organic compounds
4-Nitroanilinium triiodide monohydrate
aMolecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private bag, PO Wits 2050, South Africa
*Correspondence e-mail: dave.billing@wits.ac.za
In the title compound, C6H7N2O2+·I3−·H2O, the triiodide anions form two-dimensional sheets along the a and c axes. These sheets are separated by the 4-nitroanilinium cations and water molecules, which form part of an extended hydrogen-bonded chain with the triiodide along the c axis, represented by the graph set C33(14). The second important hydrogen-bonding interaction is between the nitro group, the water molecule and the anilinium group, which forms an R22(6) ring and may be the reason for the deviation of the torsion angle between the benzene ring and the nitro group from 180 to 163.2 (4)°. These two strong hydrogen-bonding interactions also cause the benzene rings to pack off-centre from one another, with an edge-on-edge π–π stacking distance of 3.634 (6) Å and a centroid–centroid separation of 4.843 (2) Å.
Related literature
For structures of 4-nitroanilinine-monohalide salts, see: Lemmerer & Billing (2006) (bromine) and Ploug-Sørensen & Andersen (1982) (chlorine). For other amine-based triiodide salts, see: Tebbe & Loukili (1998). For a triiodide salt containing a tetraphenylphosphonium cation, see: Parvez et al. (1996). For structure-properties relationships in trihalides, see: Shibaeva & Yagubskii (2004). For graph-set analysis, see: Etter et al. (1990).
Experimental
Crystal data
|
Refinement
|
Data collection: SMART-NT (Bruker, 1998); cell SMART-NT; data reduction: SAINT-Plus (Bruker, 1999); program(s) used to solve structure: XS in SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).
Supporting information
https://doi.org/10.1107/S1600536810014674/zs2032sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810014674/zs2032Isup2.hkl
For the preparation of (I) 0.632 g of 4-nitroaniline was dissolved in 4 ml of 55% aqueous HI. The solution was heated to dissolve the precipitate and then left to stand at room temperature. Crystals suitable for single crystal X-ray diffraction were grown by slow evaporation of the solvent over a period of one month.
The H atoms on nitroaniline were refined using a riding-model, with C—H = 0.93 Å, N—H = 0.89 Å and with Uĩso(H) = 1.2Ueq(C) or 1.5Ueq(N). The H atoms on the water were placed from the difference Fourier map with O—H = 0.90 (2) Å and constrained using the DFIX constraint (Sheldrick, 2008). The highest residual electron density peak (0.708eÅ-3) was 0.865 Å from I2.
Previously 4-nitroanilinine was crystallized with bromine (Lemmerer & Billing, 2006) and chlorine (Ploug-Sørensen et al., 1982) to produce the respective monohalide salts. In an attempt to synthesize a monoiodide salt with 4-nitroaniline, the black crystals of 4-nitroanilinium triiodide monohydrate, C6H7N2O2+ I3- . H2O (I) formed in preference, and the structure is reported here. Polyiodide salts are commonly found, but the triiodides less so. Tebbe & Loukili (1998) have successfully synthesized two tertiary ammonium triiodide salts, while Parvez et al. (1996) synthesized a tetraphenylphosphonium triiodide salt. This is important to note since the title compound has a primary amine as the cation, while in the other three reported cases, bulky counter cations are involved. There are no other structural similarities with (I) with the exception of the the I1—I2—I3 bond angle [178.209 (14)°], which compares with those of the tertiary ammonium triiodides (180, 177.09°) and the bulkier tetraphenylphosphonium triiodide (175.27°).
In the structure of (I) (Figs. 1, 2), the triiodide anions essentially form two-dimensional sheets along the a and c axes. Looking at the interactions along the a axis, the layers of triiodide anions pack parallel to each other with a separation of 4.843 (1) Å. The two intermolecular head-to-tail I1···I1 and the two I3···I3 interactions along the c axis have a separation of 4.574 (1) and 3.772 (1) Å and 4.1079 (7) and 5.2776 (8) Å respectively, completing the interactions which form the two-dimensional sheets. These sheets are separated by the 4-nitroanilium and water moieties which form part of an extended hydrogen-bonded chain with the triiodide along the c axis of the
represented by the graph set C33(14) (Etter et al., 1990). The graph set notation includes H···I hydrogen bonds with the water and the nitro oxygen (O2) i.e. (O3—H···O2), as seen in Fig 2.Besides the strong C33(14) hydrogen-bonding network, another important hydrogen-bonding association is between the nitro group, the water and the ammonium group, forming an R22(6) ring (Table 1). This ring appears to be an important interaction which gives a deviation of the torsion angle C6—C1—N1—O2 between the benzene ring and the nitro group from 180° to 163.2 (4)°. The two strong hydrogen-bonding interactions result in the benzene rings packing off-centre from one another with an edge-on-edge π-π stacking distance of 3.634 (6) Å and a centroid-to-centroid separation of 4.843 (2) Å. The many short intermolecular distances between the triiodide anions and the benzene rings may be important in the optical properties of (I), regarding charge-transfer interactions and conductivity, as found in this type of compound (Shibaeva & Yagubskii, 2004).
For structures of 4-nitroanilinine-monohalide salts, see: Lemmerer & Billing (2006) (bromine) and Ploug-Sørensen et al. (1982) (chlorine). For other amine based triodide salts, see: Tebbe & Loukili (1998). For a triiodide salt containing a tetraphenylphosphonium cation, see: Parvez et al. (1996). For structure-properties relationships in trihalides, see: Shibaeva & Yagubskii (2004). For graph-set analysis, see: Etter et al. (1990).
Data collection: SMART-NT (Bruker, 1998); cell
SMART-NT (Bruker, 1998); data reduction: SAINT-Plus (Bruker, 1999); program(s) used to solve structure: XS in SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).Fig. 1. View of (I) (50% probability displacement ellipsoids) | |
Fig. 2. A view along the a axis of an extended unit cell showing the alignment of the triiodide moieties and C33(14) H-bonding interaction. |
C6H7N2O2+·I3−·H2O | F(000) = 968 |
Mr = 537.85 | Dx = 2.737 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 9074 reflections |
a = 4.8429 (9) Å | θ = 2.6–28.3° |
b = 14.701 (3) Å | µ = 7.17 mm−1 |
c = 18.346 (3) Å | T = 298 K |
β = 91.916 (3)° | Plate, black |
V = 1305.4 (4) Å3 | 0.54 × 0.31 × 0.11 mm |
Z = 4 |
Bruker SMART 1K CCD area-detector diffractometer | 2461 reflections with I > 2σ(I) |
φ and ω scans | Rint = 0.068 |
Absorption correction: integration (XPREP; Bruker, 1999) | θmax = 28°, θmin = 1.8° |
Tmin = 0.113, Tmax = 0.506 | h = −6→4 |
8741 measured reflections | k = −19→18 |
3150 independent reflections | l = −24→24 |
Refinement on F2 | H atoms treated by a mixture of independent and constrained refinement |
Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0374P)2 + 0.3561P] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.034 | (Δ/σ)max = 0.001 |
wR(F2) = 0.081 | Δρmax = 0.71 e Å−3 |
S = 1.05 | Δρmin = −1.42 e Å−3 |
3150 reflections | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
137 parameters | Extinction coefficient: 0.0166 (6) |
0 restraints |
C6H7N2O2+·I3−·H2O | V = 1305.4 (4) Å3 |
Mr = 537.85 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 4.8429 (9) Å | µ = 7.17 mm−1 |
b = 14.701 (3) Å | T = 298 K |
c = 18.346 (3) Å | 0.54 × 0.31 × 0.11 mm |
β = 91.916 (3)° |
Bruker SMART 1K CCD area-detector diffractometer | 3150 independent reflections |
Absorption correction: integration (XPREP; Bruker, 1999) | 2461 reflections with I > 2σ(I) |
Tmin = 0.113, Tmax = 0.506 | Rint = 0.068 |
8741 measured reflections |
R[F2 > 2σ(F2)] = 0.034 | 0 restraints |
wR(F2) = 0.081 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Δρmax = 0.71 e Å−3 |
3150 reflections | Δρmin = −1.42 e Å−3 |
137 parameters |
Experimental. Numerical integration absorption corrections based on indexed crystal faces were applied using the XPREP routine (Bruker, 1999a) |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.4993 (8) | 0.2871 (3) | 0.2902 (2) | 0.0404 (8) | |
C2 | 0.6434 (9) | 0.3443 (3) | 0.3357 (2) | 0.0491 (10) | |
H2 | 0.7771 | 0.383 | 0.3179 | 0.059* | |
C3 | 0.5861 (9) | 0.3433 (3) | 0.4094 (2) | 0.0482 (10) | |
H3 | 0.6779 | 0.3822 | 0.442 | 0.058* | |
C4 | 0.3913 (8) | 0.2838 (3) | 0.4328 (2) | 0.0410 (9) | |
C5 | 0.2464 (9) | 0.2267 (3) | 0.3873 (2) | 0.0502 (10) | |
H5 | 0.1157 | 0.187 | 0.4053 | 0.06* | |
C6 | 0.2991 (9) | 0.2293 (3) | 0.3129 (2) | 0.0481 (10) | |
H6 | 0.2006 | 0.1928 | 0.2798 | 0.058* | |
N1 | 0.5625 (8) | 0.2874 (3) | 0.21247 (18) | 0.0494 (9) | |
N2 | 0.3444 (8) | 0.2797 (3) | 0.51204 (17) | 0.0574 (10) | |
H2A | 0.1948 | 0.2464 | 0.5199 | 0.086* | |
H2B | 0.3198 | 0.3357 | 0.529 | 0.086* | |
H2C | 0.4903 | 0.2545 | 0.5349 | 0.086* | |
O1 | 0.3995 (8) | 0.2526 (3) | 0.16900 (17) | 0.0692 (10) | |
O2 | 0.7804 (8) | 0.3222 (3) | 0.19569 (19) | 0.0774 (11) | |
O3 | 0.8528 (8) | 0.3133 (2) | 0.04409 (18) | 0.0583 (8) | |
H3A | 0.878 (14) | 0.316 (5) | 0.0917 (12) | 0.11 (3)* | |
H3B | 0.800 (13) | 0.366 (3) | 0.024 (3) | 0.11 (2)* | |
I1 | 0.33289 (8) | 0.50637 (2) | 0.091253 (18) | 0.06519 (14) | |
I2 | 0.22677 (6) | 0.531920 (18) | 0.244438 (16) | 0.04997 (12) | |
I3 | 0.12058 (7) | 0.55190 (2) | 0.402108 (17) | 0.06257 (14) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.047 (2) | 0.045 (2) | 0.0290 (18) | 0.0061 (17) | 0.0020 (16) | −0.0012 (16) |
C2 | 0.055 (3) | 0.051 (2) | 0.041 (2) | −0.0106 (19) | 0.003 (2) | 0.0007 (18) |
C3 | 0.057 (3) | 0.055 (2) | 0.0320 (19) | −0.003 (2) | −0.0039 (18) | −0.0060 (18) |
C4 | 0.043 (2) | 0.051 (2) | 0.0292 (18) | 0.0095 (17) | 0.0039 (16) | 0.0001 (16) |
C5 | 0.049 (3) | 0.062 (3) | 0.041 (2) | −0.005 (2) | 0.0075 (19) | 0.002 (2) |
C6 | 0.049 (2) | 0.054 (2) | 0.041 (2) | −0.0027 (19) | 0.0015 (19) | −0.0070 (19) |
N1 | 0.057 (2) | 0.057 (2) | 0.0341 (18) | 0.0053 (18) | 0.0045 (17) | −0.0046 (16) |
N2 | 0.056 (2) | 0.083 (3) | 0.0341 (18) | −0.002 (2) | 0.0071 (16) | −0.0006 (19) |
O1 | 0.078 (2) | 0.090 (3) | 0.0390 (17) | −0.009 (2) | −0.0025 (16) | −0.0066 (17) |
O2 | 0.072 (2) | 0.115 (3) | 0.0463 (19) | −0.020 (2) | 0.0136 (17) | −0.008 (2) |
O3 | 0.066 (2) | 0.067 (2) | 0.0433 (18) | −0.0040 (17) | 0.0108 (16) | −0.0020 (16) |
I1 | 0.0854 (3) | 0.0619 (2) | 0.0487 (2) | 0.00069 (17) | 0.00906 (17) | 0.00064 (14) |
I2 | 0.0543 (2) | 0.04402 (18) | 0.05185 (19) | 0.00195 (12) | 0.00491 (13) | −0.00021 (12) |
I3 | 0.0680 (2) | 0.0673 (2) | 0.0529 (2) | −0.00435 (15) | 0.01033 (16) | −0.01723 (15) |
C1—C2 | 1.361 (6) | C6—H6 | 0.93 |
C1—C6 | 1.365 (6) | N1—O1 | 1.216 (5) |
C1—N1 | 1.468 (5) | N1—O2 | 1.221 (5) |
C2—C3 | 1.389 (5) | N2—H2A | 0.89 |
C2—H2 | 0.93 | N2—H2B | 0.89 |
C3—C4 | 1.366 (6) | N2—H2C | 0.89 |
C3—H3 | 0.93 | O3—H3A | 0.88 (2) |
C4—C5 | 1.362 (6) | O3—H3B | 0.89 (5) |
C4—N2 | 1.480 (5) | I1—I2 | 2.8982 (6) |
C5—C6 | 1.398 (6) | I2—I3 | 2.9694 (6) |
C5—H5 | 0.93 | ||
C2—C1—C6 | 123.6 (4) | C1—C6—C5 | 118.0 (4) |
C2—C1—N1 | 118.3 (4) | C1—C6—H6 | 121 |
C6—C1—N1 | 118.1 (4) | C5—C6—H6 | 121 |
C1—C2—C3 | 118.4 (4) | O1—N1—O2 | 123.9 (4) |
C1—C2—H2 | 120.8 | O1—N1—C1 | 118.9 (4) |
C3—C2—H2 | 120.8 | O2—N1—C1 | 117.1 (4) |
C4—C3—C2 | 118.4 (4) | C4—N2—H2A | 109.5 |
C4—C3—H3 | 120.8 | C4—N2—H2B | 109.5 |
C2—C3—H3 | 120.8 | H2A—N2—H2B | 109.5 |
C5—C4—C3 | 123.3 (4) | C4—N2—H2C | 109.5 |
C5—C4—N2 | 119.0 (4) | H2A—N2—H2C | 109.5 |
C3—C4—N2 | 117.7 (4) | H2B—N2—H2C | 109.5 |
C4—C5—C6 | 118.4 (4) | H3A—O3—H3B | 114 (6) |
C4—C5—H5 | 120.8 | I1—I2—I3 | 178.209 (14) |
C6—C5—H5 | 120.8 | ||
C6—C1—C2—C3 | 0.7 (7) | C2—C1—C6—C5 | −2.3 (7) |
N1—C1—C2—C3 | −179.3 (4) | N1—C1—C6—C5 | 177.7 (4) |
C1—C2—C3—C4 | 1.2 (7) | C4—C5—C6—C1 | 2.0 (6) |
C2—C3—C4—C5 | −1.5 (7) | C2—C1—N1—O1 | −164.1 (4) |
C2—C3—C4—N2 | 176.4 (4) | C6—C1—N1—O1 | 15.9 (6) |
C3—C4—C5—C6 | −0.2 (7) | C2—C1—N1—O2 | 16.7 (6) |
N2—C4—C5—C6 | −178.0 (4) | C6—C1—N1—O2 | −163.2 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2A···O3i | 0.89 | 1.94 | 2.824 (5) | 173 |
N2—H2B···I3ii | 0.89 | 3.01 | 3.731 (4) | 139 |
N2—H2C···O1iii | 0.89 | 2.52 | 2.922 (5) | 108 |
N2—H2C···O3iii | 0.89 | 2.02 | 2.860 (5) | 157 |
O3—H3A···O2 | 0.88 (2) | 1.98 (3) | 2.818 (5) | 158 (6) |
O3—H3B···I1iv | 0.89 (5) | 2.88 (5) | 3.722 (3) | 157 (4) |
Symmetry codes: (i) x−1, −y+1/2, z+1/2; (ii) −x, −y+1, −z+1; (iii) x, −y+1/2, z+1/2; (iv) −x+1, −y+1, −z. |
Experimental details
Crystal data | |
Chemical formula | C6H7N2O2+·I3−·H2O |
Mr | 537.85 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 298 |
a, b, c (Å) | 4.8429 (9), 14.701 (3), 18.346 (3) |
β (°) | 91.916 (3) |
V (Å3) | 1305.4 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 7.17 |
Crystal size (mm) | 0.54 × 0.31 × 0.11 |
Data collection | |
Diffractometer | Bruker SMART 1K CCD area-detector |
Absorption correction | Integration (XPREP; Bruker, 1999) |
Tmin, Tmax | 0.113, 0.506 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8741, 3150, 2461 |
Rint | 0.068 |
(sin θ/λ)max (Å−1) | 0.661 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.081, 1.05 |
No. of reflections | 3150 |
No. of parameters | 137 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.71, −1.42 |
Computer programs: SMART-NT (Bruker, 1998), SAINT-Plus (Bruker, 1999), XS in SHELXTL (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2A···O3i | 0.89 | 1.94 | 2.824 (5) | 173 |
N2—H2B···I3ii | 0.89 | 3.01 | 3.731 (4) | 139 |
N2—H2C···O1iii | 0.89 | 2.52 | 2.922 (5) | 108 |
N2—H2C···O3iii | 0.89 | 2.02 | 2.860 (5) | 157 |
O3—H3A···O2 | 0.88 (2) | 1.98 (3) | 2.818 (5) | 158 (6) |
O3—H3B···I1iv | 0.89 (5) | 2.88 (5) | 3.722 (3) | 157 (4) |
Symmetry codes: (i) x−1, −y+1/2, z+1/2; (ii) −x, −y+1, −z+1; (iii) x, −y+1/2, z+1/2; (iv) −x+1, −y+1, −z. |
Acknowledgements
The University of the Witwatersrand and the National Research Fund (GUN: 2069064) are thanked for the award of a research grant and for providing the infrastructure required to do this work.
References
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Previously 4-nitroanilinine was crystallized with bromine (Lemmerer & Billing, 2006) and chlorine (Ploug-Sørensen et al., 1982) to produce the respective monohalide salts. In an attempt to synthesize a monoiodide salt with 4-nitroaniline, the black crystals of 4-nitroanilinium triiodide monohydrate, C6H7N2O2+ I3- . H2O (I) formed in preference, and the structure is reported here. Polyiodide salts are commonly found, but the triiodides less so. Tebbe & Loukili (1998) have successfully synthesized two tertiary ammonium triiodide salts, while Parvez et al. (1996) synthesized a tetraphenylphosphonium triiodide salt. This is important to note since the title compound has a primary amine as the cation, while in the other three reported cases, bulky counter cations are involved. There are no other structural similarities with (I) with the exception of the the I1—I2—I3 bond angle [178.209 (14)°], which compares with those of the tertiary ammonium triiodides (180, 177.09°) and the bulkier tetraphenylphosphonium triiodide (175.27°).
In the structure of (I) (Figs. 1, 2), the triiodide anions essentially form two-dimensional sheets along the a and c axes. Looking at the interactions along the a axis, the layers of triiodide anions pack parallel to each other with a separation of 4.843 (1) Å. The two intermolecular head-to-tail I1···I1 and the two I3···I3 interactions along the c axis have a separation of 4.574 (1) and 3.772 (1) Å and 4.1079 (7) and 5.2776 (8) Å respectively, completing the interactions which form the two-dimensional sheets. These sheets are separated by the 4-nitroanilium and water moieties which form part of an extended hydrogen-bonded chain with the triiodide along the c axis of the unit cell, represented by the graph set C33(14) (Etter et al., 1990). The graph set notation includes H···I hydrogen bonds with the water and the nitro oxygen (O2) i.e. (O3—H···O2), as seen in Fig 2.
Besides the strong C33(14) hydrogen-bonding network, another important hydrogen-bonding association is between the nitro group, the water and the ammonium group, forming an R22(6) ring (Table 1). This ring appears to be an important interaction which gives a deviation of the torsion angle C6—C1—N1—O2 between the benzene ring and the nitro group from 180° to 163.2 (4)°. The two strong hydrogen-bonding interactions result in the benzene rings packing off-centre from one another with an edge-on-edge π-π stacking distance of 3.634 (6) Å and a centroid-to-centroid separation of 4.843 (2) Å. The many short intermolecular distances between the triiodide anions and the benzene rings may be important in the optical properties of (I), regarding charge-transfer interactions and conductivity, as found in this type of compound (Shibaeva & Yagubskii, 2004).