2,4‐Dinitrophenyl Phenyl Sulfone

The crystal structure of the title compound, C 12 H 8 N 2 O 6 S, has been determined by single-crystal X-ray diffraction. The compound crystallizes in the noncentrosymmetric P2 1 space group. The substituted aromatic ring has a slightly deformed boat conformation. The o-NO 2 and p-NO 2 groups are twisted out of the plane of the phenyl ring. The unsubstituted aromatic ring is planar and the dihedral angle between the mean plane of the rings is 71.1 (2)°. Short C-H...O intermolecular contacts stabilize the three-dimensional structure.

symmetric P21 space group. The substituted aromatic ring has a slightly deformed boat conformation. The o-NO2 and p-NO2 groups are twisted out of the plane of the phenyl ring. The unsubstituted aromatic ring is planar and the dihedral angle between the mean plane of the rings is 71.1 (2) °. Short C--H--.O intermolecular contacts stabilize the three-dimensional structure.

Comment
This report is part of a general study on 2,4-dinitrobenzenes with variation of the substituents at different positions (Ellena et al., 1995). The aim of this investigation is to determine the parameters which govem the molecular geometry and organization both in the crystalline state and in solution. To add to the understanding of the effect of different substituents, a single-crystal X-ray study of the title compound, (I), was undertaken.
A view of the title molecule with the atom-labelling scheme is shown in Fig. 1. Analysis of the molecular geometry shows that the substituted phenyl ring has a slightly deformed boat conformation, with the C4 and C6 atoms out of the mean ring plane by 0.025 (4) and 0.030 (5)A,, respectively. The total puckering amplitude (Cremer & Pople, 1975) is QT -0.028 (4). The nitro group in the ortho position is rotated 56.5 (2) ° out of the ring plane, thus decreasing the steric interaction with the bridging group. The nitro group in the para position is twisted out of the mean ring plane by 18.5 (3) ° . The unsubstituted aromatic ring displays an essentially planar geometry.  (Johnson, 1976) view of the title molecule showing the atom labelling and 50% probability ellipsoids.
The sulfone O1---S--O2 bond angle is 118.9 (2) °. Its departure from the ideal sp 3 bond-angle value indicates repulsion between the O atoms. This effect is explained by the induction of negative charge on the O atoms via resonance effects of the 7r electrons in the S--O bond. The observed value is also in agreement with the mean value [118.9 (2) °] retrieved from the 1995 version of the Cambridge Structural Database (Allen & Kennard, 1993) for sulfone groups in bridged diphenyl sulfones. The C1--S--C7 bond angle of 106.2 (2) ° is larger than the mean value found for this angle in the same search The bonds between the sulfone group and the rings are °unsymmetrical. The C7--S bond length of 1.748 (4)A is identical, within experimental error, to the mean value found for C(aromatic)--SOzC bonds [1.763 (9),~,; , but the C1--S bond length of 1.788 (4)~, is 0.025 A larger than the corresponding value. The C4-N2 bond length of 1.481 (6) ,~, is similar to the mean value of 1.471 (2),~, obtained by Domenicano et al. (1989) for the C---N bond length in nitrobenzene derivatives for which the substituents were chosen to avoid conjugation. For the nitro group in the ortho l~osition, however, the C2--N 1 bond length of 1.459 (5)A is 0.012 ,~, smaller than the above mentioned mean value.
The three-dimensional structure is stabilized by a weak attractive interaction between one of the sulfone O atoms and the more acidic H atom of the substituted aromatic ring (see Table 2). This interaction explains the displacement of the C6 atom out of the ring plane.
The title structure was solved by direct methods with SHELXS86 (Sheldrick, 1985). The Fourier map obtained showed all non-H atoms. The model was refined by a fullmatrix least-squares procedure on F 2 by means of SHELXL93 (Sheldrick, 1992). All the H atoms were placed in calculated positions and refined riding over the bonded C atoms. Isotropic displacement parameters were used in the first steps and anisotropic ones afterwards, except for H atoms, which were refined isotropically. Calculations were carried out on a PC 486.

Abstract
The complex 3-cyclodextrin-l,7-dioxaspiro[5,5]undecane nonahydrate, C42HToO35.C9HI602.9H20, belongs to the class of 3-cyclodextrin dimeric-type complexes. The racemic guest molecule is present in a disordered position. Both enantiomers are located in two different regions inside the channel formed by the host dimers.

Comment
The cyclodextrin (CD) cyclic oligosaccharides are well known for their ability to form inclusion complexes with a variety of guest molecules (Szejtli, 1989). The present guest is the synthetic racemate of (R)and (S)-l,7-dioxaspiro[5,5]undecane (spiroacetal) which constitutes the major component of the olive fruit fly (Dacus oleae) pheromone (Baker et al., 1980;Mazomenos & Haniotakis, 1981,1985. It is a liquid too volatile at ambient temperature to be used by itself in agriculture. Previous experiments have shown that there is stabilization upon complexation but the release rate for the fl-CD-spiroacetal crystalline complex is almost negligible in dry conditions; the commercial methylated-CD-spiroacetal complexes lead to higher rates, although still too low for practical applications (Mazomenos, Kondilis, Moustakali, Hadjoudis & Tsoucaris, 1989). The crystal-structure determination of the title complex, (I), was undertaken to obtain information on the slowrelease process for this pheromone component. Of further interest is the enantiomeric discrimination of the guest molecule by cyclodextrins. The title complex crystallizes in the non-centrosymmetric space group C2; isomorphous structures have been already studied (Hamilton, Sabesan & Steinrauf, 1981;Hamilton & Sabesan, 1982;Le Bas, 1985). Normal values are observed for the bond lengths and angles of 3-CD host molecule. The torsion angles controlling the orientation of the C6--O6 bonds indicate a gauchegauche conformation for all residues. However, two primary hydroxyl groups, 062 and 065, are disordered over two sites; a trans-gauche conformation is observed for the minor site O65B while 062 exhibits positional disorder ( Table 2).
The macrocyclic ring has the usual truncated-cone shape with a pseudo-sevenfold axis; the glycosidic O4n atoms (n = 1-7) form a planar heptagon whose sides have an average length of 4.37 (1) ). This structure belongs to the class of 3-CD dimers already described in detail (Le Bas, 1985;Le Bas & Rysanek, 1987). This class of structures is characterized by the packing of the 3-CD dimers in quasi-invariant layers (Le Bas, 1985;Le Bas & Tsoucaris, 1994). Two 3-CD molecules related by the twofold crystallographic b axis form a head-to-head dimer. Faceto-face secondary hydroxyl groups are bound by seven hydrogen bonds [average distance O3n.-.O3n' 2.80,~,, average angle C3n--O3n...O3n i 118°; symmetry code: (i) -x, y, -z+l]. The axis of the dimers, defined as