Buy article online - an online subscription or single-article purchase is required to access this article.
The crystal structure of 1-chloro-2-nitrobenzene, C
6H
4ClNO
2, is made up of molecules which are linked by N—O
Cl halogen bonds. These molecular chains are involved in aromatic π–π stacking; the intermolecular O
Cl distance is 3.09 Å. Such short halogen bonds are not common. A rigid-body analysis including the non-rigidly attached rigid group provides the mean-square amplitudes of the molecular translations and librations, and of the internal torsional vibrations of the nitro group. The results reveal the driving role of the torsional vibrations of the nitro group in the phase transition to the liquid phase.
Supporting information
CCDC reference: 638344
Commercially available (POCH Poland) ortho-chloronitrobenzene, (I), was
not purified further and was not recrystallized. The crystals sublime on
exposure to the atmosphere (m.p. 304–306 K) and had to be enclosed and sealed
within thin-walled glass capillaries in order to use them for collecting X-ray
intensity data.
All H atoms were treated as riding atoms, with C—H = 0.93 Å, and were
refined isotropically, with Uiso(H) = 1.2Ueq(C). [Please
check added text]
Data collection: KM-4 CCD Software (Kuma Diffraction, 1999); cell refinement: KM-4 CCD Software; data reduction: KM-4 CCD Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al.,
2006); software used to prepare material for publication: SHELXL97.
1-chloro,2-nitrobenzene
top
Crystal data top
C6H4ClNO2 | F(000) = 320 |
Mr = 157.55 | Dx = 1.555 Mg m−3 |
Monoclinic, P21/n | Melting point = 304–306 K |
Hall symbol: -P 2yn | Mo Kα radiation, λ = 0.71073 Å |
a = 3.821 (1) Å | Cell parameters from 1188 reflections |
b = 11.725 (2) Å | θ = 3.7–22.4° |
c = 15.118 (3) Å | µ = 0.50 mm−1 |
β = 96.55 (3)° | T = 298 K |
V = 672.9 (2) Å3 | Block, pale yellow |
Z = 4 | 0.89 × 0.55 × 0.55 mm |
Data collection top
Kuma KM-4 CCD area-detector diffractometer | 975 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.083 |
Graphite monochromator | θmax = 25.8°, θmin = 5.4° |
ω scans | h = −2→4 |
2711 measured reflections | k = −13→14 |
1214 independent reflections | l = −18→18 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.075 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.205 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0867P)2 + 0.8782P] where P = (Fo2 + 2Fc2)/3 |
1214 reflections | (Δ/σ)max = 0.019 |
91 parameters | Δρmax = 0.52 e Å−3 |
0 restraints | Δρmin = −0.45 e Å−3 |
Crystal data top
C6H4ClNO2 | V = 672.9 (2) Å3 |
Mr = 157.55 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 3.821 (1) Å | µ = 0.50 mm−1 |
b = 11.725 (2) Å | T = 298 K |
c = 15.118 (3) Å | 0.89 × 0.55 × 0.55 mm |
β = 96.55 (3)° | |
Data collection top
Kuma KM-4 CCD area-detector diffractometer | 975 reflections with I > 2σ(I) |
2711 measured reflections | Rint = 0.083 |
1214 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.075 | 0 restraints |
wR(F2) = 0.205 | H-atom parameters constrained |
S = 1.09 | Δρmax = 0.52 e Å−3 |
1214 reflections | Δρmin = −0.45 e Å−3 |
91 parameters | |
Special details top
Experimental. The crystal structure is determined at the temperature close to the melting
point. Very large displacement parameters are discussed in the paper. |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Cl1 | 0.6920 (3) | 0.45536 (9) | 0.36968 (10) | 0.0772 (5) | |
N1 | 0.5122 (11) | 0.2746 (3) | 0.2224 (2) | 0.0669 (10) | |
O1 | 0.4063 (16) | 0.3650 (3) | 0.1946 (3) | 0.1232 (19) | |
O2 | 0.6344 (13) | 0.2045 (3) | 0.1770 (2) | 0.1062 (15) | |
C1 | 0.5329 (10) | 0.3205 (3) | 0.3840 (3) | 0.0501 (9) | |
C2 | 0.4672 (9) | 0.2440 (3) | 0.3146 (2) | 0.0480 (9) | |
C3 | 0.3535 (10) | 0.1345 (3) | 0.3291 (3) | 0.0545 (10) | |
H3 | 0.3163 | 0.0832 | 0.2820 | 0.065* | |
C4 | 0.2958 (11) | 0.1019 (4) | 0.4129 (3) | 0.0596 (10) | |
H4 | 0.2140 | 0.0289 | 0.4229 | 0.072* | |
C5 | 0.3592 (11) | 0.1776 (4) | 0.4825 (3) | 0.0635 (11) | |
H5 | 0.3184 | 0.1554 | 0.5395 | 0.076* | |
C6 | 0.4822 (12) | 0.2855 (4) | 0.4686 (3) | 0.0618 (11) | |
H6 | 0.5313 | 0.3351 | 0.5164 | 0.074* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cl1 | 0.0804 (9) | 0.0480 (7) | 0.1045 (11) | −0.0046 (5) | 0.0152 (7) | −0.0038 (5) |
N1 | 0.098 (3) | 0.053 (2) | 0.0515 (19) | 0.0150 (19) | 0.0152 (18) | 0.0125 (17) |
O1 | 0.219 (6) | 0.077 (3) | 0.076 (2) | 0.043 (3) | 0.029 (3) | 0.029 (2) |
O2 | 0.177 (4) | 0.085 (3) | 0.065 (2) | 0.030 (3) | 0.046 (3) | 0.0085 (19) |
C1 | 0.0500 (19) | 0.0435 (19) | 0.058 (2) | 0.0061 (15) | 0.0097 (16) | −0.0036 (16) |
C2 | 0.0503 (19) | 0.051 (2) | 0.0427 (18) | 0.0102 (15) | 0.0046 (14) | 0.0046 (16) |
C3 | 0.063 (2) | 0.047 (2) | 0.054 (2) | 0.0067 (16) | 0.0051 (17) | 0.0004 (17) |
C4 | 0.064 (2) | 0.052 (2) | 0.064 (2) | 0.0003 (18) | 0.0115 (19) | 0.011 (2) |
C5 | 0.073 (3) | 0.067 (3) | 0.053 (2) | 0.010 (2) | 0.018 (2) | 0.0101 (19) |
C6 | 0.071 (3) | 0.065 (3) | 0.050 (2) | 0.010 (2) | 0.0071 (18) | −0.0104 (19) |
Geometric parameters (Å, º) top
Cl1—C1 | 1.717 (4) | C3—C4 | 1.365 (6) |
N1—O1 | 1.194 (5) | C3—H3 | 0.9300 |
N1—O2 | 1.199 (5) | C4—C5 | 1.377 (6) |
N1—C2 | 1.468 (5) | C4—H4 | 0.9300 |
C1—C6 | 1.377 (6) | C5—C6 | 1.375 (6) |
C1—C2 | 1.382 (5) | C5—H5 | 0.9300 |
C2—C3 | 1.380 (5) | C6—H6 | 0.9300 |
| | | |
O1—N1—O2 | 123.0 (4) | C2—C3—H3 | 120.2 |
O1—N1—C2 | 118.7 (4) | C3—C4—C5 | 119.8 (4) |
O2—N1—C2 | 118.1 (3) | C3—C4—H4 | 120.1 |
C6—C1—C2 | 118.7 (4) | C5—C4—H4 | 120.1 |
C6—C1—Cl1 | 118.7 (3) | C4—C5—C6 | 120.6 (4) |
C2—C1—Cl1 | 122.6 (3) | C4—C5—H5 | 119.7 |
C3—C2—C1 | 121.1 (3) | C6—C5—H5 | 119.7 |
C3—C2—N1 | 116.8 (3) | C1—C6—C5 | 120.2 (4) |
C1—C2—N1 | 122.1 (4) | C1—C6—H6 | 119.9 |
C4—C3—C2 | 119.6 (4) | C5—C6—H6 | 119.9 |
C4—C3—H3 | 120.2 | | |
| | | |
C6—C1—C2—C3 | −0.1 (6) | C1—C2—C3—C4 | 1.7 (6) |
Cl1—C1—C2—C3 | 177.2 (3) | N1—C2—C3—C4 | −177.9 (4) |
C6—C1—C2—N1 | 179.5 (4) | C2—C3—C4—C5 | −1.5 (6) |
Cl1—C1—C2—N1 | −3.1 (5) | C3—C4—C5—C6 | −0.4 (7) |
O1—N1—C2—C3 | 136.2 (5) | C4—C5—C6—C1 | 2.1 (7) |
O2—N1—C2—C3 | −39.4 (6) | C2—C1—C6—C5 | −1.8 (6) |
O1—N1—C2—C1 | −43.5 (7) | Cl1—C1—C6—C5 | −179.2 (3) |
O2—N1—C2—C1 | 141.0 (5) | | |
Experimental details
Crystal data |
Chemical formula | C6H4ClNO2 |
Mr | 157.55 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 298 |
a, b, c (Å) | 3.821 (1), 11.725 (2), 15.118 (3) |
β (°) | 96.55 (3) |
V (Å3) | 672.9 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.50 |
Crystal size (mm) | 0.89 × 0.55 × 0.55 |
|
Data collection |
Diffractometer | Kuma KM-4 CCD area-detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2711, 1214, 975 |
Rint | 0.083 |
(sin θ/λ)max (Å−1) | 0.611 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.075, 0.205, 1.09 |
No. of reflections | 1214 |
No. of parameters | 91 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.52, −0.45 |
Selected geometric parameters (Å, º) topCl1—C1 | 1.717 (4) | N1—C2 | 1.468 (5) |
N1—O1 | 1.194 (5) | C2—C3 | 1.380 (5) |
N1—O2 | 1.199 (5) | | |
| | | |
O1—N1—O2 | 123.0 (4) | C2—C1—Cl1 | 122.6 (3) |
O1—N1—C2 | 118.7 (4) | C3—C2—C1 | 121.1 (3) |
C6—C1—C2 | 118.7 (4) | C3—C2—N1 | 116.8 (3) |
C6—C1—Cl1 | 118.7 (3) | C1—C2—N1 | 122.1 (4) |
Short intermolecular contacts (Å) in (I) topO2···Cl1i | 3.095 (5) |
O1···H4ii | 2.62 (5) |
O1···C4ii | 3.266 (4) |
Symmetry codes: (i) 3/2-x, -1/2+y, 1/2-z; (ii) 1/2-x, 1/2+y, 1/2-z. |
Subscribe to Acta Crystallographica Section C: Structural Chemistry
The full text of this article is available to subscribers to the journal.
If you have already registered and are using a computer listed in your registration details, please email
support@iucr.org for assistance.
The investigation of interactions in the crystal structure of the title compound, (I), is part of our studies concerning supramolecular aggregation in 1-substituted nitrobenzenes.
The molecule of (I) is not planar. Fig. 1 shows the molecule with the atom numbering. Table 1 reports selected geometric parameters. The dihedral angle between the planes of the benzene ring and the nitro group is 42.14°. This twist results from a steric effect. The intramolecular Cl···O distance is short, at 2.943 (5) Å.
Quantum-chemical calculations of the geometry of the molecule using GAUSSIAN03 at the RHF/6–31g** basis level (Frisch et al., 2004) indicate a similar geometry, with a dihedral angle of 40.26°. Similar Cl···O interactions have been reported, e.g. for a form of 1-chloro-2,4-dinitrobenzene (Wilkins et al., 1990), 2-chloro-1,3,5-trinitrobezene (Willis et al., 1971) and 1,2-dichloro-3-nitrobenzene (Sharma et al., 1986). The intramolecular Cl···O distances in these crystals are 2.964 (2), 2.924 (2) and 2.999 (2) Å, respectively.
An interaction of a similar nature occurs between the molecules of (I). The intermolecular Cl···O distance from the crystal structure determination is 3.095 (5) Å (Fig. 2). Such an interaction involving a halogen atom and an electronegative hetero atom is called halogen bonding, by analogy with hydrogen bonding (Metrangelo & Resnati, 2001; Ouvrard et al., 2003). In contrast withhydrogen bonding, halogen bonding, Y-halogen···X, is always linear, with the halogen atom pointing to an electron lone pair of a hetero atom. Halogen bonding is an important interaction leading to supramolecular synthons which most often involve I atoms (Saha et al., 2005). In the title structure, the benzene ring, the Cl atom and the nearest O atom of a neighbouring molecule are coplanar. These interactions create a supramolecular synthon in which Cl···O is cis to C—N (Allen et al., 1997). The second scheme illustrates this type of interaction.
Halogen bonding has been observed in the crystal structure of the high-temperature polymorph of para-chloronitrobenzene (Mak & Trotter, 1962). In the crystal structure (Of what?) the Cl···O distances are 3.183 and 3.080 Å at 300 and 100 K, respectively (Mossakowska & Wójcik, 2005). However, only O···O and Cl···Cl interactions occur in the crystal structure of meta-chloronitrobenzene (Gopalakrishna, 1965) and in the low-temperature polymorph of para-chloronitrobenzene (Meriles et al., 2000).
Translationally equivalent along the a crystallographic axis, the molecules of (I) are linked by π–π interactions; the interplanar spacing is 3.566 (5) Å and the centroid offset is 1.375 Å (Fig. 3). Thus supramolecular tapes formed via halogen bonding are involved in molecular stacking via aromatic π–π interactions. Competition between these two types of specific intermolecular interactions results in a layered structure (Figs. 2 and 3), with additional short C—H···O intermolecular contacts (Fig. 3 and Table 2).
A search of the Cambridge Structural Database (April 2006 version; Allen, 2002) resulted in 156 retrieved crystal structures of aromatic compounds with close intermolecular contacts between at least one Cl atom and a nitro group. Among these retrieved structures, 314 close contacts correspond to Cl···O—N interactions, i.e. to one O atom of a nitro group. Fig. 4 shows the distribution of the short Cl···O intermolecular distances in the retrieved structures. The asymmetric histogram reveals that very short O···Cl distances are not common.
The crystal structure of (I) is isostructural with that of 1-bromo-2-nitrobenzene (Fronczek, 2005). The crystal structure of (I) has been determined in this work at a temperature only a few degrees (about 7 K) below the melting point. Although the structure is reliable, the anisotropic displacement parameters show very large values due to pronounced molecular dynamics. In particular, the anisotropic displacement parameters of the nitro group O atoms are large, pointing to strong torsional vibrations of the nitro group. Aromatic molecules fulfil well the exigencies of the rigid-body approximation (Cruickshank, 1956; Dunitz et al., 1988; Schomaker & Trueblood, 1998), especially at elevated temperatures. Calculations within the TLS formalism, with the correlation of the internal vibration of the non-rigidly attached rigid group performed with THMA11 (Farrugia, 1999), enabled the monitoring of molecular motions in the vicinity of the melting point. The mean-square amplitudes of the molecular translations and librations are large (0.035–0.057 Å2 and 16–45°2, respectively). The largest libration occurs about the axis close to the C—Cl bond. The internal torsional vibration of the nitro group occurs about the C—N bond. The mean-square amplitude of the overall nitro group rotation is about 227°2 and may be compared with the librational contribution to the motion (from the molecular libration), which is about 31°2. The results of the rigid-body analysis of the crystal structure of (I) reveal the driving role of the torsional vibrations of the nitro group in the phase transition to the liquid phase.