4-Chloro-N'-(2-hy-droxy-4-meth-oxy-benzyl-idene)benzohydrazide methanol monosolvate

The title compound, C₁₅H₁₃ClN₂O₃·CH₃OH, was synthesized by the condensation reaction of 2-hy­droxy-4-meth­oxy­benzaldehyde with 4-chloro­benzohydrazide in methanol. The Schiff base mol­ecule displays a trans configuration with respect to the C=N and C—N bonds. The dihedral angle between the two benzene rings is 5.3 (2)°. In the crystal, mol­ecules are linked by N—H⋯O and O—H⋯O hydrogen-bond inter­actions into chains running parallel to the a axis. An intra­molecular O—H⋯N hydrogen bond is observed.

Zwitterionic (E)-1-[(4-nitro-phen-yl)iminio-meth-yl]naphthalen-2-olate

The title compound, C(17)H(12)N(2)O(3), was synthesized by the reaction of 2-hy-droxy-1-naphthaldehyde with 4-nitro-benzenamine. These condense to form the Schiff base, which crystallizes in the zwitterionic form. In the structure, the keto-amino tautomer has a fairly short intra-molecular N-H⋯O hydrogen bond between the 2-naphthalenone and amino groups, with electron delocalization. The mol-ecule is essentially planar, with a dihedral angle of 1.96 (3)° between the ring systems. In the crystal, the mol-ecules are linked via inter-molecular C-H⋯O hydrogen bonds, forming a layer parallel to (101).

N'-(2-Hydr-oxy-4-methoxy-benzyl-idene)isonicotinohydrazide

The title compound, C(14)H(13)N(3)O(3), was synthesized by the condensation reaction of 2-hydr-oxy-4-methoxy-benzaldehyde with isonicotinohydrazide in a methanol solution. The mol-ecule of the compound displays a trans configuration with respect to the C=N and C-N bonds. The dihedral angle between the benzene and the pyridine rings is 27.3 (2)°. In the crystal, mol-ecules are linked by N-H⋯N inter-actions into zigzag chains with graph-set notation C(7) along [010]. An intra-molecular O-H⋯N hydrogen bond is observed.

(E)-6-Chloro-N'-(3,5-dichloro-2-hydroxy-benzyl-idene)-nicotinohydrazide

The title Schiff base compound, C₁₃H₈Cl₃N₃O₂, was synthesized by the condensation reaction of 3,5-dichloro­salicyl­aldehyde with 6-chloro­nicotinic acid hydrazide in 95% ethanol. The mol­ecule is nearly planar, with a dihedral angle of 1.9 (2)° between the aromatic ring planes, and an intra­molecular O—H⋯N hydrogen bond is observed. In the crystal, the mol­ecules are connected by inter­molecular N—H⋯O hydrogen bonds into infinite chains propagating in [100].

N'-(2-Chloro-5-nitro-benzyl-idene)isonicotinohydrazide

The title compound, C(13)H(9)ClN(4)O(3), was synthesized by the condensation reaction of 2-chloro-5-nitro-benzaldehyde with isonicotinohydrazide in a methanol solution. The mol-ecule of the compound displays a trans configuration with respect to the C=N and C-N bonds. The dihedral angle between the benzene and pyridine rings is 12.1 (2)°. In the crystal structure, adjacent mol-ecules are linked through inter-molecular N-H⋯O hydrogen bonds, forming dimers.

6-Chloro-N'-(2-hydr-oxy-1-naphthyl-methyl-ene)nicotinohydrazide

The title compound, C₁₇H₁₂ClN₃O₂, was synthesized by the Schiff base condensation reaction of 2-hydr­oxy-1-naphthaldehyde with 6-chloro­nicotinic acid hydrazide in a methanol solution. The mol­ecule displays a trans configuration with respect to the C=N and C—N bonds. The dihedral angle between the naphthyl ring system and the pyridine ring is 7.6 (4)°. There is an intra­molecular O—H⋯N hydrogen bond. The crystal structure is stabilized by inter­molecular N—H⋯O and C—H⋯O hydrogen bonds, forming chains running along the b axis.