Lee G. Madeley

Isonicotinamide-2-naphthoic acid (1/1).

In the title 1:1 adduct, C6H6N2O·C11H8O2, the amide group is slightly twisted out of the plane of the aromatic ring, with a C—C—C—N torsion angle of 25.11 (19)°, whereas the carboxylic acid group is approximately coplanar with the bicylic ring system, with a C—C—C—O torsion angle of 10.9 (2)°. The amide groups from two isonicotinamide molecules form a dimer via N—H⋯O hydrogen bonds. In addition, the 2-naphthanoic acid molecule is hydrogen bonded to the pyridine unit of an isonicotinamide molecule via an O—H⋯N hydrogen bond. This gives rise to a centrosymmetric four-molecule chain, which is cross-linked by further N—H⋯O hydrogen bonds from the amide group.

Covalent Assistance to Supramolecular Synthesis

The similarity of crystal engineering to organic synthesis has been noted by Desiraju and many concepts and strategies have been successfully transferred. We aim to combine the two fields of research into one new concept called “Covalent Assistance to Supramolecular Synthesis”. The supramolecular reagent isonicotinic acid hydrazide (isoniazid) is a promising molecule in the supramolecular synthesis of multi-component molecular complexes (Lemmerer at al., 2010). Due to the covalent reaction of the carbohydrazide functional group with simple ketones and aldehydes, the hydrogen bonding functionality of isoniazid can be modified, where two of the hydrogen bond donors are replaced with hydrogen bonding “inert” hydrocarbons (Lemmerer et al., 2011). The “modifiers” bonded to the isoniazid then give a measure of control of the outcome of the supramolecular synthesis with various carboxylic acids depending on the identity and steric size of the modifier used. The steric size itself can be used to shield or to “mask” the remaining hydrogen bonding functionality of isoniazid such that common homomeric and heteromeric interactions are prevented from taking place.

(2E)-1-Phenyl-2-[1-(2-phenyl­prop-2-en-1-yl)pyrrolidin-2-yl­idene]ethanone

The title compound, C21H21NO, is a vinylogous amide (enaminone) produced by reaction of 1-(2-phenylprop-2-en-1-yl)pyrrolidine-2-thione with phenacyl bromide. In the molecule, the phenyl rings are twisted from the mean plane of the pyrrolidine ring by 11.2 (1) and 67.3 (1)°. In the crystal, weak C—H⋯O hydrogen bonds link the molecules related by translation along the b axis into chains.

2-[(2Z)-Azepan-2-yl-idene]-1-(4-nitro-phen-yl)ethanone.

The title compound, C14H16N2O3, is an NH-vinylogous amide (enaminone) produced by the reaction of 4-nitrophenacyl bromide with azepane-2-thione. The conformation about the C=C bond [1.3927 (14) Å] is Z, which allows for the formation of an intramolecular N—H⋯O hydrogen bond that leads to an S(6) loop. Inversion-related molecules associate via N—H⋯O hydrogen bonds to form a 12-membered {⋯OC3NH}2 synthon.

2,3-Dihydro-1H-pyrrolo­[1,2-a]indole-9-carbonitrile

The asymmetric unit of the title compound, C12H10N2, which may serve as a model for mitosenes, contains two independent molecules. The conformation of the five-membered rings in both molecules is envelope, with the central CH2—CH2—CH2 C atom at the flap in each case. In the crystal, they interact by a combination of weak C—H⋯N and π–π interactions [centroid–centroid distances = 3.616 (1) and 3.499 (1) Å] and C—H⋯π contacts.

(±)-(rel-3R,3'R)-1,1'-Dimethyl-3,3'-bipyrrolidine-2,2'-dithione.

The asymmetric unit of the racemic title compound, C10H16N2S2, a C 2-symmetric bis(thiolactam), contains one half-molecule, the complete molecule being generated by a twofold axis symmetry operation. The five-membered ring is nearly planar, with a maximum deviation of 0.025 (1) Å. In the crystal, the molecules are linked via weak C—H⋯S interactions, forming infinite chains along the b-axis direction.