Potassium clavulanate

Fujii, K.; Toyota, K.; Sekine, A.; Uekusa, H.; Nugrahani, I.; Asyarie, S.; Soewandhi, N.S.; Ibrahim, S.

doi:10.1107/S1600536810027984

Potassium clavulanate

K. Fujii, K. Toyota, A. Sekine, H. Uekusa, I. Nugrahani, S. Asyarie, N. S. Soewandhi and S. Ibrahim

The title salt, K⁺·C₈H₈NO₅⁻ [systematic name: potassium (2R,5R,Z)-3-(2-hydroxyethylidene)-7-oxo-4-oxa-1-azabicyclo[3.2.0]heptane-2-carboxylate], a widely used β-lactam antibiotic, is usually chemically unstable even in the solid state owing to its tendency to be hydrolysed. In the crystal structure, the potassium cations are arranged along the a axis, forming interactions to the carboxylate and hydroxy groups, resulting in one-dimensional ionic columns. These columns are arranged along the b axis, connected by O—H

O hydrogen bonds, forming a layer in the ab plane.

Read article Similar articles

Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536810027984/tk2689sup1.cif Contains datablocks I, global
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536810027984/tk2689Isup2.hkl Contains datablock I

CCDC reference: 788259

checkCIF report

Key indicators

Single-crystal X-ray study
T = 173 K
Mean (C-C) = 0.006 Å
R factor = 0.044
wR factor = 0.118
Data-to-parameter ratio = 15.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT340_ALERT_3_C Low Bond Precision on  C-C Bonds (x 1000) Ang ..          6
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          3
PLAT042_ALERT_1_C Calc. and Reported MoietyFormula Strings  Differ          ?
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          2

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.47
           From the CIF: _reflns_number_total               2138
           Count of symmetry unique reflns         1303
           Completeness (_total/calc)            164.08%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       835
           Fraction of Friedel pairs measured     0.641
           Are heavy atom types Z>Si present        yes
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #          9
            N1  -C4  -C5  -K1     52.00  2.00   1.555   1.555   1.555   1.555
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         10
            C6  -C4  -C5  -K1    -67.50  1.90   1.555   1.555   1.555   1.555
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         81
            C5  -O2  -K1  -O4    -45.10  1.70   1.555   1.555   1.555   3.367
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         82
            K1  -O2  -K1  -O4     72.80  1.60   1.655   1.555   1.555   3.367
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         83
            K1  -O2  -K1  -O4     18.00  0.00   3.567   1.555   1.555   3.367
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        102
            C4  -C5  -K1  -O2    -16.80  1.80   1.555   1.555   1.555   1.455
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        105
            C4  -C5  -K1  -O3    -87.60  1.80   1.555   1.555   1.555   1.555
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        109
            C4  -C5  -K1  -O2     62.80  1.80   1.555   1.555   1.555   3.467
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        113
            C4  -C5  -K1  -O4    166.50  1.80   1.555   1.555   1.555   3.467
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        116
            C4  -C5  -K1  -O2    103.30  1.90   1.555   1.555   1.555   1.555
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        120
            C4  -C5  -K1  -O4    -82.00  1.90   1.555   1.555   1.555   3.367
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        124
            C4  -C5  -K1  -C7    123.70  1.80   1.555   1.555   1.555   3.467
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        126
            O2  -C5  -K1  -C8    154.00  2.00   1.555   1.555   1.555   3.367
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        127
            O3  -C5  -K1  -C8    -15.00  2.00   1.555   1.555   1.555   3.367
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        128
            C4  -C5  -K1  -C8   -103.00  3.00   1.555   1.555   1.555   3.367
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        129
            K1  -C5  -K1  -C8    110.00  2.00   1.655   1.555   1.555   3.367
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        132
            C4  -C5  -K1  -C5    -33.00  1.90   1.555   1.555   1.555   1.455
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        136
            C4  -C5  -K1  -C8    149.40  1.80   1.555   1.555   1.555   3.467
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #        140
            C4  -C5  -K1  -K1     73.40  1.80   1.555   1.555   1.555   3.567
PLAT764_ALERT_4_G Overcomplete CIF Bond List Detected (Rep/Expd) .       1.24 Ratio
PLAT779_ALERT_4_G Suspect or Irrelevant (Bond) Angle in CIF ......      44.80 Deg.
              O2   -C5   -K1      1.555   1.555   1.655
PLAT791_ALERT_4_G Note: The Model has Chirality at C3     (Verify)          R
PLAT791_ALERT_4_G Note: The Model has Chirality at C4     (Verify)          R
PLAT804_ALERT_5_G ARU-Pack Problem in PLATON Analysis ............         14 Times

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
  25 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
  25 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check


checkCIF publication errors

Alert level A
PUBL024_ALERT_1_A The number of authors is greater than 5.
              Please specify the role of each of the co-authors
              for your paper.

Author Response: As a result of crystallographic and pharmaceutical study of two international group, the number of authors became eight. The list of author's contribution is following.

 Dr. Kotaro Fujii discussed on the structure.
 Mr. Kazuyuki Toyota analyzed the crystal structure.
 Dr. Akiko Sekinse is responsible for the low temperature crystallization.
 Dr. Hidehiro Uekusa is responsible of this international corroboration work.

 Dr. Ilma Nugrahani is responsible for the Indonesian group and also is
 studying on the hydrolysis of this
 compound with Dr. Sukmadjaja.
 Dr. N. Sundani Soewandhi and Slamet Ilbrahim are responsible for
 the pharmaceutical
 activity study of this compound.


   1 ALERT level A = Data missing that is essential or data in wrong format
   0 ALERT level G = General alerts. Data that may be required is missing

Comment top

Many pathogenic bacteria secrete β-lactamases as a defense mechanism against β-lactam antibiotics. Because such β-lactamases have the potential to inactivate β-lactam antibiotics, inhibitors for these β-lactamases are clinically very important. Clavulanic acid (CA) is a powerful naturally obtained inhibitor for bacterial β-lactamases produced by the organism Streptomyces clavuligerus. Although CA itself can act as an β-lactam antibiotic and is active against a wide spectrum of Gram-positive and Gram-negative bacteria (Mayer & Deckwer, 1996), it is much more effective as a drug in combination with β-lactamase-sensitive penicillins, such as amoxicillin. In that situation, CA protects the β-lactam ring of the amoxicillin from hydrolysis and can maintain its activity against β-lactamase producing bacteria (Bird et al., 1982). The CA potassium salt is widely used as a drug in injectable and solid form, especially combined with amoxicillin sodium and amoxicillin trihydrate (Navarro, 2005).

In this context, an understanding of the structure of CA is important in order to establish its ability to form molecular interactions. Unfortunately, CA is chemically unstable as are the other β-lactam antibiotics, being very sensitive to pH, temperature, and humidity via the hydrolysis degradation mechanism; (Bersanetti et al., 2005; Hickey et al., 2007; Saudagar et al., 2008). The decomposition is also self-catalyzed (Brethauer et al. 2008; Haginaka et al. 1985) and there have been some difficulties in obtaining a single crystals of CA. Therefore, until now there has been no report of a crystal structure of CA. In this study, single crystals of potassium clavulanate were successfully obtained by a low-temperature crystallization process and the crystal structure was determined.

In the molecular structure of potassium clavulanate, Fig. 1, the C5–O2 and C5–O3 distances of 1.262 (5)Å and 1.256 (5) Å, respectively, indicate that the negative charge of the carboxylate group is delocalised. The potassium cation is surrounded by six oxygen atoms, three O2, one O3 and two O4, deriv ed from four different clavulanate anions. The selected bond lengths around the potassium cation are listed in Table 1. These interactions are infinitely linked along the a axis and lead to an ionic (hydrophilic) column structure. These columns are connected by intermolecular O–H···O hydrogen bonds formed between O4-hydroxyl groups and carboxylate-O2 atoms, and form a hydrophobic layer in the ab plane; Fig. 2. By contrast, the remaining hydrophobic groups (i.e. bicyclo groups) form a hydrophobic layer so that the crystal structure comprises alternating hydrophilic and hydrophilic regions.

Related literature top

For the pharmacological activity of clavulanic acid and potassium clavulanate, see: Bird et al. (1982); Mayer & Deckwer (1996); Navarro (2005). For the hydrolysis properties of clavulanic acid and potassium clavulanate, see: Bersanetti et al. (2005); Brethauer et al. (2008); Haginaka et al. (1985); Hickey et al. (2007); Saudagar et al. (2008).

Experimental top

The single crystals of potassium clavulanate were grown at a low temperature in order to prevent decomposition. After the compound was dissolved into an 8:2 mixture of methanol/water, a few drops of 1-propanol were added to the solution and the solution was kept at 235 K for a few days. The crystal used in the analysis was immediately covered with inert oil in order to prevent the decomposition through contact with atmospheric water vapor.

Structure description top

Computing details top

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO (Rigaku, 1998); data reduction: PROCESS-AUTO (Rigaku, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. Molecular structure of potassium clavulanate showing numbering scheme and displacement ellipsoids at the 50% probability .
	Fig. 2. Crystal packing viewed along the a axis. The hydrogen bonds are shown with red dotted lines.

potassium (2R,5R,Z)- 3-(2-hydroxyethylidene)-7-oxo-4-oxa-1-azabicyclo[3.2.0]heptane-2-carboxylate top

Crystal data top

K⁺·C₈H₈NO₅⁻	F(000) = 488
M_r = 237.25	D_x = 1.687 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71075 Å
Hall symbol: P 2ac 2ab	Cell parameters from 9047 reflections
a = 4.3453 (6) Å	θ = 3.0–27.5°
b = 7.8191 (11) Å	µ = 0.57 mm⁻¹
c = 27.491 (3) Å	T = 173 K
V = 934.1 (2) Å³	Platet, colorless
Z = 4	0.24 × 0.04 × 0.01 mm

Data collection top

Rigaku R-AXIS RAPID IP area-detector diffractometer	2138 independent reflections
Radiation source: rotating anode, Rigaku UltraX18	1433 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.088
ω scan	θ_max = 27.5°, θ_min = 3.0°
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	h = −5→5
T_min = 0.876, T_max = 0.994	k = −10→10
9047 measured reflections	l = −35→35

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)] = 0.044	H-atom parameters constrained
wR(F²) = 0.118	w = 1/[σ²(F_o²) + (0.0305P)² + 0.8726P] where P = (F_o² + 2F_c²)/3
S = 1.12	(Δ/σ)_max = 0.001
2138 reflections	Δρ_max = 0.52 e Å⁻³
137 parameters	Δρ_min = −0.56 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 839 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.05 (9)

Crystal data top

K⁺·C₈H₈NO₅⁻	V = 934.1 (2) Å³
M_r = 237.25	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 4.3453 (6) Å	µ = 0.57 mm⁻¹
b = 7.8191 (11) Å	T = 173 K
c = 27.491 (3) Å	0.24 × 0.04 × 0.01 mm

Data collection top

Rigaku R-AXIS RAPID IP area-detector diffractometer	2138 independent reflections
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	1433 reflections with I > 2σ(I)
T_min = 0.876, T_max = 0.994	R_int = 0.088
9047 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	H-atom parameters constrained
wR(F²) = 0.118	Δρ_max = 0.52 e Å⁻³
S = 1.12	Δρ_min = −0.56 e Å⁻³
2138 reflections	Absolute structure: Flack (1983), 839 Friedel pairs
137 parameters	Absolute structure parameter: −0.05 (9)
0 restraints

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
C1	1.2101 (11)	0.3967 (6)	1.20066 (15)	0.0297 (11)
C2	1.1168 (11)	0.5309 (6)	1.23813 (13)	0.0276 (9)
H2A	1.2901	0.5798	1.2569	0.033*
H2B	0.9447	0.4964	1.2596	0.033*
C3	1.0199 (11)	0.6369 (6)	1.19340 (14)	0.0250 (10)
H3	0.8027	0.6790	1.1942	0.030*
C4	1.2417 (9)	0.5363 (6)	1.11851 (13)	0.0192 (8)
H4	1.4273	0.4611	1.1163	0.023*
C5	1.0676 (9)	0.5213 (6)	1.06982 (13)	0.0201 (8)
C6	1.3526 (11)	0.7148 (5)	1.13197 (12)	0.0218 (9)
C7	1.5398 (10)	0.8175 (6)	1.10754 (14)	0.0245 (10)
H7	1.6169	0.7752	1.0775	0.029*
C8	1.6419 (11)	0.9914 (5)	1.12198 (13)	0.0269 (9)
H8A	1.5056	1.0382	1.1476	0.032*
H8B	1.8551	0.9881	1.1346	0.032*
O1	1.3545 (10)	0.2661 (4)	1.20053 (11)	0.0458 (9)
O2	1.1415 (8)	0.6217 (4)	1.03630 (9)	0.0258 (7)
O3	0.8682 (9)	0.4058 (4)	1.06647 (10)	0.0318 (7)
O4	1.6262 (9)	1.0947 (4)	1.07905 (10)	0.0321 (8)
H4A	1.6958	1.1926	1.0851	0.038*
O5	1.2401 (7)	0.7604 (4)	1.17783 (9)	0.0266 (7)
N1	1.0715 (8)	0.4860 (5)	1.16197 (10)	0.0242 (8)
K1	0.6334 (2)	0.52404 (13)	0.97836 (3)	0.0284 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.036 (3)	0.027 (2)	0.026 (2)	−0.001 (2)	0.001 (2)	0.0026 (19)
C2	0.029 (2)	0.035 (2)	0.0185 (16)	−0.001 (3)	−0.0026 (18)	0.0049 (18)
C3	0.026 (2)	0.025 (2)	0.024 (2)	0.0001 (19)	0.0021 (19)	0.0033 (18)
C4	0.0183 (18)	0.018 (2)	0.0211 (17)	−0.0025 (18)	−0.0009 (15)	0.0023 (17)
C5	0.017 (2)	0.022 (2)	0.0214 (17)	−0.0007 (18)	0.0031 (15)	−0.0040 (17)
C6	0.020 (2)	0.028 (2)	0.0174 (17)	0.001 (2)	−0.0018 (18)	−0.0019 (16)
C7	0.027 (2)	0.026 (2)	0.0204 (18)	−0.0043 (19)	0.0037 (18)	0.0005 (17)
C8	0.030 (2)	0.025 (2)	0.0255 (18)	−0.003 (2)	−0.002 (2)	0.0008 (18)
O1	0.070 (3)	0.033 (2)	0.0340 (16)	0.020 (2)	0.006 (2)	0.0063 (15)
O2	0.0265 (16)	0.0296 (17)	0.0213 (12)	−0.0041 (16)	−0.0002 (13)	0.0045 (12)
O3	0.0366 (19)	0.0304 (17)	0.0285 (14)	−0.0127 (16)	−0.0071 (15)	0.0038 (13)
O4	0.046 (2)	0.0201 (15)	0.0304 (15)	−0.0063 (17)	−0.0020 (17)	0.0034 (12)
O5	0.0328 (18)	0.0248 (17)	0.0221 (13)	−0.0045 (13)	0.0064 (13)	−0.0013 (13)
N1	0.032 (2)	0.0236 (19)	0.0174 (14)	0.0030 (17)	0.0036 (14)	0.0043 (14)
K1	0.0242 (4)	0.0362 (5)	0.0248 (4)	0.0008 (5)	−0.0007 (4)	0.0031 (4)

Geometric parameters (Å, º) top

C1—O1	1.199 (6)	C7—H7	0.9500
C1—N1	1.408 (5)	C8—O4	1.432 (5)
C1—C2	1.525 (6)	C8—H8A	0.9900
C2—C3	1.542 (5)	C8—H8B	0.9900
C2—H2A	0.9900	O4—H4A	0.8400
C2—H2B	0.9900	O2—K1ⁱ	2.773 (3)
C3—O5	1.425 (5)	O2—K1ⁱⁱ	2.799 (3)
C3—N1	1.480 (5)	O2—K1	2.827 (3)
C3—H3	1.0000	O3—K1	2.786 (3)
C4—N1	1.459 (5)	O4—K1ⁱⁱ	2.818 (4)
C4—C6	1.522 (6)	O4—K1ⁱⁱⁱ	2.865 (4)
C4—C5	1.542 (5)	O4—H4A	0.8400
C4—H4	1.0000	K1—O2^iv	2.773 (3)
C5—O2	1.252 (5)	K1—O2^v	2.799 (3)
C5—O3	1.256 (5)	K1—O4^v	2.818 (4)
C6—C7	1.325 (6)	K1—O4^vi	2.865 (4)
C6—O5	1.398 (4)	K1—C7^v	3.198 (4)
C7—C8	1.485 (6)

O1—C1—N1	130.1 (4)	C1—N1—C4	122.4 (4)
O1—C1—C2	136.7 (4)	C1—N1—C3	91.1 (3)
N1—C1—C2	93.2 (3)	C4—N1—C3	109.9 (3)
C1—C2—C3	84.5 (3)	O2^iv—K1—O3	82.78 (10)
C1—C2—H2A	114.6	O2^iv—K1—O2^v	79.62 (9)
C3—C2—H2A	114.6	O3—K1—O2^v	116.68 (9)
C1—C2—H2B	114.6	O2^iv—K1—O4^v	176.73 (10)
C3—C2—H2B	114.6	O3—K1—O4^v	95.70 (10)
H2A—C2—H2B	111.7	O2^v—K1—O4^v	103.64 (9)
O5—C3—N1	105.3 (3)	O2^iv—K1—O2	101.77 (9)
O5—C3—C2	114.9 (4)	O3—K1—O2	46.69 (9)
N1—C3—C2	89.7 (3)	O2^v—K1—O2	78.70 (9)
O5—C3—H3	114.7	O4^v—K1—O2	79.11 (9)
N1—C3—H3	114.7	O2^iv—K1—O4^vi	79.21 (9)
C2—C3—H3	114.7	O3—K1—O4^vi	130.76 (10)
N1—C4—C6	102.0 (3)	O2^v—K1—O4^vi	104.54 (9)
N1—C4—C5	116.2 (3)	O4^v—K1—O4^vi	99.74 (9)
C6—C4—C5	115.9 (3)	O2—K1—O4^vi	176.76 (10)
N1—C4—H4	107.4	O2^iv—K1—C5	90.29 (9)
C6—C4—H4	107.4	O3—K1—C5	23.47 (10)
C5—C4—H4	107.4	O2^v—K1—C5	96.56 (11)
O2—C5—O3	125.0 (3)	O4^v—K1—C5	89.41 (10)
O2—C5—C4	117.7 (4)	O2—K1—C5	23.45 (9)
O3—C5—C4	117.2 (3)	O4^vi—K1—C5	154.16 (10)
O2—C5—K1	64.0 (2)	O2^iv—K1—C7^v	137.98 (11)
O3—C5—K1	62.1 (2)	O3—K1—C7^v	124.63 (12)
C4—C5—K1	171.2 (3)	O2^v—K1—C7^v	60.23 (10)
O2—C5—K1ⁱ	44.8 (2)	O4^v—K1—C7^v	45.13 (10)
O3—C5—K1ⁱ	115.7 (3)	O2—K1—C7^v	83.12 (10)
C4—C5—K1ⁱ	106.1 (2)	O4^vi—K1—C7^v	98.25 (10)
K1—C5—K1ⁱ	81.24 (8)	C5—K1—C7^v	105.17 (11)
C7—C6—O5	121.1 (4)	O2^iv—K1—C8^vi	89.53 (10)
C7—C6—C4	128.8 (4)	O3—K1—C8^vi	154.09 (11)
O5—C6—C4	110.0 (3)	O2^v—K1—C8^vi	85.89 (9)
C6—C7—C8	127.1 (4)	O4^v—K1—C8^vi	90.62 (10)
C6—C7—K1ⁱⁱ	105.7 (3)	O2—K1—C8^vi	158.79 (11)
C8—C7—K1ⁱⁱ	90.4 (2)	O4^vi—K1—C8^vi	23.49 (9)
C6—C7—H7	116.5	C5—K1—C8^vi	177.48 (12)
C8—C7—H7	116.5	C7^v—K1—C8^vi	76.57 (11)
K1ⁱⁱ—C7—H7	71.9	O2^iv—K1—C5^iv	18.57 (9)
O4—C8—C7	106.4 (3)	O3—K1—C5^iv	68.43 (10)
O4—C8—K1ⁱⁱⁱ	52.9 (2)	O2^v—K1—C5^iv	96.76 (10)
C7—C8—K1ⁱⁱⁱ	86.5 (2)	O4^v—K1—C5^iv	158.42 (10)
O4—C8—K1ⁱⁱ	49.2 (2)	O2—K1—C5^iv	98.32 (9)
C7—C8—K1ⁱⁱ	64.7 (2)	O4^vi—K1—C5^iv	81.62 (9)
K1ⁱⁱⁱ—C8—K1ⁱⁱ	76.39 (8)	C5—K1—C5^iv	81.24 (8)
O4—C8—H8A	110.5	C7^v—K1—C5^iv	156.37 (11)
C7—C8—H8A	110.5	C8^vi—K1—C5^iv	97.88 (10)
K1ⁱⁱⁱ—C8—H8A	160.2	O2^iv—K1—C8^v	159.90 (10)
K1ⁱⁱ—C8—H8A	101.1	O3—K1—C8^v	115.98 (12)
O4—C8—H8B	110.5	O2^v—K1—C8^v	85.05 (9)
C7—C8—H8B	110.5	O4^v—K1—C8^v	22.62 (9)
K1ⁱⁱⁱ—C8—H8B	72.8	O2—K1—C8^v	87.75 (10)
K1ⁱⁱ—C8—H8B	149.1	O4^vi—K1—C8^v	92.28 (10)
H8A—C8—H8B	108.6	C5—K1—C8^v	104.40 (10)
C5—O2—K1ⁱ	116.6 (3)	C7^v—K1—C8^v	24.83 (10)
C5—O2—K1ⁱⁱ	136.3 (3)	C8^vi—K1—C8^v	76.39 (8)
K1ⁱ—O2—K1ⁱⁱ	101.51 (10)	C5^iv—K1—C8^v	173.89 (10)
C5—O2—K1	92.6 (2)	O2^iv—K1—K1ⁱⁱ	90.24 (7)
K1ⁱ—O2—K1	101.77 (9)	O3—K1—K1ⁱⁱ	81.25 (7)
K1ⁱⁱ—O2—K1	100.16 (10)	O2^v—K1—K1ⁱⁱ	39.02 (7)
C5—O3—K1	94.5 (2)	O4^v—K1—K1ⁱⁱ	92.38 (7)
C8—O4—K1ⁱⁱ	108.2 (2)	O2—K1—K1ⁱⁱ	39.68 (6)
C8—O4—K1ⁱⁱⁱ	103.6 (3)	O4^vi—K1—K1ⁱⁱ	143.56 (7)
K1ⁱⁱ—O4—K1ⁱⁱⁱ	99.74 (9)	C5—K1—K1ⁱⁱ	58.85 (8)
C8—O4—H4A	109.5	C7^v—K1—K1ⁱⁱ	66.94 (8)
K1ⁱⁱ—O4—H4A	133.2	C8^vi—K1—K1ⁱⁱ	123.66 (8)
K1ⁱⁱⁱ—O4—H4A	97.3	C5^iv—K1—K1ⁱⁱ	99.19 (7)
C6—O5—C3	109.4 (3)	C8^v—K1—K1ⁱⁱ	85.90 (8)

O1—C1—C2—C3	168.2 (6)	C5—O2—K1—O3	−6.0 (2)
N1—C1—C2—C3	−9.2 (3)	K1ⁱ—O2—K1—O3	111.90 (16)
C1—C2—C3—O5	−98.0 (4)	K1ⁱⁱ—O2—K1—O3	−143.96 (16)
C1—C2—C3—N1	8.8 (3)	C5—O2—K1—O2^v	138.9 (2)
N1—C4—C5—O2	151.2 (4)	K1ⁱ—O2—K1—O2^v	−103.25 (11)
C6—C4—C5—O2	31.4 (5)	K1ⁱⁱ—O2—K1—O2^v	0.89 (9)
N1—C4—C5—O3	−30.8 (6)	C5—O2—K1—O4^v	−114.7 (3)
C6—C4—C5—O3	−150.6 (4)	K1ⁱ—O2—K1—O4^v	3.21 (10)
N1—C4—C5—K1	52 (2)	K1ⁱⁱ—O2—K1—O4^v	107.35 (10)
C6—C4—C5—K1	−67.5 (19)	C5—O2—K1—O4^vi	−45.1 (17)
N1—C4—C5—K1ⁱ	−161.8 (3)	K1ⁱ—O2—K1—O4^vi	72.8 (16)
C6—C4—C5—K1ⁱ	78.4 (4)	K1ⁱⁱ—O2—K1—O4^vi	177 (45)
N1—C4—C6—C7	174.2 (4)	K1ⁱ—O2—K1—C5	117.9 (3)
C5—C4—C6—C7	−58.6 (6)	K1ⁱⁱ—O2—K1—C5	−138.0 (3)
N1—C4—C6—O5	−2.6 (4)	C5—O2—K1—C7^v	−160.2 (3)
C5—C4—C6—O5	124.7 (4)	K1ⁱ—O2—K1—C7^v	−42.33 (11)
O5—C6—C7—C8	−3.7 (7)	K1ⁱⁱ—O2—K1—C7^v	61.82 (11)
C4—C6—C7—C8	179.9 (4)	C5—O2—K1—C8^vi	−176.9 (3)
O5—C6—C7—K1ⁱⁱ	−106.5 (4)	K1ⁱ—O2—K1—C8^vi	−59.1 (3)
C4—C6—C7—K1ⁱⁱ	77.1 (5)	K1ⁱⁱ—O2—K1—C8^vi	45.1 (3)
C6—C7—C8—O4	−137.0 (5)	C5—O2—K1—C5^iv	43.6 (2)
K1ⁱⁱ—C7—C8—O4	−26.9 (3)	K1ⁱ—O2—K1—C5^iv	161.47 (10)
C6—C7—C8—K1ⁱⁱⁱ	173.3 (5)	K1ⁱⁱ—O2—K1—C5^iv	−94.39 (11)
K1ⁱⁱ—C7—C8—K1ⁱⁱⁱ	−76.57 (10)	C5—O2—K1—C8^v	−135.7 (3)
C6—C7—C8—K1ⁱⁱ	−110.1 (5)	K1ⁱ—O2—K1—C8^v	−17.85 (11)
O3—C5—O2—K1ⁱ	−92.7 (4)	K1ⁱⁱ—O2—K1—C8^v	86.29 (10)
C4—C5—O2—K1ⁱ	85.1 (4)	C5—O2—K1—K1ⁱⁱ	138.0 (3)
K1—C5—O2—K1ⁱ	−104.54 (19)	K1ⁱ—O2—K1—K1ⁱⁱ	−104.15 (11)
O3—C5—O2—K1ⁱⁱ	119.4 (4)	O2—C5—K1—O2^iv	−120.1 (3)
C4—C5—O2—K1ⁱⁱ	−62.7 (5)	O3—C5—K1—O2^iv	70.9 (3)
K1—C5—O2—K1ⁱⁱ	107.6 (3)	C4—C5—K1—O2^iv	−16.8 (18)
K1ⁱ—C5—O2—K1ⁱⁱ	−147.8 (5)	K1ⁱ—C5—K1—O2^iv	−163.73 (9)
O3—C5—O2—K1	11.8 (5)	O2—C5—K1—O3	169.1 (4)
C4—C5—O2—K1	−170.3 (3)	C4—C5—K1—O3	−87.6 (18)
K1ⁱ—C5—O2—K1	104.54 (19)	K1ⁱ—C5—K1—O3	125.4 (3)
O2—C5—O3—K1	−12.0 (5)	O2—C5—K1—O2^v	−40.5 (2)
C4—C5—O3—K1	170.1 (3)	O3—C5—K1—O2^v	150.5 (3)
K1ⁱ—C5—O3—K1	−63.5 (2)	C4—C5—K1—O2^v	62.8 (18)
C7—C8—O4—K1ⁱⁱ	32.7 (4)	K1ⁱ—C5—K1—O2^v	−84.14 (9)
K1ⁱⁱⁱ—C8—O4—K1ⁱⁱ	105.23 (18)	O2—C5—K1—O4^v	63.2 (2)
C7—C8—O4—K1ⁱⁱⁱ	−72.5 (3)	O3—C5—K1—O4^v	−105.9 (3)
K1ⁱⁱ—C8—O4—K1ⁱⁱⁱ	−105.23 (18)	C4—C5—K1—O4^v	166.5 (18)
C7—C6—O5—C3	173.7 (4)	K1ⁱ—C5—K1—O4^v	19.52 (9)
C4—C6—O5—C3	−9.2 (4)	O3—C5—K1—O2	−169.1 (4)
N1—C3—O5—C6	16.9 (4)	C4—C5—K1—O2	103.3 (19)
C2—C3—O5—C6	113.9 (4)	K1ⁱ—C5—K1—O2	−43.7 (2)
O1—C1—N1—C4	−53.6 (7)	O2—C5—K1—O4^vi	174.7 (2)
C2—C1—N1—C4	124.1 (4)	O3—C5—K1—O4^vi	5.7 (4)
O1—C1—N1—C3	−168.1 (6)	C4—C5—K1—O4^vi	−82.0 (19)
C2—C1—N1—C3	9.6 (3)	K1ⁱ—C5—K1—O4^vi	131.1 (2)
C6—C4—N1—C1	−91.7 (5)	O2—C5—K1—C7^v	20.4 (3)
C5—C4—N1—C1	141.3 (4)	O3—C5—K1—C7^v	−148.7 (3)
C6—C4—N1—C3	13.0 (4)	C4—C5—K1—C7^v	123.7 (18)
C5—C4—N1—C3	−114.0 (4)	K1ⁱ—C5—K1—C7^v	−23.27 (12)
O5—C3—N1—C1	106.3 (3)	O2—C5—K1—C8^vi	154 (2)
C2—C3—N1—C1	−9.5 (3)	O3—C5—K1—C8^vi	−15 (2)
O5—C3—N1—C4	−18.9 (4)	C4—C5—K1—C8^vi	−103 (3)
C2—C3—N1—C4	−134.7 (3)	K1ⁱ—C5—K1—C8^vi	110 (2)
C5—O3—K1—O2^iv	−107.7 (3)	O2—C5—K1—C5^iv	−136.3 (2)
C5—O3—K1—O2^v	−33.2 (3)	O3—C5—K1—C5^iv	54.6 (3)
C5—O3—K1—O4^v	75.2 (3)	C4—C5—K1—C5^iv	−33.0 (19)
C5—O3—K1—O2	6.0 (2)	K1ⁱ—C5—K1—C5^iv	180.0
C5—O3—K1—O4^vi	−176.7 (2)	O2—C5—K1—C8^v	46.1 (3)
C5—O3—K1—C7^v	37.6 (3)	O3—C5—K1—C8^v	−123.0 (3)
C5—O3—K1—C8^vi	178.5 (2)	C4—C5—K1—C8^v	149.4 (18)
C5—O3—K1—C5^iv	−120.0 (3)	K1ⁱ—C5—K1—C8^v	2.41 (12)
C5—O3—K1—C8^v	64.7 (3)	O2—C5—K1—K1ⁱⁱ	−30.0 (2)
C5—O3—K1—K1ⁱⁱ	−16.4 (2)	O3—C5—K1—K1ⁱⁱ	161.0 (3)
C5—O2—K1—O2^iv	62.1 (3)	C4—C5—K1—K1ⁱⁱ	73.4 (18)
K1ⁱ—O2—K1—O2^iv	180.0	K1ⁱ—C5—K1—K1ⁱⁱ	−73.62 (7)
K1ⁱⁱ—O2—K1—O2^iv	−75.85 (11)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4A···O3^vii	0.84	1.90	2.673 (5)	153

Symmetry code: (vii) x+1, y+1, z.

Experimental details

Crystal data
Chemical formula	K⁺·C₈H₈NO₅⁻
M_r	237.25
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	173
a, b, c (Å)	4.3453 (6), 7.8191 (11), 27.491 (3)
V (Å³)	934.1 (2)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.57
Crystal size (mm)	0.24 × 0.04 × 0.01

Data collection
Diffractometer	Rigaku R-AXIS RAPID IP area-detector
Absorption correction	Multi-scan (ABSCOR; Higashi, 1995)
T_min, T_max	0.876, 0.994
No. of measured, independent and observed [I > 2σ(I)] reflections	9047, 2138, 1433
R_int	0.088
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.118, 1.12
No. of reflections	2138
No. of parameters	137
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.52, −0.56
Absolute structure	Flack (1983), 839 Friedel pairs
Absolute structure parameter	−0.05 (9)

Computer programs: PROCESS-AUTO (Rigaku, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997).

Selected bond lengths (Å) top

O2—K1ⁱ	2.773 (3)	O3—K1	2.786 (3)
O2—K1ⁱⁱ	2.799 (3)	O4—K1ⁱⁱ	2.818 (4)
O2—K1	2.827 (3)	O4—K1ⁱⁱⁱ	2.865 (4)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4A···O3^iv	0.840	1.898	2.673 (5)	152.75

Symmetry code: (iv) x+1, y+1, z.

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

Search IUCr Journals		doi		Advanced search
Author		volume	page