Redetermination of potassium benzilate

The structure of potassium benzilate, K⁺·C₁₄H₁₁O₃⁻, previously determined from visually estimated intensities, has been redetermined from CCD data. The K⁺ ion is five-coordinate and the distribution of O atoms around the metal is a flattened square-base pyramid. Pairs of edge-sharing polyhedra join to form corrugated layers parallel to ab, which stack along the c axis. The K⁺ ion is in contact with the π electrons of one phenyl ring at a perpendicular distance of 3.0899 (4) Å and is displaced laterally by 0.252 Å with respect to the ring centroid. This interaction and an intramolecular hydrogen bond account for the rigidity of this ring compared to the second ring. The two intramolecular hydrogen bonds present have graph-set motif S(5). An intermolecular hydrogen bond, which also involves the hydroxyl group, has graph-set motif C₁²(4).

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.043
• wR factor = 0.119
• Data-to-parameter ratio = 17.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           28.54
         From the CIF: _reflns_number_total               2864
         TEST2: Reflns within _diffrn_reflns_theta_max
         Count of symmetry unique reflns         3116
         Completeness (_total/calc)             91.91%
          Alert C: < 95% complete


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

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Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 1990).

Potassium α–Hydroxy–α–phenylbenzeneacetate

Crystal data

K^+·C14H11O3^−	F(000) = 552
Mr = 266.33	Dx = 1.439 Mg m^−3 Dm = 1.428 Mg m^−3 Dm measured by neutral buoyancy in CHCl3/C4H10O
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3427 reflections
a = 14.1283 (15) Å	θ = 1.6–28.5°
b = 9.023 (1) Å	µ = 0.43 mm^−1
c = 10.3639 (11) Å	T = 293 K
β = 111.474 (1)°	Plate, colorless
V = 1229.5 (2) Å^3	0.50 × 0.40 × 0.30 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	2864 independent reflections
Radiation source: fine-focus sealed tube	2213 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.040
Detector resolution: 0.70 pixels mm^-1	θmax = 28.5°, θmin = 1.6°
φ and ω scans	h = −16→18
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −8→12
Tmin = 0.757, Tmax = 0.880	l = −13→13
15415 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.120	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0698P)^2 + 0.0399P] where P = (Fo^2 + 2Fc^2)/3
2864 reflections	(Δ/σ)max < 0.001
167 parameters	Δρmax = 0.32 e Å^−3
0 restraints	Δρmin = −0.46 e Å^−3

Special details

Experimental. Siemens SMART CCD diffractometer equipped with a normal focus, 2.4 kW sealed tube X-ray source (Mo Kα radiation, λ = 0.71073 Å) operating at 30 kV and 20 mA. The data collection covered about 1.3 hemisphere of reciprocal space by a combination of three sets of exposures; each set had a different φ angle (0, 90, 180 °) for the crystal and each exposure of 12 s covered 0.3° in ω to give a total of 1315 frames. The crystal-to-detector distance was 5.029 cm and the detector swing angle was -30°. Coverage of the unique set was over 99% complete. Crystal decay was monitored by repeating fifty frames from the initial set at the end of the data collection. The analysis of the duplicate reflections indicated that crystal decay was negligible. Unit-cell parameters were determined by a least-squares fit of 3427 reflections in the range 1.55–28.54. Absorption and other corrections were made using a multi-scan technique (SADABS; Sheldrick, 1996)

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 (Ų)

	x	y	z	Uiso*/Ueq
K	0.03541 (3)	0.03185 (5)	0.81633 (4)	0.04358 (16)
O1	−0.14873 (10)	0.39938 (15)	1.06378 (13)	0.0367 (3)
H1	−0.1388 (19)	0.329 (3)	1.108 (3)	0.058 (7)*
O2	−0.07919 (10)	0.28955 (14)	0.79362 (12)	0.0382 (3)
O3	−0.07120 (10)	0.15646 (15)	0.97690 (14)	0.0462 (3)
C1	−0.10511 (13)	0.26085 (17)	0.89388 (17)	0.0300 (4)
C2	−0.18665 (12)	0.36011 (18)	0.91996 (17)	0.0294 (4)
C3	−0.28622 (13)	0.27359 (19)	0.88436 (18)	0.0347 (4)
C4	−0.30634 (16)	0.1473 (2)	0.8034 (2)	0.0532 (5)
H4	−0.2586	0.1129	0.7682	0.064*
C5	−0.3969 (2)	0.0714 (3)	0.7741 (3)	0.0743 (8)
H5	−0.4096	−0.0132	0.7191	0.089*
C6	−0.46796 (18)	0.1198 (4)	0.8253 (3)	0.0751 (8)
H6	−0.5287	0.0682	0.8051	0.090*
C7	−0.44947 (17)	0.2439 (3)	0.9061 (3)	0.0657 (7)
H7	−0.4974	0.2762	0.9418	0.079*
C8	−0.35905 (15)	0.3222 (2)	0.9352 (2)	0.0486 (5)
H8	−0.3474	0.4076	0.9890	0.058*
C9	−0.20387 (12)	0.50445 (18)	0.83704 (17)	0.0301 (4)
C10	−0.15691 (14)	0.6350 (2)	0.8976 (2)	0.0388 (4)
H10	−0.1150	0.6359	0.9908	0.047*
C11	−0.17182 (17)	0.7646 (2)	0.8206 (2)	0.0479 (5)
H11	−0.1405	0.8517	0.8630	0.057*
C12	−0.23233 (17)	0.7654 (2)	0.6825 (2)	0.0483 (5)
H12	−0.2423	0.8526	0.6315	0.058*
C13	−0.27835 (15)	0.6355 (2)	0.6199 (2)	0.0480 (5)
H13	−0.3185	0.6349	0.5260	0.058*
C14	−0.26491 (14)	0.5057 (2)	0.69657 (19)	0.0389 (4)
H14	−0.2969	0.4190	0.6539	0.047*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
K	0.0566 (3)	0.0379 (3)	0.0456 (3)	0.01317 (18)	0.0297 (2)	0.00574 (18)
O1	0.0519 (8)	0.0315 (7)	0.0284 (6)	0.0035 (6)	0.0167 (5)	0.0001 (5)
O2	0.0497 (7)	0.0349 (7)	0.0386 (7)	0.0045 (5)	0.0263 (6)	0.0017 (5)
O3	0.0550 (8)	0.0435 (8)	0.0480 (8)	0.0183 (6)	0.0284 (6)	0.0164 (6)
C1	0.0335 (8)	0.0260 (8)	0.0316 (8)	−0.0018 (6)	0.0132 (7)	−0.0029 (7)
C2	0.0324 (8)	0.0282 (8)	0.0297 (8)	0.0009 (6)	0.0141 (7)	0.0002 (6)
C3	0.0348 (9)	0.0330 (9)	0.0375 (9)	0.0001 (7)	0.0147 (7)	0.0072 (7)
C4	0.0512 (12)	0.0523 (13)	0.0603 (13)	−0.0160 (10)	0.0255 (10)	−0.0130 (10)
C5	0.0633 (15)	0.0690 (17)	0.0893 (19)	−0.0314 (13)	0.0265 (14)	−0.0174 (15)
C6	0.0433 (13)	0.081 (2)	0.097 (2)	−0.0201 (12)	0.0209 (13)	0.0139 (16)
C7	0.0409 (12)	0.0752 (17)	0.0907 (18)	0.0079 (11)	0.0356 (12)	0.0222 (15)
C8	0.0417 (10)	0.0468 (12)	0.0637 (13)	0.0058 (9)	0.0271 (9)	0.0076 (10)
C9	0.0315 (8)	0.0294 (8)	0.0340 (8)	0.0030 (6)	0.0175 (7)	0.0024 (7)
C10	0.0464 (10)	0.0334 (10)	0.0387 (9)	−0.0014 (8)	0.0182 (8)	−0.0007 (8)
C11	0.0647 (13)	0.0293 (10)	0.0566 (12)	−0.0038 (9)	0.0304 (11)	−0.0004 (9)
C12	0.0598 (12)	0.0342 (10)	0.0580 (12)	0.0089 (9)	0.0298 (10)	0.0149 (9)
C13	0.0488 (11)	0.0542 (13)	0.0401 (10)	0.0088 (9)	0.0150 (9)	0.0141 (9)
C14	0.0409 (10)	0.0359 (10)	0.0396 (10)	−0.0004 (8)	0.0142 (8)	0.0015 (8)

Geometric parameters (Å, º)

K—O2	2.7937 (13)	C9—C10	1.385 (2)
K—O3	2.8525 (13)	C9—C14	1.394 (2)
K—O1^i	3.0031 (14)	C10—C11	1.387 (3)
K—O3^ii	2.6347 (13)	C11—C12	1.373 (3)
K—O2^iii	2.6414 (13)	C12—C13	1.382 (3)
O1—C2	1.432 (2)	C13—C14	1.388 (3)
O2—C1	1.249 (2)	O1—H1	0.77 (2)
O2—K^iv	2.6414 (13)	C4—H4	0.930
O3—C1	1.247 (2)	C4—H4	0.930
O3—K^ii	2.6347 (13)	C5—H5	0.930
C1—C2	1.559 (2)	C6—H6	0.930
C2—C9	1.530 (2)	C7—H7	0.930
C2—C3	1.531 (2)	C8—H8	0.930
C3—C4	1.382 (3)	C10—H10	0.930
C3—C8	1.388 (3)	C11—H11	0.930
C4—C5	1.384 (3)	C12—H12	0.930
C5—C6	1.366 (4)	C13—H13	0.930
C6—C7	1.365 (4)	C13—H13	0.930
C7—C8	1.393 (3)	C14—H14	0.930
O3^ii—K—O2^iii	79.14 (4)	C8—C3—C2	119.41 (17)
O3^ii—K—O2	122.55 (4)	C3—C4—C5	120.6 (2)
O2^iii—K—O2	150.761 (19)	C6—C5—C4	120.6 (3)
O3^ii—K—O3	76.40 (4)	C7—C6—C5	119.8 (2)
O2^iii—K—O3	146.61 (4)	C6—C7—C8	120.2 (2)
O2—K—O3	46.18 (4)	C3—C8—C7	120.4 (2)
O3^ii—K—O3	76.40 (4)	C10—C9—C14	118.48 (16)
O2^iii—K—O3	146.61 (4)	C10—C9—C2	121.22 (15)
O2—K—O3	46.18 (4)	C14—C9—C2	120.26 (15)
O3^ii—K—O1^i	133.57 (4)	C9—C10—C11	120.63 (17)
O2^iii—K—O1^i	93.44 (4)	C12—C11—C10	120.66 (18)
O2—K—O1^i	57.60 (4)	C11—C12—C13	119.43 (18)
O3—K—O1^i	87.31 (4)	C12—C13—C14	120.31 (18)
O3—K—O1^i	87.31 (4)	C13—C14—C9	120.48 (18)
C2—O1—K^v	146.43 (10)	C2—O1—H1	109.2 (19)
C1—O2—K^iv	135.80 (11)	K^v—O1—H1	75.1 (18)
C1—O2—K	95.43 (10)	C3—C4—H4	119.7
K^iv—O2—K	120.35 (4)	C5—C4—H4	119.7
C1—O3—K^ii	163.56 (11)	C6—C5—H5	119.7
C1—O3—K	92.68 (10)	C4—C5—H5	119.7
K^ii—O3—K	103.60 (4)	C7—C6—H6	120.1
O3—C1—O2	125.11 (16)	C5—C6—H6	120.1
O3—C1—O2	125.11 (16)	C6—C7—H7	119.9
O3—C1—C2	115.85 (14)	C8—C7—H7	119.9
O3—C1—C2	115.85 (14)	C3—C8—H8	119.8
O2—C1—C2	119.05 (14)	C7—C8—H8	119.8
O1—C2—C9	107.22 (13)	C9—C10—H10	119.7
O1—C2—C9	107.22 (13)	C11—C10—H10	119.7
O1—C2—C3	109.74 (13)	C12—C11—H11	119.7
O1—C2—C3	109.74 (13)	C10—C11—H11	119.7
C9—C2—C3	110.83 (13)	C11—C12—H12	120.3
O1—C2—C1	107.70 (13)	C13—C12—H12	120.3
O1—C2—C1	107.70 (13)	C12—C13—H13	119.8
C9—C2—C1	111.55 (13)	C14—C13—H13	119.8
C3—C2—C1	109.71 (13)	C13—C14—H14	119.8
C4—C3—C8	118.35 (18)	C9—C14—H14	119.8
C4—C3—C2	122.24 (16)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2^v	0.77 (2)	2.09 (2)	2.7986 (18)	154 (2)
O1—H1···O3	0.77 (2)	2.47 (3)	2.7454 (18)	103 (2)
C10—H10···O1	0.93	2.37	2.712 (2)	101

Symmetry code: (v) x, −y+1/2, z+1/2.