5-Nitro-1-(prop-2-yn-1-yl)-2,3-dihydro-1H-1,3-benzodiazol-2-one

In the two independent mol­ecules of the title compound, C₁₀H₇N₃O₃, the nitro substitutent is twisted slightly with respect to the benzodiazol fused-ring system [dihedral angles = 4.9 (3) and 8.5 (1)°]. The two independent mol­ecules are disposed about a pseudo inversion center and are held together by N—H...O hydrogen bonds. The supramolecular dimer is essentially planar [dihedral angle between the fused rings = 2.0 (1)°]. Adjacent dimers are linked by acetyl­ene–nitro C—H...O inter­actions, generating a ribbon motif along (110).

1-Octyl-1H-benzimidazol-2(3H)-one

In the title compound, C₁₅H₂₂N₂O, the octyl group adopts an all-trans conformation. In the crystal, mol­ecules form centrosymmetric dimers with an R₂²(8) graph-set motif, linked by pairs of N—H...O hydrogen bonds. In addition, C—H...O contacts are observed.

1-Dodecyl-1H-benzo[d]imidazol-2(3H)-one

In the title compound, C₁₉H₃₀N₂O, the fused ring system is essentially planar, the maximum deviation from the mean plane being 0.013 (2) Å for the N atom bearing the dodecyl chain. The 1-dodecyl group is almost perpendicular to the 1H-benzo[d]imidazol-2(3H)-one plane as indicated by the dihedral angle of 82.9 (2)°between planes through the fused ring system and the first three C atoms of the chain. The C—C—C—C torsion angles (about ±179°) of the dodecyl group indicate an anti­periplanar conformation. In the crystal, inversion dimers are formed by pairs of N—H...O hydrogen bonds.

1-Allyl-1H-1,3-benzimidazol-2(3H)-one

The fused five- and six-membered rings in the title compound, C₁₀H₁₀N₂O, are approximately coplanar, with an r.m.s. deviation of 0.008 Å. The mean plane of the allyl group is roughly perpendicular to the mean plane of the 1,3-benzimidazol-2(3H)-one system, making a dihedral angle of 86.1 (2)°. In the crystal, each mol­ecule is linked to its symmetry equivalent partner by a pair of N—H...O and C—H...O hydrogen bonds.