In the crystal structure of the title hydrated salt, poly[(μ2-aqua)(μ4-1-sulfido-β-D-glucoside)potassium], [K(C6H11O5S)(H2O)]n or K+·C6H11O5S−·H2O, each thioglucoside anion coordinates to four K+ cations through three of its four hydroxy groups, forming a three-dimensional polymeric structure. The negatively charged thiolate group in each anion does not form an efficient coordination bond with a K+ cation, but forms intermolecular hydrogen bonds with four hydroxy groups, which appears to sustain the polymeric structure. The Cremer–Pople parameters for the thioglucoside ligand (Q = 0.575, θ = 8.233° and φ = 353.773°) indicate a slight distortion of the pyranose ring.
Supporting information
CCDC reference: 915097
A sample of 2,3,4,6-O-acetyl-1-thio-β-D-glucose (4.99 g, 0.144 mol) was
added to a solution containing KOH (2.23 g, 0.391 mol) in methanol (200 ml).
After stirring for 9 h under an N2 atmosphere, the resulting white powder
was collected by filtration, washed with ethanol and acetone, and dried in
vacuo (yield 2.47 g, 70%). Analysis calculated for C6H13KO6S: C
28.56, H 5.19%; found: C 28.53, H 4.95%. 1H NMR [400 MHz, D2O, p.p.m. from
sodium 3-(trimethylsilyl)propane-1-sulfonate (DSS)]: δ 4.52 (1H, t,
J = 9.0 Hz), 3.84 (1H, dd, J = 12.5, 1.5 Hz), 3.67–3.64
(1H, m), 3.42–3.37 (3H, m), 3.03–2.99 (1H, m). Single
crystals of (I) suitable for X-ray analysis were obtained by diffusion of
acetone to its aqueous solution.
H atoms bound to C atoms were placed at calculated positions [C—H = 0.99
(CH2) and 1.00 Å (CH)] and refined as riding, with Uiso(H) =
1.2Ueq(C). All H atoms bound to O atoms were located in a difference
Fourier map and were refined with distance restraints and constrained
displacement parameters [O—H = 0.84 (2) Å and Uiso(H) =
1.2Ueq(O)].
Data collection: RAPID-AUTO (Rigaku, 2000); cell refinement: RAPID-AUTO (Rigaku, 2000); data reduction: RAPID-AUTO (Rigaku, 2000); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Yadokari-XG 2009 (Kabuto et al., 2009); software used to prepare material for publication: Yadokari-XG 2009 (Kabuto et al., 2009).
Poly[(µ
2-aqua)(µ
4-1-sulfido-
β-D-glucoside)potassium]
top
Crystal data top
K+·C6H11O5S−·H2O | F(000) = 528 |
Mr = 252.32 | Dx = 1.726 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71075 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 9342 reflections |
a = 6.8625 (3) Å | θ = 3.3–27.5° |
b = 10.0319 (4) Å | µ = 0.76 mm−1 |
c = 14.1026 (6) Å | T = 200 K |
V = 970.88 (7) Å3 | Block, colourless |
Z = 4 | 0.30 × 0.15 × 0.15 mm |
Data collection top
Rigaku R-AXIS RAPID diffractometer | 2209 independent reflections |
Radiation source: rotating-anode X-ray tube | 2171 reflections with I > 2σ(I) |
Detector resolution: 10.000 pixels mm-1 | Rint = 0.079 |
ω scans | θmax = 27.5°, θmin = 3.3° |
Absorption correction: multi-scan (ABSCOR; Rigaku, 1995) | h = −8→8 |
Tmin = 0.803, Tmax = 0.894 | k = −12→12 |
9524 measured reflections | l = −18→17 |
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)] = 0.038 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.078 | w = 1/[σ2(Fo2) + (0.0268P)2 + 0.2347P] where P = (Fo2 + 2Fc2)/3 |
S = 1.10 | (Δ/σ)max < 0.001 |
2209 reflections | Δρmax = 0.60 e Å−3 |
145 parameters | Δρmin = −0.30 e Å−3 |
6 restraints | Absolute structure: Flack (1983), 913 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.01 (4) |
Crystal data top
K+·C6H11O5S−·H2O | V = 970.88 (7) Å3 |
Mr = 252.32 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 6.8625 (3) Å | µ = 0.76 mm−1 |
b = 10.0319 (4) Å | T = 200 K |
c = 14.1026 (6) Å | 0.30 × 0.15 × 0.15 mm |
Data collection top
Rigaku R-AXIS RAPID diffractometer | 2209 independent reflections |
Absorption correction: multi-scan (ABSCOR; Rigaku, 1995) | 2171 reflections with I > 2σ(I) |
Tmin = 0.803, Tmax = 0.894 | Rint = 0.079 |
9524 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.038 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.078 | Δρmax = 0.60 e Å−3 |
S = 1.10 | Δρmin = −0.30 e Å−3 |
2209 reflections | Absolute structure: Flack (1983), 913 Friedel pairs |
145 parameters | Absolute structure parameter: −0.01 (4) |
6 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 | Uiso*/Ueq | |
K1 | 0.31561 (6) | 0.16793 (4) | 0.45442 (3) | 0.01885 (13) | |
S1 | 0.48800 (7) | 0.05321 (4) | 0.23337 (3) | 0.01553 (13) | |
O1 | 0.6474 (2) | 0.27794 (13) | 0.37124 (9) | 0.0157 (3) | |
H1 | 0.593 (3) | 0.3434 (19) | 0.3516 (18) | 0.019* | |
O2 | 1.0557 (2) | 0.34495 (14) | 0.36133 (9) | 0.0164 (3) | |
H2 | 1.077 (4) | 0.4226 (17) | 0.3659 (18) | 0.020* | |
O3 | 1.1838 (2) | 0.38611 (14) | 0.16017 (10) | 0.0196 (3) | |
H3 | 1.268 (3) | 0.409 (2) | 0.1990 (17) | 0.023* | |
O4 | 0.80599 (19) | 0.13386 (11) | 0.14342 (9) | 0.0130 (3) | |
O5 | 1.1684 (2) | 0.07274 (13) | 0.04992 (10) | 0.0220 (3) | |
H5 | 1.251 (4) | 0.097 (2) | 0.0918 (16) | 0.026* | |
O6 | 0.4025 (3) | 0.44051 (14) | 0.50182 (11) | 0.0285 (4) | |
H6 | 0.415 (4) | 0.481 (3) | 0.4519 (15) | 0.034* | |
H6A | 0.377 (4) | 0.493 (2) | 0.5441 (17) | 0.034* | |
C1 | 0.6660 (3) | 0.18275 (17) | 0.21185 (12) | 0.0117 (3) | |
H1A | 0.5982 | 0.2622 | 0.1846 | 0.014* | |
C2 | 0.7766 (3) | 0.22580 (17) | 0.30113 (13) | 0.0116 (4) | |
H2A | 0.8406 | 0.1448 | 0.3284 | 0.014* | |
C3 | 0.9375 (3) | 0.32768 (17) | 0.27842 (12) | 0.0116 (4) | |
H3A | 0.8759 | 0.4149 | 0.2616 | 0.014* | |
C4 | 1.0637 (3) | 0.28117 (18) | 0.19605 (13) | 0.0121 (4) | |
H4 | 1.1473 | 0.2051 | 0.2170 | 0.015* | |
C5 | 0.9372 (3) | 0.23761 (16) | 0.11335 (13) | 0.0122 (4) | |
H5A | 0.8579 | 0.3158 | 0.0922 | 0.015* | |
C6 | 1.0506 (3) | 0.18609 (18) | 0.02932 (13) | 0.0152 (4) | |
H6B | 0.9579 | 0.1624 | −0.0217 | 0.018* | |
H6C | 1.1353 | 0.2584 | 0.0052 | 0.018* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
K1 | 0.0211 (2) | 0.0184 (2) | 0.0171 (2) | −0.00043 (16) | 0.00256 (16) | 0.00053 (15) |
S1 | 0.0118 (2) | 0.0161 (2) | 0.0188 (2) | −0.00296 (17) | −0.00001 (18) | −0.00087 (16) |
O1 | 0.0179 (8) | 0.0166 (6) | 0.0125 (6) | 0.0018 (5) | 0.0037 (6) | −0.0004 (5) |
O2 | 0.0194 (8) | 0.0155 (6) | 0.0144 (6) | −0.0014 (5) | −0.0051 (5) | −0.0025 (5) |
O3 | 0.0193 (8) | 0.0237 (7) | 0.0156 (7) | −0.0105 (6) | 0.0001 (6) | 0.0021 (5) |
O4 | 0.0135 (7) | 0.0134 (6) | 0.0120 (6) | −0.0027 (5) | 0.0026 (5) | −0.0017 (4) |
O5 | 0.0263 (8) | 0.0176 (7) | 0.0220 (7) | 0.0064 (6) | −0.0021 (6) | −0.0056 (5) |
O6 | 0.0476 (11) | 0.0181 (7) | 0.0197 (8) | 0.0009 (7) | 0.0056 (7) | 0.0001 (6) |
C1 | 0.0103 (9) | 0.0125 (8) | 0.0123 (8) | 0.0003 (7) | −0.0002 (6) | −0.0007 (6) |
C2 | 0.0109 (9) | 0.0131 (8) | 0.0107 (8) | 0.0006 (7) | 0.0005 (7) | −0.0001 (6) |
C3 | 0.0127 (9) | 0.0110 (7) | 0.0112 (8) | −0.0010 (7) | −0.0022 (6) | −0.0015 (6) |
C4 | 0.0117 (10) | 0.0123 (8) | 0.0123 (8) | 0.0003 (6) | 0.0008 (7) | 0.0013 (6) |
C5 | 0.0129 (10) | 0.0117 (8) | 0.0120 (8) | −0.0012 (6) | −0.0002 (7) | 0.0006 (6) |
C6 | 0.0164 (10) | 0.0163 (9) | 0.0128 (8) | −0.0016 (7) | 0.0029 (7) | 0.0000 (6) |
Geometric parameters (Å, º) top
K1—O5i | 2.7669 (14) | O4—C1 | 1.447 (2) |
K1—O1ii | 2.7699 (14) | O5—C6 | 1.425 (2) |
K1—O1 | 2.7890 (14) | O5—K1vi | 2.7669 (14) |
K1—O2iii | 2.8387 (14) | O5—H5 | 0.852 (17) |
K1—O6 | 2.8774 (16) | O6—K1iv | 3.099 (2) |
K1—O2ii | 3.0795 (15) | O6—H6 | 0.815 (18) |
K1—O6ii | 3.099 (2) | O6—H6A | 0.816 (17) |
K1—S1 | 3.5273 (6) | C1—C2 | 1.532 (2) |
K1—H1 | 2.97 (2) | C1—H1A | 1.0000 |
S1—C1 | 1.8092 (18) | C2—C3 | 1.538 (3) |
O1—C2 | 1.427 (2) | C2—H2A | 1.0000 |
O1—K1iv | 2.7699 (14) | C3—C4 | 1.522 (3) |
O1—H1 | 0.803 (17) | C3—H3A | 1.0000 |
O2—C3 | 1.434 (2) | C4—C5 | 1.518 (3) |
O2—K1v | 2.8388 (14) | C4—H4 | 1.0000 |
O2—K1iv | 3.0795 (15) | C5—C6 | 1.509 (3) |
O2—H2 | 0.795 (16) | C5—H5A | 1.0000 |
O3—C4 | 1.430 (2) | C6—H6B | 0.9900 |
O3—H3 | 0.830 (17) | C6—H6C | 0.9900 |
O4—C5 | 1.440 (2) | | |
| | | |
O5i—K1—O1ii | 75.85 (4) | K1iv—O2—H2 | 94.2 (19) |
O5i—K1—O1 | 121.18 (5) | C4—O3—H3 | 111.8 (19) |
O1ii—K1—O1 | 129.49 (4) | C5—O4—C1 | 111.49 (12) |
O5i—K1—O2iii | 142.74 (5) | C6—O5—K1vi | 128.28 (11) |
O1ii—K1—O2iii | 91.49 (4) | C6—O5—H5 | 107.0 (18) |
O1—K1—O2iii | 94.07 (4) | K1vi—O5—H5 | 123.9 (18) |
O5i—K1—O6 | 135.07 (5) | K1—O6—K1iv | 84.39 (4) |
O1ii—K1—O6 | 72.17 (4) | K1—O6—H6 | 107 (2) |
O1—K1—O6 | 63.42 (5) | K1iv—O6—H6 | 104 (2) |
O2iii—K1—O6 | 69.09 (5) | K1—O6—H6A | 138 (2) |
O5i—K1—O2ii | 62.06 (4) | K1iv—O6—H6A | 106 (2) |
O1ii—K1—O2ii | 58.81 (4) | H6—O6—H6A | 110 (3) |
O1—K1—O2ii | 86.25 (4) | O4—C1—C2 | 108.34 (14) |
O2iii—K1—O2ii | 138.82 (2) | O4—C1—S1 | 108.46 (11) |
O6—K1—O2ii | 74.52 (4) | C2—C1—S1 | 113.52 (12) |
O5i—K1—O6ii | 68.46 (5) | O4—C1—H1A | 108.8 |
O1ii—K1—O6ii | 60.71 (4) | C2—C1—H1A | 108.8 |
O1—K1—O6ii | 165.85 (4) | S1—C1—H1A | 108.8 |
O2iii—K1—O6ii | 74.74 (4) | O1—C2—C1 | 111.40 (15) |
O6—K1—O6ii | 118.48 (5) | O1—C2—C3 | 110.28 (14) |
O2ii—K1—O6ii | 107.86 (4) | C1—C2—C3 | 111.82 (14) |
O5i—K1—S1 | 97.60 (3) | O1—C2—H2A | 107.7 |
O1ii—K1—S1 | 171.19 (3) | C1—C2—H2A | 107.7 |
O1—K1—S1 | 58.91 (3) | C3—C2—H2A | 107.7 |
O2iii—K1—S1 | 90.35 (3) | O2—C3—C4 | 109.74 (14) |
O6—K1—S1 | 116.48 (4) | O2—C3—C2 | 108.46 (14) |
O2ii—K1—S1 | 123.54 (3) | C4—C3—C2 | 111.31 (14) |
O6ii—K1—S1 | 111.61 (3) | O2—C3—H3A | 109.1 |
O5i—K1—H1 | 136.8 (4) | C4—C3—H3A | 109.1 |
O1ii—K1—H1 | 125.7 (5) | C2—C3—H3A | 109.1 |
O1—K1—H1 | 15.6 (4) | O3—C4—C5 | 105.65 (15) |
O2iii—K1—H1 | 78.9 (4) | O3—C4—C3 | 111.86 (14) |
O6—K1—H1 | 54.4 (5) | C5—C4—C3 | 110.45 (15) |
O2ii—K1—H1 | 95.4 (4) | O3—C4—H4 | 109.6 |
O6ii—K1—H1 | 153.1 (4) | C5—C4—H4 | 109.6 |
S1—K1—H1 | 63.1 (5) | C3—C4—H4 | 109.6 |
C1—S1—K1 | 98.07 (6) | O4—C5—C6 | 107.83 (14) |
C2—O1—K1iv | 115.34 (11) | O4—C5—C4 | 109.83 (15) |
C2—O1—K1 | 130.80 (11) | C6—C5—C4 | 114.00 (16) |
K1iv—O1—K1 | 92.55 (4) | O4—C5—H5A | 108.3 |
C2—O1—H1 | 110.3 (19) | C6—C5—H5A | 108.3 |
K1iv—O1—H1 | 109.8 (18) | C4—C5—H5A | 108.3 |
K1—O1—H1 | 95.2 (18) | O5—C6—C5 | 113.95 (15) |
C3—O2—K1v | 131.08 (10) | O5—C6—H6B | 108.8 |
C3—O2—K1iv | 112.36 (10) | C5—C6—H6B | 108.8 |
K1v—O2—K1iv | 85.39 (4) | O5—C6—H6C | 108.8 |
C3—O2—H2 | 106.8 (18) | C5—C6—H6C | 108.8 |
K1v—O2—H2 | 117.2 (19) | H6B—C6—H6C | 107.7 |
| | | |
O5i—K1—S1—C1 | −132.51 (7) | K1—S1—C1—O4 | 159.21 (10) |
O1—K1—S1—C1 | −10.54 (7) | K1—S1—C1—C2 | 38.74 (13) |
O2iii—K1—S1—C1 | 84.00 (7) | K1iv—O1—C2—C1 | 172.83 (10) |
O6—K1—S1—C1 | 17.31 (7) | K1—O1—C2—C1 | 54.55 (19) |
O2ii—K1—S1—C1 | −71.11 (7) | K1iv—O1—C2—C3 | −62.39 (15) |
O6ii—K1—S1—C1 | 157.70 (7) | K1—O1—C2—C3 | 179.33 (10) |
O5i—K1—O1—C2 | 57.77 (15) | O4—C1—C2—O1 | 178.78 (13) |
O1ii—K1—O1—C2 | 155.14 (13) | S1—C1—C2—O1 | −60.69 (18) |
O2iii—K1—O1—C2 | −109.56 (14) | O4—C1—C2—C3 | 54.87 (18) |
O6—K1—O1—C2 | −173.73 (15) | S1—C1—C2—C3 | 175.40 (12) |
O2ii—K1—O1—C2 | 111.72 (14) | K1v—O2—C3—C4 | −53.89 (19) |
O6ii—K1—O1—C2 | −72.4 (2) | K1iv—O2—C3—C4 | −157.98 (10) |
S1—K1—O1—C2 | −21.61 (13) | K1v—O2—C3—C2 | 67.90 (18) |
O5i—K1—O1—K1iv | −69.41 (5) | K1iv—O2—C3—C2 | −36.18 (15) |
O1ii—K1—O1—K1iv | 27.96 (6) | O1—C2—C3—O2 | 65.60 (18) |
O2iii—K1—O1—K1iv | 123.26 (4) | C1—C2—C3—O2 | −169.86 (15) |
O6—K1—O1—K1iv | 59.09 (5) | O1—C2—C3—C4 | −173.58 (15) |
O2ii—K1—O1—K1iv | −15.46 (4) | C1—C2—C3—C4 | −49.0 (2) |
O6ii—K1—O1—K1iv | 160.44 (15) | O2—C3—C4—O3 | −73.20 (18) |
S1—K1—O1—K1iv | −148.79 (5) | C2—C3—C4—O3 | 166.72 (15) |
K1ii—K1—O1—K1iv | 87.04 (5) | O2—C3—C4—C5 | 169.42 (13) |
O5i—K1—O6—K1iv | 58.21 (8) | C2—C3—C4—C5 | 49.34 (19) |
O1ii—K1—O6—K1iv | 104.88 (5) | C1—O4—C5—C6 | −169.13 (14) |
O1—K1—O6—K1iv | −50.34 (4) | C1—O4—C5—C4 | 66.10 (17) |
O2iii—K1—O6—K1iv | −156.37 (5) | O3—C4—C5—O4 | −178.36 (13) |
O2ii—K1—O6—K1iv | 43.26 (3) | C3—C4—C5—O4 | −57.22 (18) |
O6ii—K1—O6—K1iv | 145.49 (5) | O3—C4—C5—C6 | 60.52 (19) |
S1—K1—O6—K1iv | −76.91 (4) | C3—C4—C5—C6 | −178.34 (14) |
K1ii—K1—O6—K1iv | 150.97 (4) | K1vi—O5—C6—C5 | 128.85 (14) |
C5—O4—C1—C2 | −64.04 (17) | O4—C5—C6—O5 | −62.2 (2) |
C5—O4—C1—S1 | 172.33 (12) | C4—C5—C6—O5 | 60.1 (2) |
Symmetry codes: (i) −x+3/2, −y, z+1/2; (ii) x−1/2, −y+1/2, −z+1; (iii) x−1, y, z; (iv) x+1/2, −y+1/2, −z+1; (v) x+1, y, z; (vi) −x+3/2, −y, z−1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···S1vii | 0.80 (2) | 2.49 (2) | 3.2659 (14) | 164 (2) |
O2—H2···O4viii | 0.80 (2) | 2.27 (2) | 3.0505 (18) | 167 (3) |
O2—H2···O5viii | 0.80 (2) | 2.55 (2) | 3.026 (2) | 119 (2) |
O3—H3···S1viii | 0.83 (2) | 2.41 (2) | 3.1839 (15) | 156 (2) |
O5—H5···S1v | 0.85 (2) | 2.61 (2) | 3.3971 (16) | 154 (2) |
O6—H6···O4vii | 0.82 (2) | 2.55 (2) | 3.163 (2) | 134 (3) |
O6—H6···S1vii | 0.82 (2) | 2.79 (2) | 3.5839 (16) | 164 (3) |
O6—H6A···O3ix | 0.82 (2) | 2.08 (2) | 2.892 (2) | 175 (3) |
Symmetry codes: (v) x+1, y, z; (vii) −x+1, y+1/2, −z+1/2; (viii) −x+2, y+1/2, −z+1/2; (ix) −x+3/2, −y+1, z+1/2. |
Experimental details
Crystal data |
Chemical formula | K+·C6H11O5S−·H2O |
Mr | 252.32 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 200 |
a, b, c (Å) | 6.8625 (3), 10.0319 (4), 14.1026 (6) |
V (Å3) | 970.88 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.76 |
Crystal size (mm) | 0.30 × 0.15 × 0.15 |
|
Data collection |
Diffractometer | Rigaku R-AXIS RAPID diffractometer |
Absorption correction | Multi-scan (ABSCOR; Rigaku, 1995) |
Tmin, Tmax | 0.803, 0.894 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9524, 2209, 2171 |
Rint | 0.079 |
(sin θ/λ)max (Å−1) | 0.649 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.078, 1.10 |
No. of reflections | 2209 |
No. of parameters | 145 |
No. of restraints | 6 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.60, −0.30 |
Absolute structure | Flack (1983), 913 Friedel pairs |
Absolute structure parameter | −0.01 (4) |
Selected bond lengths (Å) topK1—O5i | 2.7669 (14) | K1—O6 | 2.8774 (16) |
K1—O1ii | 2.7699 (14) | K1—O2ii | 3.0795 (15) |
K1—O1 | 2.7890 (14) | K1—O6ii | 3.099 (2) |
K1—O2iii | 2.8387 (14) | K1—S1 | 3.5273 (6) |
Symmetry codes: (i) −x+3/2, −y, z+1/2; (ii) x−1/2, −y+1/2, −z+1; (iii) x−1, y, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···S1iv | 0.803 (17) | 2.486 (18) | 3.2659 (14) | 164 (2) |
O2—H2···O4v | 0.795 (16) | 2.270 (17) | 3.0505 (18) | 167 (3) |
O2—H2···O5v | 0.795 (16) | 2.55 (2) | 3.026 (2) | 119 (2) |
O3—H3···S1v | 0.830 (17) | 2.410 (19) | 3.1839 (15) | 156 (2) |
O5—H5···S1vi | 0.852 (17) | 2.613 (19) | 3.3971 (16) | 154 (2) |
O6—H6···O4iv | 0.815 (18) | 2.55 (2) | 3.163 (2) | 134 (3) |
O6—H6···S1iv | 0.815 (18) | 2.792 (19) | 3.5839 (16) | 164 (3) |
O6—H6A···O3vii | 0.816 (17) | 2.078 (18) | 2.892 (2) | 175 (3) |
Symmetry codes: (iv) −x+1, y+1/2, −z+1/2; (v) −x+2, y+1/2, −z+1/2; (vi) x+1, y, z; (vii) −x+3/2, −y+1, z+1/2. |
In recent years, thiosugars, especially thiol-containing monosaccharides, have attracted considerable attention; this is because of their unique chemical reactivity due to the presence of the thiol group, as well as the physicochemical and biochemical properties that are inherent in sugars (Witczak & Culhane, 2005). Among this class of compounds, 1-thio-β-D-glucose (H5tg) is one of the simplest thiol-containing hexoses and is commonly used as a raw material for artificial organic thioglycosides. In the field of coordination chemistry, H5tg has been used as a chiral ligand toward thiophilic metal centres, giving metal complexes with a deprotonated thiolate donor (Okamoto et al., 1994; Leipnitz et al., 2001). Owing to the presence of a sugar backbone in their structures, metal complexes derived from H5tg often show hydrophilicity and biocompatibility. Hence, H5tg and/or its metal complexes have been applied not only as anti-rheumatoid drugs (Shaw, 1999), but also as coating reagents for gold nanoparticles (Watanabe et al., 2010).
While the applications of H5tg have developed rapidly, crystallographic information is not extensive. The first structural investigation was made by Waser & Watson (1963) who elucidated the molecular structure of a H5tg residue in Sinigrin [potassium (E)-1-{[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]sulfanyl}but-3-enylideneamino sulfate], which is a kind of thioglycoside extracted from cruciferous plants. After this investigation, a number of S-substituted derivatives of H5tg were prepared and structurally characterized (Marsh & Waser, 1970; Jaki et al., 2002; Kuhn et al., 2004). Nevertheless, the structural determination of H5tg itself has not yet been reported and, furthermore, only two transition metal complexes derived from H5tg, namely [Co(H3tg-κ2S,O)(en)2]NO3 [Cambridge Structural Database (CSD) refcode ZIGGOL; Okamoto et al., 1994] and [ReO(tren)(H4tg-κS)] [tren is tris(2-aminoethyl)amine; CSD refcode AMONUL; Leipnitz et al., 2001] have been structurally characterized to date. In these complexes, H5tg is partially deprotonated and strongly bound to the metal centre through its thiolate donor group.
In the course of our study on the preparation of metal complexes derived from H5tg, we found that the hydrolysis of 2,3,4,6-O-acetyl-1-thio-β-D-glucose with KOH gave a monohydrate form of potassium 1-thio-β-D-glucose, viz. KH4tg.H2O, (I), which easily crystallized from water by diffusing acetone. Herein we report the molecular and supramolecular structure of (I). This is the first structural determination of an alkaline metal salt of thioglucose.
Salt (I) consists of one K+ cation, one H4tg- anion and one water molecule, all in general positions in the asymmetric unit (Fig. 1). The absolute configuration of five asymmetric C atoms (C1, C2, C3, C4 and C5) in the H4tg- anion were determined to be S, R, S, S and R, respectively, based on the Flack (1983) parameter. For the H4tg- anion, a thiol group is deprotonated while four hydroxy groups remain protonated. This is consistent with the higher acidity of a thiol group compared with a hydroxy group. As shown in Fig. 1, a thiolate S atom and three of four hydroxy O atoms in each H4tg- anion, together with a water O atom, bind to symmetry-related K+ ions. On the other hand, each K+ ion is bound by one thiolate S atom (S1), two bridging hydroxy O atoms (O1 and O2), and one monodentate hydroxy O atom (O5) from three H4tg- anions, as well as one bridging water O atom (O6). It is noteworthy that the K—S distance [K1—S1 = 3.5273 (6) Å; Table 1] is longer than the distances found in general potassium thiolates (3.055–3.216 Å; Chadwick et al., 1997). This implies that the thiolate group in the H4tg- anion does not have high coordination ability to a K+ ion. The other bond lengths and angles, involving K—O bonds [2.7669 (14)–3.099 (2) Å], are in the ranges normally observed for related compounds.
In (I), each K+ cation is triply bridged by three bridging oxygen atoms (O1, O2 and O6) to give a one-dimensional chain structure along the crystallographic a axis (Fig. 1). This chain structure is supported by K—S bonding interactions and intermolecular O—H···S hydrogen bonds [O5···S1vi; symmetry code: (vi) x+1, y, z]. Moreover, each one-dimensional chain connects with four neighbouring chains through K1—O5 bonds, completing a three-dimensional network structure in the crystal packing (Fig. 2). There exist four different O—H···O hydrogen bonds (Table 2) which also support the three-dimensional structure in (I).
As described above, the thiolate group of the H4tg- anion does not form an efficient coordination bond with a K+ cation but forms intermolecular hydrogen bonds with four hydroxy groups in (I). This result obviously shows that the thiolate group in the H4tg- anion acts as a good hydrogen-bonding acceptor even when an alkaline metal ion exists in its vicinity. Note that the thiolate group in [Co(H3tg-S,O)(en)2]NO3 forms only one intermolecular N—H···S hydrogen bond (N···S = 3.29 Å) and [ReO(tren)(H4tg-S)] does not form any hydrogen bonds, which is understood by the formation of a strong coordination bond with the transition metal centre.
In order to estimate the distortion of the pyranose ring, the Cremer–Pople theory involving the three parameters Q, θ and ϕ (Cremer & Pople, 1975) is useful. In this theory, the puckering of a six-membered ring is described as a spherical polar coordinate, where the radial distance, azimuthal angle and polar angle of the sphere are indicated by Q, θ and ϕ, respectively. The radius (Q) that shows the magnitude of puckering measures the deviation from the perfectly flat six-membered ring (Q = 0). The azimuthal angle (θ) measures the deviation from an ideal chair conformation (θ = 0 or 180°) to boat or twist-boat conformations (θ = 90°). The polar angle (ϕ) discriminates between boat and twist-boat conformations. The parameters of (I), [Co(H3tg-S,O)(en)2]NO3 and [ReO(tren)(H4tg-S)] are as follows: Q = 0.575, θ = 8.233° and ϕ = 353.773° for (I); Q = 0.577, θ = 14.303° and ϕ = 52.810° for [Co(H3tg-S,O)(en)2]NO3; Q = 0.555, θ = 3.112° and ϕ = 313.544° for [ReO(tren)(H4tg-S)]. The θ value increases in the sequence of [ReO(tren)(H4tg-S)] < (I) < [Co(H3tg-S,O)(en)2]NO3, showing that the distortion of the pyranose ring increases in this order. This is explained by the fact that the thioglucoside ligand coordinates to a metal centre in a chelating mode in (I) and [Co(H3tg-S,O)(en)2]NO3, while the ligand coordinates to a metal centre in a monodentate mode in [ReO(tren)(H4tg-S)]. In addition, the ligand coordinates to a K+ centre much more weakly than to a Co3+ centre, which is responsible for the less distorted pyranose ring in (I) compared with that in [Co(H3tg-S,O)(en)2]NO3.
In summary, this study provides a significant insight into the molecular and supramolecular structures of an alkaline metal salt of 1-thio-β-D-glucose for the first time. The crystal structure of (I) is composed of one-dimensional chains sustained by K—O coordination bonds, which are further assembled into a three-dimensional structure by forming K—O coordination bonds and O—H···O hydrogen bonds. Unlike the known transition metal complexes derived from H5tg, the thiolate group in H4tg- does not form an efficient coordination bond with K+ but forms multiple O—H···S hydrogen bonds in (I). This observation demonstrates that the thiolate group in H4tg- acts as a good hydrogen-bonding acceptr, which should contribute to the design and development of new thioglucose-based supramolecular systems.