Crystal structure and Hirshfeld surface analysis of 1-[(benzyl­dimethyl­sil­yl)meth­yl]-1-ethyl­piperidin-1-ium ethane­sulfonate

Kirchhoff, J.-L.; Koller, S.G.; Louven, K.; Strohmann, C.

doi:10.1107/S205698902101361X

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ISSN: 2056-9890

Volume 78| Part 2| February 2022| Pages 135-139

https://doi.org/10.1107/S205698902101361X

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Crystal structure and Hirshfeld surface analysis of 1-[(benzyldimethylsilyl)methyl]-1-ethylpiperidin-1-ium ethanesulfonate

Jan-Lukas Kirchhoff,^a Stephan G. Koller,^a Kathrin Louven ^a and Carsten Strohmann ^a ^*

^aTechnische Universität Dortmund, Fakultät Chemie und Chemische Biologie, Otto-Hahn-Strasse 6, 44227 Dortmund, Germany
^*Correspondence e-mail: carsten.strohmann@tu-dortmund.de

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 29 November 2021; accepted 27 December 2021; online 7 January 2022)

The title molecular salt, C₁₇H₃₀NSi⁺·C₂H₅O₄S⁻, belongs to the class of a-aminosilanes and was synthesized by the alkylation of 1-[(benzyldimethylsilyl)methyl]piperidine using diethyl sulfate. This achiral salt crystallizes in the chiral space group P2₁. One of the Si—C bonds in the cation is unusually long [1.9075 (12) Å], which correlates with the adjacent quaternary N⁺ atom and was verified by quantum chemical calculations. In the crystal, the components are linked by weak C—H⋯O hydrogen bonds: a Hirshfeld surface analysis was performed to further investigate these intermolecular interactions and their effects on the crystal packing.

Keywords: crystal structure; α-aminosilanes; long Si—C bonds; hydrogen bonds; Hirshfeld surface analysis.

CCDC reference: 2131144

1. Chemical context

Selective bond transformations on silicon compounds for the cleavage of Si—C bonds are of high interest in silicon chemistry (Denmark et al., 2007 ; Denmark & Liu, 2010 ). Compared to C—C bonds, analogous Si—C bonds can be cleaved heterolytically using strong nucleophiles (Tomooka et al., 2000 ; Li & Hu, 2007 ). However, the selectivity of such reactions is limited to specific silanes. In particular, α-amino-functionalized silanes are well suited for these processes, as shown by our previous studies (Koller et al., 2017 ). Our group has focused on using lithium organyls as strong nucleophiles to perform these Si—C transformations on highly substituted silanes (Bauer & Strohmann, 2014 ). In particular, derivatives of α-piperdinobenzylsilanes have been intensively studied by our group (Strohmann et al., 2004 ; Otte et al., 2017 ). When strong nucleophiles are used, deprotonation in the benzyl position competes with the selective Si—C bond cleavage of the benzyl group. For this purpose, the α-aminofunctionality seems to play a key role, which could be responsible for the activation of the subsequent Si—C bond cleavage. In addition, the positively charged ammonium group leads to an increased electronegativity, which enhances the electron-withdrawing effect of the substituted α-aminofunctionality. Consequently, the π-character of the Si—C bond is more pronounced, leading to an elongation of the bond. Thus, a selective cleavage of the amino functionality due to the elongated Si—C bond is also conceivable (Bent, 1960 , 1961 ; Otte et al., 2017).

Several derivates of these α-piperdinobenzylsilanes have been synthesized by our research group: 1-[(benzyldimethylsilyl)methyl]-1-ethylpiperidin-1-ium ethanesulfonate (1), the title compound, represents a compound that could lead to an extension of the aforementioned Si—C bond to the nitrogen atom via the quaternary ammonium cation. Structural studies concerning this type of compound should better elucidate the reactivity as well as selectivity of Si—C cleavages of the benzyl-substituted α-aminosilanes.

2. Structural commentary

Compound 1 crystallized from an n-pentane solution at 243 K in the form of colorless blocks with monoclinic (P2₁) symmetry. The chiral space group indicates that the achiral compound in the elementary cell is packed chirally; the Flack absolute structure parameter amounts to −0.005 (6) (Flack, 1983 ). The molecular structure of 1 is illustrated in Fig. 1. The Si—C bonds span the range 1.862 (2) to 1.908 (1) Å, as shown in Table 1. These values for the bond lengths are consistent with those in the literature, except for the long Si1—C10 bond length, which is related to the α-aminosilane functionality (Allen et al., 1987 ). This observed elongation of the bond can be explained by the very electropositive feature of carbon atom C10. In addition, the ethylated ammonium cation pushes even more electron density from C10 toward the amino functionality. There are only a few known species with such a long Si—C bond, which in turn may play a crucial role in the reactivity of α-amino-substituted silanes. Quantum chemical calculations at the M062X/6-31+G(d) level confirm the experimentally observed long Si—C bond. The calculated structure of compound 1 is shown in Fig. 2.

Table 1
Selected bond lengths (Å)

Si1—C7	1.8814 (11)	Si1—C9	1.8662 (18)
Si1—C8	1.862 (2)	Si1—C10	1.9075 (12)

Figure 1
(a) The molecular structure of 1 illustrated using SCHAKAL99 (Keller, 1999

). (b) The molecular structure of 1 showing 50% displacement ellipsoids.

Figure 2
Visualization of the calculated structure of compound 1 with Molekel 4.3 (Flükiger et al., 2000

) performed at the M062X/6–31+G(d) (Ditchfield et al., 1970

; Zhao & Truhlar, 2008

) level.

The silicon center in 1 features a tetrahedral geometry, which is significantly distorted, as shown by the smallest angle of 98.35 (5)° (C7—Si1—C10) and the largest angle of 114.32 (7)° (C8—Si1—C10). This geometric distortion has been observed in many complex substituted silicon compounds and depends on the substituents (Otte et al., 2017). However, the distortion is large for compound 1 compared to most known silanes (Krupp et al., 2020 ).

3. Supramolecular features

The crystal packing along the b-axis of compound 1 is illustrated in Fig. 3. Further studies of the packing in the solid state were aimed at finding hydrogen bonds of compound 1 as well as discussing the intensities of those hydrogen bonds. These studies were performed using Hirshfeld surface analysis. The Hirshfeld surface mapped over d_norm in the range from −0.072 to 1.201 arbitrary units as well as the related fingerprints plots generated by CrystalExplorer2021 (Spackman et al., 2021 , Turner et al., 2017 ) are illustrated in Fig. 4. With a share of 71.4%, most of the interactions relate to weak van der Waals H⋯H contacts, which should play a minor role for the packing of the crystal. In contrast, the role of O⋯H/H⋯O contacts should be predominant in the crystal arrangement in the unit cell, as shown by the significant red spots on the Hirshfeld surface. Numerous hydrogen bonds of the ethyl sulfate group to the ammonium cation are visible on the surface. The contribution of these contacts amounts to 16.6%. C⋯H/H⋯C contacts as well as H⋯H contacts do not show as intense spots on the Hirshfeld surface and should not be considered as relevant as the O⋯H/H⋯O contacts for the crystal packing. All hydrogen bonds up to a distance of 3.4 Å as well as an angle of at least 155° are listed in Table 2. According to Perlstein (2001 ), all hydrogen bonds listed in Table 2 have a weak to moderately strong character, which can be explained in particular by the non-linear angles of 156 (7)° (C7—H7B⋯O2ⁱⁱ) to 167 (2)° (C3—H3⋯O2ⁱ). The shortest hydrogen-bond length is 3.1815 (16) Å and is the strongest supramolecular interaction with an angle of 162.8 (17)° (C17—H17A⋯O4). Analysis of the hydrogen-bonding network shows that all the hydrogen bonds shown in Table 2 can be assigned to one graph-set motif [D₁¹(2); Etter et al., 1990 ] and all of these bonds are linearly connected to two different atoms.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O2ⁱ	0.93 (3)	2.39 (3)	3.2990 (17)	167 (2)
C7—H7B⋯O2ⁱⁱ	0.91 (3)	2.54 (3)	3.3881 (16)	156 (2)
C17—H17A⋯O4	0.95 (2)	2.26 (2)	3.1815 (16)	162.8 (17)
C17—H17B⋯O3ⁱⁱ	0.93 (2)	2.47 (2)	3.3680 (15)	161.3 (19)
Symmetry codes: (i) $[-x, y-{\script{1\over 2}}, -z]$ ; (ii) .

Figure 3
A view along the b-axis direction of the crystal packing of compound 1.

Figure 4
Hirshfeld surfaces and two-dimensional fingerprint plots of 1 showing close contacts for (a) all contributions in the crystal and (b) H⋯H, (c) O⋯H/H⋯O and (d) C⋯H/H⋯C interactions. Symmetry code: −x, $[{1\over 2}]$ + y, −z.

4. Database survey

There are some other examples of crystallographically characterized α-aminosilane derivatives that are structurally based on compound 1 and its starting compound 2. Examples of such α-piperidinosilanes found in the Cambridge Structural Database (WebCSD, November 2021; Groom et al., 2016 ) are (R)-1-methyl-1-{[methyl(phenyl)(trimethylgermyl)silyl]methyl}piperidinium iodide, C₁₇H₃₂GeNSiI (CSD refcode BOFLOY; Strohmann et al., 2008 ), (triphenylsilylpiperidinylcarbene)tetracarbonyltungsten(0), C₂₈H₂₅NO₄SiW (DIZWUE; Schubert et al., 1986 ), [bis(trimethylsilyl)methyl]bis[diphenyl(N-piperidinomethylsilyl)methyl]gallium n-pentane solvate, C₄₅H₆₇GaN₂Si₄·0.5(C₅H₁₂) (MASLUN; Uhl et al., 2000 ), 8-chloro-8,8-dimethyl-1-aza-7-oxa-8-silabicyclo(4.3.0)non-6-ene, C₈H₁₆ClNOSi (FUSYIB; Macharashvili et al., 1987 ), 1-{[benzyl(methyl)phenylsilyl]methyl}piperidinium bromide, C₂₀H₂₈NSiBr (NUPMUI; Barth et al., 2015 ), N-(triphenylsilylmethyl)-5,6-aza-C60fulleroid, C₇₉H₁₇NSi (YOXBOD; Hachiya et al., 2009 ).

5. Synthesis and crystallization

The reaction scheme for the synthesis of 1 is illustrated in Fig. 5: 1-[(benzyldimethylsilyl)methyl]piperidine (2) (0.81 mmol) was dissolved in acetone (3 ml) and diethyl sulfate (0.81 mmol) was added dropwise to the solution. The reaction mixture was stirred and heated for 6 h at 329 K. Afterwards the reaction was quenched by the addition of a mixture of H₂O (2 ml) and NH₃ (2 ml). The aqueous phase was extracted three times with CH₂Cl₂ and the combined organic phases were dried over Na₂SO₄. After the removal of volatile compounds, the raw product was dissolved in n-pentane (1 ml) and stored at 243 K. The title salt (1) was isolated as colorless crystalline blocks.

Figure 5
Reaction scheme of the alkylation of 2 with diethyl sulfate for the synthesis of 1.

¹H NMR (300.25 MHz, CDCl₃): δ = 0.30 [s, 6H, Si(CH₃)₂], 1.24–1.31 (m, 6H, OCH₂CH₃, NCH₂CH₃), 1.65–1.90 [br. m, 6H, N(CH₂CH₂)₂, NCH₂CH₂CH₂], 2.29 (s, 2H, SiCH₂C_ar), 3.12 (s, 2H, SiCH₂N), 3.37–3.56 [br. m, 6H, N(CH₂)₃], 4.12 (q, 2H, ³J_H–H = 7.1Hz, OCH₂CH₃), 7.04 (d, 2H, ³J_H–H = 7.0Hz, CH_ar), 7.10–7.15 (m, 1H, CH_ar), 7.24 (d, 2H, ³J_H–H = 7.6Hz, CH_ar) ppm.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. All H atoms were refined freely using independent values for each U_iso(H).

Table 3
Experimental details

Crystal data
Chemical formula	C₁₇H₃₀NSi⁺·C₂H₅O₄S⁻
M_r	401.63
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	100
a, b, c (Å)	8.4627 (8), 12.8187 (11), 10.3926 (9)
β (°)	107.033 (3)
V (Å³)	1077.95 (17)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.23
Crystal size (mm)	0.82 × 0.44 × 0.38

Data collection
Diffractometer	Bruker D8 VENTURE
Absorption correction	Multi-scan (SADABS; Bruker, 2021 )
T_min, T_max	0.699, 0.747
No. of measured, independent and observed [I > 2σ(I)] reflections	68418, 8122, 7987
R_int	0.021
(sin θ/λ)_max (Å⁻¹)	0.766

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.024, 0.065, 1.05
No. of reflections	8122
No. of parameters	375
No. of restraints	1
H-atom treatment	All H-atom parameters refined
Δρ_max, Δρ_min (e Å⁻³)	0.53, −0.59
Absolute structure	Flack x determined using 3811 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	−0.005 (6)
Computer programs: APEX4 and SAINT (Bruker, 2021), SHELXS (Sheldrick, 2008 ), SHELXL (Sheldrick, 2015 ), OLEX2 (Dolomanov et al., 2009 ), CrystalExplorer21 (Spackman et al., 2021; Turner et al., 2017), publCIF (Westrip, 2010 ), Mercury (Macrae et al., 2020 ), GaussView 6.016 (Frisch et al., 2016 ), Gaussian 09 Revision A.02 (Frisch et al., 2016), SCHAKAL99 (Keller, 1999 ) and Molekel 4.3 (Flükiger et al., 2000 ).

Supporting information

CCDC reference: 2131144

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S205698902101361X/hb8003sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698902101361X/hb8003Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S205698902101361X/hb8003Isup3.cml

checkCIF report

Computing details top

Data collection: APEX4 (Bruker, 2021); cell refinement: SAINT (Bruker, 2021); data reduction: SAINT (Bruker, 2021); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: CrystalExplorer21 (Spackman et al., 2021; Turner et al., 2017), publCIF (Westrip, 2010), Mercury (Macrae et al., 2020), GaussView 6.016 (Frisch et al., 2016), Gaussian 09 Revision A.02 (Frisch et al., 2016), SCHAKAL99 (Keller, 1999), Molekel 4.3 (Flükiger et al., 2000).

1-[(Benzyldimethylsilyl)methyl]-1-ethylpiperidin-1-ium ethanesulfonate top

Crystal data top

C₁₇H₃₀NSi⁺·C₂H₅O₄S⁻	F(000) = 436
M_r = 401.63	D_x = 1.237 Mg m⁻³
Monoclinic, P2₁	Mo Kα radiation, λ = 0.71073 Å
a = 8.4627 (8) Å	Cell parameters from 9642 reflections
b = 12.8187 (11) Å	θ = 3.0–30.6°
c = 10.3926 (9) Å	µ = 0.23 mm⁻¹
β = 107.033 (3)°	T = 100 K
V = 1077.95 (17) Å³	Block, colourless
Z = 2	0.82 × 0.44 × 0.38 mm

Data collection top

Bruker D8 VENTURE diffractometer	8122 independent reflections
Radiation source: microfocus sealed X-ray tube, Incoatec Iµs	7987 reflections with I > 2σ(I)
HELIOS mirror optics monochromator	R_int = 0.021
Detector resolution: 10.4167 pixels mm^-1	θ_max = 33.0°, θ_min = 2.5°
ω and φ scans	h = −12→12
Absorption correction: multi-scan (SADABS; Bruker, 2021)	k = −19→19
T_min = 0.699, T_max = 0.747	l = −15→15
68418 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: difference Fourier map
Least-squares matrix: full	All H-atom parameters refined
R[F² > 2σ(F²)] = 0.024	w = 1/[σ²(F_o²) + (0.039P)² + 0.1456P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.065	(Δ/σ)_max = 0.001
S = 1.05	Δρ_max = 0.53 e Å⁻³
8122 reflections	Δρ_min = −0.59 e Å⁻³
375 parameters	Absolute structure: Flack x determined using 3811 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
1 restraint	Absolute structure parameter: −0.005 (6)
Primary atom site location: iterative

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
S1	0.88614 (3)	0.62026 (2)	0.40720 (3)	0.01913 (6)
Si1	0.05612 (4)	0.31084 (3)	0.20000 (3)	0.01987 (7)
O3	1.05747 (10)	0.61067 (7)	0.48491 (8)	0.01886 (15)
O1	0.85485 (10)	0.74269 (6)	0.37242 (10)	0.01822 (15)
O4	0.77064 (16)	0.60053 (10)	0.4817 (2)	0.0533 (5)
O2	0.85245 (18)	0.56667 (8)	0.27863 (13)	0.0439 (4)
N1	0.35820 (12)	0.43767 (7)	0.34820 (11)	0.01724 (16)
C10	0.19151 (13)	0.39252 (8)	0.34376 (12)	0.01601 (18)
C14	0.53245 (16)	0.29189 (10)	0.48490 (16)	0.0253 (2)
C17	0.41837 (15)	0.50777 (10)	0.47118 (15)	0.0230 (2)
C6	−0.27742 (13)	0.25033 (8)	0.16162 (10)	0.01469 (17)
C5	−0.31035 (14)	0.14496 (9)	0.17585 (11)	0.01782 (18)
C13	0.48527 (15)	0.35320 (9)	0.35398 (14)	0.0211 (2)
C7	−0.13320 (13)	0.30314 (9)	0.25953 (11)	0.01589 (17)
C1	−0.38217 (16)	0.30517 (11)	0.05336 (13)	0.0247 (2)
C15	0.59552 (18)	0.36517 (13)	0.60478 (17)	0.0298 (3)
C18	0.96437 (15)	0.78813 (9)	0.30464 (13)	0.0206 (2)
C4	−0.44312 (17)	0.09575 (11)	0.08387 (14)	0.0258 (2)
C3	−0.54609 (16)	0.15050 (14)	−0.02339 (13)	0.0295 (3)
C16	0.46575 (16)	0.44744 (12)	0.60249 (15)	0.0276 (3)
C11	0.35005 (16)	0.50178 (10)	0.22355 (15)	0.0245 (2)
C19	0.93127 (16)	0.90390 (9)	0.29232 (12)	0.0202 (2)
C12	0.23198 (19)	0.59372 (11)	0.19959 (18)	0.0306 (3)
C8	0.0020 (3)	0.3761 (2)	0.03268 (16)	0.0472 (5)
C2	−0.51474 (18)	0.25531 (15)	−0.03823 (14)	0.0316 (3)
C9	0.1422 (2)	0.17830 (15)	0.1885 (3)	0.0455 (5)
H13A	0.442 (2)	0.3078 (18)	0.274 (2)	0.024 (4)*
H3	−0.638 (3)	0.121 (2)	−0.085 (3)	0.043 (6)*
H13B	0.583 (3)	0.3899 (17)	0.346 (2)	0.025 (5)*
H5	−0.241 (2)	0.1076 (17)	0.250 (2)	0.024 (4)*
H11A	0.318 (2)	0.4547 (16)	0.1467 (19)	0.017 (4)*
H12A	0.122 (3)	0.5740 (19)	0.193 (2)	0.029 (5)*
H10A	0.128 (3)	0.4494 (18)	0.358 (2)	0.026 (5)*
H7A	−0.108 (3)	0.2671 (17)	0.343 (2)	0.023 (4)*
H16A	0.368 (3)	0.4130 (18)	0.614 (2)	0.032 (5)*
H7B	−0.162 (3)	0.369 (2)	0.277 (3)	0.041 (6)*
H8A	−0.071 (4)	0.332 (3)	−0.020 (3)	0.056 (8)*
H18A	1.077 (3)	0.7716 (19)	0.355 (2)	0.037 (6)*
H17A	0.512 (3)	0.5403 (16)	0.456 (2)	0.023 (5)*
H16B	0.512 (3)	0.504 (2)	0.676 (3)	0.040 (6)*
H17B	0.331 (3)	0.5512 (18)	0.475 (2)	0.032 (5)*
H12B	0.233 (3)	0.630 (2)	0.106 (3)	0.043 (6)*
H2	−0.586 (3)	0.296 (2)	−0.110 (2)	0.041 (6)*
H11B	0.454 (3)	0.525 (2)	0.235 (2)	0.033 (6)*
H14A	0.439 (3)	0.2515 (19)	0.494 (2)	0.030 (5)*
H14B	0.617 (3)	0.2459 (19)	0.477 (2)	0.033 (6)*
H19A	0.825 (3)	0.916 (2)	0.235 (3)	0.040 (6)*
H19B	0.945 (3)	0.933 (2)	0.382 (2)	0.037 (6)*
H9A	0.058 (3)	0.133 (2)	0.123 (3)	0.048 (7)*
H19C	1.009 (3)	0.943 (2)	0.251 (2)	0.031 (5)*
H1	−0.362 (3)	0.379 (2)	0.045 (3)	0.041 (6)*
H10B	0.205 (3)	0.3469 (18)	0.418 (2)	0.027 (5)*
H9B	0.231 (5)	0.175 (4)	0.154 (4)	0.090 (13)*
H4	−0.477 (3)	0.018 (2)	0.093 (3)	0.037 (6)*
H8B	0.103 (6)	0.397 (4)	0.005 (4)	0.095 (14)*
H18B	0.945 (3)	0.751 (2)	0.216 (2)	0.037 (6)*
H15A	0.700 (4)	0.397 (2)	0.597 (3)	0.058 (8)*
H12C	0.274 (3)	0.647 (2)	0.270 (3)	0.046 (7)*
H15B	0.623 (4)	0.327 (2)	0.686 (3)	0.051 (7)*
H8C	−0.044 (5)	0.439 (4)	0.038 (4)	0.078 (11)*
H9C	0.167 (5)	0.140 (4)	0.293 (4)	0.092 (12)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.01109 (10)	0.01196 (10)	0.03141 (13)	0.00019 (8)	0.00167 (8)	0.00310 (9)
Si1	0.01993 (14)	0.02043 (14)	0.02339 (14)	−0.00530 (11)	0.01279 (11)	−0.00846 (11)
O3	0.0134 (3)	0.0214 (4)	0.0193 (3)	0.0031 (3)	0.0009 (3)	0.0034 (3)
O1	0.0140 (3)	0.0118 (3)	0.0301 (4)	0.0013 (3)	0.0084 (3)	0.0021 (3)
O4	0.0297 (5)	0.0335 (7)	0.1128 (13)	0.0101 (5)	0.0458 (7)	0.0345 (7)
O2	0.0507 (7)	0.0172 (4)	0.0404 (6)	0.0058 (4)	−0.0234 (5)	−0.0085 (4)
N1	0.0133 (4)	0.0120 (4)	0.0294 (5)	−0.0001 (3)	0.0109 (3)	−0.0006 (3)
C10	0.0127 (4)	0.0146 (4)	0.0237 (5)	−0.0019 (3)	0.0099 (3)	−0.0023 (3)
C14	0.0194 (5)	0.0169 (5)	0.0405 (7)	0.0031 (4)	0.0104 (5)	0.0045 (4)
C17	0.0145 (4)	0.0161 (5)	0.0387 (6)	−0.0020 (4)	0.0082 (4)	−0.0083 (4)
C6	0.0134 (4)	0.0151 (4)	0.0158 (4)	0.0024 (3)	0.0045 (3)	−0.0004 (3)
C5	0.0185 (4)	0.0157 (4)	0.0178 (4)	−0.0026 (3)	0.0030 (3)	−0.0012 (3)
C13	0.0168 (4)	0.0148 (4)	0.0361 (6)	0.0035 (4)	0.0148 (4)	−0.0004 (4)
C7	0.0156 (4)	0.0146 (4)	0.0185 (4)	−0.0018 (3)	0.0066 (3)	−0.0030 (3)
C1	0.0215 (5)	0.0259 (5)	0.0243 (5)	0.0078 (4)	0.0032 (4)	0.0072 (5)
C15	0.0190 (5)	0.0313 (7)	0.0367 (7)	0.0027 (5)	0.0047 (5)	0.0017 (5)
C18	0.0222 (5)	0.0148 (4)	0.0282 (5)	0.0033 (4)	0.0129 (4)	0.0036 (4)
C4	0.0235 (5)	0.0286 (6)	0.0240 (5)	−0.0094 (4)	0.0052 (4)	−0.0081 (4)
C3	0.0162 (5)	0.0506 (8)	0.0197 (5)	−0.0043 (5)	0.0022 (4)	−0.0102 (5)
C16	0.0177 (5)	0.0326 (6)	0.0321 (6)	−0.0019 (5)	0.0064 (4)	−0.0093 (5)
C11	0.0217 (5)	0.0200 (5)	0.0367 (6)	0.0007 (4)	0.0163 (5)	0.0072 (5)
C19	0.0250 (5)	0.0131 (4)	0.0230 (5)	−0.0009 (4)	0.0081 (4)	−0.0012 (4)
C12	0.0283 (6)	0.0195 (5)	0.0444 (8)	0.0042 (4)	0.0115 (6)	0.0082 (5)
C8	0.0582 (11)	0.0667 (13)	0.0200 (6)	−0.0352 (11)	0.0163 (7)	−0.0063 (7)
C2	0.0201 (5)	0.0496 (9)	0.0211 (5)	0.0105 (6)	−0.0004 (4)	0.0041 (5)
C9	0.0296 (7)	0.0320 (7)	0.0824 (14)	−0.0062 (6)	0.0279 (9)	−0.0332 (9)

Geometric parameters (Å, º) top

S1—O3	1.4435 (8)	C1—C2	1.396 (2)
S1—O1	1.6149 (9)	C1—H1	0.98 (3)
S1—O4	1.4364 (12)	C15—C16	1.518 (2)
S1—O2	1.4545 (13)	C15—H15A	1.00 (3)
Si1—C7	1.8814 (11)	C15—H15B	0.95 (3)
Si1—C8	1.862 (2)	C18—C19	1.5086 (16)
Si1—C9	1.8662 (18)	C18—H18A	0.97 (3)
Si1—C10	1.9075 (12)	C18—H18B	1.00 (3)
O1—C18	1.4412 (14)	C4—C3	1.388 (2)
N1—C10	1.5130 (14)	C4—H4	1.05 (3)
N1—C17	1.5227 (17)	C3—C2	1.387 (3)
N1—C13	1.5148 (15)	C3—H3	0.93 (3)
N1—C11	1.5186 (17)	C16—H16A	0.98 (2)
C10—H10A	0.94 (2)	C16—H16B	1.04 (3)
C10—H10B	0.95 (2)	C11—C12	1.5177 (19)
C14—C13	1.5199 (19)	C11—H11A	0.97 (2)
C14—C15	1.526 (2)	C11—H11B	0.91 (2)
C14—H14A	0.97 (2)	C19—H19A	0.94 (3)
C14—H14B	0.95 (2)	C19—H19B	0.99 (2)
C17—C16	1.517 (2)	C19—H19C	1.01 (2)
C17—H17A	0.95 (2)	C12—H12A	0.94 (2)
C17—H17B	0.93 (2)	C12—H12B	1.08 (3)
C6—C5	1.3957 (15)	C12—H12C	0.99 (3)
C6—C7	1.5019 (15)	C8—H8A	0.89 (3)
C6—C1	1.4005 (16)	C8—H8B	1.01 (5)
C5—C4	1.3946 (16)	C8—H8C	0.91 (4)
C5—H5	0.95 (2)	C2—H2	0.96 (3)
C13—H13A	0.99 (2)	C9—H9A	1.01 (3)
C13—H13B	0.97 (2)	C9—H9B	0.92 (4)
C7—H7A	0.95 (2)	C9—H9C	1.15 (4)
C7—H7B	0.91 (3)

O3—S1—O1	106.26 (5)	C14—C15—H15A	106.7 (18)
O3—S1—O2	111.61 (7)	C14—C15—H15B	110.4 (18)
O4—S1—O3	114.45 (8)	C16—C15—C14	109.66 (11)
O4—S1—O1	101.47 (6)	C16—C15—H15A	111.9 (18)
O4—S1—O2	115.54 (11)	C16—C15—H15B	111.2 (18)
O2—S1—O1	106.15 (6)	H15A—C15—H15B	107 (3)
C7—Si1—C10	98.35 (5)	O1—C18—C19	108.00 (9)
C8—Si1—C10	114.32 (7)	O1—C18—H18A	108.5 (14)
C8—Si1—C7	109.31 (9)	O1—C18—H18B	107.5 (15)
C8—Si1—C9	110.06 (12)	C19—C18—H18A	112.9 (15)
C9—Si1—C10	113.19 (8)	C19—C18—H18B	114.0 (15)
C9—Si1—C7	111.06 (7)	H18A—C18—H18B	106 (2)
C18—O1—S1	114.55 (7)	C5—C4—H4	123.5 (14)
C10—N1—C17	109.32 (9)	C3—C4—C5	120.81 (13)
C10—N1—C13	111.87 (9)	C3—C4—H4	115.5 (14)
C10—N1—C11	111.84 (9)	C4—C3—H3	123.5 (18)
C13—N1—C17	109.24 (10)	C2—C3—C4	118.93 (12)
C13—N1—C11	105.96 (9)	C2—C3—H3	117.5 (18)
C11—N1—C17	108.49 (10)	C17—C16—C15	111.58 (12)
Si1—C10—H10A	107.8 (13)	C17—C16—H16A	109.3 (13)
Si1—C10—H10B	101.7 (14)	C17—C16—H16B	104.1 (15)
N1—C10—Si1	125.08 (8)	C15—C16—H16A	108.7 (14)
N1—C10—H10A	105.8 (14)	C15—C16—H16B	110.8 (15)
N1—C10—H10B	108.7 (13)	H16A—C16—H16B	112.3 (19)
H10A—C10—H10B	106.6 (18)	N1—C11—H11A	107.2 (12)
C13—C14—C15	110.47 (11)	N1—C11—H11B	105.7 (15)
C13—C14—H14A	110.8 (14)	C12—C11—N1	115.05 (11)
C13—C14—H14B	104.5 (14)	C12—C11—H11A	109.7 (12)
C15—C14—H14A	110.4 (14)	C12—C11—H11B	109.4 (16)
C15—C14—H14B	111.0 (15)	H11A—C11—H11B	109.7 (19)
H14A—C14—H14B	110 (2)	C18—C19—H19A	109.5 (16)
N1—C17—H17A	101.9 (12)	C18—C19—H19B	109.3 (15)
N1—C17—H17B	108.3 (14)	C18—C19—H19C	113.5 (14)
C16—C17—N1	112.92 (10)	H19A—C19—H19B	111 (2)
C16—C17—H17A	111.3 (13)	H19A—C19—H19C	106 (2)
C16—C17—H17B	105.7 (14)	H19B—C19—H19C	107 (2)
H17A—C17—H17B	117 (2)	C11—C12—H12A	112.9 (14)
C5—C6—C7	120.82 (10)	C11—C12—H12B	107.8 (14)
C5—C6—C1	118.15 (11)	C11—C12—H12C	109.8 (16)
C1—C6—C7	121.03 (10)	H12A—C12—H12B	108.6 (19)
C6—C5—H5	118.5 (13)	H12A—C12—H12C	112 (2)
C4—C5—C6	120.72 (11)	H12B—C12—H12C	106 (2)
C4—C5—H5	120.8 (13)	Si1—C8—H8A	103 (2)
N1—C13—C14	113.73 (10)	Si1—C8—H8B	113 (3)
N1—C13—H13A	107.5 (12)	Si1—C8—H8C	110 (2)
N1—C13—H13B	105.1 (13)	H8A—C8—H8B	118 (3)
C14—C13—H13A	112.5 (13)	H8A—C8—H8C	112 (3)
C14—C13—H13B	108.6 (13)	H8B—C8—H8C	101 (3)
H13A—C13—H13B	109.1 (17)	C1—C2—H2	118.4 (17)
Si1—C7—H7A	109.8 (13)	C3—C2—C1	120.64 (13)
Si1—C7—H7B	108.6 (17)	C3—C2—H2	121.0 (17)
C6—C7—Si1	113.71 (7)	Si1—C9—H9A	110.7 (16)
C6—C7—H7A	108.8 (13)	Si1—C9—H9B	116 (3)
C6—C7—H7B	109.9 (17)	Si1—C9—H9C	107 (2)
H7A—C7—H7B	106 (2)	H9A—C9—H9B	102 (3)
C6—C1—H1	118.4 (16)	H9A—C9—H9C	107 (3)
C2—C1—C6	120.75 (13)	H9B—C9—H9C	114 (3)
C2—C1—H1	120.8 (16)

S1—O1—C18—C19	−174.27 (8)	C5—C4—C3—C2	0.2 (2)
O3—S1—O1—C18	55.64 (10)	C13—N1—C10—Si1	−65.17 (13)
O4—S1—O1—C18	175.59 (11)	C13—N1—C17—C16	−52.78 (12)
O2—S1—O1—C18	−63.30 (11)	C13—N1—C11—C12	−178.50 (12)
N1—C17—C16—C15	56.11 (14)	C13—C14—C15—C16	56.25 (15)
C10—Si1—C7—C6	174.81 (8)	C7—C6—C5—C4	−179.20 (11)
C10—N1—C17—C16	69.94 (12)	C7—C6—C1—C2	179.19 (11)
C10—N1—C13—C14	−67.70 (13)	C1—C6—C5—C4	0.58 (17)
C10—N1—C11—C12	59.35 (15)	C1—C6—C7—Si1	−82.81 (12)
C14—C15—C16—C17	−56.65 (16)	C15—C14—C13—N1	−56.46 (14)
C17—N1—C10—Si1	173.69 (8)	C4—C3—C2—C1	−0.2 (2)
C17—N1—C13—C14	53.48 (13)	C11—N1—C10—Si1	53.52 (12)
C17—N1—C11—C12	−61.30 (14)	C11—N1—C17—C16	−167.85 (10)
C6—C5—C4—C3	−0.40 (19)	C11—N1—C13—C14	170.17 (10)
C6—C1—C2—C3	0.4 (2)	C8—Si1—C7—C6	55.31 (11)
C5—C6—C7—Si1	96.96 (11)	C9—Si1—C7—C6	−66.31 (12)
C5—C6—C1—C2	−0.59 (19)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O2ⁱ	0.93 (3)	2.39 (3)	3.2990 (17)	167 (2)
C7—H7B···O2ⁱⁱ	0.91 (3)	2.54 (3)	3.3881 (16)	156 (2)
C17—H17A···O4	0.95 (2)	2.26 (2)	3.1815 (16)	162.8 (17)
C17—H17B···O3ⁱⁱ	0.93 (2)	2.47 (2)	3.3680 (15)	161.3 (19)

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

Acknowledgements

J-LK and CS would like to thank the Fonds der Chemischen Industrie for a doctoral fellowship.

Funding information

Funding for this research was provided by: Verband der Chemischen Industrie.

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