J. Lokaj

2-(1,3-Benzoxazol-2-yl)-3-(5-diethylamino-2-furyl)propenenitrile

The title compound, C 18 H 17 N 3 O 2 , belongs to a series of large conjugated molecules with potential use as organic dyes. As indicated by the planarity of the molecule and the pattern of bond lengths and angles, a considerable amount of π-electron density is transferred from the aminofuran portion of the molecule to the cyano and benzoxazolyl groups. This fact is supported by the packing of the molecules in the crystal.

Diethyl 2-(2,3-diphenylquinoxalin-6-ylaminomethylene)malonate

The substituted aminoethylenic group in the title compound, C 28 H 25 N 3 O 4 , is approximately coplanar with the heterocyclic plane [dihedral angle 16 (2)°] and the α-C atom C(23), is disordered between two well defined sites. This disorder originates from a flipping of the aminoethylenic moiety around the C(6)−N(5) bond. The phenyl rings at C(2) and C(3) are twisted out of the plane of the quinoxaline ring system by 46.7 (8) and 38.0 (9)°, respectively

2-(phenylaminomethylidene)cyclohexane-1,3-dione.

In the title compound, C(13)H(13)NO(2), there is polarization of pi-electron density from the amine N atom to the acceptor carbonyl groups: as a result, the molecule exists predominantly in an azomethino-1,3-diketone tautomeric form. There is crystallographic evidence that the phenyl ring, although roughly coplanar with the rest of the molecule, is deconjugated with the adjacent pi system of the molecule. The cyclohexane ring adopts an unsymmetrical half-chair conformation and converts between two inversion-related conformers. The molecule is stabilized by an intramolecular hydrogen bond, while the intermolecular packing is dominated by a number of short C-H.O contacts.

1-Methyl-1H-imidazo[4,5-f]quinolin-6-ium chloride monohydrate.

The title compound, C(11)H(10)N(3)(+) x Cl(-) x H(2)O, belongs to the N1-methyl-substituted imidazo[4,5-f]quinoline family, in which the heterocyclic ring is protonated at the pyridine rather than at the imidazole N atom. The molecule as a whole is almost exactly planar. The molecular structure has been compared with that of the 2-amino analogue described in the literature, and it was found that the extra amino group of the latter is involved in conjugation with the adjacent double bond, i.e. the conjugation does not extend over the entire heterocyclic system. The cation of the title compound forms a strong hydrogen bond with the Cl(-) anion and the anions are interconnected by the water solvent molecule.

2-(1-Methyl-1,2-dihydro-2-pyridylideneaminomethylene)propanedinitrile

The title compound, C10H8N4, belongs to a series of conjugated molecules that offer potential utilization as organic dyes. As indicated by the planarity of the molecule and the pattern of bond lengths and angles, a considerable amount of π-electron density is transferred from the dihydropyridineimine portion of the molecule to the cyano groups. The principal packing interaction seems to be π-π stacking of the heterocyclic rings.

trans-2-(2-Thienyl)-3-(5-phenyl-2-furyl)propenenitrile

The title compound, C 17 H 11 NOS, belongs to a series of extensively conjugated molecules which have potential as organic dyes. As indicated by the planarity of the molecule and bond-length patterns, the π-electron delocalization extends over the whole molecule. As expected, the arrangement of the phenylfuran and thiophene moieties at the double bond is trans.

Chlorobis(N,N-diethyldithiocarbamato)(vinyl)tin(IV)

The crystal structure of the title compound, [SnCl(C 2 H 3 )(C 5 H 10 NS 2 ) 2 ], consists of relatively isolated complex molecules, the closest intermolecular contact [3.573 (6) A] being between the methyl C atom C(3) and the S atom S(2) of neighbouring molecules. The Sn atom is hexacoordinated by the vinyl group, the Cl atom and the two bidentate dithiocarbamate ligands, resulting in a distorted octahedral geometry. The vinyl group and Cl atom both occupy cis positions with respects to the dithiocarbamate ligands