meso-4,4′-Difluoro-2,2′-{[(3aR,7aS)-2,3,3a,4,5,6,7,7a-octa­hydro-1H-1,3-benzimidazole-1,3-di­yl]bis­(methyl­ene)}diphenol

In the crystal structure of the title compound, C₂₁H₂₄F₂N₂O₂, there are two intra­molecular O—H...N hydrogen bonds involving the N atoms of the imidazolidine ring and the hy­droxy groups. The crystal studied was a meso compound obtained by the reaction of the aminal (2S,7R,11S,16R)-1,8,10,17-tetra­aza­penta­cyclo­[8.8.1.1^8,17.0^2,7.0^11,16]cosane with 4-fluoro­phenol. The imidazolidine ring has a twisted conformation with a CH—CH—N—CH₂ torsion angle of 44.99 (14)° and, surprisingly, the lone pairs of the N atoms are disposed in a syn isomerism, making the title compound an exception to the typical `rabbit-ear effect' in 1,2-diamines. In the crystal, molecules are linked via C—H...F hydrogen bonds, forming chains along the c-axis direction. These chains are linked via another C—H...F hydrogen bond, forming a three-dimensional network.

Acetonyltriphenyl­phospho­nium nitrate

Crystals of the title salt, C₂₁H₂₀OP⁺·NO₃⁻, are composed of acetonyltriphenyl­phospho­nium cations and nitrate anions that mainly inter­act through electrostatic forces. The P atom in the cation has a slightly distorted tetra­hedral environment, with C—P—C angles ranging from 104.79 (7) to 112.59 (6)°. The sum of O—N—O angles of the nitrate anion is 359.99°, reflecting its trigonal–planar character. C—H...O hydrogen bonds help to consolidate the crystal packing.

meso-4,4′-Dimeth­oxy-2,2′-{[(3aR,7aS)-2,3,3a,4,5,6,7,7a-octa­hydro-1H-benz­imidazole-1,3-di­yl]bis­(methyl­ene)}diphenol

The title compound, C₂₃H₃₀N₂O₄, a di-Mannich base derived from 4-meth­oxy­phenol and cis-1,2-di­amine­cyclo­hexane, has a perhydro­benzimidazolidine nucleus, in which the cyclo­hexane ring adopts a chair conformation and the heterocyclic ring has a half-chair conformation with a C—N—C—C torsion angles of −48.14 (15) and −14.57 (16)°. The mean plane of the heterocycle makes dihedral angles of 86.29 (6) and 78.92 (6)° with the pendant benzene rings. The mol­ecular structure of the title compound shows the presence of two inter­actions between the N atoms of the imidazolidine ring and the hydroxyl groups through intra­molecular O—H...N hydrogen bonds with graph-set motif S(6). The unobserved lone pairs of the N atoms are presumed to be disposed in a syn conformation, being only the second example of an exception to the typical `rabbit-ears' effect in 1,2-di­amines.

2,2′-[(4-Methyl-2-phenyl­imidazolidine-1,3-di­yl)bis­(methyl­ene)]diphenol

The methyl-substituted imidazolidine ring of the title compound, C₂₄H₂₆N₂O₂, adopts an envelope conformation with the N atom adjacent to the methyl­ene group as the flap. The meth­yl–ethyl­ene fragment in this ring is disordered over two positions with an occupancy ratio of 0.899 (4):0.101 (4). The hy­droxy­benzyl groups are inclined at 71.57 (15) and 69.97 (19)° to the mean plane of major disorder component of the heterocyclic ring with an inter­planar angle between the two hy­droxy­benzyl groups of 66.00 (5)°. The phenyl substit­uent approaches a nearly perpendicular orientation relative to the mean plane of the imidazolidine ring, making a dihedral angle of 75.60 (12)°. This conformation is stabilized by two intra­molecular O—H...N bonds, which generate S(6) ring motifs.

2,2′-{[2-(2-Chloro­phen­yl)-4-methyl­imidazolidine-1,3-di­yl]bis­(methyl­ene)}diphenol

In the title compound, C₂₄H₂₅ClN₂O₂, the 2-hy­droxy­benzyl substituents and the 2-chloro­phenyl group occupy the sterically preferred equatorial positions, whereas the methyl group occupies the axial position. The imidazolidine ring adopts an envelope conformation with one of the N atoms adjacent to the methylene group as the flap. The chloro­phenyl substit­uent approaches a nearly perpendicular orientation relative to the mean plane of the imidazolidine ring, making a dihedral angle of 73.44 (12)° and the Cl atom is almost coplanar with the C atom bearing the chloro­phenyl substituent [Cl—C—C—C torsion angle = 1.1 (3)°]. The hy­droxy­benzyl groups make dihedral angles of 71.23 (15) and 69.13 (19)° with the mean plane of the heterocyclic ring. The dihedral angle between the two hy­droxy­benzyl groups is 69.61 (12)°. The mol­ecular structure features two intra­molecular O—H...N hydrogen bonds with graph-set motif S(6) between the phenolic hydroxyl groups and N atoms.

2,2′-{[2-(2-Hy­droxy­phen­yl)-4-methyl­imidazolidine-1,3-di­yl]bis­(methyl­ene)}diphenol

The asymmetric unit in the title compound, C₂₄H₂₆N₂O₃, comprises two independent mol­ecules (A and B). In molecule A, the central 2-hydroxyphenyl ring is inclined to the mean plane of the major component of the imidazolidine ring by 84.52 (14)°, and by 68.08 (9) and 47.48 (9)° to the outer phenol rings. The later are inclined to one another by 66.76 (9)° and by 78.12 (14) and 80.20 (14)° to the imidazoline ring mean plane. In molecule B, the central 2-hydroxyphenyl ring is inclined to the mean plane of the imidazolidine ring by 73.64 (10)°, and by 75.60 (8) and 38.32 (9)° to the outer phenol rings. The later are inclined to one another by 69.47 (9)° and by 82.60 (10) and 64.26 (10)° to the imidazolidine ring mean plane. In each of the independent mol­ecules, two intra­molecular O—H...N hydrogen bond form S(6) ring motifs. In disordered mol­ecule A, the O—H groups of the 2-hy­droxy­benzyl groups are also involved in intra­molecular O—H...O hydrogen bonds, with the O atom of the hy­droxy­phenyl group acting as the acceptor. In the crystal, A molecules are linked by pairs of O—H...O hydrogen bonds forming inversion dimers. These dimers are linked to the B molecules via O—H...O hydrogen bonds forming double-layered slabs lying parallel to the bc plane.