4-Nitro-phenyl methacrylate.

The title compound, C(10)H(9)NO(4), was obtained serendipitously during the preparation of benzyl cyclo-hexyl-carbamate. The mol-ecule consists of two approximately planar parts, the nitro-phenyl ring and the rest of the non-H atoms, with a dihedral angle of 55.05 (6)° between the two segments. The crystal structure is stabilized by weak C-H⋯O inter-actions and π stacking [3.753 (1) Å] along the b axis.

The title compound, C 10 H 9 NO 4 , was obtained serendipitously during the preparation of benzyl cyclohexylcarbamate. The molecule consists of two approximately planar parts, the nitrophenyl ring and the rest of the non-H atoms, with a dihedral angle of 55.05 (6) between the two segments. The crystal structure is stabilized by weak C-HÁ Á ÁO interactions and stacking [3.753 (1) Å ] along the b axis.
YX and FQ thank Dr Sihui Long for helpful discussions and invaluable suggestions.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FL2212).

Comment
The title compound (I) is an important building block in the preparation of functional block polymers (Tang, et al. 2007;Hwang, et al. 2007;Li, et al. 2007). Although it has been widely used as a monomer in polymerization reactions for a long time (Otsu, et al. 1968), the crystal structure, as far as we know, has never been reported before.
Here it was obtained unexpectedly during an attempt to make benzyl cyclohexylcarbamate as described in the experimental section.
The asymmetric unit of (I) ( Fig. 1) contains one molecule and bond lengths and angles are within normal ranges. The molecule consists of two approximately planar parts: the nitrophenyl ring and the rest of the non-hydrogen atoms (dihedral angle between the two segments is 55.05 (6)°). The nitro group is nearly coplanar with the phenyl ring as indicated by the torsion angle O3-N1-C8-C7 of -7.48 °. The remaining non-hydrogen atoms are almost coplanar as suggested by the torsion angle C2-C3-C4-O1 at 9.35 °. Since (I) has no classic hydrogen bonding donors, the crystal packng is stabilized by C-H···O interactions (Table 1)in two directions with aromatic C-H atoms as the donors and both oxygen atoms of the nitro group and the carbonyl oxygen as the acceptors. There is also π-stacking along the third direction, the shortest (b), where the aromatic rings are separated by a unit cell translation of 3.753 (1) Å (Fig. 2).
Experimental 4-nitrophenyl cyclohexylcarbamate (0.95 g, 3.5 mmol), phenylmethanol (0.40 g, 3.7 mmol) and triethylamine (0.36 g, 3.6 mmol) were reflxued overnight in 20 ml methylene chloride. The solution was washed with 1 N NaOH, water and brine, and then dried with anhydrous Na 2 SO 4 . After removal of the solvent, the product was recovered as a colorless solid (0.5 g).
Crystals of (I) were obtained by recrystallization from ethyl acetate as colorless rods.

Refinement
H atoms were found in difference Fourier maps and subsequently placed in idealized positions with constrained C-H distances of 0.95 Å (C Ar H) and 0.98 Å (Csp3H). U iso (H) values were set to 1.2U eq for all H atoms. Fig. 1. The molecular structure of (I), with displacement ellipsoids drawn at the 50% probability level (arbitrary spheres for the H atoms).

Figures
supplementary materials sup-2  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 > σ(F 2 ) is used only for calculating Rfactors(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.