supplementary materials


zq2199 scheme

Acta Cryst. (2013). E69, o917    [ doi:10.1107/S160053681301266X ]

2-Acetylamino-1,3,4,6-tetra-O-(trimethylsilyl)-2-deoxy-[alpha]-D-glucopyranose

Z.-D. Cheng, Y.-L. Cui and J.-W. Mao

Abstract top

The title compound, C20H47NO6Si4, was synthesized by per-O-trimethylsilylation of N-acetyl-D-glucosamine using chlorotrimethylsilane in the presence of hexamethyldisiloxane. The trimethylsilyl group and acetamido group are located on the same side of the pyran ring, showing an [alpha]-configuration glycoside. One of the trimethylsilyl groups is disordered over two orientations, with site-occupancy factors of 0.625 (9) and 0.375 (9). In the crystal, N-H...O hydrogen bonds link the molecules into supramolecular chains along the a-axis direction.

Comment top

Per-O-trimethylsilylated glycopyranose was an useful intermediate for the construction of oligosaccharides and glycoconjugates (Du & Gervais-Hague, 2005). Per-trimethylsilylation of unprotected sugar could increase its solubility in organic solvents, and made selective acetylation available (Witschi et al., 2010). Hu et al. have developed an one-pot α-glycoside method which also used per-O-trimethylsilylated glycosides as starting materials (Hu et al., 2011; Wang et al., 2007). Currently we have applied considerable effort towards the construction of α-glycosides (Augé et al., 1985; Ronnow et al., 1994; Jervis et al., 2010). We have synthesized the title compound and report its crystal structure herein (for related structures, see: Odinokov et al., 2002; Hu et al., 2011).

The molecular structure of the title compound is shown in Fig. 1. In the molecule, the trimethylsilyl group and acetamido group are located on the same side of the pyran ring, showing α configuration glycoside. One of the trimethylsilyl group is disordered over two orientations with site-occupancy factors of 0.625 (9) and 0.375 (9). In the crystal structure, weak intermolecular N—H···O hydrogen bonds link the molecules into supramolecular chains along the a axis in the crystal (Fig. 2).

Related literature top

For background to the title compound, see: Augé et al. (1985); Ronnow et al. (1994); Du & Gervais-Hague (2005); Wang et al. (2007); Witschi & Gervais-Hague (2010). For related structures, see: Odinokov et al. (2002); Hu et al. (2011). For the synthesis, see: Loganathan & Trivedi (1987); Jervis et al. (2010).

Experimental top

To a solution of N-acetyl-D-glucosamine (1.0 g, 4.52 mmol) in pyridine (10 mL), hexamethyldisiloxane (HMDS) (8.0 mL, 38.90 mmol) and chlorotrimethylsilane (TMSCl) (4.0 mL, 31.64 mmol) were added sequentially. The solution was stirred at 353 K under a nitrogen atmosphere for 2 hours. After cooling to rt the mixture was poured into ice-water and extracted with hexane. The organic layers were washed with brine, dried with MgSO4, filtered, and concentrated in vacuum to furnish the crude product. The residue was purified by silica gel chromatography (petroether/ethyl acetate = 15:1) to afford the title compound. The crystal suitable for X-ray data collection was obtained by slow evaporation from a methanol solution (Jervis et al., 2010; Loganathan et al., 1987).

Refinement top

One of the trimethylsilyl group is disordered over two orientations with site-occupancy factors of 0.625 (9) and 0.375 (9). Some restraints and constraints had to be used to correct the geometry of the disordered components and the thermal parameters of the corresponding atoms. All H atoms were placed in geometrically idealized positions (C—H = 0.93–0.97Å) and constrained to ride on their parent atoms, with Uiso(H) = 1.5Ueq(C) for the methyl H atoms, and with Uiso(H) = 1.2Ueq(C) for the remaining H atoms.

Computing details top

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with 30% probability displacement ellipsoids.
[Figure 2] Fig. 2. Crystal packing of the title compound showing N—H···O hydrogen bonds.
2-Acetylamino-1,3,4,6-tetra-O-(trimethylsilyl)-2-deoxy-α-D-glucopyranose top
Crystal data top
C20H47NO6Si4F(000) = 1112
Mr = 509.95Dx = 1.019 Mg m3
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 1672 reflections
a = 9.4500 (7) Åθ = 3.2–29.6°
b = 12.8824 (9) ŵ = 0.21 mm1
c = 27.295 (3) ÅT = 293 K
V = 3322.9 (5) Å3Needle, colourless
Z = 40.38 × 0.20 × 0.19 mm
Data collection top
Agilent Xcalibur (Atlas, Gemini ultra)
diffractometer
3438 independent reflections
Radiation source: fine-focus sealed tube2105 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.046
Detector resolution: 10.3592 pixels mm-1θmax = 25.4°, θmin = 3.2°
ω scansh = 1110
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
k = 1215
Tmin = 0.926, Tmax = 0.962l = 3032
9896 measured reflections
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)] = 0.055Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.149H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.0744P)2 + 0.3973P]
where P = (Fo2 + 2Fc2)/3
3438 reflections(Δ/σ)max < 0.001
309 parametersΔρmax = 0.26 e Å3
183 restraintsΔρmin = 0.22 e Å3
Crystal data top
C20H47NO6Si4V = 3322.9 (5) Å3
Mr = 509.95Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 9.4500 (7) ŵ = 0.21 mm1
b = 12.8824 (9) ÅT = 293 K
c = 27.295 (3) Å0.38 × 0.20 × 0.19 mm
Data collection top
Agilent Xcalibur (Atlas, Gemini ultra)
diffractometer
3438 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
2105 reflections with I > 2σ(I)
Tmin = 0.926, Tmax = 0.962Rint = 0.046
9896 measured reflectionsθmax = 25.4°
Refinement top
R[F2 > 2σ(F2)] = 0.055H-atom parameters constrained
wR(F2) = 0.149Δρmax = 0.26 e Å3
S = 1.01Δρmin = 0.22 e Å3
3438 reflectionsAbsolute structure: ?
309 parametersFlack parameter: ?
183 restraintsRogers parameter: ?
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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*/UeqOcc. (<1)
Si11.01789 (16)0.89841 (11)0.87673 (6)0.0716 (4)
Si21.03616 (19)0.43173 (13)0.99519 (7)0.0911 (6)
Si30.9320 (2)0.31145 (12)0.84396 (7)0.0842 (5)
Si40.5209 (19)0.5532 (8)0.7757 (5)0.1318 (13)0.625 (9)
O10.7944 (3)0.6870 (3)0.85017 (13)0.0726 (9)
O20.9849 (3)0.7739 (2)0.88456 (12)0.0662 (9)
O30.7055 (3)0.7511 (5)1.00819 (18)0.1157 (16)
O40.9211 (3)0.4785 (3)0.95578 (13)0.0731 (10)
O50.9704 (4)0.4351 (3)0.85373 (13)0.0751 (9)
O60.6763 (5)0.5183 (4)0.79227 (17)0.1117 (16)
N10.9130 (3)0.7012 (3)0.97859 (14)0.0604 (11)
H11.00300.69910.98310.072*
C10.8492 (5)0.7328 (4)0.8930 (2)0.0646 (13)
H1A0.78630.78950.90290.077*
C20.8562 (4)0.6535 (4)0.93482 (18)0.0581 (12)
H20.75900.63200.94210.070*
C30.9380 (4)0.5563 (4)0.91906 (17)0.0593 (12)
H31.03860.57330.91560.071*
C40.8818 (5)0.5161 (4)0.87110 (18)0.0612 (12)
H40.78630.48860.87620.073*
C50.8759 (5)0.6012 (4)0.83238 (19)0.0690 (14)
H50.97230.62500.82530.083*
C61.0050 (8)0.9663 (5)0.9361 (2)0.113 (2)
H6A0.91090.95910.94890.170*
H6B1.02621.03860.93160.170*
H6C1.07140.93660.95880.170*
C71.1984 (6)0.9046 (5)0.8523 (2)0.0970 (19)
H7A1.26480.89070.87810.146*
H7B1.21560.97260.83920.146*
H7C1.20930.85380.82690.146*
C80.8876 (7)0.9521 (5)0.8333 (3)0.113 (2)
H8A0.86820.90190.80820.169*
H8B0.92511.01400.81860.169*
H8C0.80170.96840.85040.169*
C90.8345 (5)0.7478 (5)1.0119 (2)0.0715 (15)
C100.9086 (6)0.7965 (5)1.0546 (2)0.0879 (17)
H10A0.95050.86101.04460.132*
H10B0.98120.75051.06620.132*
H10C0.84170.80921.08040.132*
C111.0461 (9)0.5095 (7)1.0526 (2)0.140 (3)
H11A1.08000.57801.04520.209*
H11B1.10970.47651.07520.209*
H11C0.95370.51411.06710.209*
C121.2153 (7)0.4319 (6)0.9680 (3)0.129 (3)
H12A1.21130.40300.93560.194*
H12B1.27760.39090.98800.194*
H12C1.25000.50180.96630.194*
C130.9806 (11)0.2963 (6)1.0071 (4)0.163 (4)
H13A0.89200.29631.02430.245*
H13B1.05110.26211.02660.245*
H13C0.96980.26030.97650.245*
C141.0962 (9)0.2396 (5)0.8588 (3)0.132 (3)
H14A1.17550.27330.84360.198*
H14B1.08880.16970.84680.198*
H14C1.10940.23840.89370.198*
C150.7800 (8)0.2703 (6)0.8809 (3)0.124 (3)
H15A0.79230.29350.91400.185*
H15B0.77320.19590.88030.185*
H15C0.69500.29980.86760.185*
C160.8882 (11)0.2878 (5)0.7775 (3)0.140 (3)
H16A0.80260.32390.76920.210*
H16B0.87540.21470.77210.210*
H16C0.96420.31260.75730.210*
C170.8067 (7)0.5670 (5)0.7852 (2)0.0922 (18)
H17A0.79330.62710.76430.111*
H17B0.86970.51950.76830.111*
C18A0.4994 (16)0.7084 (13)0.7939 (6)0.161 (3)0.625 (9)
H18A0.54110.72120.82540.242*0.625 (9)
H18B0.40130.72760.79460.242*0.625 (9)
H18C0.54760.74880.76950.242*0.625 (9)
C190.5118 (19)0.5859 (15)0.7098 (5)0.151 (3)0.625 (9)
H19A0.57190.64430.70320.226*0.625 (9)
H19B0.41610.60280.70120.226*0.625 (9)
H19C0.54280.52750.69080.226*0.625 (9)
C20A0.3849 (15)0.4802 (14)0.8078 (6)0.170 (3)0.625 (9)
H20A0.38100.41620.78980.255*0.625 (9)
H20B0.29320.51240.80760.255*0.625 (9)
H20C0.41280.46650.84100.255*0.625 (9)
Si4A0.515 (3)0.5685 (12)0.7787 (8)0.1318 (13)0.375 (9)
C180.445 (3)0.639 (2)0.8231 (9)0.161 (3)0.375 (9)
H18D0.46510.61100.85500.242*0.375 (9)
H18E0.34480.64410.81860.242*0.375 (9)
H18F0.48680.70690.82040.242*0.375 (9)
C200.432 (3)0.4260 (15)0.7663 (10)0.170 (3)0.375 (9)
H20D0.49110.38230.74650.255*0.375 (9)
H20E0.34310.43660.75020.255*0.375 (9)
H20F0.41640.39340.79750.255*0.375 (9)
C19A0.480 (3)0.526 (3)0.7151 (9)0.151 (3)0.375 (9)
H19D0.51970.57500.69260.226*0.375 (9)
H19E0.37950.52150.71000.226*0.375 (9)
H19F0.52170.45890.70980.226*0.375 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Si10.0804 (9)0.0542 (8)0.0802 (9)0.0045 (7)0.0034 (8)0.0013 (8)
Si20.1054 (12)0.0709 (10)0.0970 (12)0.0005 (9)0.0386 (10)0.0153 (9)
Si30.1152 (12)0.0534 (8)0.0839 (10)0.0089 (9)0.0044 (10)0.0025 (8)
Si40.1162 (18)0.180 (3)0.0987 (19)0.026 (3)0.0233 (15)0.043 (2)
O10.078 (2)0.058 (2)0.082 (2)0.0030 (19)0.0269 (19)0.001 (2)
O20.0583 (17)0.0556 (19)0.085 (2)0.0022 (15)0.0030 (16)0.0010 (17)
O30.0407 (19)0.177 (4)0.129 (4)0.011 (2)0.009 (2)0.036 (3)
O40.0725 (19)0.068 (2)0.079 (2)0.0113 (19)0.0134 (18)0.0178 (19)
O50.087 (2)0.0523 (18)0.086 (2)0.0013 (19)0.0010 (19)0.0020 (18)
O60.130 (3)0.094 (3)0.111 (3)0.025 (3)0.054 (3)0.004 (3)
N10.0321 (15)0.079 (3)0.070 (3)0.0023 (19)0.0012 (18)0.009 (2)
C10.054 (3)0.059 (3)0.080 (4)0.006 (2)0.008 (2)0.004 (3)
C20.038 (2)0.069 (3)0.067 (3)0.001 (2)0.005 (2)0.000 (3)
C30.048 (2)0.058 (3)0.072 (3)0.005 (2)0.005 (2)0.010 (3)
C40.064 (3)0.052 (3)0.067 (3)0.008 (2)0.009 (2)0.000 (3)
C50.076 (3)0.057 (3)0.074 (3)0.001 (3)0.008 (3)0.000 (3)
C60.158 (6)0.078 (4)0.104 (5)0.008 (4)0.023 (5)0.022 (4)
C70.100 (4)0.096 (5)0.095 (4)0.015 (4)0.003 (4)0.010 (4)
C80.112 (5)0.074 (4)0.153 (7)0.011 (4)0.012 (4)0.027 (5)
C90.047 (3)0.088 (4)0.080 (4)0.002 (3)0.005 (3)0.004 (3)
C100.073 (3)0.116 (5)0.074 (4)0.005 (4)0.008 (3)0.014 (4)
C110.167 (7)0.158 (7)0.093 (5)0.037 (6)0.053 (5)0.003 (5)
C120.099 (5)0.118 (6)0.172 (7)0.030 (5)0.046 (5)0.004 (6)
C130.186 (8)0.117 (6)0.186 (9)0.038 (6)0.079 (7)0.073 (6)
C140.157 (6)0.056 (4)0.183 (9)0.009 (4)0.006 (6)0.007 (5)
C150.148 (6)0.089 (5)0.134 (6)0.038 (5)0.013 (5)0.015 (5)
C160.244 (10)0.087 (5)0.089 (5)0.013 (6)0.029 (6)0.012 (4)
C170.128 (5)0.076 (4)0.072 (4)0.005 (4)0.026 (4)0.002 (3)
C18A0.143 (5)0.204 (7)0.137 (6)0.032 (5)0.018 (5)0.040 (5)
C190.128 (5)0.202 (7)0.122 (5)0.031 (6)0.036 (4)0.032 (6)
C20A0.145 (5)0.218 (7)0.148 (6)0.008 (6)0.015 (5)0.032 (6)
Si4A0.1162 (18)0.180 (3)0.0987 (19)0.026 (3)0.0233 (15)0.043 (2)
C180.143 (5)0.204 (7)0.137 (6)0.032 (5)0.018 (5)0.040 (5)
C200.145 (5)0.218 (7)0.148 (6)0.008 (6)0.015 (5)0.032 (6)
C19A0.128 (5)0.202 (7)0.122 (5)0.031 (6)0.036 (4)0.032 (6)
Geometric parameters (Å, º) top
Si1—O21.649 (4)C9—C101.498 (8)
Si1—C71.833 (6)C10—H10A0.9600
Si1—C81.845 (7)C10—H10B0.9600
Si1—C61.847 (6)C10—H10C0.9600
Si2—O41.644 (4)C11—H11A0.9600
Si2—C121.848 (8)C11—H11B0.9600
Si2—C131.851 (8)C11—H11C0.9600
Si2—C111.863 (7)C12—H12A0.9600
Si3—O51.655 (4)C12—H12B0.9600
Si3—C151.833 (7)C12—H12C0.9600
Si3—C141.851 (8)C13—H13A0.9600
Si3—C161.886 (7)C13—H13B0.9600
Si4—O61.60 (2)C13—H13C0.9600
Si4—C181.846 (10)C14—H14A0.9600
Si4—C191.850 (9)C14—H14B0.9600
Si4—C201.858 (10)C14—H14C0.9600
O1—C11.408 (6)C15—H15A0.9600
O1—C51.432 (6)C15—H15B0.9600
O2—C11.406 (6)C15—H15C0.9600
O3—C91.224 (5)C16—H16A0.9600
O4—C31.427 (5)C16—H16B0.9600
O5—C41.419 (6)C16—H16C0.9600
O6—C171.396 (7)C17—H17A0.9700
O6—Si4A1.69 (3)C17—H17B0.9700
N1—C91.317 (6)C18A—Si4A1.856 (10)
N1—C21.447 (6)C18A—H18A0.9600
N1—H10.8600C18A—H18B0.9600
C1—C21.532 (7)C18A—H18C0.9600
C1—H1A0.9800C19—H19A0.9600
C2—C31.533 (6)C19—H19B0.9600
C2—H20.9800C19—H19C0.9600
C3—C41.505 (6)C20A—Si4A1.856 (10)
C3—H30.9800C20A—H20A0.9600
C4—C51.525 (7)C20A—H20B0.9600
C4—H40.9800C20A—H20C0.9600
C5—C171.511 (7)Si4A—C19A1.851 (10)
C5—H50.9800C18—H18D0.9600
C6—H6A0.9600C18—H18E0.9600
C6—H6B0.9600C18—H18F0.9600
C6—H6C0.9600C20—H20D0.9600
C7—H7A0.9600C20—H20E0.9600
C7—H7B0.9600C20—H20F0.9600
C7—H7C0.9600C19A—H19D0.9600
C8—H8A0.9600C19A—H19E0.9600
C8—H8B0.9600C19A—H19F0.9600
C8—H8C0.9600
O2—Si1—C7105.4 (3)Si1—C8—H8C109.5
O2—Si1—C8108.8 (3)H8A—C8—H8C109.5
C7—Si1—C8111.8 (3)H8B—C8—H8C109.5
O2—Si1—C6109.6 (3)O3—C9—N1121.3 (5)
C7—Si1—C6111.1 (3)O3—C9—C10121.0 (5)
C8—Si1—C6110.1 (4)N1—C9—C10117.7 (4)
O4—Si2—C12110.0 (3)C9—C10—H10A109.5
O4—Si2—C13105.8 (3)C9—C10—H10B109.5
C12—Si2—C13109.4 (4)H10A—C10—H10B109.5
O4—Si2—C11112.8 (3)C9—C10—H10C109.5
C12—Si2—C11106.9 (4)H10A—C10—H10C109.5
C13—Si2—C11111.9 (5)H10B—C10—H10C109.5
O5—Si3—C15111.2 (3)Si2—C11—H11A109.5
O5—Si3—C14105.2 (3)Si2—C11—H11B109.5
C15—Si3—C14113.1 (4)H11A—C11—H11B109.5
O5—Si3—C16111.0 (3)Si2—C11—H11C109.5
C15—Si3—C16108.0 (4)H11A—C11—H11C109.5
C14—Si3—C16108.3 (4)H11B—C11—H11C109.5
O6—Si4—C18109.0 (12)Si2—C12—H12A109.5
O6—Si4—C19112.4 (9)Si2—C12—H12B109.5
C18—Si4—C19121.8 (15)H12A—C12—H12B109.5
O6—Si4—C20101.9 (11)Si2—C12—H12C109.5
C18—Si4—C20116.8 (15)H12A—C12—H12C109.5
C19—Si4—C2092.6 (13)H12B—C12—H12C109.5
C1—O1—C5114.0 (3)Si2—C13—H13A109.5
C1—O2—Si1124.1 (3)Si2—C13—H13B109.5
C3—O4—Si2130.0 (3)H13A—C13—H13B109.5
C4—O5—Si3129.2 (3)Si2—C13—H13C109.5
C17—O6—Si4130.2 (5)H13A—C13—H13C109.5
C17—O6—Si4A126.2 (7)H13B—C13—H13C109.5
C9—N1—C2123.7 (4)Si3—C14—H14A109.5
C9—N1—H1118.2Si3—C14—H14B109.5
C2—N1—H1118.2H14A—C14—H14B109.5
O2—C1—O1110.9 (4)Si3—C14—H14C109.5
O2—C1—C2109.5 (3)H14A—C14—H14C109.5
O1—C1—C2110.8 (4)H14B—C14—H14C109.5
O2—C1—H1A108.5Si3—C15—H15A109.5
O1—C1—H1A108.5Si3—C15—H15B109.5
C2—C1—H1A108.5H15A—C15—H15B109.5
N1—C2—C1110.3 (4)Si3—C15—H15C109.5
N1—C2—C3113.1 (3)H15A—C15—H15C109.5
C1—C2—C3110.9 (4)H15B—C15—H15C109.5
N1—C2—H2107.4Si3—C16—H16A109.5
C1—C2—H2107.4Si3—C16—H16B109.5
C3—C2—H2107.4H16A—C16—H16B109.5
O4—C3—C4109.2 (4)Si3—C16—H16C109.5
O4—C3—C2108.7 (4)H16A—C16—H16C109.5
C4—C3—C2110.3 (4)H16B—C16—H16C109.5
O4—C3—H3109.5O6—C17—C5113.3 (5)
C4—C3—H3109.5O6—C17—H17A108.9
C2—C3—H3109.5C5—C17—H17A108.9
O5—C4—C3109.6 (4)O6—C17—H17B108.9
O5—C4—C5108.6 (4)C5—C17—H17B108.9
C3—C4—C5111.6 (4)H17A—C17—H17B107.7
O5—C4—H4109.0Si4A—C18A—H18A109.5
C3—C4—H4109.0Si4A—C18A—H18B109.5
C5—C4—H4109.0H18A—C18A—H18B109.5
O1—C5—C17106.4 (4)Si4A—C18A—H18C109.5
O1—C5—C4109.9 (4)H18A—C18A—H18C109.5
C17—C5—C4113.4 (4)H18B—C18A—H18C109.5
O1—C5—H5109.0Si4A—C20A—H20A109.5
C17—C5—H5109.0Si4A—C20A—H20B109.5
C4—C5—H5109.0H20A—C20A—H20B109.5
Si1—C6—H6A109.5Si4A—C20A—H20C109.5
Si1—C6—H6B109.5H20A—C20A—H20C109.5
H6A—C6—H6B109.5H20B—C20A—H20C109.5
Si1—C6—H6C109.5O6—Si4A—C19A104.8 (14)
H6A—C6—H6C109.5O6—Si4A—C18A113.3 (14)
H6B—C6—H6C109.5C19A—Si4A—C18A118.8 (17)
Si1—C7—H7A109.5O6—Si4A—C20A105.7 (12)
Si1—C7—H7B109.5C19A—Si4A—C20A95.6 (16)
H7A—C7—H7B109.5C18A—Si4A—C20A116.5 (14)
Si1—C7—H7C109.5Si4A—C19A—H19D109.5
H7A—C7—H7C109.5Si4A—C19A—H19E109.5
H7B—C7—H7C109.5H19D—C19A—H19E109.5
Si1—C8—H8A109.5Si4A—C19A—H19F109.5
Si1—C8—H8B109.5H19D—C19A—H19F109.5
H8A—C8—H8B109.5H19E—C19A—H19F109.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O3i0.862.032.855 (4)160
Symmetry code: (i) x+1/2, y+3/2, z+2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O3i0.862.032.855 (4)160
Symmetry code: (i) x+1/2, y+3/2, z+2.
Acknowledgements top

This work was supported financially by the National Science Foundation of China (No. 30870553) and the Key International S&T Cooperation Project, China (No. 2010DFA34370).

references
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