-ecules A and B, respectively. In the crystal, the A and B mol-ecules are linked by N-H⋯S hydrogen bonds, forming 'dimers'. The A mol-ecules are further linked by a C-H⋯π inter-action, hence linking the A-B units to form ribbons propagating along the b-axis direction. The conformation of a number of related cyclo-hexa-nehydrazinecarbo-thio-amides are compared to that of the title compound.
  4. Arafath MA, Kwong HC, Adam F
    Acta Crystallogr E Crystallogr Commun, 2019 Oct 01;75(Pt 10):1486-1489.
    PMID: 31636980 DOI: 10.1107/S2056989019012623
    The PtII atom in the title complex, [Pt(C15H18N4O4S)(C2H6OS)], exists within a square-planar NS2O donor set provided by the N, S, O atoms of the di-anionic tridentate thio-semicarbazo ligand and a dimethyl sulfoxide S atom. The two chelate rings are coplanar, subtending a dihedral angle of 1.51 (7)°. The maximum deviation from an ideal square-planar geometry is seen in the five-membered chelate ring with an S-Pt-S bite angle of 96.45 (2)°. In the crystal, mol-ecules are linked via N-H⋯O, C-H⋯O, C-H⋯N and C-H⋯π inter-actions into two-dimensional networks lying parallel to the ab plane. The conformations of related cyclo-hexyl-hydrazine-1-carbo-thio-amide ligands are compared to that of the title compound.
  5. Ameram N, Adam F
    Acta Crystallogr E Crystallogr Commun, 2015 Sep 01;71(Pt 9):o636.
    PMID: 26396877 DOI: 10.1107/S2056989015013559
    In the title compound, C16H17N3OS, a benzoyl thio-urea derivative, the planes of the pyridine and benzene rings are inclined to one another by 66.54 (9)°. There is an intra-molecular N-H⋯O hydrogen bond present forming an S(6) ring motif. In the crystal, mol-ecules are linked via pairs of N-H⋯N hydrogen bonds, forming inversion dimers, which are reinforced by pairs of C-H⋯S hydrogen bonds. The dimers are linked via C-H⋯π inter-actions, forming ribbons along [010].
  6. Ameram N, Adam F, Fatihah NN, Al-Juaid S
    Acta Crystallogr E Crystallogr Commun, 2015 May 01;71(Pt 5):o356.
    PMID: 25995946 DOI: 10.1107/S2056989015007860
    In the title compound, C15H15N3OS, there is an intra-molecular N-H⋯O hydrogen bond and an intra-molecular C-H⋯S hydrogen bond involving the C=O and C=S bonds which lie on opposite sides of the mol-ecule. The mol-ecule is non-planar with the benzene and pyridine rings being inclined to one another by 26.86 (9)°. In the crystal, mol-ecules are linked by pairs of N-H⋯S hydrogen bonds, forming inversion dimers with an R 2 (2)(8) ring motif. The dimers are linked via C-H⋯S hydrogen bonds, forming slabs parallel to the bc plane.
  7. Arafath MA, Kwong HC, Adam F, Mohiuddin M, Sarker MS, Salim M, et al.
    Acta Crystallogr E Crystallogr Commun, 2020 Jan 01;76(Pt 1):91-94.
    PMID: 31921459 DOI: 10.1107/S2056989019016852
    The mol-ecule of the title compound, C28H22N4O9, exhibits crystallographically imposed twofold rotational symmetry, with a dihedral angle of 66.0 (2)° between the planes of the two central benzene rings bounded to the central oxygen atom. The dihedral angle between the planes of the central benzene ring and the terminal phenol ring is 4.9 (2)°. Each half of the mol-ecule exhibits an imine E configuration. An intra-molecular O-H⋯N hydrogen bond is present. In the crystal, the mol-ecules are linked into layers parallel to the ab plane via C-H⋯O hydrogen bonds. The crystal studied was refined as a two-component pseudomerohedral twin.
  8. Adam F, Charishma SP, Prabhu BR, Samshuddin S, Ameram N
    Acta Crystallogr E Crystallogr Commun, 2015 Dec 1;71(Pt 12):o1020.
    PMID: 26870475 DOI: 10.1107/S2056989015022811
    In the title compound, C24H20N2, the dihedral angles between the pyrazole ring and the pendant phenyl, toluoyl and phenyl-ethenyl rings are 41.50 (8), 4.41 (8) and 31.07 (8)°, respectively. In the crystal, inversion dimers linked by a π-π stacking inter-actions between the phenyl-ethenyl rings are observed [centroid-centroid separation = 3.5857 (9) Å].
  9. Adam F, Smitha K, Charishma SP, Samshuddin S, Ameram N
    Acta Crystallogr E Crystallogr Commun, 2015 Dec 1;71(Pt 12):o1095-6.
    PMID: 26870516 DOI: 10.1107/S2056989015024792
    The title compound, C20H20N2O, was studied as a part of our work on pyrazoline derivatives. It represents a trans-isomer. The central pyrazoline ring adopts an envelope conformation with the asymmetric C atom having the largest deviation of 0.107 (1) Å from the mean plane. It forms dihedral angles of 6.2 (1) and 86.4 (1)° with the adjacent p-tolyl and styrene groups, respectively. In the crystal, C-H⋯O inter-actions link mol-ecules into infinite chains along the c axis.
  10. Adam F, Samshuddin S, Shruthi, Narayana B, Ameram N
    Acta Crystallogr E Crystallogr Commun, 2015 Dec 1;71(Pt 12):o1093-4.
    PMID: 26870515 DOI: 10.1107/S2056989015023658
    In the title compound, C18H18N2O2, the pyrazole ring has a twisted conformation on the CH-CH2 bond. The tolyl ring and the 4-meth-oxy-phenyl ring are inclined to the mean plane of the pyrazole ring by 4.40 (9) and 86.22 (9)°, respectively, while the two aromatic rings are inclined to one another by 88.75 (9)°. In the crystal, mol-ecules are linked via bifurcated C-H⋯(O,O) hydrogen bonds and C-H⋯π inter-actions, forming sheets lying parallel to the ab plane.
  11. Zaoui Y, Ramli Y, Taoufik J, Mague JT, Jotani MM, Tiekink ERT, et al.
    Acta Crystallogr E Crystallogr Commun, 2019 Mar 01;75(Pt 3):392-396.
    PMID: 30867956 DOI: 10.1107/S205698901900241X
    The title compound, C16H18N2O3, is constructed about a central oxopyridazinyl ring (r.m.s. deviation = 0.0047 Å), which is connected to an ethyl-acetate group at the N atom closest to the carbonyl group, and benzyl and methyl groups second furthest and furthest from the carbonyl group, respectively. An approximately orthogonal relationship exists between the oxopyridazinyl ring and the best plane through the ethyl-acetate group [dihedral angle = 77.48 (3)°]; the latter lies to one side of the central plane [the Nr-Nr-Cm-Cc (r = ring, m = methyl-ene, c = carbon-yl) torsion angle being 104.34 (9)°]. In the crystal, both H atoms of the N-bound methyl-ene group form methyl-ene-C-H⋯O(ring carbon-yl) or N(pyridazin-yl) inter-actions, resulting in the formation of a supra-molecular tape along the a-axis direction. The tapes are assembled into a three-dimensional architecture by methyl- and phenyl-C-H⋯O(ring carbon-yl) and phenyl-C-H⋯O(ester carbon-yl) inter-actions. The analysis of the calculated Hirshfeld surface indicates the dominance of H⋯H contacts to the overall surface (i.e. 52.2%). Reflecting other identified points of contact between mol-ecules noted above, O⋯H/H⋯O (23.3%), C⋯H/H⋯C (14.7%) and N⋯H/H⋯N (6.6%) contacts also make significant contributions to the surface.
  12. Chia TS, Kwong HC, Wong QA, Quah CK, Arafath MA
    Acta Crystallogr E Crystallogr Commun, 2019 Jan 01;75(Pt 1):8-11.
    PMID: 30713724 DOI: 10.1107/S2056989018016900
    A new polymorphic form of the title compound, C8H8O3, is described in the centrosymmetric monoclinic space group P21/c with Z' = 1 as compared to the first polymorph, which crystallizes with two conformers (Z' = 2) in the asymmetric unit in the same space group. In the crystal of the second polymorph, inversion dimers linked by O-H⋯O hydrogen bonds occur and these are linked into zigzag chains, propagating along the b-axis direction by C-H⋯O links. The crystal structure also features a weak π-π inter-action, with a centroid-to-centroid distance of 3.8018 (6) Å. The second polymorph of the title compound is less stable than the reported first polymorph, as indicated by its smaller calculated lattice energy.
  13. Wong QA, Chia TS, Kwong HC, Chidan Kumar CS, Quah CK, Arafath MA
    Acta Crystallogr E Crystallogr Commun, 2019 Jan 01;75(Pt 1):53-57.
    PMID: 30713733 DOI: 10.1107/S2056989018017450
    The mol-ecular structure of the title chalcone derivative, C15H10FNO3, is nearly planar and the mol-ecule adopts a trans configuration with respect to the C=C double bond. The nitro group is nearly coplanar with the attached benzene ring, which is nearly parallel to the second benzene ring. In the crystal, mol-ecules are connected by pairs of weak inter-molecular C-H⋯O hydrogen bonds into inversion dimers. The dimers are further linked by another C-H⋯O hydrogen bond and a C-H⋯F hydrogen bond into sheets parallel to (104). π-π inter-actions occur between the sheets, with a centroid-centroid distance of 3.8860 (11) Å. Hirshfeld surface analysis was used to investigate and qu-antify the inter-molecular inter-actions.
  14. Chia TS, Kwong HC, Sim AJ, Ng WZ, Wong QA, Chidan Kumar CS, et al.
    Acta Crystallogr E Crystallogr Commun, 2019 Jan 01;75(Pt 1):49-52.
    PMID: 30713732 DOI: 10.1107/S2056989018017425
    In this study, a new monoclinic polymorph (space group C2/c) of 2,2'-methyl-enebis(isoindoline-1,3-dione), C17H10N2O4, is reported and compared to the previously reported triclinic polymorph (space group P ). Similarly, both polymorphs consist of a unique mol-ecule in the asymmetric unit (Z' = 1). The mol-ecular conformations of the two polymorphs are very similar, as shown by the r.m.s. deviation of 0.368 Å (excluding all H atoms). The inter-molecular inter-actions of both polymorphs are described along with the Hirshfeld surface analysis, and the lattice energies are calculated.
  15. Kwong HC, Mahmud Pathi I, Chidan Kumar CS, Quah CK, Arafath MA
    Acta Crystallogr E Crystallogr Commun, 2018 Jul 01;74(Pt 7):1030-1034.
    PMID: 30002910 DOI: 10.1107/S2056989018009131
    In the cation of the title salt, C17H23N2O+·Br-, the adamantyl moiety and the pyridiniminium ring are inclined to the ketone bridge by torsion angles of -78.1 (2) (C-C-C=O) and 58.3 (2)° (C-C-N-C), respectively, and the ketone bridge has a C-C-C-N torsion angle of 174.80 (15)°. In the crystal, the cations are connected into chains parallel to the c axis by C-H⋯O hydrogen bonds. The chains are further linked into layers parallel to the bc plane by N-H⋯Br and C-H⋯Br hydrogen bonds, C-H⋯π inter-actions and π-π stacking inter-actions [centroid-to-centroid distance = 3.5657 (11) Å]. A Hirshfeld surface analysis, which comprises the dnorm surface, electrostatic potential map and two-dimensional fingerprint plots, was carried out to verify the contribution of the various inter-molecular inter-actions.
  16. Zaini MF, Razak IA, Khairul WM, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2018 Nov 01;74(Pt 11):1589-1594.
    PMID: 30443387 DOI: 10.1107/S2056989018014329
    The asymmetric unit of the title compound, 2C17H12N2O3·H2O comprises two mol-ecules of (E)-3-(1H-indol-2-yl)-1-(4-nitro-phen-yl)prop-2-en-1-one and a water mol-ecule. The main mol-ecule adopts an s-cis configuration with respect to the C=O and C=C bonds. The dihedral angle between the indole ring system and the nitro-substituted benzene ring is 37.64 (16)°. In the crystal, mol-ecules are linked by O--H⋯O and N-H⋯O hydrogen bonds, forming chains along [010]. In addition, weak C-H⋯O, C-H⋯π and π-π inter-actions further link the structure into a three-dimensional network. The optimized structure was generated theoretically via a density functional theory (DFT) approach at the B3LYP/6-311 G++(d,p) basis level and the HOMO-LUMO behaviour was elucidated to determine the energy gap. The obtained values of 2.70 eV (experimental) and 2.80 eV (DFT) are desirable for optoelectronic applications. The inter-molecular inter-actions were qu-anti-fied and analysed using Hirshfeld surface analysis.
  17. Zaini MF, Razak IA, Anis MZ, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2019 Jan 01;75(Pt 1):58-63.
    PMID: 30713734 DOI: 10.1107/S2056989018017371
    The asymmetric unit of the title halogenated chalcone derivative, C15H10BrFO, contains two independent mol-ecules, both adopting an s-cis configuration with respect to the C=O and C=C bonds. In the crystal, centrosymmetrically related mol-ecules are linked into dimers via inter-molecular hydrogen bonds, forming rings with R 1 2(6), R 2 2(10) and R 2 2(14) graph-set motifs. The dimers are further connected by C-H⋯O inter-actions into chains parallel to [001]. A Hirshfeld surface analysis suggests that the most significant contribution to the crystal packing is by H⋯H contacts (26.3%). Calculations performed on the optimized structure obtained using density functional theory (DFT) at B3LYP with the 6-311 G++(d,p) basis set reveal that the HOMO-LUMO energy gap is 4.12 eV, indicating the suitability of this crystal for optoelectronic and biological applications. The nucleophilic and electrophilic binding site regions are elucidated using the mol-ecular electrostatic potential (MEP).
  18. Zaini MF, Razak IA, Khairul WM, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2019 May 01;75(Pt 5):685-689.
    PMID: 31110811 DOI: 10.1107/S2056989019005243
    The title compound, C23H15NO3, adopts an s-cis conformation with respect to the ethyl-ene C=C and carbonyl C=O double bonds in the enone unit. The mol-ecule is significantly twisted with a dihedral angle of 48.63 (14)° between the anthracene ring system and the benzene ring. In the crystal, mol-ecules are linked into inversion dimers with an R 2 2(10) graph-set motif via pairs of C-H⋯O hydrogen bonds. The inter-molecular inter-actions were analysed and qu-anti-fied by Hirshfeld surface analysis. The mol-ecular structure was optimized and a small HOMO-LUMO energy gap of 2.55 eV was obtained using the DFT method at the B3LYP/6-311 G++(d,p) level of theory. This value is in close agreement with the experimental value of 2.52 eV obtained from the UV-vis analysis. The crystal used was a two-component merohedral twin with a refined ratio of 0.1996 (16):0.8004 (16).
  19. Anizaim AH, Zaini MF, Laruna MA, Razak IA, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2019 May 01;75(Pt 5):632-637.
    PMID: 31110801 DOI: 10.1107/S2056989019004912
    In the title compound, C18H12O3S2, synthesized by the Claisen-Schmidt condensation method, the essentially planar chalcone unit adopts an s-cis configuration with respect to the carbonyl group within the ethyl-enic bridge. In the crystal, weak C-H⋯π inter-actions connect the mol-ecules into zigzag chains along the b-axis direction. The mol-ecular structure was optimized geometrically using Density Functional Theory (DFT) calculations at the B3LYP/6-311 G++(d,p) basis set level and compared with the experimental values. Mol-ecular orbital calculations providing electron-density plots of HOMO and LUMO mol-ecular orbitals and mol-ecular electrostatic potentials (MEP) were also computed both with the DFT/B3LYP/6-311 G++(d,p) basis set. The experimental energy gap is 3.18 eV, whereas the theoretical HOMO-LUMO energy gap value is 2.73 eV. Hirshfeld surface analysis was used to further investigate the weak inter-actions present.
  20. Zainuri DA, Razak IA, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2018 Sep 01;74(Pt 9):1302-1308.
    PMID: 30225122 DOI: 10.1107/S2056989018011131
    The title chalcones, C31H23NO and C35H23NO, were synthesized via Claisen-Schmidt condensation reactions. Both structures were solved and refined using single-crystal X-ray diffraction data and optimized at the ground state using the density functional theory (DFT) method with the B3LYP/6-311++G(d,p) level. In the crystals, π-π inter-ations and weak C-H⋯O and C-H⋯π inter-actions are observed. The effect of these inter-molecular inter-actions in the solid state can be seen by the difference between the experimental and theoretical optimized geometrical parameters. The structures have also been characterized by UV-Vis spectroscopy. The smallest energy gaps of 2.86 and 2.96 eV enhance the nonlinear responses of such mol-ecular systems. Hirshfeld surface analyses and 2D (two-dimensional) fingerprint plots were used to qu-antify the inter-molecular inter-actions present in the crystal, indicating that these are the most important contribution to the crystal packing.
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