Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Acta Crystallogr C ; 68(Pt 12): o492-7, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23221254

RESUMO

A low-temperature polymorph of 1,1':3',1'':3'',1''':3''',1''''-quinquephenyl (m-quinquephenyl), C(30)H(22), crystallizes in the space group P2(1)/c with two molecules in the asymmetric unit. The crystal is a three-component nonmerohedral twin. A previously reported room-temperature polymorph [Rabideau, Sygula, Dhar & Fronczek (1993). Chem. Commun. pp. 1795-1797] also crystallizes with two molecules in the asymmetric unit in the space group P-1. The unit-cell volume for the low-temperature polymorph is 4120.5 (4) Å(3), almost twice that of the room-temperature polymorph which is 2102.3 (6) Å(3). The molecules in both structures adopt a U-shaped conformation with similar geometric parameters. The structural packing is similar in both compounds, with the molecules lying in layers which stack perpendicular to the longest unit-cell axis. The molecules pack alternately in the layers and in the stacked columns. In both polymorphs, the only interactions between the molecules which can stabilize the packing are very weak C-H...π interactions.

2.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 3): o685-6, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22412579

RESUMO

The title compound, C(14)H(13)N(3)O(4), is close to planar, the dihedral angle between the terminal benzene rings being 5.80 (16)°; the nitro group is coplanar with the benzene ring to which it is bonded [O-N-C-C torsion angle = -177.3 (3)°]. The hy-droxy group forms an intra-molecular hydrogen bond with the imine N atom, and the conformation about the imine bond is E. In the crystal, layers in the (101) plane with an undulating topology are formed by O-H⋯O and N-H⋯O hydrogen bonds along with C-H⋯O inter-actions. Centrosymmetrically related layers are connected via π-π inter-actions [ring centroid-centroid distance = 3.5739 (19) Å] into double layers.

3.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 3): o765-6, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22412640

RESUMO

The hydrazone mol-ecule in title monohydrate, C(14)H(13)N(3)O(4)·H(2)O, is almost coplanar, the dihedral angle between the terminal benzene rings being 3.22 (15)°; the nitro group is coplanar with the benzene ring to which it is bonded [O-N-C-C = -2.8 (4)°]. The hy-droxy group forms an intra-molecular hydrogen bond with the imine N atom, and the conformation about the imine bond [1.305 (3) Å] is E. In the crystal, supra-molecular layers in the (203) plane are connected into a double layer via water-nitro O-H⋯O hydrogen bonds, along with π-π inter-actions [ring centroid-centroid distance = 3.7859 (19) Å].

4.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 3): o796-7, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22412667

RESUMO

In the title hydrazone derivative, C(19)H(16)N(2)O, a twist is found between the hy-droxy-phenyl and N-bound phenyl rings [dihedral angle = 24.37 (7)°]. The C-bound phenyl ring is almost perpendicular to each of these planes [dihedral angles = 75.30 (7) and 86.00 (7)°, respectively]. The conformation about the imine bond [1.2935 (17) Å] is E. The hy-droxy group forms an intra-molecular hydrogen bond with the imine N atom. Zigzag chains along [001] mediated by N-H⋯O hydrogen bonds feature in the crystal packing.

5.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 10): m1420-1, 2011 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22064619

RESUMO

The Sn atom in the title compound, [Sn(C(3)H(6)NO)Cl(3)(CH(4)N(2)O)], is octa-hedrally coordinated within a CCl(3)NO donor set provided by a chelating amido-ethyl ligand (C and O), a urea-O atom and three facially arranged Cl atoms. Systematic variations in the Sn-Cl bond distances are correlated with the relative trans influence exerted by the C and carbonyl-O atoms. The three-dimensional crystal packing is stabilized by N-H⋯O and N-H⋯Cl hydrogen bonds.

6.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 6): o1438-9, 2010 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-21579512

RESUMO

In the title hydrated salt, C(15)H(11)Br(2)N(2) (+)·Cl(-)·2H(2)O, the complete imidazolium cation is generated by a crystallographic twofold axis, with one C atom lying on the axis. The chloride ion and both water mol-ecules of crystallization also lie on a crystallographic twofold axis of symmetry. The cation is non-planar, the dihedral angle formed between the central imidazolium and benzene rings being 12.9 (3)°; the dihedral angle between the symmetry-related benzene rings is 25.60 (13)°. In the crystal, O-H⋯Cl hydrogen bonds result in supra-molecular chains along c mediated by eight-membered {⋯HOH⋯Cl}(2) synthons. These are consolidated by C-H⋯O and π-π [centroid-centroid distance = 3.687 (3) Å] inter-actions.

7.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 2): o486, 2010 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-21579893

RESUMO

The carboxylic acid residue in the title compound, C(6)H(4)BrNO(2), is twisted out of the plane of the other atoms, as indicated by the (Br)C-C-C-O(carbon-yl) torsion angle of -20.1 (9)°. In the crystal, supra-molecular chains mediated by O-H⋯N hydrogen bonds are formed with base vector [201] and C-H⋯O inter-actions reinforce the packing.

8.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 3): i18-i19, 2010 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-21580197

RESUMO

The asymmetric unit of the title hydrate, 2[Sn(H(2)O)(2)(OH)(2)Br(6)]·7H(2)O, comprises two [Br(3)(H(2)O)Sn(µ-OH)(2)SnBr(3)(OH(2))] units, but three independent mol-ecules as two of these are disposed about inversion centres, and seven water mol-ecules. In common with the monoclinic polymorph [Howie et al. (2005 ▶). Inorg. Chim. Acta, 358, 3283-3286], each of the dinuclear species features a central Sn(2)O(2) core, distorted octa-hedral Sn atom geometries defined by a Br(3)O(3) donor set, and an anti-disposition of the coordinated water mol-ecules. In the crystal, O(h)-H⋯O(w), O(a)-H⋯O(w), O(w)-H⋯O(w), and O(w)-H⋯Br (h = hydroxyl, a = aqua, w = water) hydrogen-bonding inter-actions generate a three-dimensional network.

9.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 3): o696-7, 2010 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-21580437

RESUMO

The organic mol-ecule in the title hydrate, C(17)H(14)ClN(3)O·H(2)O, has a small but significant twist from planarity, as seen in the dihedral angle of 12.10 (17)° between the quinoline and benzene rings. The conformation about the C=N bond is E. Chains along the b axis are formed in the crystal structure aided by water-quinoline O-H⋯N (× 2) and hydrazone-water N-H⋯O hydrogen bonds. Layers of these chains stack along the a axis via C-H⋯π and π-π inter-actions [ring centroid-ring centroid distance = 3.674 (2) Å]. C-H⋯O inter-actions are also present.

10.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 3): o698-9, 2010 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-21580438

RESUMO

In the title hydrate, C(17)H(14)ClN(3)O·H(2)O, the dihedral angle between the quinoline fused-ring system and the benzene ring is 13.4 (2)° and the conformation about the C=N bond is E. In the crystal, N(h)-H⋯O(w) and O(w)-H⋯N(q) (h = hydro-zone, w = water and q = quinoline) hydrogen bonds generate a two-dimenstional network in the ac plane. A weak C-H⋯O inter-action helps to consolidate the packing.

11.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): m1562, 2009 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-21578598

RESUMO

In the title salt, (C(5)H(13)N(2)O(2))(2)[SnBr(6)], the Sn atom (site symmetry ) exists in a slightly distorted octa-hedral geometry. The cation is non-planar as the terminal CH(2)NH(3) (+) residue lies below the plane defined by the remaining non-H atoms. In the crystal, cations associate via N-H⋯O hydrogen bonds involving the ammonium and carbonyl residues, forming a 14-membered {⋯HNC(2)NCO}(2) synthon. The cations and anions are arranged in alternating layers arranged along the a-axis direction, the major association between them being N-H⋯Br contacts.

12.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): m1645, 2009 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-21578658

RESUMO

In the title compound, [HgCl(2)(C(12)H(6)N(2)O(2))(2)], the Hg(II) atom is located on a twofold rotation axis and exists within a distorted octa-hedral geometry defined by a cis-Cl(2)N(4) donor set. Mol-ecules are connected into layers in the ac plane via extensive C-H⋯Cl contacts as each Cl atom forms two such inter-actions. Contacts between the layers are of the type C=O⋯π [O⋯centroid distance = 3.110 (8) Å].

13.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): o3104-5, 2009 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-21578831

RESUMO

The title compound, C(14)H(11)NO(2), features an essentially planar mol-ecule, the r.m.s. deviation for the 17 non-H atoms being 0.035 Å. This conformation is stabilized by an intra-molecular O-H⋯N hydrogen bond that results in the formation of an S(6) ring. In the crystal structure, methyl-ene-hydr-oxy C-H⋯O contacts result in a supra-molecular chain aligned along the b axis.

14.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): o3170-1, 2009 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-21578886

RESUMO

Two independent mol-ecules comprise the crystallographic asymmetric unit in the title anti-retroviral agent Efavirenz, C(14)H(9)ClF(3)NO(2), and these have noteworthy differences in conformation. The major difference relates to the orientation of the 2-cyclo-propyl-ethynyl residue relative to the six-membered heterocycle: this approaches an orthogonal disposition in mol-ecule a compared to a more flattened conformation in mol-ecule b, the difference being reflected in the O(ring)-C-C-C(ethyne) torsion angles of 65 (4) and 159 (5)°, respectively. The independent mol-ecules are connected via the eight-membered {⋯HNC (O)}(2) amide synthon. Disorder is noted in the cyclo-propane ring of mol-ecule b in that two orientations of equal weight were discerned.

15.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): o3204-5, 2009 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-21578913

RESUMO

The title salt, C(16)H(12)Cl(2)N(3) (+)·C(7)H(4)ClO(2) (-), features a non-planar cation, the dihedral angle between the quinolinium and benzene residues being 18.98 (10)°. The cation adopts an E conformation about the C-N bond, and the amine group is oriented towards the quinolinium residue. In the crystal, N-H⋯O hydrogen bonds link two cations with two anions, forming a 20-membered {⋯OCO⋯HNC(3)NH}(2) synthon. The dimeric units are connected into a linear supra-molecular chain along [100] via π-π inter-actions [centroid-centroid distance = 3.5625 (13) Å].

16.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 12): o3239-40, 2009 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-21578942

RESUMO

The title monohydrate, C(17)H(11)ClN(4)·H(2)O, features an essentially planar organic mol-ecule, as seen in the dihedral angle of 2.42 (8)° formed between the quinoline and benzene planes. The conformation about the imine bond is E, and the N-H group is oriented towards the quinoline residue. The major feature of the crystal packing is the formation of supra-molecular chains along [100], whereby the water mol-ecule accepts one N-H⋯O hydrogen bond and makes two O-H⋯N hydrogen bonds. A C-H⋯O link is also present.

17.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 1): o152-3, 2009 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-21580042

RESUMO

The mol-ecule of the title hydrate, C(16)H(11)ClFN(3)·H(2)O, is slightly twisted, as indicated by the dihedral angle of 9.55 (10)° formed between the quinoline ring system and the benzene ring. The conformation about the C=N double bond is E, and the amine-H atom is oriented towards the quinoline residue. In the crystal structure, the water mol-ecule accepts an N-H⋯O and makes two O-H⋯N(quinoline) hydrogen bonds, generating a two-dimensional array in the ab plane, which is further stabilized by C-H⋯O inter-actions. The most significant contacts between layers are of the type C-H⋯F.

18.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 1): o178-9, 2009 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-21580063

RESUMO

The title compound, C(12)H(8)Cl(2)N(4)O, is non-planar, the dihedral angle formed between the pendant pyrazine and benzene rings being 12.55 (11)°. An intra-molecular N-H⋯N hydrogen bond occurs. The amide groups self-associate via N-H⋯O hydrogen bonding, forming supra-molecular chains with base vector [101], which are stabilized by C-H⋯O contacts. C-H⋯N inter-actions are formed orthogonal to the chains.

19.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 3): o631-2, 2009 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-21582281

RESUMO

The crystal structure of the title compound, C(64)H(52)Br(4)O(8)·1.31C(3)H(6)O·0.69CHCl(3), is described. The structure has been reported previously [Bryant, Blanda, Vincenti & Cram (1991). J. Am. Chem. Soc.113, 2167-2172]; however, the lower data acquisition temperature results in an improved refinement model. In addition, the presence of residual acetone and (disordered) chloro-form within the mol-ecular structure of the title compound represents a new clathrate of the title compound. One half of the resorcin[4]arene cavitand mol-ecule appears in the asymmetric unit; the complete resorcin[4]arene cavitand structure was generated across a mirror plane.

20.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 4): o692-3, 2009 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-21582434

RESUMO

The title compound, C(68)H(56)O(16), was synthesized as a novel synthetic inter-mediate towards deeper and more elaborate resorcin[4]arene cavitands. The structure is the first reported example of a resorcin[4]arene cavitand bearing aromatic aldehyde functional groups at the extra-annular rim of the mol-ecule. The 2-formyl-phen-oxy residues are found to assume two different orientations above the mol-ecular cavity. One half of the resorcin[4]arene cavitand mol-ecule appears in the asymmetric unit; the complete resorcin[4]arene cavitand structure was generated across a mirror plane. In addition, a highly disordered ethyl acetate solvent mol-ecule is present within the mol-ecular cavity.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA