2-{2-[(E)-(2-Benzoyl­hydrazin-1-yl­idene)meth­yl]phen­oxy}acetic acid

In the title compound, C₁₆H₁₄N₂O₄, the dihedral angle between the aromatic rings is 12.45 (6)°. The central C(=O)—N—N=C bridge is roughly planar (r.m.s. deviation = 0.0346 Å) and makes dihedral angles of 13.01 (7) and 0.56 (7)° with the attached phenyl and benzene rings, respectively. The acetic acid unit (r.m.s. deviation = 0.0066 Å) is twisted from its attached benzene ring [dihedral angle = 19.48 (6)°]. In the crystal, mol­ecules are linked by O—H...(O,N), N—H...O and C—H...O hydrogen bonds into sheets lying parallel to the bc plane. A weak aromatic π–π stacking inter­action is also observed [centroid–centroid distance = 3.7330 (7) Å].

(N′,N′′Z,N′,N′′E)-N′,N′′-[1-(4-Chloro­phen­yl)ethane-1,2-diyl­idene]bis­(3-methyl-1-benzofuran-2-carbohydrazide)

In the title compound, C₂₈H₂₁ClN₄O₄, the benzofuran ring systems make dihedral angles of 7.43 (8) and 30.92 (9)° with the chloro-substituted benzene ring. The dihedral angle between the two benzofuran ring systems is 27.41 (7)°. The two benzofuran rings are connected to the chloro-substituted benzene ring through C—N—N=C and C—N—N=C—C bridges which are nearly planar [maximum deviations = 0.003 (1) and 0.037 (1) Å]. An intra­molecular N—H...N hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked by N—H...(O,N) and C—H...O hydrogen bonds into a tape along the c axis and these tapes are further connected by another weak C—H...O hydrogen bond into a sheet parallel to the bc plane. π–π inter­actions [centroid-to-centroid distances = 3.4845 (12)–3.6250 (13) Å] are also observed.

3-(3-Meth­oxy­phen­yl)benzo[d]thia­zolo[3,2-a]imidazol-9-ium hydrogen sulfate

In the title mol­ecular salt, C₁₆H₁₃N₂OS⁺·HSO₄⁻, the thia­zolo[3,2-a]benzimidazolium ring system is roughly planar [maximum deviation = 0.046 (3) Å] and makes a dihedral angle of 58.22 (11)° with the benzene ring. The meth­oxy group is almost coplanar with its attached benzene ring [C_meth­yl—O—C—C = −1.6 (5)°]. In the crystal, the cation is linked to the anion by a bifurcated N—H...(O,O) hydrogen bond, generating an R₁²(4) ring motif. The ion pairs are then connected by a C—H...O hydrogen bond into inversion dimers and these dimers are further linked by O—H...O hydrogen bonds into an infinite tape along [100]. A π–π stacking inter­action [centroid-to-centroid distance = 3.5738 (18) Å] and a short inter­molecular contact [S...O = 2.830 (3) Å] are also observed.