2-{(E)-[(4-Methyl-phen-yl)imino]-meth-yl}-4-nitro-phenol-2-{(E)-[(4-methyl-phen-yl)iminio]meth-yl}-4-nitro-phenolate (0.60/0.40).

The crystal of the title compound, 0.6C(14)H(12)N(2)O(3)·0.4C(14)H(12)N(2)O(3), contains a mixture of its neutral (OH containing) and zwitterionic (NH containing) forms, in a 0.60 (4):0.40 (4) ratio. The former generates an S(6) loop via an intra-molecular O-H⋯N hydrogen bond and the latter generates an S(6) loop via an N-H⋯O hydro-gren bond. The aromatic rings are oriented at a dihedral angle of 42.52 (10)°. In the crystal, C-H⋯π inter-actions occur and aromatic π-π stacking inter-actions [centroid-centroid separations = 3.7106 (12) and 3.9177 (13) Å] consolidate the packing.

5-[(E)-(2-Fluoro-benzyl-idene)amino]-2-hy-droxy-benzoic acid.

In the title compound, C(14)H(10)FNO(3), the dihedral angle between the two benzene rings is 32.66 (14)°. An S(6) ring motif is formed due to an intra-molecular O-H⋯O hydrogen bond between the hy-droxy and carbonyl groups. In the crystal, mol-ecules are consolidated into dimers with R(2) (2)(8) ring motifs by pairs of O-H⋯O hydrogen bonds.

N-[(E)-3,4-Dimeth-oxy-benzyl-idene]-2,3-dimethyl-aniline.

In the title compound, C(17)H(19)NO(2), the aromatic rings are oriented at a dihedral angle of 59.27 (12)°. In the crystal, inversion dimers linked by pairs of weak C-H⋯O inter-actions generate R(2) (2)(12) loops.

(E)-1-(4-Chloro-benzyl-idene)-2-phenyl-hydrazine.

The asymmetric unit of the title compound, C(13)H(11)ClN(2), contains two geometrically distinct mol-ecules; one mol-ecule is close to planar [dihedral angle between the aromatic rings = 2.44 (18)°] and the other is twisted about the linking hydrazide group [dihedral angle = 14.08 (19)°]. In the crystal, the N-H groups do not form hydrogen bonds and the mol-ecules are linked by weak C-H⋯π inter-actions.

N-[(E)-2,4-Dichloro-benzyl-idene]-4-methyl-aniline.

In the title compound, C(14)H(11)Cl(2)N, the dihedral angle between the 4-methyl-anilinic and 2,4-dichloro-benzaldehyde moieties is 7.37 (8)°. In the crystal, C-H⋯π inter-actions between the terminal methyl group and a symmetry-related ring of the anilinic group help to establish the packing.

2,3-Dimethyl-N-[(E)-(1H-pyrrol-2-yl)methyl-idene]aniline.

In the title compound, C(13)H(14)N(2), the dihedral angle between the aromatic rings is 69.73 (14)°. In the crystal, inversion dimers linked by pairs of N-H⋯N hydrogen bonds generate R(2) (2)(10) loops. A weak C-H⋯π inter-action also occurs.

4-Chloro-N-[(E)-(3,4-dimeth-oxy-phen-yl)methyl-idene]aniline.

The asymmetric unit of the title compound, C(15)H(14)ClNO(2), contains two mol-ecules with significantly different conformations: the dihedral angles between the 4-chloro-aniline and 3,4-dimeth-oxy-phenyl (excluding C atoms) moieties are 19.68 (7) and 45.54 (4)°. In the crystal, the mol-ecules are linked by C-H⋯O hydrogen bonds and weak C-H⋯π inter-actions.

2-[(E)-(2,3-Dimethyl-phen-yl)imino-meth-yl]phenol.

In the title compound, C(15)H(15)NO, the almost planar 2,3-dimethyl-aniline unit and the salicyl-aldehyde group (r.m.s. deviations of 0.0156 and 0.0109 Å, respectively) are oriented at a dihedral angle of 43.69 (9)° with respect to each other. An S(6) ring motif is formed due to intra-molecular O-H⋯N hydrogen bonding. In the crystal, C-H⋯π inter-actions occur between the 2,3-dimethyl-aniline unit and the salicyl-aldehyde group, where the CH is from the o-methyl group.

N-[(E)-1,3-Benzodioxol-5-yl-methyl-idene]-4-methyl-aniline.

The two symmetry-independent mol-ecules in the asymmetric unit of the title compound, C(15)H(13)NO(2), differ in conformation, with the virtually planar 4-methyl-aniline (r.m.s. deviations of 0.0511 and 0.0082 Å) and piperonal groups (r.m.s. deviations of 0.0241 and 0.0486 Å) forming dihedral angles of 19.40 (5) and 42.90 (6)°. In the crystal, mol-ecules are linked by C-H⋯O and C-H⋯π inter-actions. The H atoms of the two methyl groups are disordered over two sets of sites of equal occupancy.

Dimethyl (2-hydr-oxy-4-phenyl-but-3-en-2-yl)phospho-nate.

In the title compound, C(12)H(17)O(4)P, the phenyl-butenyl group is disordered over two sets of sites with an occupancy ratio of 0.755 (12):0.245 (12). In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds occur, forming R(2) (2)(10) ring motifs. The packing is consolidated by weak C-H⋯π inter-actions.

Diethyl (1-hydr-oxy-1,2-diphenyl-ethyl)phospho-nate.

In the title compound, C(18)H(23)O(4)P, the dihedral angle between the aromatic ring planes is 69.94 (14)°. Both ethyl side chains are disordered over two sets of sites, with occupancy ratios of 80:20 and 70:30. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds occur, leading to R(2) (1)(8) loops, and C-H⋯O and weak C-H⋯π inter-actions are also seen.

Dimethyl (1-hydr-oxy-1,2-diphenyl-ethyl)phospho-nate.

In the crystal of the title compound, C(16)H(19)O(4)P, the mol-ecules are dimerized with R(2) (2)(10) ring motifs through the hydr-oxy and P=O O atoms. The dihedral angle between the aromatic rings is 66.89 (9)°. There are π-π inter-actions [centroid-centroid distance = 3.9669 (16) Å] between the benzene rings of adjacent benzyl groups. A C-H⋯π inter-action between the aromatic rings where C-H is from a benzyl group is also present.