3-Methyl-4-nitrophenol–4-dimethylaminopyridine (1/1)

In the title adduct, C7H7NO3 .C7H10N2, the dihedral angle betwen the benzene ring and pyridine rings is 9.60 (8)° while the nitro group attached to the benzene ring makes a dihedral angle of 21.76 (13)°. The hydroxyl O atom deviates by 0.0247 (15) Å from the plane of the benzene ring. The crystal packing features O—H⋯N hydrogen bonds.

In the title adduct, C 7 H 7 NO 3 . C 7 H 10 N 2 , the dihedral angle betwen the benzene ring and pyridine rings is 9.60 (8) while the nitro group attached to the benzene ring makes a dihedral angle of 21.76 (13) . The hydroxyl O atom deviates by 0.0247 (15) Å from the plane of the benzene ring. The crystal packing features O-HÁ Á ÁN hydrogen bonds.
The carbon atom C7 deviates by deviates by 0.0677 (21)Å from the plane of the phenyl ring.
The nitrogen atom N1 deviates by -0.0285 (18)Å from the plane of the phenyl ring. The nitrogen atom N2 devaites by -0.0292 (18)Å from the plane of the pyridine ring. The crystal packing is stabilized by intermolecular O-H···N hydrogen bonds Experimental 4-Dimethylaminopyridine and 3-methyl-4-nitrophenol were taken in equimolar (1:1) ratio using acetone as solvent. The solution was filtered in a clean beaker and optimally closed. The prepared solution was kept at room temperature for two days after which crystals suitable for X-ray diffraction were obtained.

Refinement
The hydrogen atoms were placed in calculated positions with C-H = 0.93 Å to 1.08 Å refined in the riding model with fixed isotropic displacement parameters:U iso (H) = 1.5U eq (C) for methyl group and U iso (H) = 1.2U eq (C) for other groups.   The crystal packing of the title compound viewed down c axis. H-atoms not involved in H-bonds have been excluded for clarity.

Crystal data
C 7 H 7 NO 3 ·C 7 H 10 N 2 M r = 275.31 Monoclinic, P2 1 /c Hall symbol: -P 2ybc a = 11.4923 (9) Å b = 9.8362 (8) Å c = 12.7781 (10) Å β = 103.870 (5) Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness 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 threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) 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.