supplementary materials


ru2048 scheme

Acta Cryst. (2013). E69, o159-o160    [ doi:10.1107/S1600536812051434 ]

2-Chlorobenzene-1,4-diaminium bis(dihydrogenphosphate)

M. L. Mrad, M. Zeller, M. Rzaigui and C. Ben Nasr

Abstract top

The asymmetric unit of the title salt, C6H9ClN22+·2H2PO4-, contains two dihydrogenphosphate anions and one 2-chlorobenzene-1,4-diaminium dication. The H2PO4- anions are interconnected through strong O-H...O hydrogen bonds to form two-dimensional infinite layers parallel to (001). The organic entities are anchored to the inorganic layers through N-H...O hydrogen bonds, and through weak C-Cl...O halogen bonds [3.159 (2) Å, 140.48 (7)°]. No [pi]-[pi] stacking interactions between neighboring aromatic rings or C-H...[pi] interactions towards them are observed. Minor disorder is observed for the Cl atom and one hydroxy group [minor-component occupancy = 3.29 (9)%].

Comment top

In organic-cation monophosphates, the phosphate anions generally observed are the partially protonated acidic ones H2PO4- or HPO42-. In the solid state such anions are generally interconnected through strong hydrogen bonds so as to build infinite networks with various geometries (Rayes et al., 2004; Oueslati et al., 2005). If these organic-cation monophosphates hybrid materials crystallize in a noncentrosymmetric setting they are of particular interest as nonlinear optical (NLO) materials (Masse et al., 1993). The present work is devoted to the structure of an organic-cation hydrogenphosphate, C6H9ClN2(H2PO4)2, formed by the reaction of 2-chlorobenzene-1,4-diamine with orthophosphoric acid, which crystallized in a non-centrosymmetric setting.

The title organic-inorganic hybrid material, while made from achiral components, crystallizes in the chiral space group P212121. The crystal investigated is partially racemically twinned, with a twinning ratio of 0.89 (4) to 0.11 (4). Its structure consists of one 2-chlorobenzene-1,4-diaminium dication and two crystallographically distinct H2PO4- anions (Fig. 1). The chlorine atom is disordered over two chemically equivalent positions with a small but noticable presence of the second moiety (refined value 3.29 (9)%). Associated with this disorder is disorder of one phosphate hydroxyl group of one of the H2P(2)O4- anions, O6. Where not mentioned otherwise, this disorder is ignored in the following more detailed discussion of the structure.

The HPO42- anions show two types of P—O distances depending on whether the oxygen atoms are hydrogen donors or acceptors. As expected, the P—OH distances, varying between 1.54 (3) and 1.581 (1) Å, are significantly longer than the other P—O distances ranging from 1.500 (1) to 1.516 (1) Å. This is in agreement with the literature data (Chtioui & Jouini, 2006; Kaabi et al., 2004). Figure 2 shows that the H2PO4- anions are interconnected through O—H···O hydrogen bonds to form a two dimensional layer spreading parallel to the (0 0 1) plane at z = 0, 1/2 and 1 (Fig. 3). The organic cations, assembled in layers parallel to the H2PO4- anions at z = 1/4 and 3/4, are anchored to the inorganic layers through N—H···O hydrogen bonds whose geometrical characteristics are given in Table 1. The projection of the whole arrangement along the c-axis (Fig. 3) shows the alternating cationic and anionic layers. The structure also features a weak C—Cl···O halogen bond between the chlorine atom and one of the H2PO4- phosphate ions, a type of interaction that has recently attracted high levels of interest due to the observation of such interactions between halogenated compounds and the phosphate moieties in DNA (see e.g. Metrangolo & Resnati, 2008). In the title compound the Cl···O distance between Cl1 and O3i is 3.159 (2) Å, the C—Cl···O angle 140.48 (7)° (symmetry operator (i) -x + 3, y + 1/2, -z + 3/2), the equivalent values for the interaction of the minor occupied Cl atom Cl1B with O6B are 2.91 (5) Å and 130 (1)°. While the Cl···O distances are shorter than the sum of the van der Waals radii of chlorine and oxygen (ca 3.3 Å, Bondi, 1964), the angles observed are on the small side for C—Cl···O halogen bonds (160–180°, see e.g. Politzer et al., 2007; Metrangolo & Resnati, 2001), indicating that the interactions observed are quite weak and more likely a result of the stronger hydrogen bonding interactions rather than one of the major driving forces determining the outcome of the assembly of the structural components of the title compound. No π-π stacking interactions between neighboring aromatic rings or significant C—H···π interactions towards them are observed.

Related literature top

For common applications of organic phosphate complexes, see: Masse et al. (1993). For network geometries, see: Rayes et al. (2004); Oueslati et al. (2005). For reference structural data, see: Kaabi et al. (2004); Chtioui & Jouini (2006). For halogen bonding, see: Metrangolo & Resnati (2001, 2008); Politzer et al. (2007). For van der Waals radii, see: Bondi (1964).

Experimental top

Crystals of the title compound were prepared at room temperature by slow addition of a solution of orthophosphoric acid (6 mmol in 20 ml of water) to an alcoholic solution of 2-chlorobenzene-1,4-diamine (3 mmol in 20 ml of ethanol). The acid was added until the alcoholic solution became turbid. After filtration, the solution was allowed to slowly evaporate at room temperature over several days leading to formation of transparent prismatic crystals with suitable dimensions for single-crystal structural analysis (yield 58%). The crystals are stable for months under normal conditions of temperature and humidity.

Refinement top

The chlorine atom is disordered over two chemically equivalent positions with a small but noticable presence of the second moiety (refined value 3.29 (9)%). Associated with this disorder is disorder of one of the phosphate hydroxyl groups, O6. The minor moiety chlorine and oxygen atoms were constrained to have the same ADPs as their major moiety counterparts. Due to the low prevalence of the minor moiety no disorder was modeled for the aromatic ring the Cl atom is bonded to, despite of the obviously unrealistic C—C—Cl angles for the minor Cl atom.

All non hydrogen atoms were refined anisotropically. All H atoms were located in difference density Fourier maps, but were then placed in calculated positions riding on their respective carrier atom with C—H distances of 0.95, N—H distances of 0.91 Å, and O—H distances of 0.84 Å. Ammonium and hydroxyl H atoms were allowed to rotate but not to tip to best fit the observed electron density distribution. The position of the hydrogen atom of the minor occupied hydroxyl group was refined with a damping factor (DAMP 2000 in SHELXTL (Sheldrick, 2008)). In the final refinement cycles after removal of the damping factor its position was set to ride on its carrier oxygen atom. Uiso(H) values were constrained to be 1.2 Ueq(C) of the parent atom for C bound H atoms, and 1.5 times Ueq(N/O) for N and O bound H atoms.

The compound was refined as a racemic twin. The twin ratio refined to 0.89 (4) to 0.11 (4).

Computing details top

Data collection: APEX2 (Bruker, 2011); cell refinement: SAINT (Bruker, 2011); data reduction: SAINT (Bruker, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) and SHELXLE (Hübschle et al., 2011); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. A view of the title compound, showing 50% probability displacement ellipsoids and arbitrary spheres for the H atoms.
[Figure 2] Fig. 2. Projection along the c-axis of an inorganic layer in the structure of the title compound. Hydrogen bonds are denoted as red broken lines.
[Figure 3] Fig. 3. Projection of the structure along the b-axis. Hydrogen bonds are denoted as red broken lines, halogen bonds as black broken lines. For the disordered Cl atom, only the major part is shown.
2-Chlorobenzene-1,4-diaminium bis(dihydrogenphosphate) top
Crystal data top
C6H9ClN22+·2H2PO4F(000) = 696
Mr = 338.57Dx = 1.752 Mg m3
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 7956 reflections
a = 7.0084 (8) Åθ = 2.6–31.8°
b = 7.9404 (9) ŵ = 0.58 mm1
c = 23.064 (3) ÅT = 100 K
V = 1283.5 (3) Å3Block, colourless
Z = 40.55 × 0.52 × 0.51 mm
Data collection top
Bruker SMART APEX CCD
diffractometer
4134 independent reflections
Radiation source: fine-focus sealed tube4060 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.021
ω scansθmax = 32.0°, θmin = 2.7°
Absorption correction: multi-scan
(SADABS; Bruker, 2011)
h = 610
Tmin = 0.689, Tmax = 0.746k = 1111
11671 measured reflectionsl = 3333
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.025H-atom parameters constrained
wR(F2) = 0.064 w = 1/[σ2(Fo2) + (0.0328P)2 + 0.2706P]
where P = (Fo2 + 2Fc2)/3
S = 1.11(Δ/σ)max = 0.002
4134 reflectionsΔρmax = 0.44 e Å3
186 parametersΔρmin = 0.27 e Å3
0 restraintsAbsolute structure: Flack (1983), 1694 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.11 (4)
Crystal data top
C6H9ClN22+·2H2PO4V = 1283.5 (3) Å3
Mr = 338.57Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 7.0084 (8) ŵ = 0.58 mm1
b = 7.9404 (9) ÅT = 100 K
c = 23.064 (3) Å0.55 × 0.52 × 0.51 mm
Data collection top
Bruker SMART APEX CCD
diffractometer
4134 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2011)
4060 reflections with I > 2σ(I)
Tmin = 0.689, Tmax = 0.746Rint = 0.021
11671 measured reflectionsθmax = 32.0°
Refinement top
R[F2 > 2σ(F2)] = 0.025H-atom parameters constrained
wR(F2) = 0.064Δρmax = 0.44 e Å3
S = 1.11Δρmin = 0.27 e Å3
4134 reflectionsAbsolute structure: Flack (1983), 1694 Friedel pairs
186 parametersFlack parameter: 0.11 (4)
0 restraints
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
C11.3321 (2)0.15359 (17)0.76907 (6)0.0129 (2)
H11.44960.11550.78490.015*0.0329 (9)
C21.18845 (19)0.20920 (16)0.80593 (5)0.0109 (2)
C31.0154 (2)0.26208 (16)0.78290 (5)0.0131 (2)
H30.91610.29840.80800.016*
C40.9869 (2)0.26197 (17)0.72312 (5)0.0133 (2)
H40.86860.29770.70720.016*
C51.13375 (19)0.20895 (16)0.68709 (5)0.0108 (2)
C61.30604 (19)0.15298 (17)0.70924 (6)0.0129 (2)
H61.40440.11490.68410.015*0.9671 (9)
N11.21619 (16)0.20932 (15)0.86858 (4)0.01139 (19)
H1A1.21270.10160.88200.017*
H1B1.12180.27040.88570.017*
H1C1.33140.25600.87710.017*
N21.10964 (17)0.21095 (15)0.62440 (4)0.01136 (19)
H2A1.21400.25870.60760.017*
H2B1.00400.27190.61510.017*
H2C1.09590.10360.61120.017*
O11.22585 (15)0.22787 (14)0.49473 (4)0.01666 (19)
H1D1.11800.26660.48610.025*
O21.44777 (14)0.15775 (12)0.57261 (4)0.01261 (17)
O31.20902 (15)0.39458 (12)0.58809 (4)0.01507 (19)
H3A1.29900.45840.57830.023*
O41.09007 (14)0.10621 (12)0.58851 (4)0.01272 (18)
O51.66727 (16)0.25284 (15)0.50298 (4)0.0190 (2)
H51.77530.20930.49810.029*
O61.64342 (16)0.10590 (12)0.60055 (5)0.01469 (19)0.9671 (9)
H6A1.56180.04080.58610.022*0.9671 (9)
O6B1.690 (5)0.096 (4)0.5735 (15)0.01469 (19)0.0329 (9)
H6B1.59070.03610.57280.022*0.0329 (9)
O71.78483 (14)0.38754 (12)0.59744 (4)0.01286 (18)
O81.43146 (14)0.34988 (12)0.57179 (4)0.01380 (18)
P11.24379 (5)0.21374 (4)0.562311 (13)0.00959 (7)
P21.63262 (5)0.28287 (4)0.569303 (13)0.00987 (7)
Cl11.54768 (5)0.08734 (5)0.796787 (14)0.01984 (9)0.9671 (9)
Cl1B1.5045 (15)0.0693 (15)0.6861 (4)0.01984 (9)0.0329 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0096 (5)0.0148 (5)0.0141 (5)0.0021 (5)0.0011 (4)0.0012 (4)
C20.0123 (5)0.0106 (5)0.0100 (5)0.0001 (5)0.0002 (4)0.0011 (4)
C30.0119 (6)0.0155 (5)0.0119 (5)0.0031 (5)0.0008 (4)0.0000 (4)
C40.0108 (6)0.0171 (6)0.0120 (5)0.0040 (5)0.0002 (4)0.0008 (4)
C50.0133 (6)0.0101 (5)0.0091 (4)0.0008 (5)0.0002 (4)0.0000 (4)
C60.0105 (6)0.0150 (5)0.0132 (5)0.0010 (5)0.0010 (5)0.0011 (4)
N10.0123 (5)0.0118 (4)0.0100 (4)0.0000 (4)0.0011 (4)0.0004 (3)
N20.0123 (5)0.0127 (4)0.0091 (4)0.0006 (4)0.0006 (4)0.0009 (4)
O10.0131 (4)0.0260 (5)0.0109 (4)0.0043 (4)0.0005 (3)0.0040 (4)
O20.0092 (4)0.0137 (4)0.0150 (4)0.0019 (4)0.0006 (4)0.0000 (3)
O30.0132 (5)0.0101 (4)0.0220 (4)0.0001 (4)0.0028 (4)0.0011 (3)
O40.0125 (4)0.0111 (4)0.0145 (4)0.0010 (4)0.0030 (3)0.0013 (3)
O50.0158 (5)0.0301 (6)0.0111 (4)0.0048 (4)0.0007 (4)0.0045 (3)
O60.0168 (5)0.0097 (4)0.0176 (5)0.0014 (4)0.0033 (4)0.0011 (3)
O6B0.0168 (5)0.0097 (4)0.0176 (5)0.0014 (4)0.0033 (4)0.0011 (3)
O70.0129 (4)0.0110 (4)0.0146 (4)0.0013 (4)0.0023 (3)0.0019 (3)
O80.0105 (4)0.0142 (4)0.0167 (4)0.0011 (4)0.0007 (4)0.0000 (3)
P10.00924 (14)0.00981 (12)0.00974 (12)0.00071 (12)0.00054 (11)0.00102 (11)
P20.00882 (14)0.00994 (12)0.01085 (13)0.00014 (12)0.00035 (11)0.00110 (11)
Cl10.01175 (15)0.03455 (19)0.01321 (14)0.00876 (14)0.00169 (12)0.00062 (13)
Cl1B0.01175 (15)0.03455 (19)0.01321 (14)0.00876 (14)0.00169 (12)0.00062 (13)
Geometric parameters (Å, º) top
C1—C21.3898 (18)N2—H2B0.9100
C1—C61.3921 (17)N2—H2C0.9100
C1—Cl11.7228 (14)O1—P11.5678 (10)
C1—H10.9500O1—H1D0.8400
C2—C31.3889 (18)O2—P11.5159 (10)
C2—N11.4578 (14)O3—P11.5731 (10)
C3—C41.3933 (17)O3—H3A0.8400
C3—H30.9500O4—P11.5016 (10)
C4—C51.3879 (18)O5—P21.5670 (10)
C4—H40.9500O5—H50.8400
C5—C61.3843 (18)O6—P21.5811 (11)
C5—N21.4558 (14)O6—H6A0.8400
C6—Cl1B1.631 (10)O6—H6B0.9243
C6—H60.9500O6B—P21.54 (3)
N1—H1A0.9100O6B—H6B0.8400
N1—H1B0.9100O7—P21.5000 (10)
N1—H1C0.9100O8—P21.5080 (10)
N2—H2A0.9100
C2—C1—C6120.83 (12)C5—N2—H2A109.5
C2—C1—Cl1120.36 (10)C5—N2—H2B109.5
C6—C1—Cl1118.81 (10)H2A—N2—H2B109.5
C2—C1—H1119.6C5—N2—H2C109.5
C6—C1—H1119.6H2A—N2—H2C109.5
C3—C2—C1119.64 (11)H2B—N2—H2C109.5
C3—C2—N1119.69 (11)P1—O1—H1D109.5
C1—C2—N1120.65 (11)P1—O3—H3A109.5
C2—C3—C4120.22 (12)P2—O5—H5109.5
C2—C3—H3119.9P2—O6—H6A109.5
C4—C3—H3119.9P2—O6—H6B101.4
C5—C4—C3119.11 (12)P2—O6B—H6B109.2
C5—C4—H4120.4O4—P1—O2116.53 (6)
C3—C4—H4120.4O4—P1—O1112.54 (6)
C6—C5—C4121.54 (11)O2—P1—O1104.62 (6)
C6—C5—N2118.11 (11)O4—P1—O3104.82 (5)
C4—C5—N2120.34 (11)O2—P1—O3110.77 (6)
C5—C6—C1118.63 (12)O1—P1—O3107.34 (6)
C5—C6—Cl1B138.9 (4)O7—P2—O8116.93 (6)
C1—C6—Cl1B102.3 (4)O7—P2—O6B108.8 (12)
C5—C6—H6120.7O8—P2—O6B125.5 (13)
C1—C6—H6120.7O7—P2—O5113.36 (6)
C2—N1—H1A109.5O8—P2—O5103.63 (6)
C2—N1—H1B109.5O6B—P2—O582.8 (13)
H1A—N1—H1B109.5O7—P2—O6105.14 (6)
C2—N1—H1C109.5O8—P2—O6109.93 (6)
H1A—N1—H1C109.5O5—P2—O6107.60 (6)
H1B—N1—H1C109.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O7i0.911.762.6726 (15)175
N1—H1B···O4ii0.911.882.7807 (15)172
N1—H1C···O2iii0.912.052.9155 (15)158
N2—H2A···O80.911.882.7886 (15)178
N2—H2B···O7iv0.911.842.7450 (15)178
N2—H2C···O40.911.752.6545 (15)175
O1—H1D···O2v0.841.902.6525 (14)148
O3—H3A···O8vi0.841.792.5863 (14)158
O5—H5···O8vii0.842.002.6585 (14)134
O6—H6A···O20.841.792.5841 (14)156
O6B—H6B···O20.841.842.63 (3)157
Symmetry codes: (i) x+3, y1/2, z+3/2; (ii) x+2, y+1/2, z+3/2; (iii) x+3, y+1/2, z+3/2; (iv) x1, y, z; (v) x1/2, y1/2, z+1; (vi) x, y1, z; (vii) x+1/2, y+1/2, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O7i0.911.762.6726 (15)175.2
N1—H1B···O4ii0.911.882.7807 (15)172.3
N1—H1C···O2iii0.912.052.9155 (15)158.1
N2—H2A···O80.911.882.7886 (15)178.0
N2—H2B···O7iv0.911.842.7450 (15)177.7
N2—H2C···O40.911.752.6545 (15)174.8
O1—H1D···O2v0.841.902.6525 (14)148.0
O3—H3A···O8vi0.841.792.5863 (14)157.8
O5—H5···O8vii0.842.002.6585 (14)134.2
O6—H6A···O20.841.792.5841 (14)155.9
O6B—H6B···O20.841.842.63 (3)157.4
Symmetry codes: (i) x+3, y1/2, z+3/2; (ii) x+2, y+1/2, z+3/2; (iii) x+3, y+1/2, z+3/2; (iv) x1, y, z; (v) x1/2, y1/2, z+1; (vi) x, y1, z; (vii) x+1/2, y+1/2, z+1.
Acknowledgements top

The authors acknowledge the support provided by the Secretary of State for Scientific Research and Technology of Tunisia. The diffractometer was funded by NSF grant No. 0087210, by Ohio Board of Regents grant CAP-491, and by YSU.

references
References top

Bondi, A. (1964). J. Phys. Chem. 68, 441–451.

Bruker (2011). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.

Chtioui, A. & Jouini, A. (2006). Mater. Res. Bull. 41, 569–575.

Flack, H. D. (1983). Acta Cryst. A39, 876–881.

Hübschle, C. B., Sheldrick, G. M. & Dittrich, B. (2011). J. Appl. Cryst. 44, 1281–1284.

Kaabi, K., Ben Nasr, C. & Lefebvre, F. (2004). Mater. Res. Bull. 39, 205–215.

Masse, R., Bagieu-Beucher, M., Pecaut, J., Levy, J. P. & Zyss, J. (1993). Nonlinear Opt. 5, 413–423.

Metrangolo, P. & Resnati, G. (2001). Chem. Eur. J. 7, 2511–2519.

Metrangolo, P. & Resnati, G. (2008). Science (Washington, DC), 321, 918–919.

Oueslati, A., Ben Nasr, C., Durif, A. & Lefebvre, F. (2005). Mater. Res. Bull. 39, 970–980.

Politzer, P., Lane, P., Concha, M. C., Ma, Y. & Murray, J. S. (2007). J. Mol. Model. 13, 305–311.

Rayes, A., Ben Nasr, C. & Rzaigui, M. (2004). Mater. Res. Bull. 39, 1113–1121.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.