Heng-Yu Qian

4-Nitro­aniline: a redetermination

The occurrence of N—H⋯O and C—H⋯O hydrogen bonds in the title compound, C6H6N2O2, results in the formation of two-dimensional sheets parallel to the (101) plane.

Electrochemical Properties and Regioselectivity of Cyclopalladation of Chiral Ferrocenylimines Deriving from (S)-Ferrocenylethylamine

Treatment of a cyclopalladated complex derived from chiral ferrocenylimine (eta(5)-C5H5) Fe(eta(5)-C5H4)-CH(CH3)-N=CH-2-C4H3S, (Sc)-1, with PPh3 produced the heteroannular palladacycle (Sc)-3 in which palladation occurred at the unsubstituted cyclopentadiene ring. While for (eta(5)-C5H5)Fe(eta(5)-C5H4)-CH(CH3)-N=CH-C6H5, (Sc)-4, cyclopalladation took place mainly at the phenyl ring; the heteroannular palladacycle (Sc)-6, as a minor product, was also obtained. Single crystal X-ray analysis, electrochemical, and computational studies have been performed, showing good agreement with experimental results.

Thio-phene-2-carbaldehyde 2,4-dinitro-phenyl-hydrazone.

In the approximately planar molecule of the title compound, C11H8N4O4S, the dihedral angle between the thiophene and benzene rings is 5.73 (10)°. In the crystal structure, bifurcated inter/intramolecular N—H⋯(O,O) hydrogen bonds are present. The intermolecular links lead to inversion dimers containing an R 2 2(12) graph-set motif.

[μ-1,1′-(Butane-1,4-di­yl)di-1H-benz­imidazole-κ2N3:N3′]bis­{[N,N′-bis(car­boxy­meth­yl)ethyl­enediamine-N,N′-di­acetato-κ5O,O′,O′′,N,N′]mercury(II)} methanol disolvate

The binuclear title complex, [Hg2(C10H14N2O8)2(C18H18N4)]·2CH3OH, lies on an inversion center with the unique HgII ion coordinated in a disorted octahedral environment with one Hg—N bond significantly shorter than the other two. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link complex and solvent molecules into a three-dimensional network.

An ortho­rhom­bic polymorph of 1-benzyl-1H-benzimidazole

The title compound, C14H12N2, in contrast to the previously reported monoclinic polymorph [Lei et al. (2009 ▶). Acta Cryst. E65, o2613], crystallizes in the orthorhombic crystal system. The dihedral angle between the imidazole ring system and the phenyl ring is 76.78 (16)°. Weak C—H⋯N and C—H⋯π interactions are observed in the crystal structure.

3-(1,3-Benzodioxol-5-yl)-1-phenyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazine

In the title compound, C25H19NO3, the oxazine ring displays a half-chair conformation. The fused benzene ring is nearly parallel to the naphthyl ring system, the dihedral angle between this benzene ring and the naphthyl system being 8.52 (11)°. The imino group is not involved in hydrogen bonding in the crystal structure.

Crystal structure of 4-aminopyridinium 2-(pyridine-4-ylcarbamoyl)- benzoate hydrate, [C5H7N2][C13H9N2O4] · H2O

C18H18N4O4, triclinic, P1 (no. 2), a = 8.252(2) Å, b = 9.748(2) Å, c = 10.918(2) Å, * = 97.45(1)°, ) = 96.45(3)°, & = 96.82(2)°, V = 857.4 Å, Z = 2, Rgt(F) = 0.048, wRref(F) = 0.107, T = 291 K. Source of material The title compound was synthesized by the reaction of 4-aminopyridine and phthalic anhydride in a molar ratio of 2 : 1. Single crystals were grown by slowly evaporating the reaction mixture solution in repeated syntheses. Experimental details Hydrogen atoms potentially involved in hydrogen-bonding interactions were located by difference methods and their positional and isotropic displacement parameters were refined. Other H atoms were included in the refinement at calculated positions with d(C—Haromatic) = 0.93 Å and treated as riding with Uiso(H) = 1.2 Ueq(C). Discussion 4-Aminopyridine is used clinically for treatment of LamberEaton myasthenic syndrome and multiple sclerosis because by blocking potassium channel it prolongs action potentials thereby increasing transmitter release at the neuromuscular junction [1]. As an extension of our systematic study of the hydrogen bonding patterns of 4-aminopyridine with carboxylic acid, the title compound has been synthesized and the crystal structure determined. The asymmetric unit of the title crystal structure contains of one molecule of 4-aminopyridine cation, one molecule of 2(pyridine-4-ylcarbamoyl)benzoate anion and one water molecule. A proton transfer from the carboxyl group of 2-(pyridine-4ylcarbamoyl)benzoic acid to atom N3 of 4-aminopyridine resulted in the formation of salt. This protonation leads to the widening of C16–N3–C17 angle of the pyridine ring to 120.8(2)°, compared to 115.3(1)° in the unprotonated 4-aminopyridine [2]. This type of protonation is observed in various 4-aminopyridine acid complexes [3,4]. Other bond lengths and bond angles in 4aminopyridinium are comparable to the values reported earlier for 4-aminopyridine [5]. The crystal packing is consolidated by intermolecular O–H···O and N–H···O hydrogen bonds. The molecules are further interlinked by the C–H···O non-classical hydrogen bonds and ,-, stacking into the 3D supramolecular architecture. Z. Kristallogr. NCS 225 (2010) 593-594 / DOI 10.1524/ncrs.2010.0259 593

1-Chloro­methyl-1H-1,2,3-benzotriazole

In the title compound, C7H6ClN3, the benzotriazole ring is essentially planar with a maximum deviation of 0.0110 (15)Å, and makes a dihedral angle of 0.46 (8)° with the benzene ring. In the crystal, molecules are linked through intermolecular C—H⋯N hydrogen bonds, forming chains along the c axis.

2-Eth-oxy-4-{[(2-nitro-phen-yl)hydrazono]meth-yl}phenol.

The title compound, C15H15N3O4, a Schiff base, was obtained from a condensation reaction of 3-ethoxy-4-hydroxybenzaldehyde and 2-nitrophenylhydrazine. The molecule is approximately planar, the largest deviation from the mean plane being 0.1449 (16) Å. An intramolecular N—H⋯O interaction is also present. In the crystal, intermolecular O—H⋯O hydrogen bonds link the molecules, forming chain parallel to the b axis.

1-(2-Furylmethyl­ene)-2-(2-nitro­phen­yl)hydrazine

The title Schiff base compound, C11H9N3O3, was obtained from a condensation reaction of furan-2-carbaldehyde and 2-nitrophenylhydrazine. The molecule is roughly planar, the largest deviation from the mean plane defined by all non-H atoms being 0.097 (4). An in ntramolecular N—H⋯O hydrogen bond might influence the planar conformation of the molecule. In the crystal, weak C—H⋯O hydrogen bonds link the molecules, forming a chain.