2,3:4,6-Di-O-isopropylidene-alpha-L-sorbofuranose and 2,3-O-isopropylidene-alpha-L-sorbofuranose

In the title compounds, C(12)H(20)O(6), (I), and C(9)H(16)O(6), (II), the five-membered furanose ring adopts a (4)T(3) conformation and the five-membered 1,3-dioxolane ring adopts an E(3) conformation. The six-membered 1,3-dioxane ring in (I) adopts an almost ideal (O)C(3) conformation. The hydrogen-bonding patterns for these compounds differ substantially: (I) features just one intramolecular O-H...O hydrogen bond [O...O = 2.933 (3) A], whereas (II) exhibits, apart from the corresponding intramolecular O-H...O hydrogen bond [O...O = 2.7638 (13) A], two intermolecular bonds of this type [O...O = 2.7708 (13) and 2.7730 (12) A]. This study illustrates both the similarity between the conformations of furanose, 1,3-dioxolane and 1,3-dioxane rings in analogous isopropylidene-substituted carbohydrate structures and the only negligible influence of the presence of a 1,3-dioxane ring on the conformations of furanose and 1,3-dioxolane rings. In addition, in comparison with reported analogs, replacement of the -CH(2)OH group at the C1-furanose position by another group can considerably affect the conformation of the 1,3-dioxolane ring.

An interpenetrating primitive cubic net formed by hydrogen bonds and coordination bonds in catena-poly[[bis(methanol-kappaO)bis(thiocyanato-kappaN)iron(II)]-mu-1,2-bis(4-pyridylmethylene)hydrazine-kappa2N:N']

In the title compound, [Fe(NCS)(2)(C(12)H(10)N(4))(CH(4)O)(2)](n), at 153 (2) K, the Fe atom is located on an inversion centre, as is the centre of the N-N bond in the ligand molecule. The structure contains a one-dimensional coordination polymer with an Fe...Fe distance of 15.866 (7) A and can be described as two interpenetrating six-connected primitive cubic (pcu) three-dimensional networks when additional intermolecular O-H...S hydrogen bonds are taken into account. The compound is not isostructural with the corresponding Mn(II) compound as they differ in the rotation around the M-O bond by 90 degrees , giving rise to completely different hydrogen-bond patterns. This study demonstrates the impact of conformational differences on the final supramolecular arrangement.

catena-Poly[[bis(N,N′-dimethylformamide)cadmium(II)]-μ2-oxalato]

The title compound, [Cd(C₂O₄)(C₃H₇NO)₂]_n, is isostructural with its Mn^II analogue. The structure comprises zigzag polymeric chains with the oxalate groups situated on inversion centres and the Cd^II atoms located on twofold rotation axes. The coordination geometry around Cd^II is distorted octa­hedral and the intra­chain Cd⋯Cd distance is 5.842 (1) Å. C—H⋯O hydrogen bonds exist between the parallel polymeric chains.

(E)-Methyl 2-anilinomethylene-3-oxobutanoate: X-ray and density functional theory studies

Molecules of the title compound, C(12)H(13)NO(3), are not planar and are stabilized by electrostatic interactions, as the dipole moment of the molecule is 3.76 D. They are also stabilized by intramolecular hydrogen bonds of N...O and C...O types, and by a complicated network of weak intermolecular hydrogen bonds of the C...O type. This paper also reports the theoretical investigation of the hydrogen bonding and electronic structure of the title compound using natural bond orbital (NBO) analysis.

Synthesis and Structure of Silver Complexes with Nicotinate-Type Ligands Having Antibacterial Activities against Clinically Isolated Antibiotic Resistant Pathogens

The synthesis and low-temperature X-ray crystal structures of five new silver complexes, [Ag(2)-mu-O,O'(2-aminonicotinium)(2)(NO(3))(2)](n) (7), [Ag(isonicotinamide)(2)-mu-O,O'(NO(3))](2) (8), [Ag(ethyl nicotinate)(2)](NO(3)) (9), [Ag(ethyl isonicotinate)(2)(NO(3))] (10), and [Ag(methyl isonicotinate)(2)(H(2)O)](NO(3)) (11), are presented and fully characterized by spectral and elemental analysis. The antimicrobial activities of these complexes were screened using 12 different clinical isolates belonging to four pathogenic bacteria, S. aureus, S. pyogenes, P. mirabilis, and Ps. Aeruginosa, all obtained from diabetic foot ulcers. These tested bacteria were resistant for at least 10 antibiotics commonly used for treatment of diabetic foot ulcers. Compounds 7 and 8 had considerable activity against Ps. Aeruginosa (MIC values 2-8 microg/mL), compound 9 against S. aureus (MIC 4-16 microg/mL) and S. pyogenes (MIC 2-4 microg/mL), and also 9 and 11 against P. mirabilis (MIC 1-16 microg/mL). All complexes were non-toxic for daphnia at concentrations above 512 microg/mL overnight.

3-(4-Bromophenyl)-5-(4-dimethylaminophenyl)-1-phenyl-2-pyrazoline: X-ray and density functional theory (DFT) studies

In the crystal structure of the title compound, C(23)H(22)BrN(3), a strong conjugation of the pyrazoline chromophore with the aromatic rings at positions 1 and 3 is observed, as well as a significant shift in the synclinal-->synperiplanar direction. The absolute structure was unequivocally determined. In the absence of clasical hydrogen-bond donors, the structure is stabilized by weak C-H...pi interactions. This paper also reports the electronic structure of the title compound using NBO (natural bond order) analysis. The contributions of lone pairs to the relevant bonds were revealed.

4,4'-(Azinodimethylene)dipyridinium bis(tetrafluoroborate) and 4-[(4-pyridylmethylene)hydrazonomethyl]pyridinium perchlorate: two different hydrogen-bonding motifs

In the crystal structures of the title compounds, C(12)H(12)N(4)(2+).2BF(4)-, (I), and C(12)H(11)N(4)+.ClO(4)-, (II), respectively, infinite two- and one-dimensional architectures are built up via N-H...F [in (I)] and conventional N-H...N [in (II)] hydrogen bonding. The N-N single bond in (I) lies on a crystallographic centre of symmetry; as a result, the two pyridinium rings are parallel. In (II), the pyridinium and pyridyl ring planes are inclined with a dihedral angle of 14.45 (3) degrees.