Acta Cryst. (2011). E67, o1651-o1652 [ doi:10.1107/S1600536811022239 ]
The asymmetric unit of the second polymorph of the title compound, C2H9NO6P2, contains one molecule existing as a zwitterion. The N atom of the ammonio group is protonated and one of the phosphonic acid groups is deprotonated. Bond lengths and angles are similar in both polymorphs. Besides the differences in cell parameters, the most significant structural difference between this structure and that of the first polymorph [Dudko, Bon, Kozachkova, Tsarik & Pekhno (2008), Ukr. Khim. Zh. 74, 104-106] is the presence of strong symmetric hydrogen bonds between neighbouring phosphonate groups. H atoms involved in these hydrogen bonds are located at inversion centres and O
O distances are observed in the range 2.458 (5)-2.523 (5) Å. These bonds and additional O-HO and N-HO hydrogen bonds interlink the molecules, giving a three-dimensional supromolecular network.
The title compound C2H9NO6P2, was obtained by the reaction of acetonitrile which was brought into contact with the dry hydrogen chloride and phosphorus trichloride at 278 K followed by the dropwise addition of water. The obtained solution was treated by a mixture of acetone and diethyl ether, resulting in a white precipitate of the title compound. The resulting residue was dissolved in water and was stored in a dark place for slow evaporation. After 14 d of staying, suitable crystals for X-ray data collection were obtained.
H atoms bonded to O and N atoms were located in a difference Fourier map. Their positions were refined freely whereas thermal parameters were fixed to Uiso(H) = 1.5Ueq(N,O). Other H atoms which bonded to C were positioned geometrically and refined using a riding model with C—H = 0.96 Å for CH3 with Uiso(H) = 1.5Ueq(C).
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
![[Figure 1]](./im2293fig1thm.gif)
| Fig. 1. View of the molecular structure of the title compound. Ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii. |
![[Figure 2]](./im2293fig2thm.gif)
| Fig. 2. Crystal packing of title compound, projection along b axis. Dashed pink lines indicate symmetrical hydrogen bonds while dashed yellow lines indicate ordinary hydrogen bonds. |
| C2H9NO6P2 | Z = 2 |
| Mr = 205.04 | F(000) = 212 |
| Triclinic, P1 | Dx = 1.889 Mg m−3 |
| Hall symbol: -P 1 | Melting point: 551 K |
| a = 5.5674 (11) Å | Mo Kα radiation, λ = 0.71073 Å |
| b = 5.9023 (12) Å | Cell parameters from 1315 reflections |
| c = 11.385 (2) Å | θ = 3.6–25.3° |
| α = 82.334 (10)° | µ = 0.59 mm−1 |
| β = 82.145 (9)° | T = 296 K |
| γ = 78.148 (10)° | Needle, colourless |
| V = 360.56 (12) Å3 | 0.56 × 0.16 × 0.09 mm |
| Bruker APEXII CCD diffractometer | 1401 independent reflections |
| Radiation source: fine-focus sealed tube | 861 reflections with I > 2σ(I) |
| graphite | Rint = 0.058 |
| φ and ω scans | θmax = 26.0°, θmin = 1.8° |
| Absorption correction: multi-scan (SADABS; Bruker, 2007) | h = −6→6 |
| Tmin = 0.734, Tmax = 0.949 | k = −7→7 |
| 4331 measured reflections | l = −12→14 |
| 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)] = 0.049 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.122 | H atoms treated by a mixture of independent and constrained refinement |
| S = 1.06 | w = 1/[σ2(Fo2) + (0.0387P)2 + 0.6717P] where P = (Fo2 + 2Fc2)/3 |
| 1401 reflections | (Δ/σ)max < 0.001 |
| 116 parameters | Δρmax = 0.45 e Å−3 |
| 0 restraints | Δρmin = −0.43 e Å−3 |
| C2H9NO6P2 | γ = 78.148 (10)° |
| Mr = 205.04 | V = 360.56 (12) Å3 |
| Triclinic, P1 | Z = 2 |
| a = 5.5674 (11) Å | Mo Kα radiation |
| b = 5.9023 (12) Å | µ = 0.59 mm−1 |
| c = 11.385 (2) Å | T = 296 K |
| α = 82.334 (10)° | 0.56 × 0.16 × 0.09 mm |
| β = 82.145 (9)° |
| Bruker APEXII CCD diffractometer | 1401 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2007) | 861 reflections with I > 2σ(I) |
| Tmin = 0.734, Tmax = 0.949 | Rint = 0.058 |
| 4331 measured reflections | θmax = 26.0° |
| R[F2 > 2σ(F2)] = 0.049 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.122 | Δρmax = 0.45 e Å−3 |
| S = 1.06 | Δρmin = −0.43 e Å−3 |
| 1401 reflections | Absolute structure: ? |
| 116 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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. |
| x | y | z | Uiso*/Ueq | ||
| P1 | 0.4512 (2) | −0.0726 (2) | 0.18108 (11) | 0.0243 (4) | |
| P2 | 0.2798 (2) | 0.2733 (2) | 0.36756 (11) | 0.0266 (4) | |
| O1 | 0.3269 (6) | −0.1949 (6) | 0.1024 (3) | 0.0327 (9) | |
| H1O | 0.337 (11) | −0.133 (11) | 0.034 (5) | 0.049* | |
| O2 | 0.6470 (5) | 0.0492 (6) | 0.1152 (3) | 0.0337 (9) | |
| O3 | 0.5438 (7) | −0.2366 (6) | 0.2838 (4) | 0.0475 (11) | |
| H3O | 0.531 (12) | −0.379 (12) | 0.301 (6) | 0.071* | |
| O4 | 0.5260 (5) | 0.3445 (5) | 0.3268 (3) | 0.0236 (8) | |
| O5 | 0.2923 (6) | 0.0865 (7) | 0.4724 (3) | 0.0344 (9) | |
| H5O | 0.5000 | 0.0000 | 0.5000 | 0.052* | |
| O6 | 0.0723 (6) | 0.4792 (7) | 0.3914 (3) | 0.0421 (10) | |
| H6O | 0.0000 | 0.5000 | 0.5000 | 0.063* | |
| N1 | −0.0104 (8) | 0.0192 (9) | 0.2928 (4) | 0.0287 (11) | |
| H1A | −0.086 (10) | −0.025 (9) | 0.237 (5) | 0.043* | |
| H1B | −0.151 (10) | 0.102 (10) | 0.316 (5) | 0.043* | |
| H1C | 0.030 (10) | −0.091 (10) | 0.342 (5) | 0.043* | |
| C1 | 0.1979 (8) | 0.1433 (8) | 0.2439 (4) | 0.0195 (10) | |
| C2 | 0.1069 (9) | 0.3297 (8) | 0.1441 (4) | 0.0278 (12) | |
| H2A | 0.0827 | 0.2556 | 0.0776 | 0.042* | |
| H2B | 0.2276 | 0.4265 | 0.1191 | 0.042* | |
| H2C | −0.0464 | 0.4235 | 0.1730 | 0.042* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| P1 | 0.0236 (7) | 0.0195 (7) | 0.0316 (7) | −0.0033 (5) | −0.0072 (6) | −0.0066 (6) |
| P2 | 0.0204 (7) | 0.0387 (9) | 0.0230 (7) | −0.0080 (6) | −0.0030 (5) | −0.0074 (6) |
| O1 | 0.038 (2) | 0.028 (2) | 0.037 (2) | −0.0124 (17) | −0.0077 (18) | −0.0095 (17) |
| O2 | 0.0203 (18) | 0.045 (2) | 0.042 (2) | −0.0155 (16) | 0.0069 (16) | −0.0208 (18) |
| O3 | 0.065 (3) | 0.016 (2) | 0.068 (3) | −0.0036 (19) | −0.042 (2) | 0.002 (2) |
| O4 | 0.0182 (16) | 0.0200 (18) | 0.0344 (19) | −0.0022 (13) | −0.0056 (14) | −0.0091 (15) |
| O5 | 0.0272 (19) | 0.055 (2) | 0.0241 (18) | −0.0172 (17) | −0.0077 (15) | 0.0035 (17) |
| O6 | 0.0231 (19) | 0.067 (3) | 0.034 (2) | 0.0124 (18) | −0.0057 (16) | −0.0270 (19) |
| N1 | 0.017 (2) | 0.036 (3) | 0.033 (3) | −0.009 (2) | −0.006 (2) | 0.005 (2) |
| C1 | 0.016 (2) | 0.022 (3) | 0.022 (2) | −0.0064 (19) | −0.0040 (19) | 0.000 (2) |
| C2 | 0.031 (3) | 0.023 (3) | 0.027 (3) | 0.000 (2) | −0.007 (2) | −0.001 (2) |
| P1—O2 | 1.490 (3) | O5—H5O | 1.229 (0) |
| P1—O3 | 1.493 (4) | O6—H6O | 1.261 (0) |
| P1—O1 | 1.533 (4) | N1—C1 | 1.502 (6) |
| P1—C1 | 1.831 (5) | N1—H1A | 0.90 (6) |
| P2—O4 | 1.510 (3) | N1—H1B | 0.86 (6) |
| P2—O5 | 1.512 (4) | N1—H1C | 0.82 (6) |
| P2—O6 | 1.520 (3) | C1—C2 | 1.534 (6) |
| P2—C1 | 1.840 (4) | C2—H2A | 0.9600 |
| O1—H1O | 0.81 (6) | C2—H2B | 0.9600 |
| O3—H3O | 0.85 (7) | C2—H2C | 0.9600 |
| O2—P1—O3 | 111.7 (2) | C1—N1—H1B | 118 (4) |
| O2—P1—O1 | 114.3 (2) | H1A—N1—H1B | 87 (4) |
| O3—P1—O1 | 110.8 (2) | C1—N1—H1C | 113 (4) |
| O2—P1—C1 | 109.0 (2) | H1A—N1—H1C | 110 (5) |
| O3—P1—C1 | 106.5 (2) | H1B—N1—H1C | 111 (6) |
| O1—P1—C1 | 103.86 (19) | N1—C1—C2 | 107.8 (4) |
| O4—P2—O5 | 112.46 (18) | N1—C1—P1 | 107.2 (3) |
| O4—P2—O6 | 112.8 (2) | C2—C1—P1 | 109.4 (3) |
| O5—P2—O6 | 111.7 (2) | N1—C1—P2 | 107.4 (3) |
| O4—P2—C1 | 107.07 (18) | C2—C1—P2 | 111.7 (3) |
| O5—P2—C1 | 106.2 (2) | P1—C1—P2 | 113.1 (2) |
| O6—P2—C1 | 105.98 (19) | C1—C2—H2A | 109.5 |
| P1—O1—H1O | 110 (4) | C1—C2—H2B | 109.5 |
| P1—O3—H3O | 128 (4) | H2A—C2—H2B | 109.5 |
| P2—O5—H5O | 115.9 (0) | C1—C2—H2C | 109.5 |
| P2—O6—H6O | 115.1 (0) | H2A—C2—H2C | 109.5 |
| C1—N1—H1A | 115 (3) | H2B—C2—H2C | 109.5 |
| O2—P1—C1—N1 | 171.5 (3) | O4—P2—C1—N1 | 166.1 (3) |
| O3—P1—C1—N1 | −67.9 (3) | O5—P2—C1—N1 | 45.8 (3) |
| O1—P1—C1—N1 | 49.2 (3) | O6—P2—C1—N1 | −73.2 (4) |
| O2—P1—C1—C2 | 54.9 (4) | O4—P2—C1—C2 | −76.0 (3) |
| O3—P1—C1—C2 | 175.5 (3) | O5—P2—C1—C2 | 163.7 (3) |
| O1—P1—C1—C2 | −67.4 (3) | O6—P2—C1—C2 | 44.7 (4) |
| O2—P1—C1—P2 | −70.3 (3) | O4—P2—C1—P1 | 48.0 (3) |
| O3—P1—C1—P2 | 50.3 (3) | O5—P2—C1—P1 | −72.4 (3) |
| O1—P1—C1—P2 | 167.4 (2) | O6—P2—C1—P1 | 168.7 (2) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O1—H1O···O2i | 0.81 (6) | 1.70 (6) | 2.507 (5) | 170 (6) |
| O3—H3O···O4ii | 0.85 (7) | 1.63 (7) | 2.475 (5) | 175 (7) |
| O5—H5O···O5iii | 1.23 (1) | 1.23 (1) | 2.458 (5) | 180 (0) |
| O6—H6O···O6iv | 1.26 (1) | 1.26 (1) | 2.523 (6) | 180 (1) |
| N1—H1A···O2v | 0.90 (6) | 2.11 (6) | 2.929 (6) | 150 (5) |
| N1—H1B···O4v | 0.86 (6) | 2.06 (6) | 2.896 (5) | 165 (5) |
| N1—H1C···O6ii | 0.82 (6) | 2.50 (6) | 3.196 (6) | 145 (5) |
| Symmetry codes: (i) −x+1, −y, −z; (ii) x, y−1, z; (iii) −x+1, −y, −z+1; (iv) −x, −y+1, −z+1; (v) x−1, y, z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O1—H1O···O2i | 0.81 (6) | 1.70 (6) | 2.507 (5) | 170 (6) |
| O3—H3O···O4ii | 0.85 (7) | 1.63 (7) | 2.475 (5) | 175 (7) |
| O5—H5O···O5iii | 1.23 (1) | 1.23 (1) | 2.458 (5) | 180 (0) |
| O6—H6O···O6iv | 1.26 (1) | 1.26 (1) | 2.523 (6) | 180 (1) |
| N1—H1A···O2v | 0.90 (6) | 2.11 (6) | 2.929 (6) | 150 (5) |
| N1—H1B···O4v | 0.86 (6) | 2.06 (6) | 2.896 (5) | 165 (5) |
| N1—H1C···O6ii | 0.82 (6) | 2.50 (6) | 3.196 (6) | 145 (5) |
| Symmetry codes: (i) −x+1, −y, −z; (ii) x, y−1, z; (iii) −x+1, −y, −z+1; (iv) −x, −y+1, −z+1; (v) x−1, y, z. |
The authors gratefully acknowledge Dr V. V. Bon for his help with the preparation of this article.
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Diphosphonic acids with the P–C–P fragment, commonly named bisphosphonates, are well known since the 19th century. Due to the specific geometry and mutual influence of phosphonate fragments, compounds of this class possess a number of unique properties compared to other derivatives of phosphonic acids. Diphosphonic acids are structural analogues of inorganic pyrophosphate, one of the major metabolites in the cells, involved as a product in more than sixty biochemical reactions. Drugs prepared on the basis of bisphosphonates are highly efficient as a regulator of calcium metabolism and the immune response, they are used as anti-neoplastic, anti-inflammatory and antiviral agents and drugs with analgesic effect and as a component of toothpastes biphosphonates prevent the formation of tartar (Matkovskaya et al., 2001).
However, it is still not clearly understood why small structural modifications of the bisphosphonates may lead to extensive alterations in their physicochemical, biological and toxicological characteristics (Matczak-Jon & Videnova-Adrabinska, 2005). As a consequence of that determination of the structure of the bisphosphonates is very important to understand the influence of structural modifications on complex-forming abilities and physiological activities and deriving structure properties relations in general. In the present work we report a second polymorph of the title compound which crystallizes in the space group (P1) whereas the previously described polymorph modification also crystallizes in the triclinic space group P1 but with different cell parameters and cell volume (Dudko et al., 2008). The asymmetric unit of the title compound (Fig. 1) contains one molecule in zwitterionic form with a proton transferred from one of the phosphonic groups to the amino group which is typical for all investigated 1-aminodiphosphonic acids (Fernández et al., 2003; Li et al., 2009). Bond lengths and angles are within normal ranges (Allen et al., 1987) and are comparable with the first polymorph modification of the compound. It is generally accepted that, for O—H—O interactions where O···O is about 2.50 Å, examples can be found of truly symmetric hydrogen bonds, most of which have crystallographic equivalence between donor–acceptor atoms (Meot-Ner, 2005; Catti & Ferraris, 1976). The title compound, displays such short and strong symmetric hydrogen bonds between neighboring phosphonate groups, with the H atoms located at inversion centres and O···O distances of 2.458 (5) and 2,523 (5) Å. Multiple N—H···O and O—H···O hydrogen bonds in the crystal structure form an intricate three-dimensional supramolecular network (Fig.2, Table 1).