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In the crystal structure of the title salt, C7H7Cl2N2O2+·Cl, the chloride anions participate in extensive hydrogen bonding with the aminium cations and indirectly link the mol­ecules through multiple N+—H...Cl salt bridges. There are two independent mol­ecules in the asymmetric unit, related by a pseudo-inversion center. The direct inter­molecular coupling is established by C—H...O, C—H...Cl and C—Cl...Cl inter­actions. A rare three-center (donor bifurcated) C—H...(O,O) hydrogen bond is observed between the methyl­ene and nitro groups, with a side-on intra­molecular component of closed-ring type and a head-on inter­molecular component.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270105038114/av1275sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270105038114/av1275Isup2.hkl
Contains datablock I

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Portable Document Format (PDF) file https://doi.org/10.1107/S0108270105038114/av1275Isup3.pdf
Supplementary material

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Portable Document Format (PDF) file https://doi.org/10.1107/S0108270105038114/av1275Isup4.pdf
Supplementary material

CCDC reference: 296347

Comment top

Identification and characterization of novel structural motifs, stabilized by intermolecular interactions, is one of the concurrent topics of investigation in the geometric rule-based design of molecular solids possessing novel properties (Desiraju & Steiner, 1999). The three-center hydrogen-bond configuration (i.e. bifurcated donor or acceptor) is one such structural motif. Numerous examples of three-center bonds formed by conventional strong hydrogen bonds exist (Jeffrey & Saenger, 1991). In contrast, the bifurcation of weak interactions, such as between a weak donor and strong acceptors, are less well characterized. In this communication, we report the structure of a halide salt, 2-methyl-ammonium-3,4-dichloro-nitrobenzene chloride (I), the crystal structure of which is predominantly stabilized by multiple N+—H···Cl- salt bridges and C—H···O/Cl bonds (Desiraju, 2005), including a rare donor bifurcated C—H···(O,O) hydrogen bond. The asymmetric unit consists of two independent molecules, hereafter referred to as A and B, with protonated amine groups (N2A/N2B), and two discrete chloride anions, Cl3 and Cl4 (Fig. 1). The molecular identifier in the atomic nomenclature is denoted by the last letter. Apart from the N atom of the protruding methylammonium groups, the non-H atoms form a planar structure, with a maximum atomic deviations of -0.13 (1) Å for O2A in molecule A and 0.12 (1) Å for C7B in molecule B. The ammonium groups of the methylammonium substituents are twisted out of the planes of the aryl rings with C1A—C2A—C7A—N2A and C1B—C2B—C7B—N2B torsion angles of -92.5 (4) and 84.4 (5)°, respectively. The interplanar angles between the benzene rings (C1A–C6A and C1B–C6B) and the attached nitro groups (N1A/O1/O2A/C1A and N1B/O1B/O2B/C1B) are 2.7 (2) and 5.0 (2)°, respectively, in A and B. The two molecules are related by a pseudo-inversion center and the r.m.s. deviation for all the corresponding superposed atoms of A and inverted B is 0.07 Å (see Fig. 3, available with the supplementary material).

The crystal structure is held together by intermolecular N+—H···Cl-, C—H···O, C—H···Cl and C—Cl···Cl- interactions (Fig. 2). Pertinent geometric details and symmetry codes are provided in Table 1. Intramolecular C7A—H72A···O1A and C7B—H71B···O1B hydrogen bonds form an S(6) closed pattern, while C6B—H6B···O2B, C7A—H71A···Cl1A and C7B—H72B···Cl1B bonds form an S(5) pattern (Bernstein et al., 1995). Intermolecular C5A—H5A···Cl1Bv, C7A—H72A···O1B and C5B—H5B···O2Avi bonds directly link A and B. The intramolecular C7A—H72A···O1A and intermolecular C7A—H72A···O1B interactions collectively form a planar three-center hydrogen-bond configuration (Fig. 1), where the sum of angles [350 (5)°] about atom H72A is slightly less then the ideal value (360°; Parthasarthy, 1969). The term three-center hydrogen bond (Jeffrey & Saenger, 1991) indicates that the H atom is at the center of the three participating donor and acceptor atoms, and indistinguishably refers to both bifurcated donor and acceptor bonds. While bifurcation of both donors and acceptors is observed in strong interactions, the bifurcation of weak interactions, such as C—H···O, between a weak donor and strong acceptors, is generally observed at the acceptor (C—H···O···H—C type; Desiraju & Steiner, 1999). H atom (or donor) bifurcated C—H···(O,O) bonds have been observed in very few cases, and the present arrangement of a three-center bond with one side-on intramolecular component of closed-ring type and a head-on intermolecular component is the most favored arrangement (Steiner & Saenger, 1992). For interactions as weak as C—H···O, it is difficult to evaluate their contribution towards determining the overall crystal packing, especially in the presence of strong interactions such as N+—H···Cl- observed here. A qualitative assessment has been suggested by Desiraju (2005), who classifies such weak interactions into three different categories, namely, innocuous, supportive and intrusive. In terms of geometry and directionality, the present three-center configuration appears to fit in the supportive category, and hence is a structural determinant.

Molecules A and B are indirectly connected via chloride anions through multiple intermolecular N+—H···Cl- salt bridges. Each Cl- acts as an acceptor for three hydrogen bonds with ammonium cations. The Cl3- anion forms intermolecular N2A—H22A···Cl3, N2A—H23A···Cl3ii and N2B—H23B···Cl3 hydrogen bonds. The Cl4- anion links molecules A and Bvia N2A—H21A···Cl4i, N2B—H21B···Cl4iii and N2B—H22B···Cl4 bonds. The H···Cl- and N+···Cl- distances are in the ranges 2.20 (5)–2.55 (5) Å and 3.062 (5)–3.255 (5) Å, while the database average values are 2.247 (5) and 3.207 (4) Å, respectively, for N+H3···Cl- bonds (Steiner, 1998). Atom Cl4 is additionally involved in a linear C4A—Cl2A···Cl4iv short contact interaction. This type of short Cl···Cl- contact was also reported previously in the structure of 2-(chloromethyl)pyridinium chloride (Jones et al., 2002). The type of X—halogen···halogen interaction observed here should be distinguished – in terms of both geometry and nature – from interhalogen interactions of the X—halogen···halogen—Y type, where X and Y are commonly C atoms (Desiraju & Parthasarthy, 1989; Price et al., 1994). A short halogen–nitro contact [Cl3···O1B = 3.258 (5) Å] (Allen et al., 1997) is also observed, which presumably is due to the presence of the other interactions described previously. Molecules A and B associate directly via intermolecular C—H···O/Cl and C—Cl···Cl- interactions and form a sheet structure approximately about the (224) plane (see Fig. 4 in the supplementary material). The intersheet link is established by N+—H···Cl- salt links and is devoid of any significant ππ overlaps among aryl rings. Two popular modes of packing, namely stacked (André et al., 1997a), such as observed in (I), and herringbone (André et al., 1997b), have been widely observed among nitrobenzene derivatives.

The validity of the C—H···O hydrogen bond as a structural determinant is beyond doubt, and the important question that now emerges is `how it may be used and applied [in molecular recognition and crystal engineering]' (Desiraju, 2005). Towards this end, the present example is a useful addition in the current body of knowledge on such weak interactions.

Experimental top

The title compound was obtained from Cipla, Mumbai. Suitable single crystals for X-ray diffraction were grown by slow evaporation of a solution in methanol.

Refinement top

H atoms were located in difference electron-density maps and were refined isotropically without any restraints, except the N2B—H23B bond, which was restrained to 0.87 (1) Å. The H-atom distances are in the following ranges: Car—H = 0.88 (4)–0.94 (4) Å and for methylene C—H = 0.87 (4)–0.94 (4) Å, with Uiso(H) = 1.2Ueq(C), and N—H = 0.87 (1)–0.94 (5) Å, with Uiso(H) = 1.5Ueq(N). The inclusion and restrained refinement of multiple sites of the nitro group (O1A/O2A) of molecule A, carried out in view of the relatively large displacement parameter, did not yield satisfactory results.

Structure description top

Identification and characterization of novel structural motifs, stabilized by intermolecular interactions, is one of the concurrent topics of investigation in the geometric rule-based design of molecular solids possessing novel properties (Desiraju & Steiner, 1999). The three-center hydrogen-bond configuration (i.e. bifurcated donor or acceptor) is one such structural motif. Numerous examples of three-center bonds formed by conventional strong hydrogen bonds exist (Jeffrey & Saenger, 1991). In contrast, the bifurcation of weak interactions, such as between a weak donor and strong acceptors, are less well characterized. In this communication, we report the structure of a halide salt, 2-methyl-ammonium-3,4-dichloro-nitrobenzene chloride (I), the crystal structure of which is predominantly stabilized by multiple N+—H···Cl- salt bridges and C—H···O/Cl bonds (Desiraju, 2005), including a rare donor bifurcated C—H···(O,O) hydrogen bond. The asymmetric unit consists of two independent molecules, hereafter referred to as A and B, with protonated amine groups (N2A/N2B), and two discrete chloride anions, Cl3 and Cl4 (Fig. 1). The molecular identifier in the atomic nomenclature is denoted by the last letter. Apart from the N atom of the protruding methylammonium groups, the non-H atoms form a planar structure, with a maximum atomic deviations of -0.13 (1) Å for O2A in molecule A and 0.12 (1) Å for C7B in molecule B. The ammonium groups of the methylammonium substituents are twisted out of the planes of the aryl rings with C1A—C2A—C7A—N2A and C1B—C2B—C7B—N2B torsion angles of -92.5 (4) and 84.4 (5)°, respectively. The interplanar angles between the benzene rings (C1A–C6A and C1B–C6B) and the attached nitro groups (N1A/O1/O2A/C1A and N1B/O1B/O2B/C1B) are 2.7 (2) and 5.0 (2)°, respectively, in A and B. The two molecules are related by a pseudo-inversion center and the r.m.s. deviation for all the corresponding superposed atoms of A and inverted B is 0.07 Å (see Fig. 3, available with the supplementary material).

The crystal structure is held together by intermolecular N+—H···Cl-, C—H···O, C—H···Cl and C—Cl···Cl- interactions (Fig. 2). Pertinent geometric details and symmetry codes are provided in Table 1. Intramolecular C7A—H72A···O1A and C7B—H71B···O1B hydrogen bonds form an S(6) closed pattern, while C6B—H6B···O2B, C7A—H71A···Cl1A and C7B—H72B···Cl1B bonds form an S(5) pattern (Bernstein et al., 1995). Intermolecular C5A—H5A···Cl1Bv, C7A—H72A···O1B and C5B—H5B···O2Avi bonds directly link A and B. The intramolecular C7A—H72A···O1A and intermolecular C7A—H72A···O1B interactions collectively form a planar three-center hydrogen-bond configuration (Fig. 1), where the sum of angles [350 (5)°] about atom H72A is slightly less then the ideal value (360°; Parthasarthy, 1969). The term three-center hydrogen bond (Jeffrey & Saenger, 1991) indicates that the H atom is at the center of the three participating donor and acceptor atoms, and indistinguishably refers to both bifurcated donor and acceptor bonds. While bifurcation of both donors and acceptors is observed in strong interactions, the bifurcation of weak interactions, such as C—H···O, between a weak donor and strong acceptors, is generally observed at the acceptor (C—H···O···H—C type; Desiraju & Steiner, 1999). H atom (or donor) bifurcated C—H···(O,O) bonds have been observed in very few cases, and the present arrangement of a three-center bond with one side-on intramolecular component of closed-ring type and a head-on intermolecular component is the most favored arrangement (Steiner & Saenger, 1992). For interactions as weak as C—H···O, it is difficult to evaluate their contribution towards determining the overall crystal packing, especially in the presence of strong interactions such as N+—H···Cl- observed here. A qualitative assessment has been suggested by Desiraju (2005), who classifies such weak interactions into three different categories, namely, innocuous, supportive and intrusive. In terms of geometry and directionality, the present three-center configuration appears to fit in the supportive category, and hence is a structural determinant.

Molecules A and B are indirectly connected via chloride anions through multiple intermolecular N+—H···Cl- salt bridges. Each Cl- acts as an acceptor for three hydrogen bonds with ammonium cations. The Cl3- anion forms intermolecular N2A—H22A···Cl3, N2A—H23A···Cl3ii and N2B—H23B···Cl3 hydrogen bonds. The Cl4- anion links molecules A and Bvia N2A—H21A···Cl4i, N2B—H21B···Cl4iii and N2B—H22B···Cl4 bonds. The H···Cl- and N+···Cl- distances are in the ranges 2.20 (5)–2.55 (5) Å and 3.062 (5)–3.255 (5) Å, while the database average values are 2.247 (5) and 3.207 (4) Å, respectively, for N+H3···Cl- bonds (Steiner, 1998). Atom Cl4 is additionally involved in a linear C4A—Cl2A···Cl4iv short contact interaction. This type of short Cl···Cl- contact was also reported previously in the structure of 2-(chloromethyl)pyridinium chloride (Jones et al., 2002). The type of X—halogen···halogen interaction observed here should be distinguished – in terms of both geometry and nature – from interhalogen interactions of the X—halogen···halogen—Y type, where X and Y are commonly C atoms (Desiraju & Parthasarthy, 1989; Price et al., 1994). A short halogen–nitro contact [Cl3···O1B = 3.258 (5) Å] (Allen et al., 1997) is also observed, which presumably is due to the presence of the other interactions described previously. Molecules A and B associate directly via intermolecular C—H···O/Cl and C—Cl···Cl- interactions and form a sheet structure approximately about the (224) plane (see Fig. 4 in the supplementary material). The intersheet link is established by N+—H···Cl- salt links and is devoid of any significant ππ overlaps among aryl rings. Two popular modes of packing, namely stacked (André et al., 1997a), such as observed in (I), and herringbone (André et al., 1997b), have been widely observed among nitrobenzene derivatives.

The validity of the C—H···O hydrogen bond as a structural determinant is beyond doubt, and the important question that now emerges is `how it may be used and applied [in molecular recognition and crystal engineering]' (Desiraju, 2005). Towards this end, the present example is a useful addition in the current body of knowledge on such weak interactions.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Bruker, 2001); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997) and PLATON (Spek, 2003).

Figures top
[Figure 1]
[Figure 2]
Fig. 1. The asymmetric unit of (I), showing the three-center (donor bifurcated) C—H···O hydrogen-bond configuration. Hydrogen bonds (see text) are shown as dashed lines. The values given in the figure are the angles subtended at H72A, which participates in the bifurcated hydrogen bond. The displacement ellipsoids are drawn at the 30% probability level.

Fig. 2. The intermolecular interactions in (I), including the three-centered hydrogen-bond configuration. For clarity, only relevant H atoms and intramolecular interactions are shown. The atoms marked with symbols are at the following positions: ($) x + 1, y, z; (#) -x + 2, -y + 1, -z + 1; (*) -x + 1, -y + 1, -z + 1; ($$) -x + 2, -y, -z + 1; (##) -x + 2, -y + 1, -z; (**) x - 1, y + 1, z. [For the online version, the color key is C black, H white, Cl green, N blue, O red.]

Fig. 3. (Supplementary material): Superposition image of (A) (in red) on to inverted structure of (B) (rmsd = 0.07 Å), drawn with PLATON.

Fig. 4. (Supplementary material): The edge-on view of molecular packing, displaying the sheet structure, formed approximately parallel to the (224) plane.
2,3-dichloro-6-nitrobenzylaminium chloride top
Crystal data top
C7H7Cl2N2O2+·ClZ = 4
Mr = 257.50F(000) = 520
Triclinic, P1Dx = 1.676 Mg m3
Hall symbol: -P 1Melting point: 516 K
a = 6.889 (7) ÅMo Kα radiation, λ = 0.71073 Å
b = 12.116 (12) ÅCell parameters from 363 reflections
c = 13.286 (13) Åθ = 5–27°
α = 102.128 (15)°µ = 0.87 mm1
β = 100.939 (16)°T = 293 K
γ = 103.523 (16)°Plate, colorless
V = 1020.3 (17) Å30.55 × 0.52 × 0.21 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
4146 independent reflections
Radiation source: fine-focus sealed tube3161 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.036
φ and ω scansθmax = 26.4°, θmin = 1.6°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 88
Tmin = 0.631, Tmax = 0.842k = 1515
10895 measured reflectionsl = 1616
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.056Hydrogen site location: difference Fourier map
wR(F2) = 0.152Only H-atom coordinates refined
S = 1.05 w = 1/[σ2(Fo2) + (0.076P)2 + 0.7937P]
where P = (Fo2 + 2Fc2)/3
4146 reflections(Δ/σ)max = 0.003
295 parametersΔρmax = 0.72 e Å3
1 restraintΔρmin = 0.71 e Å3
Crystal data top
C7H7Cl2N2O2+·Clγ = 103.523 (16)°
Mr = 257.50V = 1020.3 (17) Å3
Triclinic, P1Z = 4
a = 6.889 (7) ÅMo Kα radiation
b = 12.116 (12) ŵ = 0.87 mm1
c = 13.286 (13) ÅT = 293 K
α = 102.128 (15)°0.55 × 0.52 × 0.21 mm
β = 100.939 (16)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
4146 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
3161 reflections with I > 2σ(I)
Tmin = 0.631, Tmax = 0.842Rint = 0.036
10895 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0561 restraint
wR(F2) = 0.152Only H-atom coordinates refined
S = 1.05Δρmax = 0.72 e Å3
4146 reflectionsΔρmin = 0.71 e Å3
295 parameters
Special details top

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.

================================================================== Plane Calculations from PARST ==================================================================

Weighted least-squares planes through the starred atoms (Nardelli, Musatti, Domiano & Andreetti Ric·Sci.(1965),15(II—A),807). Equation of the plane: m1*X+m2*Y+m3*Z=d

Plane 1 m1 = -0.53486(0.00042) m2 = -0.33738(0.00042) m3 = -0.77466(0.00027) D = -5.60217(0.00191) Atom d s d/s (d/s)**2 C1A * 0.0093 0.0039 2.394 5.730 C2A * 0.0153 0.0035 4.336 18.800 C3A * 0.0198 0.0036 5.428 29.466 C4A * 0.0172 0.0036 4.816 23.194 C5A * -0.0094 0.0042 - 2.254 5.080 C6A * -0.0107 0.0044 - 2.431 5.911 N1A * 0.0255 0.0042 6.104 37.259 O1A * -0.0061 0.0050 - 1.242 1.542 O2A * -0.1332 0.0070 - 19.081 364.103 Cl1A * -0.0068 0.0013 - 5.437 29.558 Cl2A * 0.0009 0.0011 0.766 0.587 C7A * 0.0279 0.0042 6.635 44.027 H5A 0.0019 0.0419 0.046 0.002 H6A -0.0241 0.0446 - 0.541 0.292 N2A -1.3393 0.0037 - 362.281 131247.656 H71A 0.4717 0.0419 11.247 126.488 H72A 0.4177 0.0427 9.773 95.510 H21A -1.8918 0.0487 - 38.846 1508.996 H22A -1.3732 0.0461 - 29.796 887.789 H23A -1.7103 0.0496 - 34.513 1191.168 ============ Sum((d/s)**2) for starred atoms 565.258 Chi-squared at 95% for 9 degrees of freedom: 16.90 The group of atoms deviates significantly from planarity

Plane 2 m1 = -0.46588(0.00044) m2 = -0.38166(0.00041) m3 = -0.79831(0.00036) D = -4.87014(0.00301) Atom d s d/s (d/s)**2 C1B * -0.0277 0.0036 - 7.705 59.363 C2B * 0.0163 0.0035 4.721 22.290 C3B * -0.0004 0.0037 - 0.100 0.010 C4B * -0.0055 0.0040 - 1.393 1.940 C5B * -0.0251 0.0043 - 5.785 33.470 C6B * -0.0549 0.0042 - 13.116 172.036 N1B * 0.0098 0.0038 2.598 6.748 O1B * 0.1188 0.0042 28.611 818.571 O2B * -0.1027 0.0042 - 24.286 589.799 Cl1B * -0.0286 0.0015 - 19.659 386.466 Cl2B * 0.0257 0.0015 16.862 284.321 C7B * 0.1202 0.0044 27.394 750.417 H5B 0.0301 0.0460 0.654 0.427 H6B -0.1417 0.0439 - 3.228 10.417 N2B -1.1719 0.0036 - 328.375 107829.820 H71B 0.7240 0.0449 16.112 259.612 H72B 0.6442 0.0431 14.961 223.829 H21B -1.6523 0.0480 - 34.408 1183.896 H22B -1.0748 0.0484 - 22.206 493.119 H23B -1.7832 0.0427 - 41.797 1747.019 ============ Sum((d/s)**2) for starred atoms 3125.431 Chi-squared at 95% for 9 degrees of freedom: 16.90 The group of atoms deviates significantly from planarity

Plane 3 m1 = -0.48445(0.00350) m2 = -0.35348(0.00290) m3 = -0.80023(0.00176) D = -5.34994(0.01842) Atom d s d/s (d/s)**2 N1A * 0.0451 0.0041 10.904 118.896 O1A * -0.0235 0.0049 - 4.740 22.472 O2A * -0.0443 0.0069 - 6.429 41.329 C1A * -0.0110 0.0038 - 2.865 8.208 C2A -0.0867 0.0035 - 24.756 612.881 C6A 0.0187 0.0044 4.287 18.378 ============ Sum((d/s)**2) for starred atoms 190.905 Chi-squared at 95% for 1 degrees of freedom: 3.84 The group of atoms deviates significantly from planarity

Plane 4 m1 = -0.52544(0.00141) m2 = -0.34179(0.00157) m3 = -0.77916(0.00104) D = -5.55501(0.00649) Atom d s d/s (d/s)**2 C1A * 0.0063 0.0039 1.636 2.677 C2A * -0.0032 0.0035 - 0.896 0.804 C3A * -0.0025 0.0036 - 0.683 0.467 C4A * 0.0060 0.0036 1.688 2.848 C5A * -0.0055 0.0042 - 1.323 1.749 C6A * -0.0026 0.0044 - 0.599 0.359 H5A 0.0134 0.0418 0.321 0.103 H6A -0.0057 0.0445 - 0.127 0.016 Cl1A -0.0479 0.0013 - 38.103 1451.823 Cl2A -0.0154 0.0011 - 13.546 183.486 C7A -0.0031 0.0042 - 0.735 0.541 N2A -1.3752 0.0037 - 372.598 138829.328 ============ Sum((d/s)**2) for starred atoms 8.903 Chi-squared at 95% for 3 degrees of freedom: 7.81 The group of atoms deviates significantly from planarity

Plane 5 m1 = -0.40041(0.00244) m2 = -0.32417(0.00237) m3 = -0.85708(0.00156) D = -4.44319(0.01373) Atom d s d/s (d/s)**2 N1B * 0.0088 0.0037 2.389 5.708 O1B * -0.0040 0.0042 - 0.960 0.921 O2B * -0.0040 0.0041 - 0.972 0.946 C1B * -0.0023 0.0036 - 0.639 0.408 C2B -0.0681 0.0034 - 19.966 398.641 C6B 0.1101 0.0041 26.756 715.904 ============ Sum((d/s)**2) for starred atoms 7.983 Chi-squared at 95% for 1 degrees of freedom: 3.84 The group of atoms deviates significantly from planarity

Plane 6 m1 = -0.44752(0.00130) m2 = -0.38026(0.00151) m3 = -0.80940(0.00084) D = -4.85220(0.00990) Atom d s d/s (d/s)**2 C1B * -0.0030 0.0036 - 0.830 0.689 C2B * 0.0115 0.0034 3.336 11.127 C3B * -0.0128 0.0037 - 3.493 12.201 C4B * 0.0025 0.0040 0.628 0.395 C5B * 0.0115 0.0043 2.657 7.059 C6B * -0.0097 0.0042 - 2.331 5.432 H5B 0.0798 0.0459 1.737 3.017 H6B -0.0784 0.0438 - 1.789 3.201 Cl1B -0.0770 0.0015 - 52.947 2803.354 Cl2B 0.0232 0.0015 15.245 232.416 C7B 0.0917 0.0044 20.953 439.012 N2B -1.2085 0.0036 - 340.052 115635.555 ============ Sum((d/s)**2) for starred atoms 36.902 Chi-squared at 95% for 3 degrees of freedom: 7.81 The group of atoms deviates significantly from planarity

Dihedral angles formed by LSQ-planes Plane - plane angle (s.u.) angle (s.u.) 1 2 4.89 (0.03) 175.11 (0.03) 1 3 3.37 (0.19) 176.63 (0.19) 1 4 0.65 (0.08) 179.35 (0.08) 1 5 9.08 (0.13) 170.92 (0.13) 1 6 5.92 (0.08) 174.08 (0.08) 2 3 1.94 (0.18) 178.06 (0.18) 2 4 4.25 (0.09) 175.75 (0.09) 2 5 6.02 (0.13) 173.98 (0.13) 2 6 1.23 (0.07) 178.77 (0.07) 3 4 2.72 (0.19) 177.28 (0.19) 3 5 6.05 (0.21) 173.95 (0.21) 3 6 2.67 (1/5) 177.33 (1/5) 4 5 8.51 (0.15) 171.49 (0.15) 4 6 5.27 (0.12) 174.73 (0.12) 5 6 5.01 (0.15) 174.99 (0.15)

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
xyzUiso*/Ueq
Cl1A0.62532 (17)0.08359 (9)0.42940 (9)0.0599 (3)
Cl2A0.74528 (15)0.14532 (8)0.44508 (8)0.0471 (3)
N1A1.0971 (7)0.1296 (3)0.1684 (3)0.0649 (11)
O1A1.0655 (7)0.2193 (4)0.1584 (4)0.1110 (16)
O2A1.2278 (12)0.0975 (5)0.1346 (5)0.179 (3)
C1A1.0034 (6)0.0673 (3)0.2398 (3)0.0416 (8)
C2A0.8684 (5)0.1079 (3)0.2940 (3)0.0351 (7)
C3A0.7893 (5)0.0396 (3)0.3570 (3)0.0369 (8)
C4A0.8433 (5)0.0631 (3)0.3648 (3)0.0370 (8)
C5A0.9791 (6)0.0987 (3)0.3112 (3)0.0464 (9)
H5A1.016 (6)0.168 (4)0.315 (3)0.056*
C6A1.0595 (7)0.0334 (3)0.2482 (3)0.0505 (10)
H6A1.153 (7)0.057 (4)0.211 (3)0.061*
C7A0.8024 (6)0.2184 (3)0.2883 (3)0.0417 (8)
H71A0.672 (7)0.210 (3)0.296 (3)0.050*
H72A0.810 (6)0.232 (3)0.226 (3)0.050*
N2A0.9374 (6)0.3212 (3)0.3737 (3)0.0447 (8)
H21A1.069 (8)0.321 (4)0.383 (4)0.067*
H22A0.921 (7)0.391 (4)0.363 (3)0.067*
H23A0.910 (7)0.321 (4)0.439 (4)0.067*
Cl1B0.29060 (18)0.73858 (11)0.21504 (11)0.0701 (4)
Cl2B0.4742 (2)0.88054 (11)0.06980 (11)0.0794 (4)
N1B0.7533 (6)0.4642 (3)0.1286 (3)0.0555 (9)
O1B0.6725 (6)0.3978 (3)0.1764 (3)0.0874 (12)
O2B0.8930 (7)0.4510 (4)0.0895 (3)0.0949 (13)
C1B0.6795 (5)0.5684 (3)0.1210 (3)0.0388 (8)
C2B0.5262 (5)0.5945 (3)0.1695 (3)0.0371 (8)
C3B0.4698 (5)0.6945 (3)0.1536 (3)0.0403 (8)
C4B0.5550 (6)0.7601 (3)0.0903 (3)0.0467 (9)
C5B0.7016 (7)0.7298 (4)0.0432 (3)0.0536 (11)
H5B0.749 (7)0.773 (4)0.002 (4)0.064*
C6B0.7672 (6)0.6341 (4)0.0596 (3)0.0487 (10)
H6B0.869 (7)0.615 (4)0.036 (3)0.058*
C7B0.4149 (7)0.5232 (4)0.2331 (3)0.0473 (9)
H71B0.379 (7)0.449 (4)0.200 (3)0.057*
H72B0.277 (7)0.526 (4)0.221 (3)0.057*
N2B0.5270 (6)0.5515 (3)0.3449 (3)0.0470 (8)
H21B0.506 (7)0.616 (4)0.390 (4)0.070*
H22B0.495 (7)0.491 (4)0.371 (4)0.070*
H23B0.6618 (17)0.572 (4)0.360 (4)0.070*
Cl31.01236 (16)0.59704 (8)0.37521 (8)0.0506 (3)
Cl40.40484 (15)0.32041 (8)0.40738 (7)0.0462 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl1A0.0702 (7)0.0577 (6)0.0864 (8)0.0379 (5)0.0542 (6)0.0392 (6)
Cl2A0.0611 (6)0.0356 (4)0.0553 (6)0.0139 (4)0.0265 (5)0.0239 (4)
N1A0.096 (3)0.055 (2)0.071 (2)0.029 (2)0.056 (2)0.0350 (19)
O1A0.128 (3)0.135 (4)0.164 (4)0.085 (3)0.105 (3)0.123 (3)
O2A0.324 (8)0.142 (4)0.242 (6)0.160 (5)0.256 (7)0.140 (4)
C1A0.050 (2)0.0385 (18)0.042 (2)0.0112 (16)0.0222 (17)0.0159 (16)
C2A0.0387 (19)0.0300 (16)0.0399 (19)0.0102 (14)0.0134 (15)0.0128 (14)
C3A0.0369 (19)0.0326 (17)0.046 (2)0.0114 (14)0.0170 (15)0.0122 (15)
C4A0.043 (2)0.0300 (16)0.0407 (19)0.0079 (15)0.0163 (16)0.0133 (15)
C5A0.060 (2)0.0324 (18)0.059 (2)0.0219 (18)0.029 (2)0.0167 (17)
C6A0.068 (3)0.042 (2)0.059 (2)0.027 (2)0.039 (2)0.0184 (19)
C7A0.051 (2)0.0394 (19)0.045 (2)0.0196 (18)0.0175 (18)0.0217 (17)
N2A0.058 (2)0.0345 (16)0.052 (2)0.0234 (16)0.0199 (17)0.0159 (15)
Cl1B0.0601 (7)0.0860 (8)0.0926 (9)0.0438 (6)0.0408 (6)0.0384 (7)
Cl2B0.1027 (10)0.0636 (7)0.0873 (9)0.0337 (7)0.0165 (7)0.0476 (7)
N1B0.058 (2)0.059 (2)0.050 (2)0.0304 (18)0.0028 (17)0.0096 (17)
O1B0.094 (3)0.068 (2)0.116 (3)0.040 (2)0.015 (2)0.049 (2)
O2B0.112 (3)0.115 (3)0.095 (3)0.080 (3)0.053 (2)0.029 (2)
C1B0.0396 (19)0.0437 (19)0.0319 (18)0.0147 (16)0.0040 (15)0.0093 (15)
C2B0.0336 (18)0.0450 (19)0.0334 (18)0.0097 (15)0.0050 (14)0.0171 (15)
C3B0.0333 (19)0.049 (2)0.042 (2)0.0122 (16)0.0101 (15)0.0197 (17)
C4B0.048 (2)0.046 (2)0.046 (2)0.0100 (17)0.0042 (18)0.0239 (18)
C5B0.056 (3)0.066 (3)0.042 (2)0.006 (2)0.0175 (19)0.028 (2)
C6B0.040 (2)0.067 (3)0.040 (2)0.0131 (19)0.0161 (17)0.0135 (19)
C7B0.043 (2)0.052 (2)0.050 (2)0.0061 (19)0.0143 (18)0.0268 (19)
N2B0.063 (2)0.0412 (18)0.0396 (18)0.0052 (17)0.0232 (17)0.0175 (15)
Cl30.0626 (6)0.0463 (5)0.0487 (5)0.0163 (5)0.0213 (5)0.0176 (4)
Cl40.0573 (6)0.0416 (5)0.0508 (5)0.0182 (4)0.0232 (4)0.0221 (4)
Geometric parameters (Å, º) top
Cl1A—C3A1.721 (4)Cl1B—C3B1.727 (4)
Cl2A—C4A1.730 (3)Cl2B—C4B1.732 (4)
N1A—O1A1.186 (5)N1B—O2B1.203 (5)
N1A—O2A1.186 (6)N1B—O1B1.225 (5)
N1A—C1A1.481 (5)N1B—C1B1.483 (5)
C1A—C6A1.382 (5)C1B—C6B1.378 (5)
C1A—C2A1.395 (5)C1B—C2B1.400 (5)
C2A—C3A1.392 (5)C2B—C3B1.400 (5)
C2A—C7A1.522 (5)C2B—C7B1.513 (5)
C3A—C4A1.397 (5)C3B—C4B1.391 (5)
C4A—C5A1.371 (5)C4B—C5B1.365 (6)
C5A—C6A1.373 (5)C5B—C6B1.381 (6)
C5A—H5A0.94 (4)C5B—H5B0.93 (5)
C6A—H6A0.94 (4)C6B—H6B0.88 (4)
C7A—N2A1.473 (5)C7B—N2B1.465 (5)
C7A—H71A0.91 (4)C7B—H71B0.87 (4)
C7A—H72A0.89 (4)C7B—H72B0.94 (4)
N2A—H21A0.89 (5)N2B—H21B0.94 (5)
N2A—H22A0.91 (5)N2B—H22B0.87 (5)
N2A—H23A0.92 (5)N2B—H23B0.87 (1)
O1A—N1A—O2A120.5 (4)O2B—N1B—O1B123.6 (4)
O1A—N1A—C1A120.6 (4)O2B—N1B—C1B118.0 (4)
O2A—N1A—C1A117.9 (4)O1B—N1B—C1B118.3 (4)
C6A—C1A—C2A123.0 (3)C6B—C1B—C2B123.0 (3)
C6A—C1A—N1A115.1 (3)C6B—C1B—N1B115.0 (3)
C2A—C1A—N1A122.0 (3)C2B—C1B—N1B121.9 (3)
C3A—C2A—C1A115.8 (3)C1B—C2B—C3B115.4 (3)
C3A—C2A—C7A118.9 (3)C1B—C2B—C7B126.1 (3)
C1A—C2A—C7A125.2 (3)C3B—C2B—C7B118.5 (3)
C2A—C3A—C4A121.5 (3)C4B—C3B—C2B121.9 (3)
C2A—C3A—Cl1A119.5 (3)C4B—C3B—Cl1B118.9 (3)
C4A—C3A—Cl1A119.0 (3)C2B—C3B—Cl1B119.2 (3)
C5A—C4A—C3A120.6 (3)C5B—C4B—C3B120.3 (4)
C5A—C4A—Cl2A118.9 (3)C5B—C4B—Cl2B119.5 (3)
C3A—C4A—Cl2A120.5 (3)C3B—C4B—Cl2B120.2 (3)
C4A—C5A—C6A119.3 (3)C4B—C5B—C6B119.8 (4)
C4A—C5A—H5A122 (3)C4B—C5B—H5B118 (3)
C6A—C5A—H5A119 (3)C6B—C5B—H5B122 (3)
C5A—C6A—C1A119.8 (3)C1B—C6B—C5B119.5 (4)
C5A—C6A—H6A120 (3)C1B—C6B—H6B117 (3)
C1A—C6A—H6A120 (3)C5B—C6B—H6B123 (3)
N2A—C7A—C2A111.2 (3)N2B—C7B—C2B113.5 (3)
N2A—C7A—H71A107 (3)N2B—C7B—H71B115 (3)
C2A—C7A—H71A111 (3)C2B—C7B—H71B109 (3)
N2A—C7A—H72A109 (3)N2B—C7B—H72B115 (3)
C2A—C7A—H72A109 (3)C2B—C7B—H72B110 (3)
H71A—C7A—H72A110 (4)H71B—C7B—H72B92 (4)
C7A—N2A—H21A111 (3)C7B—N2B—H21B115 (3)
C7A—N2A—H22A113 (3)C7B—N2B—H22B111 (3)
H21A—N2A—H22A111 (4)H21B—N2B—H22B108 (4)
C7A—N2A—H23A113 (3)C7B—N2B—H23B118 (3)
H21A—N2A—H23A104 (4)H21B—N2B—H23B100 (4)
H22A—N2A—H23A104 (4)H22B—N2B—H23B104 (4)
O1A—N1A—C1A—C6A177.2 (5)O2B—N1B—C1B—C6B6.3 (5)
O2A—N1A—C1A—C6A8.4 (7)O1B—N1B—C1B—C6B175.6 (4)
O1A—N1A—C1A—C2A2.8 (7)O2B—N1B—C1B—C2B176.2 (4)
O2A—N1A—C1A—C2A171.6 (6)O1B—N1B—C1B—C2B2.0 (5)
C6A—C1A—C2A—C3A0.9 (6)C6B—C1B—C2B—C3B1.4 (5)
N1A—C1A—C2A—C3A179.0 (4)N1B—C1B—C2B—C3B178.8 (3)
C6A—C1A—C2A—C7A179.6 (4)C6B—C1B—C2B—C7B176.6 (4)
N1A—C1A—C2A—C7A0.5 (6)N1B—C1B—C2B—C7B0.7 (5)
C1A—C2A—C3A—C4A0.1 (5)C1B—C2B—C3B—C4B2.5 (5)
C7A—C2A—C3A—C4A179.6 (3)C7B—C2B—C3B—C4B175.7 (3)
C1A—C2A—C3A—Cl1A178.7 (3)C1B—C2B—C3B—Cl1B177.0 (3)
C7A—C2A—C3A—Cl1A1.8 (5)C7B—C2B—C3B—Cl1B4.8 (5)
C2A—C3A—C4A—C5A1.0 (6)C2B—C3B—C4B—C5B1.5 (6)
Cl1A—C3A—C4A—C5A177.7 (3)Cl1B—C3B—C4B—C5B178.0 (3)
C2A—C3A—C4A—Cl2A179.2 (3)C2B—C3B—C4B—Cl2B178.0 (3)
Cl1A—C3A—C4A—Cl2A0.5 (4)Cl1B—C3B—C4B—Cl2B2.5 (5)
C3A—C4A—C5A—C6A1.1 (6)C3B—C4B—C5B—C6B0.7 (6)
Cl2A—C4A—C5A—C6A179.3 (3)Cl2B—C4B—C5B—C6B179.8 (3)
C4A—C5A—C6A—C1A0.3 (6)C2B—C1B—C6B—C5B0.6 (6)
C2A—C1A—C6A—C5A0.8 (6)N1B—C1B—C6B—C5B176.9 (3)
N1A—C1A—C6A—C5A179.2 (4)C4B—C5B—C6B—C1B1.8 (6)
C3A—C2A—C7A—N2A88.0 (4)C1B—C2B—C7B—N2B84.4 (5)
C1A—C2A—C7A—N2A92.5 (4)C3B—C2B—C7B—N2B97.6 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2A—H21A···Cl4i0.89 (6)2.28 (6)3.168 (5)180 (6)
N2A—H22A···Cl30.92 (5)2.39 (5)3.255 (5)158 (4)
N2A—H23A···Cl3ii0.92 (5)2.36 (5)3.200 (5)151 (4)
N2B—H21B···Cl4iii0.94 (5)2.55 (5)3.223 (4)129 (4)
N2B—H22B···Cl40.88 (5)2.20 (5)3.062 (5)170 (5)
N2B—H23B···Cl30.87 (3)2.33 (2)3.191 (5)170 (5)
C4A—Cl2A···Cl4iv1.73 (1)3.30 (1)-173 (1)
C5A—H5A···Cl1Bv0.94 (5)2.82 (4)3.476 (6)128 (3)
C7A—H71A···Cl1A0.91 (5)2.59 (4)2.982 (5)107 (3)
C7A—H72A···O1A0.89 (4)2.14 (4)2.729 (7)123 (3)
C7A—H72A···O1B0.89 (4)2.56 (4)3.082 (6)118 (3)
C5B—H5B···O2Avi0.93 (5)2.60 (5)3.497 (8)163 (4)
C6B—H6B···O2B0.88 (5)2.28 (5)2.640 (7)105 (4)
C7B—H71B···O1B0.87 (5)2.31 (5)2.704 (7)108 (4)
C7B—H72B···Cl1B0.94 (5)2.57 (5)2.972 (6)106 (3)
Symmetry codes: (i) x+1, y, z; (ii) x+2, y+1, z+1; (iii) x+1, y+1, z+1; (iv) x+1, y, z+1; (v) x+1, y1, z; (vi) x+2, y+1, z.

Experimental details

Crystal data
Chemical formulaC7H7Cl2N2O2+·Cl
Mr257.50
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)6.889 (7), 12.116 (12), 13.286 (13)
α, β, γ (°)102.128 (15), 100.939 (16), 103.523 (16)
V3)1020.3 (17)
Z4
Radiation typeMo Kα
µ (mm1)0.87
Crystal size (mm)0.55 × 0.52 × 0.21
Data collection
DiffractometerBruker SMART CCD area-detector
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.631, 0.842
No. of measured, independent and
observed [I > 2σ(I)] reflections
10895, 4146, 3161
Rint0.036
(sin θ/λ)max1)0.626
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.056, 0.152, 1.05
No. of reflections4146
No. of parameters295
No. of restraints1
H-atom treatmentOnly H-atom coordinates refined
Δρmax, Δρmin (e Å3)0.72, 0.71

Computer programs: SMART (Bruker, 2001), SAINT-Plus (Bruker, 2001), SAINT-Plus, SHELXTL (Bruker, 2001), ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2003), SHELXL97 (Sheldrick, 1997) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2A—H21A···Cl4i0.89 (6)2.28 (6)3.168 (5)180 (6)
N2A—H22A···Cl30.92 (5)2.39 (5)3.255 (5)158 (4)
N2A—H23A···Cl3ii0.92 (5)2.36 (5)3.200 (5)151 (4)
N2B—H21B···Cl4iii0.94 (5)2.55 (5)3.223 (4)129 (4)
N2B—H22B···Cl40.88 (5)2.20 (5)3.062 (5)170 (5)
N2B—H23B···Cl30.87 (3)2.33 (2)3.191 (5)170 (5)
C4A—Cl2A···Cl4iv1.730 (3)3.302 (4)-173.4 (1)
C5A—H5A···Cl1Bv0.94 (5)2.82 (4)3.476 (6)128 (3)
C7A—H71A···Cl1A0.91 (5)2.59 (4)2.982 (5)107 (3)
C7A—H72A···O1A0.89 (4)2.14 (4)2.729 (7)123 (3)
C7A—H72A···O1B0.89 (4)2.56 (4)3.082 (6)118 (3)
C5B—H5B···O2Avi0.93 (5)2.60 (5)3.497 (8)163 (4)
C6B—H6B···O2B0.88 (5)2.28 (5)2.640 (7)105 (4)
C7B—H71B···O1B0.87 (5)2.31 (5)2.704 (7)108 (4)
C7B—H72B···Cl1B0.94 (5)2.57 (5)2.972 (6)106 (3)
Symmetry codes: (i) x+1, y, z; (ii) x+2, y+1, z+1; (iii) x+1, y+1, z+1; (iv) x+1, y, z+1; (v) x+1, y1, z; (vi) x+2, y+1, z.
 

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