Methyl­phospho­nic acid, CH3PO(OH)2

Reuter, H.; Reichelt, M.

doi:10.1107/S1600536814003572

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 70| Part 3| March 2014| Page o353

doi:10.1107/S1600536814003572

Open

access

Methylphosphonic acid, CH₃PO(OH)₂

Hans Reuter ^a ^* and Martin Reichelt ^a

^aInstitute of Chemistry of New Materials, University of Osnabrück, Barbarastrasse 7, 49069 Osnabrück, Germany
^*Correspondence e-mail: hreuter@uos.de

(Received 12 February 2014; accepted 17 February 2014; online 26 February 2014)

The asymmetric unit of the title compound, CH₅O₃P, contains two independent molecules with nearly identical bond lengths and angles. In the crystal, each of the molecules acts as acceptor (P=O) and donor (P—OH) of four hydrogen bonds to three adjacent molecules, resulting in the formation of two different bilayers (one for each molecule) stacked perpendicular to the a axis in the crystal.

CCDC reference: 987419

Related literature

For organic and inorganic tin compounds of methyl phosphonic acid, see: Adair et al. (1998 ); Ribot et al. (2001 ). For structural data on phenyl phosphonic acid, see: Weakley (1976 ); Mahmoudkhani & Langer (2002 ). For a brief communication on the unit-cell parameters of methyl phosphonic acid, see: Kodolov et al. (1977 ). For comparative studies of dimeric carboxylic acids, see: Allan et al. (2000); Bruno & Randaccio (1980 ).

Experimental

Crystal data

CH₅O₃P
M_r = 96.02
Monoclinic, P 2₁ /c
a = 15.1015 (8) Å
b = 5.7704 (3) Å
c = 9.9549 (6) Å
β = 108.262 (2)°
V = 823.79 (8) Å³
Z = 8
Mo Kα radiation
μ = 0.51 mm⁻¹
T = 200 K
0.45 × 0.26 × 0.12 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ) T_min = 0.805, T_max = 0.942
58588 measured reflections
1989 independent reflections
1763 reflections with I > 2σ(I)
R_int = 0.075

Refinement

R[F² > 2σ(F²)] = 0.028
wR(F²) = 0.087
S = 1.08
1989 reflections
97 parameters
H-atom parameters constrained
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.35 e Å⁻³

Table 1
Selected bond lengths (Å)

P1—O13	1.4993 (11)
P1—O11	1.5441 (11)
P1—O12	1.5443 (12)
P1—C1	1.7586 (17)
P2—O23	1.4989 (11)
P2—O21	1.5478 (11)
P2—O22	1.5504 (12)
P2—C2	1.7612 (17)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O22—H22⋯O23ⁱ	0.96	1.59	2.5528 (15)	180
O21—H21⋯O23ⁱⁱ	0.96	1.65	2.5768 (16)	161
O12—H12⋯O13ⁱⁱⁱ	0.96	1.61	2.5649 (15)	174
O11—H11⋯O13^iv	0.96	1.62	2.5671 (16)	169
Symmetry codes: (i) -x, -y+2, -z+1; (ii) $[-x, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (iii) -x+1, -y+1, -z+1; (iv) $[-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006 ) and Mercury (Macrae et al., 2008 ); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Supporting information

CCDC reference: 987419

Crystal structure: contains datablocks I, New_Global_Publ_Block. DOI: 10.1107/S1600536814003572/hg5383sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536814003572/hg5383Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536814003572/hg5383Isup3.cml

checkCIF report

Experimental top

Synthesis and crystallization top

Single crystals of methyl phosphonic acid (Merck-Schuchardt) were obtained as side products from several experiments when we tried to growth singles crystals of diorganotin(IV) methyl phosphonates by solvent evaporation. A suitable single crystal was selected under a polarization microscope and mounted on a 50 µm MicroMesh MiTeGen Micromount^TM using FROMBLIN Y perfluoropolyether (LVAC 16/6, Aldrich).

Refinement top

All hydrogen atoms could be localized in difference Fourier synthesis. Those of the methyl groups were idealized and refined at calculated positions riding on the carbon atoms with C—H distance of 0.98 Å. Those of the hydroxyl groups were refined with respect to a common O—H distance of 0.96 Å before they were fixed and allowed to ride on the corresponding oxygen atoms. For the hydrogen atoms of each methyl group a common isotropic displacement parameter was refined as well as one common isotropic displacement parameter for the hydrogen atoms of all hydroxyl groups.

Results and discussion top

Methylphosphonic acid, CH₃PO(OH)₂, is a well-established reagent in inorganic as well as in organometallic chemistry forming numerous salts respectively coordination compounds with a lot of different metals and organometallic fragments. For an example, from tin(II) the synthesis and structural characterization of the mixed methylphosphonate oxalate Sn₂(MePO₃)(C₂O₄) was described by Adair et al. (1998) whereas diorganotin(IV) moieties will give rise to the formation of dimeric species like [Bu₂Sn(MePO(OH))₂]₂ as was shown by Ribot et al. (2001). During a systematic study on the complex formation of methylphosphonic acid towards other organotin(IV) compounds we became aware, that the crystal structure of the title compound was never determined in detail. Only Kodolov et al. (1977) referred in a brief communication to the cell parameters of a monoclinic unit cell but no atomic coordinates were given.

During our studies, we never were able to confirm these cell parameters, although we also found a monoclinic unit cell. Moreover, we observed a strong broadening and multiplication of the reflections on cooling down the crystal to 100 K. For this reason, we present the results of a measurement at T = 200 K, before reflection broadening started.

The asymmetric unit of the title compound consists of two crystallographic independent molecules (Fig. 1) with nearly identical geometrical parameters (Tab. 1). These values correspond very well with those of phenyl phosphonic acid that was determined by Mahmoudkhani et al. (2002) at T = 183 (2) K [d(P—O) = 1.536 (2) Å, 1.555 (2) Å; d(P=O) = 1.506 (2) Å and d(P—C) = 1.782 (3) Å] and Weakley (1976) at ambient temperature [d(P—O) = 1.539 (3) Å, 1.550 (4) Å; d(P=O) = 1.496 (4) Å and d(P—C) = 1.773 (5) Å]. With respect to bond angles at phosphorous, tetrahedral environment is much more distorted in the present compound [103.46 (8)° -112.94 (7)°] than in the corresponding phenyl compound [106.9 (2)° - 112.1 (2)°, Weakley (1976); 107.5 (1)°-111.7 (1)°, Mahmoudkhani et al. (2002)]

Each of the two molecules in the asymmetric unit is involved into four hydrogen bonds with molecules of the same kind giving rise to two different bilayers stacked perpendicular to the crystallographic a-axis (Fig. 2). Within each bilayer, each molecule of the upper layer is hydrogen bonded to three molecules of the lower layer and vice versa. In summary, the arrangement of the phosphorous atoms in each bilayer corresponds to the arrangement of the arsenic atoms in the double-layer structure of grey arsenic consisting of an extended network of fused, six-membered rings of arsenic atoms with chair conformation.

Two of the four hydrogen bonds of each molecule result from centrosymmetric dimers (Fig. 3) in which one hydroxyl group (O22—H22) acts as donor and the double-bonded oxygen atom (O22) as acceptor for almost linear hydrogen bonds with a bond angle H···O—P of about 120° at the double bonded oxygen atom. These dimers are very similar those found in carbonic acids like propionic acid (Allan et al. 2000) or benzoic acid (Bruno & Randaccio, 1980). The double bonded oxygen atoms, additionally, are involved into a second pair of intermolecular hydrogen bonds to the second hydroxyl group. These hydrogen bonds, also being less linear as the former one, are of similar length (Tab. 2).

Related literature top

For organic and inorganic tin compounds of methyl phosphonic acid, see: Adair et al. (1998); Ribot et al. (2001). For structural data on phenyl phosphonic acid, see: Weakley (1976); Mahmoudkhani & Langer (2002). For a brief communication on the unit-cell parameters of methyl phosphonic acid, see: Kodolov et al. (1977). For comparative studies of dimeric carboxylic acids, see: Allan et al. (2000); Bruno & Randaccio (1980).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. Ball-and-stick model of the two molecules in the asymmetric unit of the title compound with the atomic numbering scheme used; with exception of the hydrogen atoms, which are shown as spheres with a common isotropic radius, all other atoms are represented as thermal displacement ellipsoids at the 50% probability level; hydrogen bonds are indicated by broken sticks (red).
	Fig. 2. Simplified ball-and-stick model of the crystal packing of MePO(OH)₂ showing its bilayer structure; color code: oxygen = red, phosphorous = orange, carbon = dark grey, hydrogen = light grey; hydrogen bonds are shown as broken sticks (red).
	Fig. 3. Hydrogen bonding system in the bilayer of MePO(OH)₂ resulting from molecule 2; with exception of the hydrogen atoms, which are shown as spheres with a common isotropic radius, all other atoms are represented as thermal displacement ellipsoids at the 50% probability level; methyl groups are omitted for clarity; hydrogen bonds are indicated by broken sticks (red); small black balls = center of symmetry; symmetry transformations used to generate equivalent atoms: 1) -x, 2 - y, 1 - z; 2) -x, 1/2 + y, 3/2 - z; 3) -x, -1/2 + y, 3/2 - z.

Methylphosphonic acid top

Crystal data top

CH₅O₃P	F(000) = 400
M_r = 96.02	D_x = 1.548 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 9876 reflections
a = 15.1015 (8) Å	θ = 2.8–28.7°
b = 5.7704 (3) Å	µ = 0.51 mm⁻¹
c = 9.9549 (6) Å	T = 200 K
β = 108.262 (2)°	Rhomboidal plate, colourless
V = 823.79 (8) Å³	0.45 × 0.26 × 0.12 mm
Z = 8

Data collection top

Bruker APEXII CCD diffractometer	1989 independent reflections
Radiation source: fine-focus sealed tube	1763 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.075
φ and ω scans	θ_max = 28.0°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −19→19
T_min = 0.805, T_max = 0.942	k = −7→7
58588 measured reflections	l = −13→13

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.028	H-atom parameters constrained
wR(F²) = 0.087	w = 1/[σ²(F_o²) + (0.0446P)² + 0.3474P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max = 0.001
1989 reflections	Δρ_max = 0.33 e Å⁻³
97 parameters	Δρ_min = −0.35 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0089 (18)

Crystal data top

CH₅O₃P	V = 823.79 (8) Å³
M_r = 96.02	Z = 8
Monoclinic, P2₁/c	Mo Kα radiation
a = 15.1015 (8) Å	µ = 0.51 mm⁻¹
b = 5.7704 (3) Å	T = 200 K
c = 9.9549 (6) Å	0.45 × 0.26 × 0.12 mm
β = 108.262 (2)°

Data collection top

Bruker APEXII CCD diffractometer	1989 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	1763 reflections with I > 2σ(I)
T_min = 0.805, T_max = 0.942	R_int = 0.075
58588 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.028	0 restraints
wR(F²) = 0.087	H-atom parameters constrained
S = 1.08	Δρ_max = 0.33 e Å⁻³
1989 reflections	Δρ_min = −0.35 e Å⁻³
97 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.

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

	x	y	z	U_iso*/U_eq
P1	0.41034 (3)	0.35924 (6)	0.60908 (4)	0.02670 (13)
O11	0.40297 (9)	0.4245 (2)	0.75562 (13)	0.0446 (3)
H11	0.4433	0.5450	0.8066	0.070 (4)*
O12	0.38152 (8)	0.5724 (2)	0.51127 (14)	0.0466 (3)
H12	0.4251	0.6363	0.4691	0.070 (4)*
O13	0.50590 (7)	0.2779 (2)	0.61564 (12)	0.0365 (3)
C1	0.32469 (13)	0.1438 (3)	0.5486 (2)	0.0480 (5)
H111	0.3212	0.0982	0.4522	0.083 (5)*
H112	0.2641	0.2045	0.5488	0.083 (5)*
H113	0.3411	0.0086	0.6111	0.083 (5)*
P2	0.09029 (3)	0.86636 (6)	0.69483 (4)	0.02720 (13)
O21	0.09504 (9)	0.9190 (2)	0.84939 (12)	0.0459 (3)
H21	0.0495	1.0299	0.8568	0.070 (4)*
O22	0.11315 (8)	1.0935 (2)	0.62934 (12)	0.0414 (3)
H22	0.0712	1.1440	0.5404	0.070 (4)*
O23	−0.00227 (7)	0.7710 (2)	0.60798 (11)	0.0377 (3)
C2	0.18264 (13)	0.6703 (3)	0.71256 (18)	0.0436 (4)
H211	0.1700	0.5260	0.7551	0.069 (4)*
H212	0.2409	0.7385	0.7733	0.069 (4)*
H213	0.1885	0.6373	0.6191	0.069 (4)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
P1	0.0301 (2)	0.0254 (2)	0.0277 (2)	−0.00282 (13)	0.01342 (15)	−0.00150 (13)
O11	0.0563 (7)	0.0486 (7)	0.0382 (6)	−0.0219 (6)	0.0283 (6)	−0.0172 (5)
O12	0.0384 (6)	0.0457 (7)	0.0635 (8)	0.0146 (5)	0.0269 (6)	0.0244 (6)
O13	0.0345 (6)	0.0381 (6)	0.0405 (6)	0.0082 (5)	0.0172 (5)	0.0157 (5)
C1	0.0487 (10)	0.0457 (10)	0.0550 (11)	−0.0194 (8)	0.0239 (9)	−0.0222 (8)
P2	0.0305 (2)	0.0268 (2)	0.0223 (2)	0.00449 (13)	0.00533 (15)	0.00254 (12)
O21	0.0605 (8)	0.0509 (7)	0.0246 (5)	0.0224 (6)	0.0108 (5)	0.0001 (5)
O22	0.0369 (6)	0.0361 (6)	0.0413 (6)	−0.0076 (5)	−0.0019 (5)	0.0111 (5)
O23	0.0345 (6)	0.0411 (6)	0.0329 (5)	−0.0065 (5)	0.0038 (4)	0.0135 (5)
C2	0.0449 (9)	0.0420 (9)	0.0392 (9)	0.0169 (8)	0.0065 (7)	−0.0033 (7)

Geometric parameters (Å, º) top

P1—O13	1.4993 (11)	P2—O23	1.4989 (11)
P1—O11	1.5441 (11)	P2—O21	1.5478 (11)
P1—O12	1.5443 (12)	P2—O22	1.5504 (12)
P1—C1	1.7586 (17)	P2—C2	1.7612 (17)
O11—H11	0.9583	O21—H21	0.9584
O12—H12	0.9584	O22—H22	0.9580
C1—H111	0.9800	C2—H211	0.9800
C1—H112	0.9800	C2—H212	0.9800
C1—H113	0.9800	C2—H213	0.9800

O13—P1—O11	112.86 (7)	O23—P2—O21	112.94 (7)
O13—P1—O12	110.73 (6)	O23—P2—O22	110.99 (6)
O11—P1—O12	108.17 (8)	O21—P2—O22	107.75 (7)
O13—P1—C1	112.85 (8)	O23—P2—C2	112.83 (8)
O11—P1—C1	103.46 (8)	O21—P2—C2	103.76 (7)
O12—P1—C1	108.39 (9)	O22—P2—C2	108.15 (9)
P1—O11—H11	117.1	P2—O21—H21	113.4
P1—O12—H12	119.1	P2—O22—H22	118.4
P1—C1—H111	109.5	P2—C2—H211	109.5
P1—C1—H112	109.5	P2—C2—H212	109.5
H111—C1—H112	109.5	H211—C2—H212	109.5
P1—C1—H113	109.5	P2—C2—H213	109.5
H111—C1—H113	109.5	H211—C2—H213	109.5
H112—C1—H113	109.5	H212—C2—H213	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O22—H22···O23ⁱ	0.96	1.59	2.5528 (15)	180
O21—H21···O23ⁱⁱ	0.96	1.65	2.5768 (16)	161
O12—H12···O13ⁱⁱⁱ	0.96	1.61	2.5649 (15)	174
O11—H11···O13^iv	0.96	1.62	2.5671 (16)	169

Symmetry codes: (i) −x, −y+2, −z+1; (ii) −x, y+1/2, −z+3/2; (iii) −x+1, −y+1, −z+1; (iv) −x+1, y+1/2, −z+3/2.

Selected bond lengths (Å) top

P1—O13	1.4993 (11)	P2—O23	1.4989 (11)
P1—O11	1.5441 (11)	P2—O21	1.5478 (11)
P1—O12	1.5443 (12)	P2—O22	1.5504 (12)
P1—C1	1.7586 (17)	P2—C2	1.7612 (17)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O22—H22···O23ⁱ	0.96	1.59	2.5528 (15)	179.5
O21—H21···O23ⁱⁱ	0.96	1.65	2.5768 (16)	161.2
O12—H12···O13ⁱⁱⁱ	0.96	1.61	2.5649 (15)	173.5
O11—H11···O13^iv	0.96	1.62	2.5671 (16)	169.3

Symmetry codes: (i) −x, −y+2, −z+1; (ii) −x, y+1/2, −z+3/2; (iii) −x+1, −y+1, −z+1; (iv) −x+1, y+1/2, −z+3/2.

Acknowledgements

We thank the Deutsche Forschungsgemeinschaft and the Government of Lower Saxony for funding the diffractometer.

References

Adair, B., Natarajan, S. & Cheetham, A. K. (1998). J. Mater. Chem. 8, 1477–1479. Web of Science CSD CrossRef CAS Google Scholar
Allan, D. R., Clark, S. J., Parsons, S. & Ruf, M. (2000). J. Phys. Condens. Matter, 12, L613–L618. Web of Science CSD CrossRef CAS Google Scholar
Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2009). APEX2, SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruno, G. & Randaccio, L. (1980). Acta Cryst. B36, 1711–1712. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Kodolov, V. I., Povslugar, V. I., Alyamovskii, S. I. & Pletnev, R. N. (1977). Russ. Chem. Bull. pp. 142–143. CrossRef Web of Science Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Mahmoudkhani, A. H. & Langer, V. (2002). J. Mol. Struct. 609, 97–108. Web of Science CSD CrossRef CAS Google Scholar
Ribot, F., Sanchez, C., Biesemans, M., Mercier, F. A. G., Martins, J. C., Gielen, M. & Willem, R. (2001). Organometallics, 20, 2593–2603. Web of Science CSD CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Weakley, T. J. R. (1976). Acta Cryst. B32, 2889–2890. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 70| Part 3| March 2014| Page o353

doi:10.1107/S1600536814003572

Open

access