Crystal structure of (E)-3-((naphthalen-1-ylimino)methyl)-4-nitrophenol, C₁₇H₁₂N₂O₃

Source of material

(E)-3-((naphthalen-1-ylimino)methyl)-4-nitrophenol was prepared by refluxing a mixture of a solution containing 5-hydroxy-2-nitro-benzaldehyde (8.4 mg, 0.05 mmol) in ethanol (20 mL) and a solution containing 1-naphthylamine (7.2 mg, 0.05 mmol) in ethanol (20 mL). The reaction mixture was stirred for 5 h under reflux. Single crystals of the title compound were obtained by slow evaporation of an ethanolic solution (Yield 70%; m.p. 458–459 K).

Experimental details

For least-squares refinement of the crystal structure all H atoms were placed in calculated positions using a suitable riding model, with C—H distances of 0.93 Å and O—H distances of 0.82 Å, U_iso(H) = 1.2U_eq(C) and 1.5U_eq(O).

Discussion

Schiff bases are an important class of organic molecules which contain imine and azomethine groups. Schiff bases were first discovered by Hugo Schiff in 1864 [1]. Some Schiff bases show biological activities such as anti-inflammatory, antimicrobial, anticonvulsant, anticancer, analgesic etc. [2; 3; 4]. And also, their metal complexes often exhibit antibacterial, antiviral, fungicidal or antitubarculoral activity [5, 6].

In the title compound, C₁₇H₁₂N₂O₃, the naphthalen and phenyl ring groups are planar with an r.m.s. deviation of 0.010(4) Å for atom C12 in naphthalen group and −0.005(3) Å for atom C5 in the phenyl group, respectively. However the whole molecule is also nearly planar with the dihedral angle is 5.79(8)° between the related ring systems. The torsion angle around the C1—C7—N2—C8 is −178.8(3)° shows that the molecular structure has E configuration. The C = N bond length is 1.154(4) Å, slightly shorther than in related structures [7, 8].

The molecular structure contains O—H⋯O type intermolecular and C—H⋯O and C—H⋯N type intramolecular H bonds. O1—H1⋯O2 (with symmetry code: x, −y + 1/2, + z−1/2) creates an infinite chain along the c-axis and generates a C(8) motif [9]. S(6) and S(5) loops are created by the intramolecular H bonds C7—H7⋯O3 and C10—H10⋯N2, respectively [9]. There is also π-π stacking which contributes to stabilization between the ring centroids of Cg(1)—Cg(2) [distance between ring centroids is 3.695(2) Å with symmetry code: 1−x, 1−y, 1−z where Cg(1) belongs to the C1—C6 ring and Cg(2) to C8/C9/C14/C15/C16/C17].