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Acta Cryst. (2011). E67, o101    [ doi:10.1107/S1600536810051159 ]

2,6-Diethylanilinium dihydrogen phosphate-phosphoric acid (1/1)

H. Khemiri, S. T. Akriche, S. S. Al-Deyab and M. Rzaigui

Abstract top

In the crystal structure of the title salt, C10H16N+·H2PO4-·H3PO4, the H2PO4- and H3PO4 components are connected into infinite chains extending along the b-axis direction by way of O-H...O links. These chains are also linked through O-H...O hydrogen bonds thus building up a supramolecular two-dimensional framework extending parallel to (001). The organic cations cross-link the anionic layers by way of multiple N-H...O interactions, leading to a cohesive network.

Comment top

The H3PO4 molecules play an important role for structure cohesion of adduct materials, by connecting the other components of crystal by a network of hydrogen bonds particularly strong (Desiraju, 1995; Blessing, 1986). Such hydrogen bonds are of interest because of their widespread biological occurrence. For example, hydrogen bonds between phosphate groups and histidyl, imidazolyl groups are involved in the active-site substrate-binding mechanism of ribonuclease (Richards et al., 1972) and in the regulation of the oxygen affinity of deoxyhemoglobin by 2,3-diphosphoglycerate (Perutz et al., 1972). The influence of the hydrogen bond scheme on the building of supramolecular anionic packing for the title compound is discussed with regard to other adduct phosphates.

The asymmetric unit of (I) consists of two phosphoric entities (H2PO4- and H3PO4) and one 2,6-diethylanilinium organic cation (Fig. 1). A view of the structure projected along the b direction (Fig. 2) shows that inorganic layers are built by H2PO4- anions and H3PO4 molecules. Via O2—H2···O1 and O6—H6···O7 intermolecular hydrogen bonds, each phosphoric entity form a corrugated chain extending along the b-axis. These undulating chains are further linked through O3—H3···O8, O4—H4···O7 and O5—H5···O1 hydrogen bonds with short distances varying between 1.72 and 1.86 Å (Table 1), thus building up an extended supramolecular two-dimensional framework parallel to the ab plane. This topology is slightly different from that of (C6H14N)H2PO4H3PO4 (Belam et al., 2005) adduct one, where the H2PO4- anions and H3PO4 molecules are connected alternatively by O—H···O hydrogen bonds to form infinite corrugated chains parallel to the c direction.

It is also useful to compare the geometrical parameters of phosphoric entities in the title compound and in the crystallized H3PO4 (Mighell et al., 1969; Smith et al., 1955). This comparison does not show significant differences that could be generated by the organic molecule in the provided geometric properties of these species. The 2,6-diethylanilinium cations are pendant on both the faces of the two-dimensional inorganic sheet by establishing intermolecular N—H···O hydrogen bonds thanks to the NH3+ group. Among the three hydrogen atoms of the ammonium group only one, establishes a hydrogen bond with the H3PO4 molecule. The remaining ones are connected to oxygen atoms of H2PO4- anions.

The geometrical hydrogen bonding scheme are given in Table 1. Examination of geometrical features of the organic entity shows that bond lengths and angles exhibit no deviations from the usually values observed in others related 2,6-diethylanilinium structures (C10H16N)ClO4 (Smirani Sta et al., 2010) and (C10H16N)2H2P2O7.2H2O (Akriche et al., 2008).

Related literature top

For hydrogen bonds, see: Blessing (1986); Desiraju (1995). For their biological occurence, see: Richards et al. (1972); Perutz et al. (1972). For related phosphoric structures, see: Belam et al. (2005); Mighell et al. (1969); Smith et al. (1955). For related organic cations, see: Akriche & Rzaigui (2008); Smirani Sta et al. (2010).

Experimental top

A solution of orthophosphoric acid (0,50 mmol in 30 ml of water) was added drop by drop to an ethanolic solution (5 ml) of 2,6-diethylaniline (2,488 mmol in 5 ml of ethanol). The so-obtained solution is kept in a sealed tube for three days and then submitted to a slow evaporation until the formation of good quality crystals, stable under normal conditions of temperature and moisture.

Refinement top

All H atoms attached to C, N and O atoms were fixed geometrically and treated as riding with C—H = 0.93 Å, N—H= 0.86 Å and O—H = 0.86 Å with Uiso(H) = 1.2 Ueq(C, N or O).

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. View of (I) with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii. Hydrogen bonds are represented as dashed lines.
[Figure 2] Fig. 2. Projection of (I) along the a axis. The H-atoms not involved in H-bonding are omitted. H bonds are shown as dashed lines.
2,6-Diethylanilinium dihydrogen phosphate–phosphoric acid (1/1) top
Crystal data top
C10H16N+·H2O4P−·H3O4PF(000) = 728
Mr = 345.22Dx = 1.455 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 25 reflections
a = 8.1634 (10) Åθ = 9–11°
b = 7.707 (2) ŵ = 0.31 mm−1
c = 25.680 (6) ÅT = 293 K
β = 102.686 (19)°Prism, colourless
V = 1576.2 (6) Å30.45 × 0.30 × 0.20 mm
Z = 4
Data collection top
Enraf–Nonius TurboCAD-4
diffractometer		Rint = 0.011
Radiation source: fine-focus sealed tubeθmax = 25.0°, θmin = 2.6°
graphiteh = −9→9
non–profiled ω scansk = −9→0
5173 measured reflectionsl = −30→26
2776 independent reflections2 standard reflections every 120 min
2417 reflections with I > 2σ(I) intensity decay: 4%
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)] = 0.036Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.104H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0631P)2 + 0.6675P]
where P = (Fo2 + 2Fc2)/3
2776 reflections(Δ/σ)max = 0.001
198 parametersΔρmax = 0.27 e Å−3
0 restraintsΔρmin = −0.47 e Å−3
Crystal data top
C10H16N+·H2O4P−·H3O4PV = 1576.2 (6) Å3
Mr = 345.22Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.1634 (10) ŵ = 0.31 mm−1
b = 7.707 (2) ÅT = 293 K
c = 25.680 (6) Å0.45 × 0.30 × 0.20 mm
β = 102.686 (19)°
Data collection top
Enraf–Nonius TurboCAD-4
diffractometer		Rint = 0.011
5173 measured reflectionsθmax = 25.0°
2776 independent reflections2 standard reflections every 120 min
2417 reflections with I > 2σ(I) intensity decay: 4%
Refinement top
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.104Δρmax = 0.27 e Å−3
S = 1.06Δρmin = −0.47 e Å−3
2776 reflectionsAbsolute structure: ?
198 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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.

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
P10.89551 (6)0.42643 (7)0.69762 (2)0.02954 (17)
P20.57483 (6)0.63702 (6)0.78754 (2)0.02854 (16)
O10.90841 (18)0.36241 (19)0.75328 (6)0.0396 (4)
O20.9067 (2)0.6272 (2)0.69495 (7)0.0520 (5)
H20.98500.66160.71840.078*
O30.72469 (17)0.39370 (19)0.65968 (6)0.0391 (4)
H30.67830.31130.67060.059*
O41.0255 (2)0.3435 (3)0.67058 (7)0.0600 (5)
H41.11760.34370.69130.090*
O50.69580 (18)0.48369 (19)0.80976 (6)0.0388 (4)
H50.75480.46120.78860.058*
O60.49043 (19)0.59476 (19)0.72822 (6)0.0387 (4)
H60.43720.50410.72690.058*
O70.66900 (17)0.80396 (18)0.78532 (7)0.0400 (4)
O80.44861 (18)0.63937 (18)0.82220 (6)0.0379 (4)
N10.6019 (2)0.8023 (2)0.64703 (7)0.0376 (4)
H1A0.52470.74060.65850.056*
H1B0.59390.91330.65580.056*
H1C0.70360.76260.66210.056*
C10.5743 (3)0.7867 (3)0.58854 (9)0.0389 (5)
C20.4324 (3)0.7015 (3)0.56111 (10)0.0469 (6)
C30.4120 (4)0.6914 (3)0.50585 (11)0.0575 (7)
H3A0.31830.63560.48560.069*
C40.5292 (4)0.7631 (4)0.48074 (10)0.0613 (7)
H4A0.51360.75460.44390.074*
C50.6679 (4)0.8466 (3)0.50942 (10)0.0555 (7)
H5A0.74530.89380.49170.067*
C60.6953 (3)0.8624 (3)0.56494 (9)0.0452 (6)
C70.3079 (4)0.6215 (4)0.59107 (12)0.0626 (7)
H7A0.36500.52910.61360.075*
H7B0.27830.70950.61440.075*
C80.1485 (4)0.5490 (5)0.55760 (15)0.0829 (10)
H8A0.08730.63980.53620.124*
H8B0.08120.50130.58040.124*
H8C0.17500.45940.53480.124*
C90.8439 (4)0.9572 (4)0.59828 (11)0.0589 (7)
H9A0.80111.04950.61730.071*
H9B0.90360.87680.62480.071*
C100.9693 (4)1.0357 (5)0.56996 (13)0.0706 (8)
H10A1.02190.94530.55370.106*
H10B1.05321.09770.59520.106*
H10C0.91281.11430.54290.106*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
P10.0263 (3)0.0247 (3)0.0378 (3)0.00059 (19)0.0075 (2)0.0007 (2)
P20.0267 (3)0.0179 (3)0.0428 (3)0.00200 (18)0.0113 (2)0.0022 (2)
O10.0415 (8)0.0350 (8)0.0435 (8)0.0127 (6)0.0116 (7)0.0082 (6)
O20.0617 (11)0.0258 (9)0.0574 (11)−0.0121 (7)−0.0108 (8)0.0056 (7)
O30.0319 (8)0.0319 (8)0.0508 (9)−0.0057 (6)0.0033 (7)0.0076 (7)
O40.0376 (9)0.0916 (15)0.0514 (10)0.0181 (9)0.0113 (7)−0.0113 (10)
O50.0412 (8)0.0293 (8)0.0496 (9)0.0141 (6)0.0182 (7)0.0093 (7)
O60.0469 (9)0.0261 (8)0.0437 (8)−0.0069 (6)0.0111 (7)0.0043 (6)
O70.0295 (7)0.0216 (7)0.0689 (10)−0.0021 (6)0.0105 (7)0.0031 (7)
O80.0375 (8)0.0277 (8)0.0533 (9)0.0065 (6)0.0203 (7)0.0026 (7)
N10.0473 (10)0.0293 (9)0.0390 (10)0.0005 (8)0.0154 (8)0.0022 (7)
C10.0564 (13)0.0247 (10)0.0368 (11)0.0084 (9)0.0130 (10)0.0011 (8)
C20.0609 (14)0.0301 (12)0.0472 (13)0.0067 (11)0.0065 (11)0.0013 (10)
C30.0760 (18)0.0397 (14)0.0497 (15)0.0056 (13)−0.0014 (13)−0.0045 (11)
C40.101 (2)0.0459 (15)0.0362 (13)0.0114 (15)0.0134 (14)−0.0023 (11)
C50.0851 (19)0.0433 (14)0.0443 (14)0.0056 (13)0.0279 (13)0.0005 (11)
C60.0645 (15)0.0335 (12)0.0421 (12)0.0054 (10)0.0215 (11)0.0010 (10)
C70.0640 (17)0.0617 (18)0.0573 (16)−0.0121 (14)0.0027 (13)0.0002 (13)
C80.074 (2)0.079 (2)0.089 (2)−0.0143 (18)0.0033 (18)−0.0070 (19)
C90.0748 (18)0.0567 (16)0.0522 (15)−0.0140 (14)0.0290 (13)−0.0032 (12)
C100.077 (2)0.077 (2)0.0653 (18)−0.0115 (17)0.0303 (15)0.0042 (16)
Geometric parameters (Å, °) top
P1—O11.4937 (16)C2—C71.532 (4)
P1—O41.5296 (16)C3—C41.381 (4)
P1—O31.5364 (15)C3—H3A0.9300
P1—O21.5525 (17)C4—C51.368 (4)
P2—O81.5022 (15)C4—H4A0.9300
P2—O71.5063 (15)C5—C61.399 (3)
P2—O61.5622 (16)C5—H5A0.9300
P2—O51.5652 (14)C6—C91.511 (4)
O2—H20.8200C7—C81.501 (4)
O3—H30.8200C7—H7A0.9700
O4—H40.8200C7—H7B0.9700
O5—H50.8200C8—H8A0.9600
O6—H60.8200C8—H8B0.9600
N1—C11.474 (3)C8—H8C0.9600
N1—H1A0.8900C9—C101.507 (4)
N1—H1B0.8900C9—H9A0.9700
N1—H1C0.8900C9—H9B0.9700
C1—C21.382 (3)C10—H10A0.9600
C1—C61.395 (3)C10—H10B0.9600
C2—C31.394 (4)C10—H10C0.9600
O1—P1—O4112.72 (10)C5—C4—H4A119.6
O1—P1—O3114.58 (9)C3—C4—H4A119.6
O4—P1—O3105.49 (10)C4—C5—C6121.2 (3)
O1—P1—O2112.27 (10)C4—C5—H5A119.4
O4—P1—O2110.04 (12)C6—C5—H5A119.4
O3—P1—O2100.93 (9)C1—C6—C5115.9 (2)
O8—P2—O7115.74 (9)C1—C6—C9120.9 (2)
O8—P2—O6111.54 (9)C5—C6—C9123.2 (2)
O7—P2—O6105.11 (9)C8—C7—C2116.7 (3)
O8—P2—O5104.66 (8)C8—C7—H7A108.1
O7—P2—O5111.86 (9)C2—C7—H7A108.1
O6—P2—O5107.82 (9)C8—C7—H7B108.1
P1—O2—H2109.5C2—C7—H7B108.1
P1—O3—H3109.5H7A—C7—H7B107.3
P1—O4—H4109.5C7—C8—H8A109.5
P2—O5—H5109.5C7—C8—H8B109.5
P2—O6—H6109.5H8A—C8—H8B109.5
C1—N1—H1A109.5C7—C8—H8C109.5
C1—N1—H1B109.5H8A—C8—H8C109.5
H1A—N1—H1B109.5H8B—C8—H8C109.5
C1—N1—H1C109.5C10—C9—C6117.8 (2)
H1A—N1—H1C109.5C10—C9—H9A107.8
H1B—N1—H1C109.5C6—C9—H9A107.8
C2—C1—C6124.9 (2)C10—C9—H9B107.8
C2—C1—N1118.8 (2)C6—C9—H9B107.8
C6—C1—N1116.4 (2)H9A—C9—H9B107.2
C1—C2—C3116.4 (2)C9—C10—H10A109.5
C1—C2—C7120.6 (2)C9—C10—H10B109.5
C3—C2—C7123.0 (2)H10A—C10—H10B109.5
C4—C3—C2120.8 (3)C9—C10—H10C109.5
C4—C3—H3A119.6H10A—C10—H10C109.5
C2—C3—H3A119.6H10B—C10—H10C109.5
C5—C4—C3120.9 (2)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O1i0.821.842.540 (2)142
O3—H3···O8ii0.821.722.520 (2)166
O4—H4···O7iii0.821.742.521 (2)158
O5—H5···O10.821.862.664 (2)165
O6—H6···O7ii0.821.762.577 (2)171
N1—H1A···O60.892.182.927 (2)141
N1—H1B···O8iv0.891.892.772 (2)172
N1—H1C···O20.891.982.861 (3)168
Symmetry codes: (i) −x+2, y+1/2, −z+3/2; (ii) −x+1, y−1/2, −z+3/2; (iii) −x+2, y−1/2, −z+3/2; (iv) −x+1, y+1/2, −z+3/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O1i0.821.842.540 (2)142
O3—H3···O8ii0.821.722.520 (2)166
O4—H4···O7iii0.821.742.521 (2)158
O5—H5···O10.821.862.664 (2)165
O6—H6···O7ii0.821.762.577 (2)171
N1—H1A···O60.892.182.927 (2)141
N1—H1B···O8iv0.891.892.772 (2)172
N1—H1C···O20.891.982.861 (3)168
Symmetry codes: (i) −x+2, y+1/2, −z+3/2; (ii) −x+1, y−1/2, −z+3/2; (iii) −x+2, y−1/2, −z+3/2; (iv) −x+1, y+1/2, −z+3/2.
references
References top

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