Displaying publications 1 - 20 of 77 in total

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  1. Zulperi ZM, Omar AR, Arshad SS
    Virus Genes, 2009 Jun;38(3):383-91.
    PMID: 19242786 DOI: 10.1007/s11262-009-0337-2
    Two Malaysian infectious bronchitis virus isolates, MH5365/95 and V9/04 were characterized based on sequence and phylogenetic analyses of S1, S2, M, and N genes. Nucleotide sequence alignments revealed many point mutations, short deletions, and insertions in S1 region of both IBV isolates. Phylogenetic analysis of S1 gene and sequences analysis of M gene indicated that MH5365/95 and V9/04 belong to non-Massachusetts strain. However, both isolates share only 77% identity. Analysis based on S1 gene showed that MH5365/95 shared more than 87% identity to several Chinese strains. Meanwhile, V9/04 showed only 67-77% identity to all the previously studied IBV strains included in this study suggesting it is a variant of IBV isolate that is unique to Malaysia. Phylogenetic analysis suggests, although both isolates were isolated 10 years apart from different states in Malaysia, they shared a common origin. Analysis based on S2 and N genes indicated that both strains are highly related to each other, and there are fewer mutations which occurred in the respective genes.
  2. Arshad S, Min Allah NU, Khamis MF
    J Pak Med Assoc, 2020 Jul;70(7):1293.
    PMID: 32799286 DOI: 10.5455/JPMA.59669
  3. 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.
  4. Zainuri DA, Razak IA, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2018 Aug 01;74(Pt 8):1087-1092.
    PMID: 30116568 DOI: 10.1107/S205698901800974X
    The title compounds, C24H18O2 and C24H17FO2, were synthesized using the Claisen-Schmidt condensation method and characterized by UV-Vis spectroscopy. Weak inter-molecular C-H⋯O, C-H⋯π and π-π hydrogen-bonding inter-actions help to stabilize the crystal structures of both compounds. The geometrical parameters obtained from the mol-ecular structure were optimized using density functional theory (DFT) calculations at the B3LYP/6-311++G(d,p) level, showing a good correlation with the experimental results. The small HOMO-LUMO energy gaps of 3.11 and 3.07 eV enhances the non-linear responses of these mol-ecular systems.
  5. Zainuri DA, Razak IA, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2018 Jun 01;74(Pt 6):780-785.
    PMID: 29951229 DOI: 10.1107/S2056989018006527
    The mol-ecular and crystal structure of two new chalcone derivatives, (E)-1-(anthracen-9-yl)-3-[4-(piperidin-1-yl)phen-yl]prop-2-en-1-one, C28H25NO, (I), and (E)-1-(anthracen-9-yl)-3-[4-(di-phenyl-amino)-phen-yl]prop-2-en-1-one, C35H25NO, (II), with the fused-ring system at the same position are described. In the crystals of (I) and (II), the mol-ecules are linked via C-H⋯O hydrogen bonds into inversion dimers, forming R22(22) and R22(14) ring motifs, respectively. Weak inter-molecular C-H⋯π inter-actions further help to stabilize the crystal structure, forming a two-dimensional architecture. The mol-ecular structures are optimized using density functional theory (DFT) at B3LYP/6-311 G++(d,p) level and compared with the experimental results. The smallest HOMO-LUMO energy gaps of (I) (exp . 2.76 eV and DFT 3.40 eV) and (II) (exp . 2.70 eV and DFT 3.28 eV) indicates the suitability of these crystals in optoelectronic applications. All inter-molecular contacts and weaker contributions involved in the supra-molecular stabilization are investigated using Hirshfeld surface analysis. The mol-ecular electrostatic potential (MEP) further identifies the positive, negative and neutral electrostatic potential regions of the mol-ecules.
  6. Zainuri DA, Razak IA, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2018 May 01;74(Pt 5):650-655.
    PMID: 29850084 DOI: 10.1107/S2056989018005467
    The title chalcone compounds, C27H18O (I) and C33H20O (II), were synthesized using a Claisen-Schmidt condensation. Both compounds display an s-trans configuration of the enone moiety. The crystal structures feature inter-molecular C-H⋯O and C-H⋯π inter-actions. Quantum chemical analysis of density functional theory (DFT) with a B3LYP/6-311++G(d,p) basis set has been employed to study the structural properties of the compound. The effect of the inter-molecular inter-actions in the solid state are responsible for the differences between the experimental and theoretical optimized geometrical parameters. The small HOMO-LUMO energy gap in (I) (exp : 3.18 eV and DFT: 3.15 eV) and (II) (exp : 2.76 eV and DFT: 2.95 eV) indicates the suitability of these compounds for optoelectronic applications. The inter-molecular contacts and weak contributions to the supra-molecular stabilization are analysed using Hirshfeld surface analysis.
  7. Zainuri DA, Razak IA, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2018 Apr 01;74(Pt 4):492-496.
    PMID: 29765753 DOI: 10.1107/S2056989018003791
    The title compound, C31H20O, was synthesized using a Claisen-Schmidt condensation. The enone group adopts an s-trans conformation and the anthracene ring systems are twisted at angles of 85.21 (19) and 83.98 (19)° from the enone plane. In the crystal, mol-ecules are connected into chains along [100] via weak C-H⋯π inter-actions. The observed band gap of 3.03 eV is in excellent agreement with that (3.07 eV) calculated using density functional theory (DFT) at the B3LYP/6-311++G(d,p) level. The Hirshfeld surface analysis indicates a high percentage of C⋯H/H⋯C (41.2%) contacts in the crystal.
  8. Zainuri DA, Razak IA, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2018 Oct 01;74(Pt 10):1491-1496.
    PMID: 30319808 DOI: 10.1107/S2056989018013087
    The crystal structures of (E)-1-(anthracen-9-yl)-3-(3H-indol-2-yl)prop-2-en-1-one, C25H17NO, and (E)-1-(anthracen-9-yl)-3-[4-(di-methyl-amino)-naphthalen-1-yl]prop-2-en-1-one, C29H23NO, are reported. In each case the anthracene ring system and pendant ring system are almost perpendicular to each other [dihedral angles = 75.57 (7)° and 70.26 (10)°, respectively]. In the extended structures, weak N-H⋯O, C-H⋯O and C-H⋯π inter-actions influence the centrosymmetric crystal packing. Density functional theory calculations were carried out using a 6-311 G++(d,p) basis set and the calculated structures are in good agreement with the crystal structures. The compounds were also characterized by UV-Vis absorption spectroscopy and the smallest (HOMO-LUMO) energy gaps of 2.89 and 2.54 eV indicate the enhanced non-linear responses (inter-molecular charge transfers) of these systems.
  9. Zainuri DA, Razak IA, Arshad S
    Acta Crystallogr E Crystallogr Commun, 2018 Oct 01;74(Pt 10):1427-1432.
    PMID: 30319794 DOI: 10.1107/S2056989018012641
    The structures of two new anthracenyl chalcones, namely (E)-1-(anthracen-9-yl)-3-(4-nitro-phen-yl)prop-2-en-1-one, C23H15NO3, and (E)-1-(anthracen-9-yl)-3-(4-iodo-phen-yl)prop-2-en-1-one, C23H15IO are reported. A structural comparative study between the two chalcones was performed and some effects on the geometrical parameters, such as planarity and dihedral angles, are described. The mol-ecular geometry was determined by single-crystal X-ray diffraction, and density functional theory (DFT) at B3LYP with the 6-311++G(d,p) basis set was applied to optimize the ground-state geometry. In addition, inter-molecular inter-actions responsible for the crystal packing were analysed. The electronic properties, such as excitation energies and HOMO-LUMO energies were calculated by time-dependent density functional theory (TD-DFT) and the results complement the experimental findings. The mol-ecular electrostatic potential (MEP) was also investigated at the same level of theory in order to identify and qu-antify the possible reactive sites.
  10. Dhanabalan N, Thanigaimani K, Arshad S, Razak IA, Santhanaraj KJ
    Acta Crystallogr Sect E Struct Rep Online, 2014 Jun 1;70(Pt 6):o657-8.
    PMID: 24940241 DOI: 10.1107/S160053681401023X
    The asymmetric unit of the title hydrated salt, C13H11N2 (+)·C7H6NO2 (-)·2H2O, consists of two independent 9-amino-acridinium cations, two 4-amino-benzoate anions and four water mol-ecules. Both 9-amino-acridinium cations are essentially planar, with maximum deviations of 0.034 (1) and 0.025 (2) Å, and are protonated at the pyridine N atoms. The 4-amino-benzoate anions are approximately planar, with dihedral angles of 9.16 (19) and 5.4 (2)° between the benzene ring and the carboxyl-ate group. In the crystal, the two independent anions are connected by N-H⋯O hydrogen bonds, forming a layer parallel to (100). The layers are connected through the cations by N-H⋯N and N-H⋯O hydrogen bonds. The water mol-ecules, which form O-H⋯O hydrogen-bonded chains along the b-axis direction, connect the anions and the cations by O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds. The crystal structure also features π-π inter-actions [centroid-centroid distances = 3.6343 (9)-3.8366 (10) Å] and a C-H⋯π inter-action.
  11. Khalib NC, Thanigaimani K, Arshad S, Razak IA
    PMID: 24046675 DOI: 10.1107/S1600536813016310
    In the title salt, C6H9N2 (+)·C7H5O3 (-), the anion is essentially planar, with a dihedral angle of 2.72 (17)° between the benzene ring and the carboxyl-ate group. In the crystal, the anions are connected by O-H⋯O hydrogen bonds, forming a 41 helical chain along the c axis. The protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl-ate O atoms of the anion via a pair of N-H⋯O hydrogen bonds with an R 2 (2)(8) ring motif. The ion pairs are further connected via another N-H⋯O hydrogen bond, resulting in a three-dimensional network.
  12. Farhadikoutenaei A, Thanigaimani K, Arshad S, Razak IA
    PMID: 24046674 DOI: 10.1107/S1600536813016322
    In the 3-hy-droxy-picolinate anion of the title salt, C6H9N2 (+)·C6H4NO3 (-), an intra-molecular O-H⋯O hydrogen bond with an S(6) graph-set motif is formed, so that the anion is essentially planar, with a dihedral angle of 9.55 (9)° between the pyridine ring and the carboxyl-ate group. In the crystal, the cations and anions are linked via N-H⋯O hydrogen bonds, forming a centrosymmetric 2 + 2 aggregate with R 2 (2)(8) and R 4 (2)(8) ring motifs. The crystal structure also features N-H⋯N and weak C-H⋯π inter-actions.
  13. Thanigaimani K, Arshad S, Razak IA, Makeshvaran D, Balasubramani K
    PMID: 23795126 DOI: 10.1107/S1600536813013895
    The 4-methyl-benzoic acid mol-ecule of the title adduct, C10H11N5·C8H8O2, is approximately planar with a dihedral angle of 6.3 (2)° between the carb-oxy-lic acid group and the benzene ring. In the triazine mol-ecule, the plane of the triazine ring makes a dihedral angle of 29.2 (2)° with that of the adjacent benzene ring. In the crystal, the acid and base mol-ecules are linked via N-H⋯O and O-H⋯N hydrogen bonds with an R 2 (2)(8) motif, and the acid-base pairs are further connected via N-H⋯N hydrogen bonds with R 2 (2)(8) motifs, forming a supra-molecular ribbon along [101]. Between the tapes, a weak C-H⋯π inter-action is observed.
  14. Thanigaimani K, Khalib NC, Arshad S, Razak IA
    Acta Crystallogr Sect E Struct Rep Online, 2013 Apr 1;69(Pt 4):o539-40.
    PMID: 23634079 DOI: 10.1107/S1600536813006673
    The asymmetric unit of the title salt, C10H11N2 (+)·C4H5O4 (-), consists of two independent 5-amino-6-methyl-quinolin-1-ium cations and two 3-carb-oxy-propano-ate anions. Both cations are protonated at the pyridine N atoms and are essentially planar, with maximum deviations of 0.026 (3) and 0.016 (2) Å. In the crystal, the cations and anions are linked via N-H⋯O and O-H⋯O hydrogen bonds, forming a layer parallel to the ab plane. In the layer, weak C-H⋯O hydrogen bonds and π-π stacking inter-actions, with centroid-to-centroid distances of 3.7283 (15) and 3.8467 (15) Å, are observed. The crystal structure also features weak C-H⋯O hydrogen bonds between the layers.
  15. Thanigaimani K, Khalib NC, Arshad S, Razak IA
    Acta Crystallogr Sect E Struct Rep Online, 2013 Apr 1;69(Pt 4):o537-8.
    PMID: 23634078 DOI: 10.1107/S160053681300665X
    In the 5-chloro-salicylate anion of the title salt, C5H6BrN2 (+)·C7H4ClO3 (-), an intra-molecular O-H⋯O hydrogen bond with an S(6) graph-set motif is formed, so that the anion is essentially planar with a dihedral angle of 1.3 (5)° between the benzene ring and the carboxyl-ate group. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl-ate O atoms via a pair of N-H⋯O hydrogen bonds, forming an R 2 (2)(8) ring motif. The crystal structure also features N-H⋯O and weak C-H⋯O inter-actions, resulting in a layer parallel to the (10-1) plane.
  16. Thanigaimani K, Razak IA, Arshad S, Jagatheesan R, Santhanaraj KJ
    Acta Crystallogr Sect E Struct Rep Online, 2012 Oct 1;68(Pt 10):o2910.
    PMID: 23125702 DOI: 10.1107/S1600536812038019
    In the title compound, C(10)H(11)N(5)O, the triazine ring forms a dihedral angle of 10.37 (4)° with the benzene ring. In the crystal, adjacent mol-ecules are linked by a pair of N-H⋯N hydrogen bonds, forming an inversion dimer with an R(2) (2)(8) ring motif. The dimers are further connected via N-H⋯O and N-H⋯N hydrogen bonds, resulting in a three-dimensional network.
  17. Thanigaimani K, Razak IA, Arshad S, Jagatheesan R, Santhanaraj KJ
    Acta Crystallogr Sect E Struct Rep Online, 2012 Oct 1;68(Pt 10):o2938-9.
    PMID: 23125724 DOI: 10.1107/S1600536812038743
    The asymmetric unit of the title compound, 2C(10)H(11)N(5)O·C(6)H(10)O(4), consists of a 2,4-diamino-6-(4-meth-oxy-phen-yl)-1,3,5-triazine mol-ecule and one-half mol-ecule of adipic acid which lies about an inversion center. The triazine ring makes a dihedral angle of 12.89 (4)° with the adjacent benzene ring. In the crystal, the components are linked by N-H⋯O and O-H⋯N hydrogen bonds, thus generating a centrosymmetric 2 + 1 unit of triazine and adipic acid mol-ecules with R(2) (2)(8) motifs. The triazine mol-ecules are connected to each other by N-H⋯N hydrogen bonds, forming an R(2) (2)(8) motif and a supra-molecular ribbon along the c axis. The 2 + 1 units and the supra-molecular ribbons are further inter-linked by weak N-H⋯O, C-H⋯O and C-H⋯π inter-actions, resulting in a three-dimensional network.
  18. Thanigaimani K, Khalib NC, Arshad S, Razak IA
    Acta Crystallogr Sect E Struct Rep Online, 2012 Dec 1;68(Pt 12):o3343.
    PMID: 23476180 DOI: 10.1107/S1600536812046156
    The asymmetric unit of the title compound, 2C5H6ClN3O·C4H6O4, consists of one 4-chloro-6-meth-oxy-pyrimidin-2-amine mol-ecule and one half-mol-ecule of succinic acid which lies about an inversion centre. In the crystal, the acid and base mol-ecules are linked through N-H⋯O and O-H⋯N hydrogen bonds, forming a tape along [1-10] in which R2(2)(8) and R4(2)(8) hydrogen-bond motifs are observed. The tapes are further inter-linked through a pair of C-H⋯O hydrogen bonds into a sheet parallel to (11-2).
  19. Thanigaimani K, Khalib NC, Farhadikoutenaei A, Arshad S, Razak IA
    Acta Crystallogr Sect E Struct Rep Online, 2012 Dec 1;68(Pt 12):o3321-2.
    PMID: 23476164 DOI: 10.1107/S1600536812045308
    In the title salt, 2C4H6ClN4(+)·C4H2O4(2-), the complete fumarate dianion is generated by crystallographic inversion symmetry. The cation is essentially planar, with a maximum deviation of 0.018 (1) Å. In the anion, the carboxyl-ate group is twisted slightly away from the attached plane, the dihedral angle between the carboxyl-ate and (E)-but-2-ene planes being 12.78 (13)°. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl-ate O atoms of the anion via a pair of N-H⋯O hydrogen bonds, forming an R2(2)(8) ring motif. In addition, another type of R2(2)(8) motif is formed by centrosymmetrically related pyrimidinium cations via N-H⋯N hydrogen bonds. These two combined motifs form a heterotetra-mer. The crystal structure is further stabilized by stong N-H⋯O, N-H⋯Cl and weak C-H⋯O hydrogen bonds, resulting a three-dimensional network.
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