28 research outputs found
3-(2-Chloroethyl)-2-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidinium 2,4,6-trinitrophenolate
In the cation of the title salt, C11H12ClN2O+·C6H2N3O7
−, the chloroethyl side chain is in a syn conformation, nearly orthogonal to the pyrimidine ring, with a dihedral angle of 78.9 (6)° between the plane of the chloroethyl chain and the pyrimidine ring. The dihedral angle between the fused rings is 4.3 (3)°. In the picrate anion, the benzene mean plane makes dihedral angles of 26.7 (1), 33.6 (2) and 5.3 (6)° with the two o-NO2 groups and the p-NO2 group, respectively. Extensive hydrogen-bond interactions occur between the cation–anion pair which help to establish the crystal packing. A three-center O⋯(H,H)—(N,C) acceptor hydrogen bond is observed between the phenolate O atom of the picrate anion and the amine and methyl groups of the cation. An N—H⋯(O,O) bifurcated hydrogen bond is observed between the amine group and two O atoms from the phenolate and o-NO2 groups
Redetermination of 5α-androstane-3,17-dione
The structure of the title compound, C19H28O2, has been redermined at 295 (2) K, with much improved precision. The structure and molecular packing of the title compound was first reported by Coiro et al. [Acta Cryst. (1973). B29, 1404–1409] by means of potential-energy calculations. The cell parameters in this study differ considerably in space group C2. It is a derivative of testosterone and consists of a cyclopentanone ring (A) fused to to successive cyclohexane (B and C) and cyclohexanone (D) rings. The three cyclohexanone rings are in slightly distorted boat configurations and the cyclopentanone ring is a distorted half-chair. The crystal packing is stabilized by weak intermolecular C—H⋯O interactions involving O atoms from each of the cyclohexanone and cyclopentanone rings and H atoms from each of their respective rings
Gabapentin-lactum–chloranilic acid (1/1)
In the title compound, C9H15NO·C6H2Cl2O4 [sytematic name: 2-azaspiro[4.5]decan-3-one–chloranilic acid (1/1)], the cyclohexane ring of the lactam molecule adopts a slightly distorted normal chair conformation and the five-membered 3-azaspiro ring is in a slightly distorted chair conformation. The dihedral angle between the least-squares planes of the cyclohexane and 3-azaspiro rings is 84.0 (3)°. In the crystal, the chloranilic acid molecule and the gabapentin-lactum molecules are held together by strong intermolecular N—H⋯O and O—H⋯O hydrogen bonds with two bifurcated O acceptor atoms on the chloranilic acid molecule and one on the gabapentin-lactum molecule, each bonding with an inter- and intramolecular hydrogen bond. The molecules are linked into chains parallel to (011) and propagating along the b axis
4-(4-Chlorophenyl)-1-[3-(4-fluorobenzoyl)propyl]-4-hydroxypiperidin-1-ium 2,4,6-trinitrophenolate (haloperidol picrate)
In the title salt, C21H24ClFNO2
+·C6H2N3O7
−, the dihedral angle between the aromatic rings in the cation is 16.5 (1)°. The piperidium ring adopts a slightly distorted chair conformation. Strong hydrogen-bonding interactions occur between the N—H and O—H functions of the 4-hydroxypiperidin-1-ium ring and the phenolate and p-NO2 O atoms of the picrate anion. In addition, a variety of weak C—H⋯O and π–π ring interactions between cations and cation–anion neighbors [centroid–centroid distances = 3.597 (1) and 3.848 (10) Å] further consolidate the packing
Lomefloxacinium picrate
In the cation of the title compound [systematic name: (RS)-4-(3-carboxy-1-ethyl-6,8-difluoro-4-oxo-1,4-dihydroquinolin-7-yl)-2-methylpiperazin-1-ium 2,4,6-trinitrophenolate], C17H20F2N3O3
+·C6H2N3O7
−, the piperazine ring adopts a slightly distorted chair conformation and contains a protonated N atom. An intramolecular O—H⋯O hydrogen bond occurs in the cation. The dihedral angles between the mean planes of the six-atom piperazine ring and the 10-atom fused ring system is 43.3 (5)°. The picrate anion interacts with the protonated N atom of an adjacent cation through a bifurcated N—H⋯(O,O) three-center hydrogen bond. Strong N—H⋯O hydrogen bonds in concert with weak π–π stacking interactions [centroid–centroid distance = 3.6460 (14) Å] dominate the crystal packing, creating a two-dimensional network structure along [011]
2-Bromo-1,3-bis(4-chlorophenyl)prop-2-en-1-one
In the title compound, C15H9BrCl2O, the two benzene rings are twisted from each other with a dihedral angle of 47.33 (8)°. The crystal structure is stabilized by aromatic π–π interactions between the benzene rings of neighbouring molecules [centroid–centroid distance = 3.680 (2) Å], and by weak intermolecular C—H⋯O and C—H⋯Cl interactions. Additionally, the crystal structure exhibits a short intramolecular C—H⋯Br contact (H⋯Br = 2.69 Å)
4-(4-Carboxybenzyl)-1-methylpiperazin-1-ium picrate
The title compound, C13H19N2O2+·C6H2N3O7−, is a salt obtained by cocrystallization of 4-[(4-methylpiperazin-1-yl)methyl]benzoic acid and picric acid. The cations adopt an `L-shaped' conformation and are linked into chains along [010] by O—H⋯N hydrogen bonds. The NH group of each piperazinium ring forms a hydrogen bond to the phenolate O atom of a picrate anion, and the picrate anions form face-to-face contacts with an interplanar separation of 3.023 (1) Å
Dibenzo[b,e]thiepin-11(6H)-one
In the title compound, C14H10OS, the seven-membered thiepin ring adopts a distorted boat conformation with the dihedral angle between the mean planes of the two fused benzene rings being 56.5 (1)°
1-(1,3-Benzodioxol-5-yl)ethanone
In the title compound, C9H8O3, the dihedral angle between the mean planes of the benzene and dioxole rings is 1.4 (8)°, with the dioxole group in a slightly distorted envelope configuration with the flap C atom displaced by 0.0645 Å from the plane through the other four atoms. In the crystal, weak intermolecular C—H⋯O hydrogen-bond interactions link the molecules into chains propagating in [011]. The crystal packing exhibits weak π–π interactions as evidenced by the relatively short distances [3.801 (9) Å] between the centroids of adjacent benzene rings
N,N′-Bis[(E)-2-fluorobenzylidene]-1-(2-fluorophenyl)methanediamine
In the title compound, C21H15F3N2, the benzene ring bonded to the central C atom forms dihedral angles of 77.5 (7) and 89.0 (5)°, respectively, with the remaining two benzene rings. Weak intermolecular C—H⋯F hydrogen bonds link the molecules into chains propagated in [101]. The crystal packing exhibits weak π–π interactions as evidenced by relatively short distances between the centroids of the aromatic rings [3.820 (7) and 3.971 (5) Å]. A MOPAC PM3 optimization of the molecular geometry in vacuo supports a suggestion that intermolecular forces have a significnt influence on the molecular conformation in the crystal