Displaying publications 1 - 20 of 21 in total

Abstract:
Sort:
  1. Caracelli I, Zukerman-Schpector J, Kwong HC, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2020 Jul 01;76(Pt 7):1051-1056.
    PMID: 32695451 DOI: 10.1107/S2056989020007380
    The title compound, C20H20N4O3, is constructed about a tri-substituted 1,2,3-triazole ring, with the substituent at one C atom flanked by the C and N atoms being a substituted amide group, and with the adjacent C and N atoms bearing phenyl and benzyl groups, respectively; the dihedral angle between the pendant phenyl rings is 81.17 (12)°, indicative of an almost orthogonal disposition. In the crystal, pairwise amide-N-H⋯O(carbon-yl) hydrogen bonds lead to a centrosymmetric dimer incorporating methyl-ene-C-H⋯π(benzene) inter-actions. The dimers are linked into a supra-molecular layer in the ab plane via methyl-ene-C-H⋯N(azo) and benzene-C-H⋯O(amide) inter-actions; the layers stack along the c-axis direction without directional inter-actions between them. The above-mentioned inter-molecular contacts are apparent in the analysis of the calculated Hirshfeld surface, which also provides evidence for short inter-layer H⋯C contacts with a significant dispersion energy contribution.
  2. Zukerman-Schpector J, Caracelli I, Stefani HA, Khan AN, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2014 Oct 1;70(Pt 10):o1122-3.
    PMID: 25484707 DOI: 10.1107/S1600536814020832
    In the title compound, C15H20BrNO2, there are two independent mol-ecules (A and B) comprising the asymmetric unit and these adopt very similar conformations. In A, the dihedral angle between the CO2 and MeC=CMe2 groups is 80.7 (3)°, and these make dihedral angles of 3.5 (3) and 84.09 (16)°, respectively, with the bromo-benzene ring. The equivalent dihedral angles for mol-ecule B are 78.4 (3), 2.1 (3) and 78.37 (12)°, respectively. The most prominent inter-actions in the crystal packing are amine-N-H⋯O(carbon-yl) hydrogen bonds between the two independent mol-ecules, resulting in non-centrosymmetric ten-membered {⋯OC2NH}2 synthons. Statistical disorder is noted for each of the terminal methyl groups of the ethyl residues.
  3. Caracelli I, Zukerman-Schpector J, Stefani HA, Ali B, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Aug 1;71(Pt 8):o582-3.
    PMID: 26396808 DOI: 10.1107/S2056989015013353
    In the title compound, C13H15NO4, the oxopyrrolidin-3-yl ring has an envelope conformation, with the C atom bearing the acetate group being the flap. The acetate and phenyl groups are inclined with respect to the central ring, forming dihedral angles of 50.20 (12) and 87.40 (9)°, respectively, with the least-squares plane through the ring. The dihedral angle between the acetate group and the phenyl ring is 63.22 (8)°, indicating a twisted conformation in the mol-ecule. In the crystal, supra-molecular chains along the b axis are formed by (hy-droxy)O-H⋯O(ring carbon-yl) hydrogen bonds. The chains are consolidated into the three-dimensional architecture by C-H⋯O inter-actions.
  4. Caracelli I, Hino CL, Zukerman-Schpector J, Biaggio FC, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Aug 1;71(Pt 8):o558-9.
    PMID: 26396795 DOI: 10.1107/S2056989015012670
    In the title compound, C10H11NO2, two independent but virtually superimposable mol-ecules, A and B, comprise the asymmetric unit. The heterocyclic ring in each mol-ecule has a screw-boat conformation, and the methyl-hydroxyl group occupies a position to one side of this ring with N-C-C-O torsion angles of -55.30 (15) (mol-ecule A) and -55.94 (16)° (mol-ecule B). In the crystal, O-H⋯O and N-H⋯O hydrogen bonding leads to 11-membered {⋯HNCO⋯HO⋯HNC2O} heterosynthons, involving three different mol-ecules, which are edge-shared to generate a supra-molecular chain along the a axis. Inter-actions of the type C-H⋯O provide additional stability to the chains, and link these into a three-dimensional architecture.
  5. Zukerman-Schpector J, Caracelli I, Stefani HA, Shamim A, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Jan 1;71(Pt 1):o53-4.
    PMID: 25705505 DOI: 10.1107/S205698901402564X
    In the title compound, C12H15IO7, the 3,4-di-hydro-2H-pyran ring is in a distorted half-boat conformation with the atom bearing the acet-yloxy group adjacent to the C atom bearing the methyl-acetate group lying 0.633 (6) Å above the plane of the remaining ring atoms (r.m.s. deviation = 0.0907 Å). In the crystal, mol-ecules are linked into a supra-molecular chain along the a axis through two C-H⋯O inter-actions to the same acceptor carbonyl O atom; these chains pack with no specific inter-molecular inter-actions between them.
  6. Zukerman-Schpector J, Caracelli I, Stefani HA, Gozhina O, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Mar 1;71(Pt 3):o167-8.
    PMID: 25844230 DOI: 10.1107/S2056989015002455
    In the title compound, C11H12O2S2, two independent but virtually superimposable mol-ecules, A and B, comprise the asymmetric unit. In each mol-ecule, the 1,3-di-thiane ring has a chair conformation with the 1,4-disposed C atoms being above and below the plane through the remaining four atoms. The substituted benzene ring occupies an equatorial position in each case and forms dihedral angles of 85.62 (9) (mol-ecule A) and 85.69 (8)° (mol-ecule B) with the least-squares plane through the 1,3-di-thiane ring. The difference between the mol-ecules rests in the conformation of the five-membered 1,3-dioxole ring which is an envelope in mol-ecule A (the methyl-ene C atom is the flap) and almost planar in mol-ecule B (r.m.s. deviation = 0.046 Å). In the crystal, mol-ecules of A self-associate into supra-molecular zigzag chains (generated by glide symmetry along the c axis) via methyl-ene C-H⋯π inter-actions. Mol-ecules of B form similar chains. The chains pack with no specific directional inter-molecular inter-actions between them.
  7. Caracelli I, Maganhi SH, Stefani HA, Gueogjian K, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Feb 1;71(Pt 2):o90-1.
    PMID: 25878887 DOI: 10.1107/S2056989014027790
    The coumarin ring system in the title asymmetric alkyne, C18H12O2, is approximately planar (r.m.s. deviation of the 11 non-H atoms = 0.048 Å), and is inclined with respect to the methyl-benzene ring, forming a dihedral angle of 33.68 (4)°. In the crystal, supra-molecular zigzag chains along the c-axis direction are formed via weak C-H⋯O hydrogen bonds, and these are connected into double layers via weak C-H⋯π inter-actions; these stack along the a axis.
  8. Caracelli I, Zukerman-Schpector J, Moran PJ, de Paula BR, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Apr 1;71(Pt 4):o222-3.
    PMID: 26029424 DOI: 10.1107/S2056989015003084
    Two independent mol-ecules (A and B) comprise the asymmetric unit of the title compound, C21H18O4. There are significant conformational differences between the mol-ecules relating in particular to the relative orientation of the 3-oxo-2-(phenyl-methyl-idene)but-oxy substituent with respect to the superimposable chromen-2-one residues. To a first approximation, the substituents are mirror images; both are approximately perpendicular to the chromen-2-one fused ring system with dihedral angles of 88.50 (7) (A) and 81.96 (7)° (B). Another difference between the independent mol-ecules is noted in the dihedral angles between the adjacent phenyl and but-3-en-2-one groups of 8.72 (12) (A) and 27.70 (10)° (B). The conformation about the ethene bond in both mol-ecules is E. The crystal packing features C-H⋯O, C-H⋯π(ar-yl) and π-π [Cg⋯Cg = 3.6657 (8) and 3.7778 (8) Å] stacking inter-actions, which generate a three-dimensional network.
  9. Zukerman-Schpector J, Caracelli I, Stefani HA, Gozhina O, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Mar 1;71(Pt 3):o179-80.
    PMID: 25844236 DOI: 10.1107/S2056989015002832
    In the title compound, C10H11BrS2, the 1,3-di-thiane ring has a chair conformation with the 1,4-disposed C atoms being above and below the remaining four atoms. The bromo-benzene ring occupies an equatorial position and forms a dihedral angle of 86.38 (12)° with the least-squares plane through the 1,3-di-thiane ring. Thus, to a first approximation the mol-ecule has mirror symmetry with the mirror containing the bromo-benzene ring and the 1,4-disposed C atoms of the 1,3-di-thiane ring. In the crystal, mol-ecules associate via weak methyl-ene-bromo-benzene C-H⋯π and π-π [Cg⋯Cg = 3.7770 (14) Å for centrosymmetrically related bromo-benzene rings] inter-actions, forming supra-molecular layers parallel to [10-1]; these stack with no specific inter-molecular inter-actions between them.
  10. Caracelli I, Maganhi SH, Moran PJ, de Paula BR, Delling FN, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2014 Sep 01;70(Pt 9):o1051-2.
    PMID: 25309220 DOI: 10.1107/S1600536814018819
    In the title compound, C17H14N2O6, the conformation about the C=C double bond [1.345 (2) Å] is E, with the ketone moiety almost coplanar [C-C-C-C torsion angle = 9.5 (2)°] along with the phenyl ring [C-C-C-C = 5.9 (2)°]. The aromatic rings are almost perpendicular to each other [dihedral angle = 86.66 (7)°]. The 4-nitro moiety is approximately coplanar with the benzene ring to which it is attached [O-N-C-C = 4.2 (2)°], whereas the one in the ortho position is twisted [O-N-C-C = 138.28 (13)°]. The mol-ecules associate via C-H⋯O inter-actions, involving both O atoms from the 2-nitro group, to form a helical supra-molecular chain along [010]. Nitro-nitro N⋯O inter-actions [2.8461 (19) Å] connect the chains into layers that stack along [001].
  11. Caracelli I, Zukerman-Schpector J, Traesel HJ, Olivato PR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2018 May 01;74(Pt 5):703-708.
    PMID: 29850096 DOI: 10.1107/S2056989018006072
    The title compound, C15H13ClO2S, comprises (4-chloro-phen-yl)sulfanyl, benzaldehyde and meth-oxy residues linked at a chiral methine-C atom (the crystal is racemic). A twist in the methine-C-C(carbon-yl) bond [O-C-C-O torsion angle = 19.3 (7)°] leads to a dihedral angle of 22.2 (5)° between the benzaldehyde and methine+meth-oxy residues. The chloro-benzene ring is folded to lie over the O atoms, with the dihedral angle between the benzene rings being 42.9 (2)°. In the crystal, the carbonyl-O atom accepts two C-H⋯O inter-actions with methyl- and methine-C-H atoms being the donors. The result is an helical supra-molecular chain aligned along the c axis; chains pack with no directional inter-actions between them. An analysis of the Hirshfeld surface points to the important contributions of weak H⋯H and C⋯C contacts to the mol-ecular packing.
  12. Caracelli I, Olivato PR, Traesel HJ, Valença J, Rodrigues DN, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Sep 01;71(Pt 9):o657-8.
    PMID: 26396889 DOI: 10.1107/S2056989015014565
    In the title β-thio-carbonyl compound, C16H16O3S, the adjacent meth-oxy and carbonyl O atoms are synperiplanar [the O-C-C-O torsion angle is 19.8 (4)°] and are separated by 2.582 (3) Å. The dihedral angle between the rings is 40.11 (16)°, and the meth-oxy group is coplanar with the benzene ring to which it is connected [the C-C-O-C torsion angle is 179.1 (3)°]. The most notable feature of the crystal packing is the formation of methine and methyl C-H⋯O(carbon-yl) inter-actions that lead to a supra-molecular chain with a zigzag topology along the c axis. Chains pack with no specific inter-molecular inter-actions between them.
  13. Caracelli I, Zukerman-Schpector J, Stefani HA, Gozhina O, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Mar 01;71(Pt 3):o181-2.
    PMID: 25844237 DOI: 10.1107/S2056989015002844
    In the title compound, C10H11NO2S2, the 1,3-di-thiane ring has a chair conformation with the 1,4-disposed C atoms being above and below the remaining four atoms. The nitro-benzene substituent occupies an equatorial position and forms a dihedral angle of 88.28 (5)° with the least-squares plane through the 1,3-di-thiane ring. The nitro group is twisted out of the plane of the benzene ring to which it is connected, forming a dihedral angle of 10.12 (3)°. In the crystal, mol-ecules aggregate into supra-molecular zigzag chains (glide symmetry along the c axis) via nitro-benzene N-O⋯π [N-O⋯Cg(benzene) = 3.4279 (18) Å and angle at O = 93.95 (11)°] inter-actions. The chains pack with no specific inter-molecular inter-actions between them.
  14. Caracelli I, Maganhi SH, Stefani HA, Gueogjian K, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Mar 01;71(Pt 3):o154-5.
    PMID: 25844223 DOI: 10.1107/S2056989015002157
    In the title compound, C15H8O2S, the coumarin moiety is approximately planar (r.m.s. deviation of the 11 non-H atoms = 0.025 Å) and is slightly inclined with respect to the plane of the thio-phen-3-yl ring, forming a dihedral angle of 11.75 (8)°. In the crystal, the three-dimensional architecture features a combination of coumarin-thio-phene C-H⋯π and π-π [inter-centroid distance = 3.6612 (12) Å] inter-actions.
  15. Caracelli I, Zukerman-Schpector J, Traesel HJ, Olivato PR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2019 Jun 01;75(Pt 6):816-822.
    PMID: 31391973 DOI: 10.1107/S2056989019006765
    The title compound, C15H13BrO2S, comprises three different substituents bound to a central (and chiral) methine-C atom, i.e. (4-bromo-phen-yl)sulfanyl, benzaldehyde and meth-oxy residues: crystal symmetry generates a racemic mixture. A twist in the mol-ecule is evident about the methine-C-C(carbon-yl) bond as evidenced by the O-C-C-O torsion angle of -20.8 (7)°. The dihedral angle between the bromo-benzene and phenyl rings is 43.2 (2)°, with the former disposed to lie over the oxygen atoms. The most prominent feature of the packing is the formation of helical supra-molecular chains as a result of methyl- and methine-C-H⋯O(carbon-yl) inter-actions. The chains assemble into a three-dimensional architecture without directional inter-actions between them. The nature of the weak points of contacts has been probed by a combination of Hirshfeld surface analysis, non-covalent inter-action plots and inter-action energy calculations. These point to the importance of weaker H⋯H and C-H⋯C inter-actions in the consolidation of the structure.
  16. Caracelli I, Zukerman-Schpector J, Schwab RS, da Silva EM, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2019 Aug 01;75(Pt 8):1232-1238.
    PMID: 31417798 DOI: 10.1107/S2056989019010284
    The di-substituted acetyl-ene residue in the title compound, C11H11NO3, is capped at either end by di-methyl-hydroxy and 4-nitro-benzene groups; the nitro substituent is close to co-planar with the ring to which it is attached [dihedral angle = 9.4 (3)°]. The most prominent feature of the mol-ecular packing is the formation, via hy-droxy-O-H⋯O(hy-droxy) hydrogen bonds, of hexa-meric clusters about a site of symmetry . The aggregates are sustained by 12-membered {⋯OH}6 synthons and have the shape of a flattened chair. The clusters are connected into a three-dimensional architecture by benzene-C-H⋯O(nitro) inter-actions, involving both nitro-O atoms. The aforementioned inter-actions are readily identified in the calculated Hirshfeld surface. Computational chemistry indicates there is a significant energy, primarily electrostatic in nature, associated with the hy-droxy-O-H⋯O(hy-droxy) hydrogen bonds. Dispersion forces are more important in the other identified but, weaker inter-molecular contacts.
  17. Seng HL, Von ST, Tan KW, Maah MJ, Ng SW, Rahman RN, et al.
    Biometals, 2010 Feb;23(1):99-118.
    PMID: 19787298 DOI: 10.1007/s10534-009-9271-y
    Crystal structure analysis of the zinc complex establishes it as a distorted octahedral complex, bis(3-methylpicolinato-kappa(2) N,O)(2)(1,10-phenanthroline-kappa(2) N,N)-zinc(II) pentahydrate, [Zn(3-Me-pic)(2)(phen)]x5H(2)O. The trans-configuration of carbonyl oxygen atoms of the carboxylate moieties and orientation of the two planar picolinate ligands above and before the phen ligand plane seems to confer DNA sequence recognition to the complex. It cannot cleave DNA under hydrolytic condition but can slightly be activated by hydrogen peroxide or sodium ascorbate. Circular Dichroism and Fluorescence spectroscopic analysis of its interaction with various duplex polynucleotides reveals its binding mode as mainly intercalation. It shows distinct DNA sequence binding selectivity and the order of decreasing selectivity is ATAT > AATT > CGCG. Docking studies lead to the same conclusion on this sequence selectivity. It binds strongly with G-quadruplex with human tolemeric sequence 5'-AG(3)(T(2)AG(3))(3)-3', can inhibit topoisomerase I efficiently and is cytotoxic against MCF-7 cell line.
  18. Seng HL, Ong HK, Rahman RN, Yamin BM, Tiekink ER, Tan KW, et al.
    J Inorg Biochem, 2008 Nov;102(11):1997-2011.
    PMID: 18778856 DOI: 10.1016/j.jinorgbio.2008.07.015
    The binding selectivity of the M(phen)(edda) (M=Cu, Co, Ni, Zn; phen=1,10-phenanthroline, edda=ethylenediaminediacetic acid) complexes towards ds(CG)(6), ds(AT)(6) and ds(CGCGAATTCGCG) B-form oligonucleotide duplexes were studied by CD spectroscopy and molecular modeling. The binding mode is intercalation and there is selectivity towards AT-sequence and stacking preference for A/A parallel or diagonal adjacent base steps in their intercalation. The nucleolytic properties of these complexes were investigated and the factors affecting the extent of cleavage were determined to be: concentration of complex, the nature of metal(II) ion, type of buffer, pH of buffer, incubation time, incubation temperature, and the presence of hydrogen peroxide or ascorbic acid as exogenous reagents. The fluorescence property of these complexes and its origin were also investigated. The crystal structure of the Zn(phen)(edda) complex is reported in which the zinc atom displays a distorted trans-N(4)O(2) octahedral geometry; the crystal packing features double layers of complex molecules held together by extensive hydrogen bonding that inter-digitate with adjacent double layers via pi...pi interactions between 1,10-phenanthroline residues. The structure is compared with that of the recently described copper(II) analogue and, with the latter, included in molecular modeling.
  19. Dallasta Pedroso S, Caracelli I, Zukerman-Schpector J, Soto-Monsalve M, De Almeida Santos RH, Correia CRD, et al.
    Acta Crystallogr E Crystallogr Commun, 2020 Jun 01;76(Pt 6):967-972.
    PMID: 32523774 DOI: 10.1107/S205698902000701X
    The title compound, C13H19NO8, is based on a tetra-substituted pyrrolidine ring, which has a twisted conformation about the central C-C bond; the Cm-Ca-Ca-Cme torsion angle is 38.26 (15)° [m = methyl-carboxyl-ate, a = acet-yloxy and me = methyl-ene]. While the N-bound ethyl-carboxyl-ate group occupies an equatorial position, the remaining substituents occupy axial positions. In the crystal, supra-molecular double-layers are formed by weak methyl- and methyl-ene-C-H⋯O(carbon-yl) inter-actions involving all four carbonyl-O atoms. The two-dimensional arrays stack along the c axis without directional inter-actions between them. The Hirshfeld surface is dominated by H⋯H (55.7%) and H⋯C/C⋯H (37.0%) contacts; H⋯H contacts are noted in the inter-double-layer region. The inter-action energy calculations point to the importance of the dispersion energy term in the stabilization of the crystal.
  20. Dallasta Pedroso S, Caracelli I, Zukerman-Schpector J, Soto-Monsalve M, De Almeida Santos RH, Correia CRD, et al.
    Acta Crystallogr E Crystallogr Commun, 2020 Jul 01;76(Pt 7):1080-1086.
    PMID: 32695456 DOI: 10.1107/S2056989020007914
    The title compound, C23H24N2O9, is a tetra-substituted pyrrolidine derivative with a twisted conformation, with the twist evident in the C-C bond bearing the adjacent acet-yloxy substituents. These are flanked on one side by a C-bound 4-meth-oxy-phen-yl group and on the other by a methyl-ene group. The almost sp 2-N atom [sum of angles = 357°] bears a 4-nitro-benzyl-oxycarbonyl substituent. In the crystal, ring-methyl-ene-C-H⋯O(acet-yloxy-carbon-yl) and methyl-ene-C-H⋯O(carbon-yl) inter-actions lead to supra-molecular layers lying parallel to (01); the layers stack without directional inter-actions between them. The analysis of the calculated Hirshfeld surfaces indicates the combined importance of H⋯H (42.3%), H⋯O/O⋯H (37.3%) and H⋯C/C⋯H (14.9%) surface contacts. Further, the inter-action energies, largely dominated by the dispersive term, point to the stabilizing influence of H⋯H and O⋯O contacts in the inter-layer region.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator ([email protected])

External Links