1,246 research outputs found
Poly[[tris(μ-4,4′-bipyridine-κ2 N:N′)bis(μ-l-lysinato-κ3 N 1,O 1:O 1′)dizinc(II)] tetranitrate 0.6-hydrate dimethylformamide disolvate]
In the title compound, {[Zn2(C6H14N2O2)2(C10H8N2)3](NO3)4·0.6H2O·2C3H7NO}n, the ZnII ion is six-coordinated with a distorted octahedral geometry by two carboxylate O atoms and one amino N atom from two l-lysinate (l-lys) ligands, and three N atoms from three 4,4′-bipyridine (4,4′-bipy) ligands. The ZnII ions are connected by the carboxylate groups of the l-lys ligands in the a-axis direction and the bridging 4,4′-bipy ligands in the b- and c-axis directions, forming a three-dimensional cationic framework with channels along [100]. The nitrate anions and solvent water and dimethylformamide (DMF) molecules are located in the channels and linked to the cationic framework by N—H⋯O and O—H⋯O hydrogen bonds. The occupancy of the water molecule was fixed at 0.6. One of the DMF molecules is disordered over two sets of sites, with an occupancy ratio of 0.632:0.368 (11)
2-(4-tert-Butylphenyl)-5-{3,4-dibutoxy-5-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]-2-thienyl}-1,3,4-oxadiazole
In the title compound, C36H44N4O4S, the dihedral angles between the central thiophene ring and the pendent oxadiazole rings are 12.7 (2) and 13.7 (2)°, and the dihedral angles between the oxadiazole rings and their adjacent benzene rings are 6.1 (2) and 17.5 (2)°. An intramolecular C—H⋯O interaction may help to establish the conformation
On sumsets involving th power residues
In this paper, we study some topics concerning the additive decompostions of
the set of all th power residues modulo a prime . For example, we
prove that
where is the number of primes and denotes the
cardinality of the set
\{p\le x: p\equiv1\pmod k; D_k\ \text{has a non-trivial 2-additive
decomposition}\}.$
Effective Tag Set Selection in Chinese Word Segmentation via Conditional Random Field Modeling
PACLIC 20 / Wuhan, China / 1-3 November, 200
(4Z)-4-[(2-Chloroanilino)(phenyl)methylidene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one
The title compound, C23H18ClN3O, exists in an enamine–keto form with the amino group involved in an intramolecular N—H⋯O hydrogen bond. The five-membered ring is nearly planar, the largest deviation being 0.0004 (7) Å, and makes dihedral angles of 16.62 (6), 41.89 (5) and 71.27 (4)° with the phenyl rings. In the crystal, weak C—H⋯O hydrogen bonds link the molecules into supramolecular chains along the b axis
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