Ferda Erşahin

2-[(2,4-Dimethyl­phen­yl)imino­meth­yl]-6-methyl­phenol

The title compound, C16H17NO, is a Schiff base which adopts the phenol–imine tautomeric form in the solid state. The molecule is almost planar, with a dihedral angle of 4.61 (4)° between the aromatic rings. The molecular structure is stabilized by an intramolecular O—H⋯N hydrogen bond which generates a six membered ring.

(E)-4-Bromo-2-[(4-ethyl­phen­yl)imino­meth­yl]phenol

In the title compound, C15H14BrNO, the dihedral angle between the two benzene rings is 43.99 (2)°. The molecular conformation is influenced by an intramolecular O—H⋯N hydrogen bond.

2-[(2,4-Dimethyl­phen­yl)imino­meth­yl]-3,5-dimethoxy­phenol

The title compound, C(17)H(19)NO(3), adopts the phenol-imine tautomeric form, with a resonance-assisted O-H⋯N intra-molecular hydrogen bond [O⋯N = 2.551 (3) Å]. The dihedral angle between the two benzene rings is 45.42 (7)°. The two meth-oxy groups are coplanar with the attached benzene ring [C-O-C-C torsion angles = -1.1 (5) and 3.2 (4)°].

2-Amino-4-nitro-phenol monohydrate.

The title compound, C6H6N2O3·H2O, crystallizes with two formula units in the asymmetric unit. The molecules are essentially planar with the nitro groups twisted slightly out of the ring planes [maximum deviations from the ring plane of 0.13 (2) and 0.22 (2) Å in the two molecules]. The respective O—N—C—C torsion angles are 6.0 (4) and 12.5 (4)°. In the crystal structure, molecules are linked by intermolecular N—H⋯O, C—H⋯O, O—H⋯O and O—H⋯N interactions into a three-dimensional network.

(E)-4-Methyl-2-{[tris(hydroxymethyl)methyl]iminiomethyl}phenolate

In the zwitterionic title compound, C12H17NO4, an intramolecular N—H⋯O hydrogen bond generates a six-membered ring, producing an S(6) ring. In the crystal structure, molecules are linked by intermolecular C—H⋯O and O—H⋯O interactions.

(E)-2-[(2,4-Dichloro-phen-yl)imino-methyl]-6-methyl-phenol

The title compound, C14H11Cl2NO, is a Schiff base which adopts the phenol–imine tautomeric form in the solid state. There are two molecules in the asymmetric unit. Head-to-tail π–π interactions [centroid-to-centroid distances of 3.682 (2), 3.708 (2), 3.904 (2) and 3.910 (2) Å] between adjacent molecules produce two symmetry-independent infinite chains running along the b axis.

(E)-2-Methyl-6-[3-(trifluoromethyl)phenyliminomethyl]phenol

The title compound, C15H12F3NO2, adopts the phenol–imine tautomeric form, with the H atom attached to oxygen rather than to nitrogen. There are two independent molecules aligned nearly parallel in the asymmetric unit with their trifloramethyl groups pointing in opposite directions. The dihedral angles between the aromatic rings are 40.43 (1) in the first molecule and 36.12 (1) in the second. Strong intramolecular O—H N hydrogen bonding generates S(6) ring motifs. Weak intermolecular C—H O hydrogen bonds link the independent molecules separately into sheets normal to [010]. In addition, C—H interactions are also observed. The F atoms of the trifluoromethyl groups are disordered over two sets of sites with refined site occupancies of 0.59 (2)/ 0.41 (2) and 0.62 (3)/0.38 (3), respectively.

Experimental and computational study of (E)-4-methyl-2-{[tris(hydroxymethyl)methyl]iminiomethyl} phenolate

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2-[(4-Bromophenyl)iminomethyl]-3,5-dimethoxyphenol

There are two independent molecules in the asymmetric unit of the title compound, C15H14BrNO3, with very similar geometrical parameters. Each molecule adopts the phenol–imine tautomeric form, with strong intramolecular O—H⋯N hydrogen bonds. The two molecules are non-planar, the dihedral angles between the two aromatic rings being are 24.6 (2) and 30.30 (13)°.

3,5-Dimeth­oxy-2-[(4-propyl­phen­yl)imino­meth­yl]phenol

The title compound, C18H21NO3, crystallizes in the phenol–imine tautomeric form, with the H atom attached to oxygen rather than on nitrogen. This H atom is involved in a strong intramolecular O—H⋯N hydrogen bond. A C—H⋯π interaction is also present. The dihedral angle between the aromatic rings is 12.23 (7)°.