N-(4-Methylbenzyl)-3-nitroaniline

In the title compound, C14H14N2O2, the angle between the mean plane of the N-methyl-3-nitroaniline system (r.m.s. deviation = 0.0185 Å) and the p-tolyl unit is 89.79 (4)°. In the crystal, hydrogen-bonded chains running along [10-1] are generated by the linking of neighbouring molecules via N—H⋯O and C—H⋯O hydrogen bonds involving the 3-nitroaniline systems and forming R 2 2(8) motifs.

In the title compound, C 14 H 14 N 2 O 2 , the angle between the mean plane of the N-methyl-3-nitroaniline system (r.m.s. deviation = 0.0185 Å ) and the p-tolyl unit is 89.79 (4) . In the crystal, hydrogen-bonded chains running along [101] are generated by the linking of neighbouring molecules via N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds involving the 3nitroaniline systems and forming R 2 2 (8) motifs.   Table 1 Hydrogen-bond geometry (Å , ).

Marijana Đaković, Tomislav Portada and Tin Klačić Comment
The title compound, N-(4-methylbenzyl)-3-nitroaniline, is prepared as a part of the laboratory work with high school students, and the synthesis followed the Preparatory problems for the 40th International Chemistry Olympiad (Magyarfalvi, 2008) involving slight modifications.
Recently, N-benzyl-3-nitroaniline was reported (Stilinović & Portada, 2011). The difference between the title compound and the previously reported one is only in methyl substituent on the N-benzyl moiety, since it was of interest to study the influence of the benzyl moiety substituents on the molecular conformation, and consequently the hydrogen bonding formation.
The addition of methyl substituent on the benzyl moiety in the title compound did not cause any significant conformational difference. The molecule retained a bent conformation with the torsion angle about the central C-N bond of 73.9 (2)° being very similar to analogous one in the recently reported compound (Stilinović & Portada, 2011).
Furthermore, the N-methyl-3-nitroaniline system in the title compound is nearly ideally planar (r.m.s. deviation of the atoms C1-C7/N1/N2/O1/O2 from their mean plane is 0.0185 Å, with oxygen atom O2 being the one that deviates most from that plane, 0.031 (2) Å). The p-tolyl substituent is tilted at an angle of 89.79 (4)° to the rest of the molecule.
Two neighbouring molecules are connected through the set of N-H···O and C-H···O hydrogen bonds in the head to tail manner forming R 2 2 (8) motifs (Etter, 1990;Bernstein et al., 1995) that generate one-dimensional chains running in the [101] direction. The same hydrogen bonding pattern is also found in N-benzyl-3-nitroaniline (Stilinović & Portada, 2011) what leads to the conclusion that the methyl substituent in p-position to the central C-N bond do not influence neither hydrogen bonding geometry nor general hydrogen bonding framework formation.

Refinement
In the final cycles of refinement, in the absence of significant anomalous scattering effect, 1856 Friedel pairs were merged and Δf′′ set to zero. The amine H atom was located in the difference Fourier map and freely refined, giving N-H distance of 0.78 (3) Å. All other H atoms were placed in geometrically idealized positions and constrained to ride on their parent C atom at distances of 0.93, 0.96 and 0.97 Å for aromatic, methyl and CH 2 H atoms, respectively, and with U iso (H) = 1.2U eq (C) (for aromatic and CH 2 H atoms), and U iso (H) = 1.5U eq (C) (for methyl group).

Figure 1
Molecular structure of the title compound with the atom labelling scheme. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level. Hydrogen atoms are shown as a spheres of arbitrary radius.

Figure 2
Infinite one-dimensional chains running in the [101] direction constructed via N-H···O and C-H···O hydrogen bonds between neighbouring molecules forming R 2 2 (8) motifs. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.16 e Å −3 Δρ min = −0.11 e Å −3 Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.