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In the title compound, Na+·H+·2C8H7O3, the anion contains a short Speakman-type hydrogen bond [O...O = 2.413 (2) Å]. The anions and the Na atoms lie across twofold axes.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100018175/gd1129sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270100018175/gd1129Isup2.hkl
Contains datablock I

CCDC reference: 162546

Comment top

The structure of the title compound, (I), was determined during an investigation into the effect of impurities on the crystallization and intermolecular interactions of phenoxyacetic acid. Anhydrous sodium phenoxyacetate (NaPAA) was crystallized from tap water to mimic the industrial manufacturing process undergoing investigation. The ratio of sodium to phenoxyacetate ions in (I) is 1:2 so an acidic hydrogen atom is required to balance the charges. H22 was located on a twofold axis between two carboxy oxygen atoms O22···O22i (i = 1 - x, y, 5/2 - z) which are 2.413 (2) Å apart. This hydrogen bond is very short but precedented (Freyhardt et al., 2000; Speakman & Muir, 1982; Speakman et al., 1981). This link is another strand which weaves around the inner ionic Na—O—Na core. H22 makes another, longer bond with O21. This carboxylate O atom has close contacts with sodium ions whereas the other O atom, O22, has a closer contact with H22 [1.215 (5) Å]. \sch

The polymeric core of (I) consists of a carboxylate oxygen atom (O21) bridging sodium atoms forming a twisted ribbon, where the two Na-µ-O—Na planes are inclined at 48.5° to each other. These ribbons lie parallel to the crystallographic c axis. The sodium co-ordination sphere consists of four Na—O21 contacts: two of 2.3385 (15) and two of 2.3815 (14) Å from four phenoxyacetic acid molecules. The latter two molecules with the longer Na—O21 contacts also bond to sodium via the phenoxy O atom, O1, where the Na—O1 distance is 2.6102 (15) Å. This packing arrangement is significantly different from that in sodium phenoxyacetate hemihydrate (Prout et al., 1971), where the sodium ion is surrounded by oxygen atoms from one water and two phenoxyacetate molecules. The NaO core of (I) is surrounded on either side by the phenoxy groups which form hydrocarbon layers above and below the ionic core.

The carboxylate group is almost coplanar with the phenyl ring (angle between the planes containing COO and Ph groups, 8.2°) and several structural trends were identified in the carboxylate chain. Firstly, distortion of exo-O1 angles where both C15—C10—O1 and C11—C10—O1 [123.3 (18) and 116.34 (17)°, respectively] deviate from the trigonal angle (120°). The distortion is thought to arise from the steric requirements of the carboxylate side chain, which is well documented among the phenoxyalkanoic series (Kennard et al., 1982). The distances of 1.273 (2) and 1.235 (2) Å (C21—O22, C21—O21) and the angles, 111.75 (16) and 121.59 (17)° (O22—C21—C20 and O21—C21—C20, respectively) are similar to those seen in the hemi-hydrate [1.276 (10), 1.240 (10) Å, 114.2 (7) and 117.5 (7)°] (Prout et al., 1971). In phenoxyacetic acid, the similar CO and C—OH distances [1.266 (3) and 1.263 (3) Å] are considered to originate from disorder of the acidic proton (Kennard et al., 1982).

Related literature top

For related literature, see: Freyhardt et al. (2000); Kennard et al. (1982); Prout et al. (1971); Speakman & Muir (1982); Speakman et al. (1981).

Experimental top

A sample of powdered sodium phenoxyacetate hemihydrate (Sigma-Aldrich) was dissolved in Edinburgh tap water, and single crystals of (I) were obtained by slow evaporation.

Refinement top

The hydrogen atom H22 was located in the difference map and coordinates were freely refined. Other H atoms were treated as riding with C—H 0.95–099 Å.

Computing details top

Data collection: XSCANS (Bruker, 1996); cell refinement: XSCANS; data reduction: SHELXTL (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. The asymmtric unit of (I): atoms H22 and Na lie on twofold rotation axes. Displacement ellipsoids are shown at the 50% probability level.
[Figure 2] Fig. 2. Packing arrangement viewed down the b axis. Oxygen atoms are cross-hatched and sodium atoms have a diagonal stripe.
Sodium hydrogenbis(phenoxyacetate) top
Crystal data top
[Na(C8H7O3)2H]F(000) = 676
Mr = 326.27Dx = 1.454 Mg m3
Orthorhombic, PbcnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2abCell parameters from 39 reflections
a = 21.484 (3) Åθ = 1.9–17.5°
b = 9.4624 (8) ŵ = 0.14 mm1
c = 7.3293 (7) ÅT = 160 K
V = 1490.0 (3) Å3Plate, colourless
Z = 40.58 × 0.34 × 0.06 mm
Data collection top
Bruker P4
diffractometer
1020 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.036
Graphite monochromatorθmax = 25.0°, θmin = 1.9°
ω scansh = 125
Absorption correction: ψ scan
(North et al., 1968)
k = 111
Tmin = 0.966, Tmax = 0.992l = 18
1814 measured reflections3 standard reflections every 97 reflections
1312 independent reflections intensity decay: none
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)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.109H atoms treated by a mixture of independent and constrained refinement
S = 0.96 w = 1/[σ2(Fo2) + (0.0636P)2 + 0.2133P]
where P = (Fo2 + 2Fc2)/3
1311 reflections(Δ/σ)max < 0.001
107 parametersΔρmax = 0.17 e Å3
0 restraintsΔρmin = 0.23 e Å3
Crystal data top
[Na(C8H7O3)2H]V = 1490.0 (3) Å3
Mr = 326.27Z = 4
Orthorhombic, PbcnMo Kα radiation
a = 21.484 (3) ŵ = 0.14 mm1
b = 9.4624 (8) ÅT = 160 K
c = 7.3293 (7) Å0.58 × 0.34 × 0.06 mm
Data collection top
Bruker P4
diffractometer
1020 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.036
Tmin = 0.966, Tmax = 0.9923 standard reflections every 97 reflections
1814 measured reflections intensity decay: none
1312 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.109H atoms treated by a mixture of independent and constrained refinement
S = 0.96Δρmax = 0.17 e Å3
1311 reflectionsΔρmin = 0.23 e Å3
107 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
xyzUiso*/Ueq
Na10.50000.02051 (11)0.75000.0223 (3)
O10.41147 (6)0.20753 (15)0.71555 (19)0.0242 (4)
O210.47164 (6)0.14081 (14)1.02304 (18)0.0225 (4)
O220.46179 (8)0.36168 (14)1.1294 (2)0.0337 (4)
C100.37299 (9)0.2366 (2)0.5683 (3)0.0207 (5)
C110.36417 (9)0.1277 (2)0.4444 (3)0.0240 (5)
H11A0.38520.04030.46030.029*
C120.32447 (10)0.1471 (2)0.2973 (3)0.0275 (5)
H12A0.31840.07250.21250.033*
C130.29347 (10)0.2749 (2)0.2728 (3)0.0292 (5)
H13A0.26600.28770.17270.035*
C140.30341 (9)0.3829 (2)0.3967 (3)0.0264 (5)
H14A0.28220.47020.38140.032*
C150.34372 (9)0.3661 (2)0.5428 (3)0.0228 (5)
H15A0.35120.44220.62440.027*
C200.41523 (10)0.3152 (2)0.8520 (3)0.0243 (5)
H20A0.37280.34050.89360.029*
H20B0.43470.40080.79960.029*
C210.45322 (10)0.2641 (2)1.0125 (3)0.0210 (5)
H220.50000.346 (4)1.25000.076 (15)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Na10.0320 (6)0.0178 (5)0.0171 (5)0.0000.0012 (5)0.000
O10.0312 (8)0.0220 (7)0.0193 (7)0.0073 (6)0.0064 (6)0.0026 (6)
O210.0302 (8)0.0175 (7)0.0199 (7)0.0042 (6)0.0013 (6)0.0012 (6)
O220.0527 (10)0.0201 (7)0.0283 (9)0.0085 (7)0.0168 (8)0.0052 (7)
C100.0204 (9)0.0244 (10)0.0174 (10)0.0007 (8)0.0004 (8)0.0032 (9)
C110.0265 (11)0.0215 (10)0.0242 (10)0.0003 (8)0.0033 (9)0.0009 (9)
C120.0279 (11)0.0321 (11)0.0224 (11)0.0066 (9)0.0003 (9)0.0027 (9)
C130.0234 (9)0.0393 (12)0.0250 (11)0.0056 (10)0.0052 (9)0.0070 (10)
C140.0236 (10)0.0271 (11)0.0285 (11)0.0002 (9)0.0013 (9)0.0076 (9)
C150.0249 (10)0.0222 (10)0.0214 (10)0.0002 (9)0.0021 (9)0.0015 (9)
C200.0338 (11)0.0189 (10)0.0203 (11)0.0032 (9)0.0047 (9)0.0020 (8)
C210.0241 (10)0.0193 (10)0.0196 (10)0.0008 (8)0.0024 (8)0.0010 (8)
Geometric parameters (Å, º) top
Na1—O21i2.3385 (15)C10—C111.386 (3)
Na1—O21ii2.3385 (15)C10—C151.390 (3)
Na1—O212.3815 (14)C11—C121.387 (3)
Na1—O21iii2.3815 (14)C11—H11A0.9500
Na1—O1iii2.6102 (15)C12—C131.392 (3)
Na1—O12.6102 (15)C12—H12A0.9500
Na1—Na1iv3.6851 (4)C13—C141.384 (3)
Na1—Na1ii3.6851 (4)C13—H13A0.9500
O1—C101.387 (2)C14—C151.386 (3)
O1—C201.430 (2)C14—H14A0.9500
O21—C211.235 (2)C15—H15A0.9500
O21—Na1ii2.3385 (15)C20—C211.511 (3)
O22—C211.273 (2)C20—H20A0.9900
O22—H221.216 (6)C20—H20B0.9900
O21i—Na1—O21ii98.50 (7)C21—O21—Na1ii138.15 (13)
O21i—Na1—O21147.47 (7)C21—O21—Na1118.77 (13)
O21ii—Na1—O2177.34 (5)Na1ii—O21—Na1102.66 (5)
O21i—Na1—O21iii77.34 (5)C21—O22—H22119.7 (18)
O21ii—Na1—O21iii147.47 (7)C11—C10—O1116.34 (17)
O21—Na1—O21iii122.89 (8)C11—C10—C15120.36 (19)
O21i—Na1—O1iii134.52 (5)O1—C10—C15123.30 (18)
O21ii—Na1—O1iii100.60 (5)C10—C11—C12119.65 (19)
O21—Na1—O1iii77.35 (5)C10—C11—H11A120.2
O21iii—Na1—O1iii64.58 (5)C12—C11—H11A120.2
O21i—Na1—O1100.60 (5)C11—C12—C13120.6 (2)
O21ii—Na1—O1134.52 (5)C11—C12—H12A119.7
O21—Na1—O164.58 (5)C13—C12—H12A119.7
O21iii—Na1—O177.35 (5)C14—C13—C12118.87 (19)
O1iii—Na1—O194.63 (7)C14—C13—H13A120.6
O21i—Na1—Na1iv39.09 (3)C12—C13—H13A120.6
O21ii—Na1—Na1iv129.69 (6)C13—C14—C15121.24 (19)
O21—Na1—Na1iv152.37 (5)C13—C14—H14A119.4
O21iii—Na1—Na1iv38.25 (3)C15—C14—H14A119.4
O1iii—Na1—Na1iv99.65 (4)C14—C15—C10119.18 (19)
O1—Na1—Na1iv88.58 (4)C14—C15—H15A120.4
O21i—Na1—Na1ii129.69 (6)C10—C15—H15A120.4
O21ii—Na1—Na1ii39.09 (3)O1—C20—C21110.34 (15)
O21—Na1—Na1ii38.25 (3)O1—C20—H20A109.6
O21iii—Na1—Na1ii152.37 (5)C21—C20—H20A109.6
O1iii—Na1—Na1ii88.58 (4)O1—C20—H20B109.6
O1—Na1—Na1ii99.65 (4)C21—C20—H20B109.6
Na1iv—Na1—Na1ii167.91 (6)H20A—C20—H20B108.1
C10—O1—C20115.91 (14)O21—C21—O22126.65 (19)
C10—O1—Na1130.08 (11)O21—C21—C20121.59 (17)
C20—O1—Na1111.97 (11)O22—C21—C20111.75 (16)
O21i—Na1—O1—C1021.89 (16)O1iii—Na1—O21—Na1ii104.10 (6)
O21ii—Na1—O1—C10135.15 (15)O1—Na1—O21—Na1ii154.47 (7)
O21—Na1—O1—C10171.29 (16)Na1iv—Na1—O21—Na1ii169.24 (8)
O21iii—Na1—O1—C1052.42 (15)C20—O1—C10—C11173.82 (17)
O1iii—Na1—O1—C10115.07 (16)Na1—O1—C10—C1124.0 (2)
Na1iv—Na1—O1—C1015.50 (15)C20—O1—C10—C155.6 (3)
Na1ii—Na1—O1—C10155.59 (15)Na1—O1—C10—C15156.60 (14)
O21i—Na1—O1—C20175.33 (12)O1—C10—C11—C12177.60 (18)
O21ii—Na1—O1—C2062.06 (15)C15—C10—C11—C121.9 (3)
O21—Na1—O1—C2025.93 (12)C10—C11—C12—C130.1 (3)
O21iii—Na1—O1—C20110.36 (13)C11—C12—C13—C140.7 (3)
O1iii—Na1—O1—C2047.72 (11)C12—C13—C14—C150.4 (3)
Na1iv—Na1—O1—C20147.28 (12)C13—C14—C15—C102.2 (3)
Na1ii—Na1—O1—C2041.63 (13)C11—C10—C15—C142.9 (3)
O21i—Na1—O21—C21100.17 (15)O1—C10—C15—C14176.51 (18)
O21ii—Na1—O21—C21173.87 (17)C10—O1—C20—C21174.29 (16)
O21iii—Na1—O21—C2121.76 (13)Na1—O1—C20—C2120.30 (19)
O1iii—Na1—O21—C2169.77 (15)Na1ii—O21—C21—O2224.3 (3)
O1—Na1—O21—C2131.66 (14)Na1—O21—C21—O22146.74 (18)
Na1iv—Na1—O21—C2116.9 (2)Na1ii—O21—C21—C20154.49 (15)
Na1ii—Na1—O21—C21173.87 (17)Na1—O21—C21—C2034.5 (2)
O21i—Na1—O21—Na1ii85.96 (13)O1—C20—C21—O216.6 (3)
O21ii—Na1—O21—Na1ii0.0O1—C20—C21—O22174.50 (17)
O21iii—Na1—O21—Na1ii152.11 (6)
Symmetry codes: (i) x, y, z1/2; (ii) x+1, y, z+2; (iii) x+1, y, z+3/2; (iv) x+1, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O22—H22···O22v1.22 (1)1.22 (1)2.413 (2)166 (4)
Symmetry code: (v) x+1, y, z+5/2.

Experimental details

Crystal data
Chemical formula[Na(C8H7O3)2H]
Mr326.27
Crystal system, space groupOrthorhombic, Pbcn
Temperature (K)160
a, b, c (Å)21.484 (3), 9.4624 (8), 7.3293 (7)
V3)1490.0 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.14
Crystal size (mm)0.58 × 0.34 × 0.06
Data collection
DiffractometerBruker P4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.966, 0.992
No. of measured, independent and
observed [I > 2σ(I)] reflections
1814, 1312, 1020
Rint0.036
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.109, 0.96
No. of reflections1311
No. of parameters107
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.17, 0.23

Computer programs: XSCANS (Bruker, 1996), XSCANS, SHELXTL (Bruker, 1999), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL.

Selected geometric parameters (Å, º) top
Na1—O21i2.3385 (15)Na1—Na1iv3.6851 (4)
Na1—O21ii2.3385 (15)Na1—Na1ii3.6851 (4)
Na1—O212.3815 (14)O21—C211.235 (2)
Na1—O21iii2.3815 (14)O22—C211.273 (2)
Na1—O1iii2.6102 (15)O22—H221.216 (6)
Na1—O12.6102 (15)
O21—C21—C20121.59 (17)O22—C21—C20111.75 (16)
Symmetry codes: (i) x, y, z1/2; (ii) x+1, y, z+2; (iii) x+1, y, z+3/2; (iv) x+1, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O22—H22···O22v1.215 (5)1.215 (5)2.413 (2)166 (4)
Symmetry code: (v) x+1, y, z+5/2.
 

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