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Biomedical subjects

Janet M S Skakle

Publications and source records attributed to Janet M S Skakle.

At least 19 recordsLinked to original sources
PubMed2006

Isomeric N-(iodophenyl)nitrobenzamides form different three-dimensional framework structures.

The isomeric N-(iodophenyl)nitrobenzamides, C(13)H(9)IN(2)O(3), all form different three-dimensional framework structures. Molecules of N-(2-iodophenyl)-3-nitrobenzamide (II) are linked by a combination of N-H...O and C-H...O hydrogen bonds and a two-centre iodo...carbonyl interaction. The supramolecular structure of N-(2-iodophenyl)-4-nitrobenzamide (III) is built from one N-H...O and two C-H...O hydrogen bonds, but short I...O contacts are absent from the structure. In N-(3-iodophenyl)-2-nitrobenzamide (IV), which crystallizes with Z' = 2 in space group P2(1), the structure contains two N-H...O hydrogen bonds, four C-H...O hydrogen bonds, two two-centre iodo...nitro interactions and an aromatic pi...pi stacking interaction. The structure of N-(3-iodophenyl)-3-nitrobenzamide (V) contains one N-H...O hydrogen bond and three C-H...O hydrogen bonds, together with a two-centre iodo...nitro interaction and an aromatic pi...pi stacking interaction, while in N-(3-iodophenyl)-4-nitrobenzamide (VI), the combination of one N-H...O hydrogen bond and two C-H...O hydrogen bonds is augmented not only by a two-centre iodo...nitro interaction and an aromatic pi...pi stacking interaction, but also by a dipolar carbonyl...carbonyl interaction. In the supramolecular structure of N-(4-iodophenyl)-4-nitrobenzamide (IX), which crystallizes with Z' = 2 in space group P\overline 1, there are two N-H...O hydrogen bonds, four C-H...O hydrogen bonds and two three-centre iodo...nitro interactions.

Journal Article↗
PubMed2006

Isomers and polymorphs of (E,E)-1,4-bis(nitrophenyl)-2,3-diaza-1,3-butadienes.

The structures of five of the possible six isomers of (E,E)-1,4-bis(nitrophenyl)-2,3-diaza-1,3-butadiene are reported, including two polymorphs of one of the isomers. (E,E)-1,4-Bis(2-nitrophenyl)-2,3-diaza-1,3-butadiene, C(14)H(10)N(4)O(4) (I), crystallizes in two polymorphic forms (Ia) and (Ib) in which the molecules lie across centres of inversion in space groups P2(1)/n and P2(1)/c, respectively: the molecules in (Ia) and (Ib) are linked into chains by aromatic pi...pi stacking interactions and C-H...pi(arene) hydrogen bonds, respectively. Molecules of (E,E)-1-(2-nitrophenyl)-4-(3-nitrophenyl)-2,3-diaza-1,3-butadiene (II) are linked into sheets by two independent C-H...O hydrogen bonds. The molecules of (E,E)-1,4-bis(3-nitrophenyl)-2,3-diaza-1,3-butadiene (III) lie across inversion centres in the space group P2(1)/n, and a combination of a C-H...O hydrogen bond and a pi...pi stacking interaction links the molecules into sheets. A total of four independent C-H...O hydrogen bonds link the molecules of (E,E)-1-(3-nitrophenyl)-4-(4-nitrophenyl)-2,3-diaza-1,3-butadiene (IV) into sheets. In (E,E)-1,4-bis(4-nitrophenyl)-2,3-diaza-1,3-butadiene (V) the molecules, which lie across centres of inversion in the space group P2(1)/n, are linked by just two independent C-H...O hydrogen bonds into a three-dimensional framework.

Journal Article↗
PubMed2006

N-(2-Hydroxy-3-iodo-5-nitrobenzylidene)-3-nitroaniline: conformational isomers linked into complex sheets by five C-H...O hydrogen bonds and a two-centre iodo-nitro interaction.

The title compound, C(13)H(8)IN(3)O(5), crystallizes with Z' = 2 in the space group P2(1)/n. The two independent molecules, which are both almost planar, are conformational isomers. The molecules are linked into complex sheets by a combination of five independent C-H...O hydrogen bonds and an almost linear two-centre iodo-nitro interaction.

Journal Article↗
PubMed2006

4-Iodo-N,N-bis(2-nitrophenylsulfonyl)aniline: a three-dimensional framework structure built from six independent C-H...O hydrogen bonds.

In the title compound [systematic name: 4-iodophenylimino bis(2-nitrobenzenesulfinate)], C(18)H(12)IN(3)O(8)S(2), where the molecules do not exhibit even approximate local symmetry, the molecules are linked into a complex three-dimensional structure by six independent C-H...O hydrogen bonds, which utilize O atoms in nitro and sulfonyl groups as the acceptors.

Journal Article↗
PubMed2006

Formation of ladders from R(4)4(8) and R(6)6(12) rings in 8-hydroxyquinolinium chloride monohydrate: comparisons with the supramolecular arrangements in related salts.

Molecules of the title compound, C9H8NO+.Cl-.H2O, are linked into two rings by strong hydrogen bonding via the free water molecules and the Cl- anions. The two hydrogen-bonded rings are joined to give a corrugated chain along [001]. Comparisons with other 8-hydroxyquinoline-based salts are also presented, highlighting similar ring structures in a 1:1 salt with Kemp's triacid (r-1,c-3,c-5-trimethylcyclohexane-1,3,5-tricarboxylic acid) and in 8-hydroxy-1-methylquinolinium chloride monohydrate.

Crystallography, X-Ray↗
PubMed2005

2-Amino-5-trifluoromethyl-1,3,4-thiadiazole and a redetermination of 2-amino-1,3,4-thiadiazole, both at 120 K: chains of edge-fused R(2)(2)(8) and R(4)(4)(10) rings, and sheets of R(2)(2)(8) and R(6)(6)(20) rings.

Molecules of 2-amino-5-trifluoromethyl-1,3,4-thiadiazole, C3H2F3N3S, are linked by two independent N-H...N hydrogen bonds into sheets of alternating R(2)(2)(8) and R(6)(6)(20) rings, while the molecules of the unsubstituted 2-amino-1,3,4-thiadiazole, C2H3N3S, are linked, again by two independent N-H...N hydrogen bonds, but into chains of edge-fused R(2)(2)(8) and R(4)(4)(10) rings.

Journal Article↗
PubMed2005

Three-dimensional supramolecular structures in (E,E)-N,N'-bis(4-nitrobenzylidene)butane-1,4-diamine and (E,E)-N,N'-bis(4-nitrobenzylidene)hexane-1,6-diamine.

In both (E,E)-N,N'-bis(4-nitrobenzylidene)butane-1,4-diamine, C18H18N4O4, (III), and (E,E)-N,N'-bis(4-nitrobenzylidene)hexane-1,6-diamine, C20H22N4O4, (IV), the molecules lie across centres of inversion in space groups P-1 and P2(1)/c, respectively. In (III), the three-dimensional supramolecular structure is built from pi-stacked chains of edge-fused R(2)(2)(30) rings, while in (IV), chains of edge-fused R(2)(2)(38) rings are linked by dipolar nitro-nitro interactions.

Journal Article↗
PubMed2005

1,2,3,4-Tetra-O-acetyl-beta-D-glucopyranuronic acid monohydrate at 120 K and anhydrous 1,2,3,4-tetra-O-acetyl-beta-D-glucopyranose at 292 K.

The structure of the title acid as the monohydrate, C14H18O11.H2O, displays hydrogen bonding which connects the molecules in layers parallel to (101). In the anhydrous glucopyranose, C14H20O10, only chain connectivity is attained but, due to disorder of the OH group, only partially and in two modes, one less favoured than the other. This provides incomplete connectivity between molecules in corrugated layers parallel to (010).

Journal Article↗
PubMed2005

Contrasting three-dimensional framework structures in the isomeric pair 2-iodo-N-(2-nitrophenyl)benzamide and N-(2-iodophenyl)-2-nitrobenzamide.

In 2-iodo-N-(2-nitrophenyl)benzamide, C(13)H(9)IN(2)O(3), the molecules are linked into a three-dimensional framework structure by a combination of a C-H...O hydrogen bond, and iodo-nitro, carbonyl-carbonyl and aromatic pi-pi stacking interactions. In the isomeric compound N-(2-iodophenyl)-2-nitrobenzamide, the framework structure is built from N-H...O, C-H...O and C-H...pi(arene) hydrogen bonds and an iodo-nitro interaction.

Journal Article↗
PubMed2005

Three isomeric (E)-nitrobenzaldehyde nitrophenylhydrazones: chains of rings in isomorphous (E)-2-nitrobenzaldehyde 3-nitrophenylhydrazone and (E)-3-nitrobenzaldehyde 2-nitrophenylhydrazone, and centrosymmetric dimers in (E)-4-nitrobenzaldehyde 2-nitrophenylhydrazone.

The isomeric compounds (E)-2-nitrobenzaldehyde 3-nitrophenylhydrazone and (E)-3-nitrobenzaldehyde 2-nitrophenylhydrazone, both C13H10N4O4, are isomorphous and effectively isostructural, and in both, the molecules are disordered across centres of inversion in the space group P21/c. The molecules are linked into complex chains of rings by N-H...O and C-H...O hydrogen bonds. In the isomeric compound (E)-4-nitrobenzaldehyde 2-nitrophenylhydrazone, the fully ordered molecules are linked by N-HO hydrogen bonds into centrosymmetric dimers.

Journal Article↗
PubMed2005

(1RS,2RS)-N,N'-Bis(4-nitrophenylmethylene)cyclohexane-1,2-diamine: complex sheets built from C-H...O and C-H...pi(arene) hydrogen bonds.

The racemic title compound, C20H20N4O4, crystallizes with Z'=2 in the space group P2(1)/c. Each independent molecule exhibits approximate twofold rotation symmetry, but conformational differences between the molecules preclude any higher symmetry. The molecules are linked into complex sheets by a combination of four C-H...O hydrogen bonds and two C-H...pi(arene) hydrogen bonds.

Journal Article↗
PubMed2005

Glyoxal 4-nitrophenylhydrazone: triple helices linked into a three-dimensional channel structure.

The molecules of the title compound, C8H7N3O3, which are nearly planar, are linked by an N-H...O hydrogen bond into helical chains, three of which are required to define the structure completely. These triply intertwined helices are linked by a C-H...O hydrogen bond into a three-dimensional framework enclosing two distinct types of channel, with average cross-sectional areas of 15.0 and 8.2 A2.

Journal Article↗
PubMed2005

Solvent-dependent polymorphism in isomeric N-(nitrobenzylidene)iodoanilines.

Three of the nine isomeric N-(nitrobenzylidene)iodoanilines, C13H9IN2O2, have been found, when crystallized from acetone, to yield polymorphs which differ from those obtained upon crystallization from ethanol. In the second polymorph of 2-iodo-N-(2-nitrobenzylidene)aniline, the molecules are disordered across inversion centres in space group C2/c, but there are no direction-specific interactions between the molecules. In the second polymorph of 2-iodo-N-(3-nitrobenzylidene)aniline, the molecules adopt a different conformation from those in the first polymorph, and they are linked into sheets by a combination of a three-centre iodo-nitro interaction and an aromatic pi-pi stacking interaction, both of which are absent from the supramolecular structure of the first polymorph. The second polymorph of 3-iodo-N-(2-nitrobenzylidene)aniline crystallizes with Z' = 2 in space group P2(1), and the molecules are linked into sheets by one C-H...O hydrogen bond and two C-H...pi(arene) hydrogen bonds.

Journal Article↗
PubMed2005

Concomitant polymorphism and a temperature-dependent phase change in (E)-[1-(4-methoxyphenyl)-3-phenyl-2-propenylideneamino]oxyacetic acid.

The title compound, C(18)H(17)NO(4), crystallizes from ethanol at ambient temperature as two concomitant polymorphs (I) and (II), both monoclinic P2(1)/c with Z' = 1. The less abundant form (I) undergoes a reversible phase-transition at ca 173 K to a third monoclinic polymorph (III), P2(1)/n, with Z' = 2, while the more abundant polymorph (II) is unchanged down to 120 K. In each polymorph of (I)-(III) the molecules are linked by pairs of O-H...O hydrogen bonds into cyclic dimers which are crystallographically centrosymmetric in (I) and (II), and approximately, but not crystallographically, centrosymmetric in (III). There are no direction-specific interactions between the hydrogen-bonded dimers in polymorph (I); in polymorph (II) the dimers are linked into sheets by C-H...N and C-H...pi(arene) hydrogen bonds; in polymorph (III) the dimers are linked into chains by a C-H...pi(arene) hydrogen bond. The interconversion of polymorphs (I) and (III) is a simple displacive phase transition.

Acetates↗