supplementary materials
A second C-centred monoclinic modification of racemic potassium hydrogen malate monohydrate
The K+ cation in the racemic title compound, poly[aqua-![[mu]](/logos/entities/mu_rmgif.gif)
6-malato-potassium(I)], [K(C4H5O5)(H2O)]n, exists in an irregular eight-coordinate environment. The anions are linked through hydrogen bonds into a three-dimensional network. The coordination environment differs from the six-coordinate environment reported in another C-centred monoclinic modification [Geise, van Loock & Lenstra (1983). Acta Cryst. C39, 69-70].
DL-Malic acid (27 mg, 0.2 mmol) was mixed with potassium hydroxide (12 mg, 0.2 mmol) in water (10 ml) to give a blue solution. Slow evaporation of the solution gave colorless prismatic crystals.
Carbon- and oxygen-bound H atoms were positioned geometrically (C–H 0.97 – 0.97, O–H 0.82 Å), and were included in the refinement in the riding model approximation, with Uiso(H) set to 1.2 or 1.5Ueq(C,O).
The Flack parameter was refined from 82 Friedel pairs.
Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2007).
poly[aqua-µ
6-malato-potassium(I)]
top
Crystal data top
| [K(C4H5O5)(H2O)] | F(000) = 392 |
| Mr = 190.20 | Dx = 1.759 Mg m−3 |
| Monoclinic, Cc | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: C -2yc | Cell parameters from 1338 reflections |
| a = 10.534 (1) Å | θ = 3.0–27.0° |
| b = 10.494 (1) Å | µ = 0.72 mm−1 |
| c = 7.5640 (8) Å | T = 291 K |
| β = 120.801 (1)° | Prism, colorless |
| V = 718.19 (13) Å3 | 0.42 × 0.21 × 0.15 mm |
| Z = 4 | |
Data collection top
Bruker APEX area-detector
diffractometer | 876 independent reflections |
| Radiation source: fine-focus sealed tube | 839 reflections with I > 2σ(I) |
| graphite | Rint = 0.014 |
| φ and ω scans | θmax = 27.0°, θmin = 2.9° |
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996) | h = −13→10 |
| Tmin = 0.717, Tmax = 0.900 | k = −13→11 |
| 1561 measured reflections | l = −3→9 |
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)] = 0.034 | H-atom parameters constrained |
| wR(F2) = 0.124 | w = 1/[σ2(Fo2) + (0.0732P)2 + 2.0212P]
where P = (Fo2 + 2Fc2)/3 |
| S = 1.19 | (Δ/σ)max = 0.001 |
| 876 reflections | Δρmax = 0.41 e Å−3 |
| 100 parameters | Δρmin = −0.28 e Å−3 |
| 2 restraints | Absolute structure: Flack (1983), 82 Friedel pairs |
| Primary atom site location: structure-invariant direct methods | Flack parameter: −0.1 (1) |
Crystal data top
| [K(C4H5O5)(H2O)] | V = 718.19 (13) Å3 |
| Mr = 190.20 | Z = 4 |
| Monoclinic, Cc | Mo Kα radiation |
| a = 10.534 (1) Å | µ = 0.72 mm−1 |
| b = 10.494 (1) Å | T = 291 K |
| c = 7.5640 (8) Å | 0.42 × 0.21 × 0.15 mm |
| β = 120.801 (1)° | |
Data collection top
Bruker APEX area-detector
diffractometer | 876 independent reflections |
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996) | 839 reflections with I > 2σ(I) |
| Tmin = 0.717, Tmax = 0.900 | Rint = 0.014 |
| 1561 measured reflections | θmax = 27.0° |
Refinement top
| R[F2 > 2σ(F2)] = 0.034 | H-atom parameters constrained |
| wR(F2) = 0.124 | Δρmax = 0.41 e Å−3 |
| S = 1.19 | Δρmin = −0.28 e Å−3 |
| 876 reflections | Absolute structure: Flack (1983), 82 Friedel pairs |
| 100 parameters | Flack parameter: −0.1 (1) |
| 2 restraints | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top| | x | y | z | Uiso*/Ueq | |
| K1 | 0.50000 (12) | 0.56252 (10) | 0.50000 (14) | 0.0192 (3) | |
| O1 | 0.6110 (4) | 0.8267 (4) | 0.5299 (6) | 0.0203 (8) | |
| O2 | 0.8346 (4) | 0.8883 (4) | 0.5947 (6) | 0.0203 (8) | |
| O3 | 0.7334 (4) | 0.6285 (3) | 0.3048 (6) | 0.0202 (8) | |
| H3 | 0.8143 | 0.5933 | 0.3621 | 0.030* | |
| O4 | 0.6024 (4) | 0.6425 (4) | −0.1149 (6) | 0.0214 (8) | |
| O5 | 0.7244 (4) | 0.8251 (3) | −0.0892 (6) | 0.0212 (8) | |
| H5 | 0.6844 | 0.8079 | −0.2120 | 0.032* | |
| O6 | 0.8351 (5) | 0.5749 (4) | 0.7211 (7) | 0.0273 (9) | |
| H61 | 0.8632 | 0.6450 | 0.7751 | 0.041* | |
| H62 | 0.8621 | 0.5636 | 0.6381 | 0.041* | |
| C1 | 0.7049 (6) | 0.8543 (5) | 0.4753 (8) | 0.0158 (10) | |
| C2 | 0.6503 (6) | 0.8418 (5) | 0.2466 (8) | 0.0163 (10) | |
| H2A | 0.6570 | 0.9236 | 0.1921 | 0.020* | |
| H2B | 0.5477 | 0.8151 | 0.1729 | 0.020* | |
| C3 | 0.7450 (6) | 0.7435 (5) | 0.2164 (7) | 0.0163 (11) | |
| H3A | 0.8482 | 0.7717 | 0.2860 | 0.020* | |
| C4 | 0.6835 (6) | 0.7304 (5) | −0.0148 (8) | 0.0153 (10) | |
Atomic displacement parameters (Å2) top| | U11 | U22 | U33 | U12 | U13 | U23 |
| K1 | 0.0231 (5) | 0.0221 (5) | 0.0108 (5) | 0.0012 (5) | 0.0076 (4) | −0.0016 (5) |
| O1 | 0.0222 (18) | 0.0286 (19) | 0.0117 (18) | 0.0017 (16) | 0.0098 (16) | 0.0009 (15) |
| O2 | 0.0234 (19) | 0.0249 (18) | 0.0124 (18) | −0.0062 (16) | 0.0092 (16) | −0.0031 (16) |
| O3 | 0.027 (2) | 0.0168 (16) | 0.017 (2) | 0.0058 (15) | 0.0117 (17) | 0.0033 (14) |
| O4 | 0.0211 (19) | 0.0282 (19) | 0.0129 (18) | −0.0082 (16) | 0.0072 (16) | −0.0055 (15) |
| O5 | 0.026 (2) | 0.0260 (19) | 0.0121 (17) | −0.0078 (16) | 0.0097 (16) | −0.0032 (15) |
| O6 | 0.030 (2) | 0.032 (2) | 0.022 (2) | −0.0099 (19) | 0.0149 (18) | −0.0025 (18) |
| C1 | 0.024 (3) | 0.009 (2) | 0.014 (3) | 0.0053 (18) | 0.009 (2) | 0.0013 (17) |
| C2 | 0.017 (2) | 0.020 (2) | 0.010 (2) | 0.003 (2) | 0.006 (2) | 0.0007 (19) |
| C3 | 0.015 (2) | 0.025 (2) | 0.009 (3) | −0.0009 (19) | 0.007 (2) | 0.000 (2) |
| C4 | 0.019 (2) | 0.017 (2) | 0.014 (2) | 0.0032 (19) | 0.011 (2) | 0.0000 (18) |
Geometric parameters (Å, °) top
| K1—O1 | 2.972 (4) | O4—C4 | 1.222 (6) |
| K1—O2i | 2.858 (4) | O4—K1ix | 2.671 (4) |
| K1—O2ii | 2.689 (4) | O4—K1viii | 2.740 (4) |
| K1—O3iii | 3.094 (4) | O5—C4 | 1.318 (6) |
| K1—O4iv | 2.671 (4) | O5—K1x | 2.876 (4) |
| K1—O4iii | 2.740 (4) | O5—H5 | 0.8200 |
| K1—O5v | 2.876 (4) | O6—H61 | 0.8200 |
| K1—O6 | 3.038 (5) | O6—H62 | 0.8200 |
| O1—C1 | 1.285 (7) | C1—C2 | 1.524 (7) |
| O2—C1 | 1.243 (6) | C2—C3 | 1.531 (7) |
| O2—K1vi | 2.689 (4) | C2—H2A | 0.9700 |
| O2—K1vii | 2.858 (4) | C2—H2B | 0.9700 |
| O3—C3 | 1.415 (7) | C3—C4 | 1.529 (6) |
| O3—K1viii | 3.094 (4) | C3—H3A | 0.9800 |
| O3—H3 | 0.8200 | | |
| | | |
| O4iv—K1—O2ii | 147.89 (13) | K1vi—O2—K1vii | 92.34 (12) |
| O4iv—K1—O4iii | 126.01 (15) | C3—O3—K1viii | 115.4 (3) |
| O2ii—K1—O4iii | 85.38 (12) | C3—O3—H3 | 108.4 |
| O4iv—K1—O2i | 83.42 (12) | K1viii—O3—H3 | 108.4 |
| O2ii—K1—O2i | 106.65 (14) | C4—O4—K1ix | 132.6 (3) |
| O4iii—K1—O2i | 88.08 (13) | C4—O4—K1viii | 131.3 (4) |
| O4iv—K1—O5v | 85.55 (12) | K1ix—O4—K1viii | 95.41 (12) |
| O2ii—K1—O5v | 70.55 (11) | C4—O5—K1x | 136.1 (3) |
| O4iii—K1—O5v | 139.62 (12) | C4—O5—H5 | 103.1 |
| O2i—K1—O5v | 69.48 (12) | K1x—O5—H5 | 103.1 |
| O4iv—K1—O1 | 72.57 (11) | K1—O6—H61 | 109.5 |
| O2ii—K1—O1 | 84.69 (12) | K1—O6—H62 | 109.5 |
| O4iii—K1—O1 | 123.58 (12) | H61—O6—H62 | 109.5 |
| O2i—K1—O1 | 147.59 (12) | O2—C1—O1 | 124.9 (5) |
| O5v—K1—O1 | 86.90 (11) | O2—C1—C2 | 119.0 (5) |
| O4iv—K1—O6 | 71.32 (12) | O1—C1—C2 | 116.1 (5) |
| O2ii—K1—O6 | 120.74 (12) | C1—C2—C3 | 109.3 (4) |
| O4iii—K1—O6 | 70.91 (12) | C1—C2—H2A | 109.8 |
| O2i—K1—O6 | 125.09 (12) | C3—C2—H2A | 109.8 |
| O5v—K1—O6 | 149.39 (12) | C1—C2—H2B | 109.8 |
| O1—K1—O6 | 67.50 (11) | C3—C2—H2B | 109.8 |
| O4iv—K1—O3iii | 70.60 (11) | H2A—C2—H2B | 108.3 |
| O2ii—K1—O3iii | 141.05 (12) | O3—C3—C4 | 112.1 (4) |
| O4iii—K1—O3iii | 55.67 (11) | O3—C3—C2 | 106.5 (4) |
| O2i—K1—O3iii | 75.66 (11) | C4—C3—C2 | 107.7 (4) |
| O5v—K1—O3iii | 139.64 (12) | O3—C3—H3A | 110.1 |
| O1—K1—O3iii | 114.59 (11) | C4—C3—H3A | 110.1 |
| O6—K1—O3iii | 50.32 (11) | C2—C3—H3A | 110.1 |
| C1—O1—K1 | 121.6 (3) | O4—C4—O5 | 125.6 (5) |
| C1—O2—K1vi | 135.4 (3) | O4—C4—C3 | 121.9 (5) |
| C1—O2—K1vii | 125.8 (3) | O5—C4—C3 | 112.4 (4) |
| | | |
| O4iv—K1—O1—C1 | 127.0 (4) | O1—C1—C2—C3 | −119.5 (5) |
| O2ii—K1—O1—C1 | −76.0 (4) | K1viii—O3—C3—C4 | −21.2 (5) |
| O4iii—K1—O1—C1 | 4.9 (4) | K1viii—O3—C3—C2 | 96.4 (4) |
| O2i—K1—O1—C1 | 171.0 (3) | C1—C2—C3—O3 | 57.7 (5) |
| O5v—K1—O1—C1 | −146.7 (4) | C1—C2—C3—C4 | 178.1 (4) |
| O6—K1—O1—C1 | 50.5 (4) | K1ix—O4—C4—O5 | 12.0 (8) |
| O3iii—K1—O1—C1 | 68.7 (4) | K1viii—O4—C4—O5 | −179.5 (3) |
| K1viii—K1—O1—C1 | −33.2 (4) | K1ix—O4—C4—C3 | −170.3 (3) |
| K1vi—O2—C1—O1 | −3.5 (8) | K1viii—O4—C4—C3 | −1.8 (7) |
| K1vii—O2—C1—O1 | −147.1 (4) | K1x—O5—C4—O4 | −126.8 (5) |
| K1vi—O2—C1—C2 | 177.4 (3) | K1x—O5—C4—C3 | 55.3 (6) |
| K1vii—O2—C1—C2 | 33.8 (6) | O3—C3—C4—O4 | 17.0 (7) |
| K1—O1—C1—O2 | −112.4 (5) | C2—C3—C4—O4 | −99.9 (6) |
| K1—O1—C1—C2 | 66.7 (5) | O3—C3—C4—O5 | −165.0 (4) |
| O2—C1—C2—C3 | 59.7 (6) | C2—C3—C4—O5 | 78.1 (5) |
| Symmetry codes: (i) x−1/2, y−1/2, z; (ii) x−1/2, −y+3/2, z−1/2; (iii) x, −y+1, z+1/2; (iv) x, y, z+1; (v) x−1/2, −y+3/2, z+1/2; (vi) x+1/2, −y+3/2, z+1/2; (vii) x+1/2, y+1/2, z; (viii) x, −y+1, z−1/2; (ix) x, y, z−1; (x) x+1/2, −y+3/2, z−1/2. |
Hydrogen-bond geometry (Å, °) top
| D—H···A | D—H | H···A | D···A | D—H···A |
| O3—H3···O6viii | 0.82 | 2.13 | 2.607 (5) | 117 |
| O5—H5···O1ix | 0.82 | 1.70 | 2.491 (5) | 160 |
| O6—H61···O1vi | 0.82 | 2.34 | 2.831 (6) | 119 |
| O6—H62···O3 | 0.82 | 2.27 | 2.815 (6) | 124 |
| Symmetry codes: (viii) x, −y+1, z−1/2; (ix) x, y, z−1; (vi) x+1/2, −y+3/2, z+1/2. |
Table 1
Selected geometric parameters (Å) top| K1—O1 | 2.972 (4) | K1—O4iv | 2.671 (4) |
| K1—O2i | 2.858 (4) | K1—O4iii | 2.740 (4) |
| K1—O2ii | 2.689 (4) | K1—O5v | 2.876 (4) |
| K1—O3iii | 3.094 (4) | K1—O6 | 3.038 (5) |
| Symmetry codes: (i) x−1/2, y−1/2, z; (ii) x−1/2, −y+3/2, z−1/2; (iii) x, −y+1, z+1/2; (iv) x, y, z+1; (v) x−1/2, −y+3/2, z+1/2. |
Table 2
Hydrogen-bond geometry (Å, °) top
| D—H···A | D—H | H···A | D···A | D—H···A |
| O3—H3···O6vi | 0.82 | 2.13 | 2.607 (5) | 117 |
| O5—H5···O1vii | 0.82 | 1.70 | 2.491 (5) | 160 |
| O6—H61···O1viii | 0.82 | 2.34 | 2.831 (6) | 119 |
| O6—H62···O3 | 0.82 | 2.27 | 2.815 (6) | 124 |
| Symmetry codes: (vi) x, −y+1, z−1/2; (vii) x, y, z−1; (viii) x+1/2, −y+3/2, z+1/2. |
We thank Hunan University of Science and Engineering, China, and the University of Malaya for supporting this work.
Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191.
Bruker (2004). SMART (Version 6.36A) and SAINT (Version 6.36A). Bruker AXS Inc., Madison, Wisconsin, USA.
Flack, H. D. (1983). Acta Cryst. A39, 876–881.
Geise, H. J., Van Loock, J. F. J. & Lenstra, A. T. H. (1983). Acta Cryst. C39, 69–70.
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.
Westrip, S. P. (2007). publCIF. In preparation.
![[Figure 1]](./xu2280fig1thm.gif)
In the previous C-centered monoclinic modification of racemic potassium hydrogen malate hydrate (Geize et al., 1983), the potassium atom is in an octahedron of oxygen atoms, and for the carboxylate anion the ionized and un-ionized groups cannot be distinguished. In the present C-centered monoclinic modification, the potassium atom exists in an irregular, eight-coordinate environment (Table 1). The anion features unambiguous ionized and un-ionized groups; interestingly, the double-bond oxygen atom of the ionized group is the oxygen atom that is closest to potassium despite being involved in another briding interaction.