Displaying publications 1 - 20 of 220 in total

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  1. Harrison WT, Plater MJ, Yin LJ
    Acta Crystallogr E Crystallogr Commun, 2016 Mar 1;72(Pt 3):407-11.
    PMID: 27006818 DOI: 10.1107/S2056989016002942
    The title compounds, C14H12O, (I), and C15H11BrO2, (II), were prepared and characterized as part of our studies of potential new photo-acid generators. In (I), which crystallizes in the ortho-rhom-bic space group Pca21, compared to P21/n for the previously known monoclinic polymorph [Cornella & Martin (2013 ▸). Org. Lett. 15, 6298-6301], the dihedral angle between the aromatic rings is 4.35 (6)° and the OH group is disordered over two sites in a 0.795 (3):0.205 (3) ratio. In the crystal of (I), mol-ecules are linked by O-H⋯π inter-actions involving both the major and minor -OH disorder components, generating [001] chains as part of the herringbone packing motif. The asymmetric unit of (II) contains two mol-ecules with similar conformations (weighted r.m.s. overlay fit = 0.183 Å). In the crystal of (II), both mol-ecules form carboxyl-ate inversion dimers linked by pairs of O-H⋯O hydrogen bonds, generating R 2 (2)(8) loops in each case. The dimers are linked by pairs of C-H⋯O hydrogen bonds to form [010] chains.
  2. Hizam SM, Yamin BM
    Acta Crystallogr E Crystallogr Commun, 2015 Jun 1;71(Pt 6):o378.
    PMID: 26090175 DOI: 10.1107/S2056989015008385
    The title salt, C5H11N2S(+)·C7H4ClO2 (-), comprises a 2-amino-3-ethyl-4,5-di-hydro-1,3-thia-zol-3-ium cation in which the five-membered ring adopts an envelope conformation with the methyl-ene C adjacent to the S atom being the flap, and a planar 3-chloro-benzoate anion (r.m.s. deviation for the 10 non-H atoms = 0.021 Å). The most prominent feature of the crystal packing are N-H⋯O hydrogen bonds whereby the two amine H atoms bridge two carboxyl-ate O atoms resulting in the formation of a centrosymmetric 12-membered {⋯HNH⋯OCO}2 synthon involving two cations and two anions. These aggregates are linked by C-H⋯O inter-actions to form a supra-molecular chain along the a-axis direction.
  3. Then LY, Chidan Kumar CS, Kwong HC, Win YF, Mah SH, Quah CK, et al.
    Acta Crystallogr E Crystallogr Commun, 2017 Jul 01;73(Pt 7):1087-1091.
    PMID: 28775889 DOI: 10.1107/S2056989017009422
    The compounds 2-(1-benzo-furan-2-yl)-2-oxoethyl 2-nitro-benzoate, C17H11NO6 (I), and 2-(1-benzo-furan-2-yl)-2-oxoethyl 2-amino-benzoate, C17H13NO4 (II), were synthesized under mild conditions. Their mol-ecular structures were characterized by both spectroscopic and single-crystal X-ray diffraction analysis. The mol-ecular conformations of both title compounds are generally similar. However, different ortho-substituted moieties at the phenyl ring of the two compounds cause deviations in the torsion angles between the carbonyl group and the attached phenyl ring. In compound (I), the ortho-nitro-phenyl ring is twisted away from the adjacent carbonyl group whereas in compound (II), the ortho-amino-phenyl ring is almost co-planar with the carbonyl group. In the crystal of compound (I), two C-H⋯O hydrogen bonds link the mol-ecules into chains propagating along the c-axis direction and the chains are inter-digitated, forming sheets parallel to [20-1]. Conversely, pairs of N-H⋯O hydrogen bonds in compound (II) link inversion-related mol-ecules into dimers, which are further extended by C-H⋯O hydrogen bonds into dimer chains. These chains are inter-connected by π-π inter-actions involving the furan rings, forming sheets parallel to the ac plane.
  4. Sim A, Chidan Kumar CS, Kwong HC, Then LY, Win YF, Quah CK, et al.
    Acta Crystallogr E Crystallogr Commun, 2017 Jun 01;73(Pt 6):896-900.
    PMID: 28638654 DOI: 10.1107/S2056989017007460
    In the title compounds, (2E,2'E)-3,3'-(1,4-phenyl-ene)bis-[1-(2-meth-oxy-phen-yl)prop-2-en-1-one], C26H22O4 (I), (2E,2'E)-3,3'-(1,4-phenyl-ene)bis-[1-(3-meth-oxy-phen-yl)prop-2-en-1-one], C26H22O4 (II) and (2E,2'E)-3,3'-(1,4-phenyl-ene)bis-[1-(3,4-di-meth-oxy-phen-yl)prop-2-en-1-one], C28H26O6 (III), the asymmetric unit consists of a half-mol-ecule, completed by crystallographic inversion symmetry. The dihedral angles between the central and terminal benzene rings are 56.98 (8), 7.74 (7) and 7.73 (7)° for (I), (II) and (III), respectively. In the crystal of (I), mol-ecules are linked by pairs of C-H⋯π inter-actions into chains running parallel to [101]. The packing for (II) and (III), features inversion dimers linked by pairs of C-H⋯O hydrogen bonds, forming R2(2)(16) and R2(2)(14) ring motifs, respectively, as parts of [201] and [101] chains, respectively.
  5. Kwong HC, Sim A, Chidan Kumar CS, Then LY, Win YF, Quah CK, et al.
    Acta Crystallogr E Crystallogr Commun, 2017 Dec 01;73(Pt 12):1812-1816.
    PMID: 29250392 DOI: 10.1107/S205698901701564X
    The asymmetric unit of the title compound, C24H14F4O2, comprises of one and a half mol-ecules; the half-mol-ecule is completed by crystallographic inversion symmetry. In the crystal, mol-ecules are linked into a three-dimensional network by C-H⋯F and C-H⋯O hydrogen bonds. Some of the C-H⋯F links are unusually short (< 2.20 Å). Hirshfeld surface analyses (dnorm surfaces and two-dimensional fingerprint plots) for the title compound are presented and discussed.
  6. Then LY, Chidan Kumar CS, Kwong HC, Win YF, Mah SH, Quah CK, et al.
    Acta Crystallogr E Crystallogr Commun, 2017 Jul 01;73(Pt 8):1227-1231.
    PMID: 28932442 DOI: 10.1107/S2056989017010556
    2-(Benzo-furan-2-yl)-2-oxoethyl 2-chloro-benzoate, C17H11ClO4 (I), and 2-(benzo-furan-2-yl)-2-oxoethyl 2-meth-oxy-benzoate, C18H14O5 (II), were synthesized under mild conditions. Their chemical and mol-ecular structures were analyzed by spectroscopic and single-crystal X-ray diffraction studies, respectively. These compounds possess different ortho-substituted functional groups on their phenyl rings, thus experiencing extra steric repulsion force within their mol-ecules as the substituent changes from 2-chloro (I) to 2-meth-oxy (II). The crystal packing of compound (I) depends on weak inter-molecular hydrogen bonds and π-π inter-actions. Mol-ecules are related by inversion into centrosymmetric dimers via C-H⋯O hydrogen bonds, and further strengthened by π-π inter-actions between furan rings. Conversely, mol-ecules in compound (II) are linked into alternating dimeric chains propagating along the [101] direction, which develop into a two-dimensional plate through extensive inter-molecular hydrogen bonds. These plates are further stabilized by π-π and C-H⋯π inter-actions.
  7. Chidan Kumar CS, Sim AJ, Ng WZ, Chia TS, Loh WS, Kwong HC, et al.
    Acta Crystallogr E Crystallogr Commun, 2017 Jul 01;73(Pt 7):927-931.
    PMID: 28775853 DOI: 10.1107/S2056989017007836
    The asymmetric unit of the title compound, C15H15N3O3·0.5H2O, comprises two 2-{[(4-iminiumyl-3-methyl-1,4-di-hydro-pyridin-1-yl)meth-yl]carbamo-yl}benzoate zwitterions (A and B) and a water mol-ecule. The dihedral angles between the pyridine and phenyl rings in the zwitterions are 53.69 (10) and 73.56 (11)° in A and B, respectively. In the crystal, mol-ecules are linked by N-H⋯O, O-H⋯O, C-H⋯O and C-H⋯π(ring) hydrogen bonds into a three-dimensional network. The crystal structure also features π-π inter-actions involving the centroids of the pyridine and phenyl rings [centroid-centroid distances = 3.5618 (12) Å in A and 3.8182 (14) Å in B].
  8. Sanjeeva Murthy TN, Naveen S, Chidan Kumar CS, Veeraiah MK, Quah CK, Siddaraju BP, et al.
    Acta Crystallogr E Crystallogr Commun, 2018 Aug 01;74(Pt 8):1134-1137.
    PMID: 30116578 DOI: 10.1107/S2056989018010216
    In the title chalcone-thio-phene derivative, C13H6Cl3FOS, the aromatic rings are inclined to one another by 12.9 (2)°, and the thio-phene ring is affected by π-conjugation. In the crystal, mol-ecules are linked by C-H⋯F hydrogen bonds, forming an R22(8) ring motif. A Hirshfeld surface analysis was conducted to verify the contribution of the different inter-molecular inter-actions. The shape-index surface clearly shows that the two sides of the mol-ecules are involved in the same contacts with neighbouring mol-ecules and the curvedness plots show flat surface patches characteristic of planar stacking.
  9. Sheshadri SN, Kwong HC, Chidan Kumar CS, Quah CK, Siddaraju BP, Veeraiah MK, et al.
    Acta Crystallogr E Crystallogr Commun, 2018 May 01;74(Pt 5):752-756.
    PMID: 29850106 DOI: 10.1107/S2056989018006217
    In the cation of the title salt, C20H19N2O+·Br-, the phenyl rings are inclined to one another by 38.38 (8)°, whereas the central phenyl ring and the pyridiniminium ring are almost perpendicular with a dihedral angle of 87.37 (9)°. The N+=C cationic double bond was verified by the shortened bond length of 1.337 (2) Å. In the crystal, the Br- anion is linked to the cation by an N-H⋯Br hydrogen bond. C-H⋯O hydrogen bonds link adjacent pyridiniminium cations into inversion dimers with an R22(18) graph-set motif. These dimers are stacked in a phen-yl-phenyl T-shaped geometry through C-H⋯π inter-actions. A Hirshfeld surface analysis was conducted to verify the contributions of the different inter-molecular inter-actions.
  10. Kwong HC, Sim AJ, Chidan Kumar CS, Quah CK, Chantrapromma S, Naveen S, et al.
    Acta Crystallogr E Crystallogr Commun, 2018 Jun 01;74(Pt 6):835-839.
    PMID: 29951241 DOI: 10.1107/S2056989018007429
    In the bis-chalcone mol-ecule of the title compound, C24H18O4·2C3H7NO, the central benzene and terminal hy-droxy-phenyl rings form a dihedral angle of 14.28 (11)° and the central C=C double bond adopts a trans configuration. In the crystal, the bis-chalcone and solvate mol-ecules are inter-connected via O-H⋯O hydrogen bonds, which were investigated by Hirshfeld surface analysis. Solid-state fluorescence was measured at λex = 4400 Å. The emission wavelength appeared at 5510 Å, which corresponds to yellow light and the solid-state fluorescence quantum yield (Ff) is 0.18.
  11. Sheshadri SN, Atioğlu Z, Akkurt M, Chidan Kumar CS, Quah CK, Siddaraju BP, et al.
    Acta Crystallogr E Crystallogr Commun, 2018 Jul 01;74(Pt 7):935-938.
    PMID: 30002889 DOI: 10.1107/S205698901800837X
    In title compound, C17H15ClO3, the dihedral angle between the benzene and chloro-phenyl rings is 18.46 (7)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen contacts, enclosing an R22(14) ring motif, and by a further C-H⋯O hydrogen contact, forming a two-dimensional supra-molecular structure extending along the direction parallel to the ac plane. Hirshfeld surface analysis shows that van der Waals inter-actions constitute the major contribution to the inter-molecular inter-actions, with H⋯H contacts accounting for 36.2% of the surface.
  12. Zaldi NB, Hussen RSD, Lee SM, Halcovitch NR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Jun 01;73(Pt 6):842-848.
    PMID: 28638641 DOI: 10.1107/S2056989017006855
    The title compound, [Sn(CH3)2(C5H8NOS2)2], has the Sn(IV) atom bound by two methyl groups which lie over the weaker Sn-S bonds formed by two asymmetrically chelating di-thio-carbamate ligands so that the coordination geometry is skew-trapezoidal bipyramidal. The most prominent feature of the mol-ecular packing are secondary Sn⋯S inter-actions [Sn⋯S = 3.5654 (7) Å] that lead to centrosymmetric dimers. These are connected into a three-dimensional architecture via methyl-ene-C-H⋯S and methyl-C-H⋯O(morpholino) inter-actions. The Sn⋯S inter-actions are clearly evident in the Hirshfeld surface analysis of the title compound along with a number of other inter-molecular contacts.
  13. Amin NABM, Hussen RSD, Lee SM, Halcovitch NR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 May 01;73(Pt 5):667-672.
    PMID: 28529772 DOI: 10.1107/S2056989017005072
    The Sn(IV) atom in the title diorganotin compound, [Sn(C7H6F)2Cl2(C2H6OS)2], is located on a centre of inversion, resulting in the C2Cl2O2 donor set having an all-trans disposition of like atoms. The coordination geometry approximates an octa-hedron. The crystal features C-H⋯F, C-H⋯Cl and C-H⋯π inter-actions, giving rise to a three-dimensional network. The respective influences of the Cl⋯H/H⋯Cl and F⋯H/H⋯F contacts to the mol-ecular packing are clearly evident from the analysis of the Hirshfeld surface.
  14. Zukerman-Schpector J, Prado KE, Name LL, Cella R, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Jun 01;73(Pt 6):918-924.
    PMID: 28638659 DOI: 10.1107/S2056989017007605
    The title organoselenium compound, C19H13ClO3Se {systematic name: 2-[(4-chloro-phen-yl)selan-yl]-2H,3H,4H,5H,6H-naphtho-[1,2-b]pyran-5,6-dione}, has the substituted 2-pyranyl ring in a half-chair conformation with the methyl-ene-C atom bound to the methine-C atom being the flap atom. The dihedral angle between the two aromatic regions of the mol-ecule is 9.96 (9)° and indicates a step-like conformation. An intra-molecular Se⋯O inter-action of 2.8122 (13) Å is noted. In the crystal, π-π contacts between naphthyl rings [inter-centroid distance = 3.7213 (12) Å] and between naphthyl and chloro-benzene rings [inter-centroid distance = 3.7715 (13) Å], along with C-Cl⋯π(chloro-benzene) contacts, lead to supra-molecular layers parallel to the ab plane, which are connected into a three-dimensional architecture via methyl-ene-C-H⋯O(carbon-yl) inter-actions. The contributions of these and other weak contacts to the Hirshfeld surface is described.
  15. Lee SM, Halcovitch NR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Apr 01;73(Pt 4):630-636.
    PMID: 28435737 DOI: 10.1107/S2056989017004790
    In the title isonicotinohydrazide hydrate, C14H12BrN3O2·H2O {systematic name: N'-[(1E)-1-(5-bromo-2-hy-droxy-phen-yl)ethyl-idene]pyridine-4-carbohydrazide monohydrate}, the central CN2O region of the organic mol-ecule is planar and the conformation about the imine-C=N bond is E. While an intra-molecular hy-droxy-O-H⋯N(imine) hydrogen bond is evident, the dihedral angle between the central residue and the benzene rings is 48.99 (9)°. Overall, the mol-ecule is twisted, as seen in the dihedral angle of 71.79 (6)° between the outer rings. In the crystal, hydrogen-bonding inter-actions, i.e. hydrazide-N-H⋯O(water), water-O-H⋯O(carbon-yl) and water-O-H⋯N(pyrid-yl), lead to supra-molecular ribbons along the a-axis direction. Connections between these, leading to a three-dimensional architecture, are mediated by Br⋯Br halogen bonding [3.5366 (3) Å], pyridyl-C-H⋯O(carbon-yl) as well as weak π-π inter-actions [inter-centroid separation between benzene rings = 3.9315 (12) Å]. The Hirshfeld surface analysis reveals the importance of hydrogen atoms in the supra-molecular connectivity as well as the influence of the Br⋯Br halogen bonding.
  16. Wardell JL, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Apr 01;73(Pt 4):579-585.
    PMID: 28435725 DOI: 10.1107/S2056989017004352
    In the anion of the title salt hydrate, H5N2(+)·C7H5N2O4(-)·2H2O, the carboxyl-ate and nitro groups lie out of the plane of the benzene ring to which they are bound [dihedral angles = 18.80 (10) and 8.04 (9)°, respectively], and as these groups are conrotatory, the dihedral angle between them is 26.73 (15)°. An intra-molecular amino-N-H⋯O(carboxyl-ate) hydrogen bond is noted. The main feature of the crystal packing is the formation of a supra-molecular chain along the b axis, with a zigzag topology, sustained by charge-assisted water-O-H⋯O(carboxyl-ate) hydrogen bonds and comprising alternating twelve-membered {⋯OCO⋯HOH}2 and eight-membered {⋯O⋯HOH}2 synthons. Each ammonium-N-H atom forms a charge-assisted hydrogen bond to a water mol-ecule and, in addition, one of these forms a hydrogen bond with a nitro-O atom. The amine-N-H atoms form hydrogen bonds to carboxyl-ate-O and water-O atoms, and the amine N atom accepts a hydrogen bond from an amino-H atom. The hydrogen bonds lead to a three-dimensional architecture. An analysis of the Hirshfeld surface highlights the major contribution of O⋯H/H⋯O hydrogen bonding to the overall surface, i.e. 46.8%, compared with H⋯H contacts (32.4%).
  17. Zukerman-Schpector J, Cunha R, Omori ÁT, Sousa Madureira L, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Apr 01;73(Pt 4):564-568.
    PMID: 28435722 DOI: 10.1107/S2056989017003887
    Two independent mol-ecules comprise the asymmetric unit in the title benzoxatellurole compound, C12H17ClOTe. The mol-ecules, with the same chirality at the methine C atom, are connected into a loosely associated dimer by Te⋯O inter-actions, leading to a {⋯Te-O}2 core. The resultant C2ClO2 donor set approximates a square pyramid with the lone pair of electrons projected to occupy a position trans to the n-butyl substituent. Inter-estingly, the Te(IV) atoms exhibit opposite chirality. The major difference between the independent mol-ecules relates to the conformation of the five-membered chelate rings, which is an envelope with the O atom being the flap, in one mol-ecule and is twisted about the O-C(methine) bond in the other. No directional inter-molecular inter-actions are noted in the mol-ecular packing beyond the aforementioned Te⋯O secondary bonding. The analysis of the Hirshfeld surface reveals the dominance of H⋯H contacts, i.e. contributing about 70% to the overall surface, and clearly differentiates the immediate crystalline environments of the two independent mol-ecules in terms of both H⋯H and H⋯Cl/Cl⋯H contacts.
  18. Yusof ENM, Tahir MIM, Ravoof TBSA, Tan SL, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Apr 01;73(Pt 4):543-549.
    PMID: 28435717 DOI: 10.1107/S2056989017003991
    The title di-thio-carbazate ester (I), C18H18N2S2 [systematic name: (E)-4-methyl-benzyl 2-[(E)-3-phenyl-allyl-idene]hydrazinecarbodi-thio-ate, comprises an almost planar central CN2S2 residue [r.m.s. deviation = 0.0131 Å]. The methyl-ene(tolyl-4) group forms a dihedral angle of 72.25 (4)° with the best plane through the remaining non-hydrogen atoms [r.m.s. deviation = 0.0586 Å] so the mol-ecule approximates mirror symmetry with the 4-tolyl group bis-ected by the plane. The configuration about both double bonds in the N-N=C-C=C chain is E; the chain has an all trans conformation. In the crystal, eight-membered centrosymmetric thio-amide synthons, {⋯HNCS}2, are formed via N-H⋯S(thione) hydrogen bonds. Connections between the dimers via C-H⋯π inter-actions lead to a three-dimensional architecture. A Hirshfeld surface analysis shows that (I) possesses an inter-action profile similar to that of a closely related analogue with an S-bound benzyl substituent, (II). Computational chemistry indicates the dimeric species of (II) connected via N-H⋯S hydrogen bonds is about 0.94 kcal mol(-1) more stable than that in (I).
  19. Tan YJ, Yeo CI, Halcovitch NR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Apr 01;73(Pt 4):493-499.
    PMID: 28435705 DOI: 10.1107/S205698901700353X
    The title compound, (C6H11)3PS (systematic name: tri-cyclo-hexyl-λ(5)-phosphane-thione), is a triclinic (P-1, Z' = 1) polymorph of the previously reported ortho-rhom-bic form (Pnma, Z' = 1/2) [Kerr et al. (1977 ▸). Can. J. Chem. 55, 3081-3085; Reibenspies et al. (1996 ▸). Z. Kristallogr. 211, 400]. While conformational differences exist between the non-symmetric mol-ecule in the triclinic polymorph, cf. the mirror-symmetric mol-ecule in the ortho-rhom-bic form, these differences are not chemically significant. The major feature of the mol-ecular packing in the triclinic polymorph is the formation of linear chains along the a axis sustained by methine-C-H⋯S(thione) inter-actions. The chains pack with no directional inter-actions between them. The analysis of the Hirshfeld surface for both polymorphs indicates a high degree of similarity, being dominated by H⋯H (ca 90%) and S⋯H/H⋯S contacts.
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