Amino­silanes derived from 1H-benzimidazole-2(3H)-thione

Palomo-Molina, J.; García-Báez, E.V.; Contreras, R.; Pineda-Urbina, K.; Ramos-Organillo, A.

doi:10.1107/S2053229615014503

research papers

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 71| Part 9| September 2015| Pages 788-792

doi:10.1107/S2053229615014503

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Aminosilanes derived from 1H-benzimidazole-2(3H)-thione

Juliana Palomo-Molina,^a Efrén V. García-Báez,^b Rosalinda Contreras,^c,^d Kayim Pineda-Urbina ^a and Angel Ramos-Organillo ^a ^*

^aFacultad de Ciencias Químicas, Universidad de Colima, Carretera Coquimatlán-Colima, Coquimatlán Colima 28400, Mexico, ^bUnidad Profesional Interdisciplinaria de Biotecnología, Instituto Politécnico Nacional, Avenida Acueducto s/n, Barrio La Laguna Ticomán, México DF 07340, Mexico, ^cDepartamento de Química, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México DF 07000, Mexico, and ^dBarrio La Laguna Ticomán, México DF 07340, Mexico
^*Correspondence e-mail: aaramos@ucol.mx

Edited by P. Fanwick, Purdue University, USA (Received 23 June 2015; accepted 31 July 2015; online 12 August 2015)

Two new molecular structures, namely 1,3-bis(trimethylsilyl)-1H-benzimidazole-2(3H)-thione, C₁₃H₂₂N₂SSi₂, (2), and 1-trimethylsilyl-1H-benzimidazole-2(3H)-thione, C₁₀H₁₄N₂SSi, (3), are reported. Both systems were derived from 1H-benzimidazole-2(3H)-thione. Noncovalent C—H⋯π interactions between the centroid of the benzmidazole system and the SiMe₃ groups form helicoidal arrangements in (2). Dimerization of (3) results in the formation of R₂²(8) rings via N—H⋯S interactions, along with parallel π–π interactions between imidazole and benzene rings.

Keywords: 1H-benzimidazole-2(3H)-thione; aminosilanes; crystal structure; N—H⋯S interactions; hydrogen bonding.

CCDC references: 1416509; 1416508

1. Introduction

1H-Benzimidazole-2(3H)-thione, (1) (see Scheme 1), is a planar molecule with two substitutable acidic H atoms. The N atoms of this molecule have demonstrated the ability to form Lewis acid–base coordination compounds. Under basic conditions, the corresponding salt of (1) has been shown to react with p-block elements (O'Sullivan & Wallis, 1972 ).

The 1H-benzimidazole-2(3H)-thione heterocycle has been found in compounds with biological activity, such as progesterone agonists (Zhang et al., 2007 ). Antinematode activity was evaluated for {[(1H-benzimidazol-2-yl)thio]acetyl}piperazine (Mavrova et al., 2010 ), while 2-(alkylthio)benzimidazole with a β-lactam ring presented antibacterial and antifungal activities (Desai & Desai, 2006 ). Isomeric 2-(methylthio)benzimidazole compounds were synthesized as acyclic analogues of the HIV-1 RT inhibitor ring system (Gardiner & Loyns, 1995 ). More recently, isoxazole–mercaptobenzimidazole hybrids have presented analgesic and anti-inflammatory activities (Shravankumar et al., 2013 ). Furthermore, a wide range of biological activities have been reported for the benzimidazole fragment, such as antifungal, antibacterial, vasodilator, antispasmodic, anti-ulcer (Akkurt et al., 2012 ), antimicrobial (De Almeida et al., 2007 ), antihistamine (Mor et al., 2004 ), neutropic (Bakhareva et al., 1996 ) and analgesic (Anandarajagopal et al., 2010 ). Additionally, alkylsilyl-substituted benzimidazole has shown in vitro cytotoxicity, for example, 1-[3-(trimethylsilyl)propyl]benzimidazole inhibits carcinoma S180 tumour (Lukevics et al., 2001 ). In 2012, 1-{[dimethyl(phenyl)silyl]methyl}-3-(2-phenylethyl)-1-benzimidazol-3-ium bromide monohydrate was synthesized and its crystal structure elucidated (Akkurt et al., 2012). Silylated compounds are stable at low temperatures and, in some cases, under atmospheric conditions. Aminosilanes are soluble in nonpolar solvents, while the presence of trimethylsilyl groups increases the volatility of the organic fragments, most of which can be distilled without decomposition and, sometimes, even crystallized (Ghose & Gilchrist, 1991 ). Alkoxysilanes, thiosilanes and aminosilanes are stable at low temperatures, while the last class become unstable under atmospheric conditions (Colvin, 1981 ).

We report here the crystal structures of two new trimethylsilyl-substituted derivatives of 1H-benzimidazole-2(3H)-thione, namely 1,3-bis(trimethylsilyl)-1H-benzimidazole-2(3H)-thione, (2), and 1-trimethylsilyl-1H-benzimidazole-2(3H)-thione, (3).

2. Experimental

All reagents were purchased from Aldrich and were used as received. All solvents were dried before use. ¹H NMR (300.13185 MHz) and ¹³C NMR (75.47564 MHz) analyses in CDCl₃ were performed on a Bruker 300 MHz spectrometer, using TMS as the internal reference. Chemical shifts (δ) are reported in p.p.m. IR spectra were recorded on a Perkin–Elmer FT–IR 1600 spectrophotometer in the 4000–400 cm⁻¹ range. Elemental analyses were performed in a Thermofinniga Flash 112 instrument under standard conditions.

2.1. Synthesis and crystallization

Compound (2) was obtained by mixing 1H-benzimidazole-2(3H)-thione (0.5 g, 3.3 mmol) and chlorotrimethylsilane (0.89 ml, 75.9 mg, 6.9 mmol) in triethylamine (15 ml). The reaction was kept under constant stirring and reflux for 6 h. The resulting compound was a yellow liquid (yield 92%, 1.87 g) which solidified after 24 h. Crystals of (2) suitable for X-ray diffraction analysis were collected. MS: m/z (intensity, %): 294 (M⁺, 100), 206 (25), 150 (11); IR (KBr, ν_max, cm⁻¹): 1623 (C=N), 1514 and 1470 (N—C—S), 1181 (Si—N), 714 and 710 (Si—C); ¹H NMR (C₆D₆/THF, 1:1): δ AA′BB′ 7.26 (m, H4, H7), 7.04 (m, H5, H6), 0.73 (s, H_Me); ¹³C NMR: δ 182.3 (C2), 112.2 (C4, C7), 122.6 (C5, C6), 2.5 (C_Me). Elemental analysis calculated for C₁₃H₂₂N₂SSi₂: C 53.01, H 7.53, N 9.51, S 10.89%; found: C 53.03, H 7.60, N 9.60, S 10.69%.

Compound (3) was obtained from the partial hydrolysis of (2); both (2) and (3) are readily hydrolysed under atmospheric conditions. This compound was not analysed by spectroscopic techniques. However, crystals of (3) suitable for X-ray diffraction analysis were obtained from a hexane solution and a single crystal immersed in oil was analysed.

2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. H atoms were included in geometrically calculated positions, riding on the C or N atoms to which they were bonded. C—H distances were restrained to 0.93 (aromatic) or 0.96 Å (methyl) and the N—H bond length was restrained to 0.86 Å. H-atom displacement parameters were set at U_iso(H) = 1.5U_eq(C) for methyl H atoms and at 1.2U_eq(C,N) otherwise.

Table 1
Experimental details

	(2)	(3)
Crystal data
Chemical formula	C₁₃H₂₂N₂SSi₂	C₁₀H₁₄N₂SSi
M_r	294.56	222.38
Crystal system, space group	Orthorhombic, P2₁2₁2₁	Monoclinic, P2₁/c
Temperature (K)	293	293
a, b, c (Å)	10.0302 (3), 10.6172 (3), 16.2428 (6)	9.8057 (2), 15.8032 (4), 15.8658 (5)
α, β, γ (°)	90, 90, 90	90, 93.859 (1), 90
V (Å³)	1729.74 (10)	2453.01 (11)
Z	4	8
Radiation type	Mo Kα	Mo Kα
μ (mm⁻¹)	0.31	0.33
Crystal size (mm)	0.25 × 0.20 × 0.10 × 0.15 (radius)	0.20 × 0.20 × 0.15 × 0.15 (radius)

Data collection
Diffractometer	Nonius KappaCCD area-detector diffractometer	Nonius KappaCCD area-detector diffractometer
Absorption correction	Spherical (Dwiggins, 1975 )	Spherical (Dwiggins, 1975)
T_min, T_max	0.861, 0.862	0.861, 0.862
No. of measured, independent and observed [I > 2σ(I)] reflections	15678, 3889, 2472	29355, 5554, 3199
R_int	0.064	0.096
(sin θ/λ)_max (Å⁻¹)	0.648	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.048, 0.104, 1.01	0.049, 0.138, 1.00
No. of reflections	3889	5554
No. of parameters	164	259
H-atom treatment	H-atom parameters constrained	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.20	0.21, −0.24
Absolute structure	Flack x parameter determined using 838 quotients, [(I⁺) − (I⁻)]/[(I⁺) + (I⁻)] (Parsons et al., 2013 )	–
Absolute structure parameter	0.01 (7)	–
Computer programs: COLLECT (Nonius, 2000 ), DENZO and SCALEPACK (Otwinowski & Minor, 1997 ), SHELXS97 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), and XPMA in ZORTEP (Zsolnai, 1997 ).

3. Results and discussion

Compound (2) crystallizes in the orthorhombic space group P2₁2₁2₁. The average N1—Si1—Me_10,11,12 angle is 109.0 (2)° and the average N1—Si1—Me_13,14,15 angle is 109.1 (2)°. The Si—N distances of 1.809 (3) and 1.803 (3) Å are slightly longer than those reported previously for 1,3-bis(trimethylsilyl)imidazolidin-2-one [1.739 (7) Å] and 4-methyl-1,3-bis(trimethylsilyl)imidazolidin-2-one [1.745 (3) Å] (Szalay et al., 2005 ), which might be caused by the difference in electronegativities of the O and S atoms.

Compound (3) crystallizes with two independent molecules, A and B, in the asymmetric unit in the monoclinic space group P2₁/c. The average N1—Si1—Me_20,21,22 angle is 108.49 (12)° and the average N11—Si2—Me_23,24,25 angle is 108.66 (12)°. The Si—N distances are 1.817 (2) and 1.804 (2) Å.

Overall, compounds (2) and (3) have very similar structures, which are shown in Figs. 1 and 2, respectively. Selected bond lengths and angles are listed in Tables 2 and 3, respectively. The average C—Si bond length for both compounds is 1.847 (3) Å and the average C—Si—C angle is 109.5 (2)°, in agreement with sp³-hybridization of the Si atoms. These values agree with those in similar structures reported previously (Wagler et al., 2010 ).

Table 2
Selected geometric parameters (Å, °) for (2)

Si1—N1	1.809 (3)	Si2—C13	1.839 (6)
Si1—C11	1.842 (5)	Si2—C15	1.854 (6)
Si1—C12	1.842 (5)	Si2—C14	1.861 (5)
Si1—C10	1.847 (5)	S1—C2	1.669 (4)
Si2—N3	1.803 (3)

N1—Si1—C11	109.0 (2)	N3—Si2—C14	109.3 (2)
N1—Si1—C12	109.53 (19)	C13—Si2—C14	113.7 (3)
C11—Si1—C12	113.9 (3)	C15—Si2—C14	107.7 (3)
N1—Si1—C10	108.4 (2)	C2—N1—Si1	121.7 (3)
C11—Si1—C10	109.4 (3)	C8—N1—Si1	130.9 (3)
C12—Si1—C10	106.4 (3)	C2—N3—Si2	120.8 (3)
N3—Si2—C13	109.4 (2)	C9—N3—Si2	132.3 (2)
N3—Si2—C15	108.5 (2)	N1—C2—S1	125.1 (3)
C13—Si2—C15	108.2 (3)	N3—C2—S1	124.8 (3)

C11—Si1—N1—C2	70.3 (4)	C14—Si2—N3—C9	113.9 (4)
C12—Si1—N1—C2	−55.0 (4)	Si2—N3—C9—C4	−4.8 (7)
C10—Si1—N1—C2	−170.7 (3)	Si2—N3—C9—C8	179.1 (3)
C11—Si1—N1—C8	−113.2 (4)	Si1—N1—C8—C7	10.2 (6)
C12—Si1—N1—C8	121.5 (4)	Si1—N1—C8—C9	−174.1 (3)
C10—Si1—N1—C8	5.8 (4)	Si1—N1—C2—N3	173.6 (2)
C13—Si2—N3—C2	59.4 (4)	C8—N1—C2—S1	175.3 (3)
C15—Si2—N3—C2	177.2 (4)	Si1—N1—C2—S1	−7.5 (5)
C14—Si2—N3—C2	−65.7 (4)	Si2—N3—C2—N1	−177.2 (2)
C13—Si2—N3—C9	−121.0 (4)	C9—N3—C2—S1	−175.9 (3)
C15—Si2—N3—C9	−3.2 (4)	Si2—N3—C2—S1	3.9 (5)

Table 3
Selected geometric parameters (Å, °) for (3)

S1—C2	1.676 (3)	S2—C12	1.675 (2)
Si1—N1	1.817 (2)	Si2—N11	1.804 (2)
Si1—C22	1.841 (3)	Si2—C24	1.827 (3)
Si1—C20	1.846 (3)	Si2—C23	1.830 (4)
Si1—C21	1.850 (3)	Si2—C25	1.841 (3)

N1—Si1—C22	108.72 (12)	N11—Si2—C24	111.21 (15)
N1—Si1—C20	107.62 (12)	N11—Si2—C23	105.51 (15)
C22—Si1—C20	109.24 (16)	C24—Si2—C23	113.3 (2)
N1—Si1—C21	109.12 (13)	N11—Si2—C25	109.27 (13)
C22—Si1—C21	108.81 (18)	C24—Si2—C25	106.95 (19)
C20—Si1—C21	113.23 (16)	C23—Si2—C25	110.6 (2)
C2—N1—Si1	122.00 (16)	C12—N11—Si2	123.12 (16)
C8—N1—Si1	130.56 (17)	C18—N11—Si2	128.88 (17)
N3—C2—S1	125.48 (19)	N13—C12—S2	125.02 (19)
N1—C2—S1	126.65 (18)	N11—C12—S2	127.12 (18)

C22—Si1—N1—C2	176.3 (2)	C24—Si2—N11—C12	56.7 (3)
C20—Si1—N1—C2	−65.5 (2)	C23—Si2—N11—C12	−66.5 (2)
C21—Si1—N1—C2	57.8 (2)	C25—Si2—N11—C12	174.5 (2)
C22—Si1—N1—C8	−1.1 (3)	C24—Si2—N11—C18	−133.4 (3)
C20—Si1—N1—C8	117.1 (2)	C23—Si2—N11—C18	103.4 (3)
C21—Si1—N1—C8	−119.6 (2)	C25—Si2—N11—C18	−15.6 (3)
C9—N3—C2—S1	179.14 (18)	C19—N13—C12—S2	−179.11 (18)
Si1—N1—C2—N3	−177.32 (16)	Si2—N11—C12—N13	171.28 (16)
C8—N1—C2—S1	−178.90 (19)	C18—N11—C12—S2	179.38 (19)
Si1—N1—C2—S1	3.2 (3)	Si2—N11—C12—S2	−8.8 (3)
Si1—N1—C8—C9	177.06 (17)	Si2—N11—C18—C17	8.5 (5)
Si1—N1—C8—C7	−3.0 (4)	Si2—N11—C18—C19	−171.09 (18)

Figure 1
The molecular structure of compound (2)

, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
The molecular structures of the two independent molecules of compound (3)

, showing the atom-numbering schemes. Displacement ellipsoids are drawn at the 30% probability level.

The C=S distances for compounds (2) and (3) range from 1.669 (4) to 1.675 (2) Å. The average N_1,3—C2=S1 angle is 125.0 (3)° for (2) and the average N_1,11—C_2,12=S12 angle is 126.9 (18)° for (3). These angles agree with sp²-hybridization of the C and S atoms which is typical of thiourea groups (Wagler et al., 2010). The S atom of (3) has a slight displacement of 0.007 (1) Å from the benzimidazole molecular plane, whereas in (2), the S atom is out of the plane by 0.155 (2) Å. This displacement could be caused by noncovalent intramolecular interactions between the S-atom nucleus and both Si atoms, or between the methyl H atoms and the S atom. Compound (2) presents four noncovalent C—H⋯S interactions (Table 4), with C⋯S distances ranging from 2.77 to 2.96 Å and angles ranging from 122 to 125°, which amount to less than the sum of the van der Waals radii of S and H atoms (3.25 Å; Bondi, 1964 ).

Table 4
Hydrogen-bond geometry (Å, °) for (2)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C11—H11B⋯S1	0.96	2.96	3.564 (7)	122
C12—H12C⋯S1	0.96	2.77	3.415 (5)	125
C13—H13B⋯S1	0.96	2.79	3.423 (7)	125
C14—H14C⋯S1	0.96	2.86	3.480 (5)	123

Another noncovalent intramolecular interaction (Table 5) was observed in (3), viz. C21—H21⋯S1, with a C⋯S distance of 2.83 Å and an angle of 126°, similar to that observed in (2).

Table 5
Hydrogen-bond geometry (Å, °) for (3)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3⋯S2ⁱ	0.86	2.52	3.374 (2)	170
N13—H13⋯S1ⁱ	0.86	2.45	3.282 (2)	164
C21—H21B⋯S1	0.96	2.83	3.480 (4)	126
Symmetry code: (i) -x+1, -y+1, -z.

Comparing the structures of (2) and (3), it becomes obvious that the fused rings in (2) are not completely flat. Specifically, the thiourea unit composed of atoms N1/C2/N3/S1 is offset from the molecular plane defined by the benzene ring. This is a consequence of the intramolecular noncovalent C—H⋯S interactions present in the system.

Fig. 3(a) shows the spiral arrangement of (2), which forms a linking interaction between molecules through the imidazole ring (C10—H10A⋯Cg1 = 2.94 Å; Cg1 is the centroid of the imidazole ring) and the benzene ring [C10—H10B⋯Cg2 = 2.83 Å; Cg2 is the centroid of the benzene ring at (x − $[{1\over 2}]$ , −y + $[{3\over 2}]$ , −z)]. These interactions form a helicoidal repeat unit of 10.03 Å, which extends along the crystallographic a axis. Fig. 3(b) presents the helix overlap of this system. A third interaction, viz. C13—H13⋯π(x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z), has a C⋯π distance of 2.77 Å, which further supports the helicoidal arrangement.

Figure 3
(a) The spiral arrangement for (2)

and (b) the overlap of the helix along the direction of the a axis.

Molecules A and B of (3) are auto-assembled by N—H⋯S interactions (N3—H3⋯S2ⁱ = 2.52 Å and N13—H13⋯S1ⁱ = 2.45 Å; see Table 5 for symmetry code). This arrangement forms a cyclic system with an $[R_{2}^{2}]$ (8) hydrogen-bonding pattern (Bernstein et al., 1995 ) (Fig. 4). Furthermore, π–π interactions between the imidazole and benzene rings are observed in the dimerization of the compound and extend in the ab plane (Fig. 4). The distance between the ring centroids in these interactions is 3.64 Å (symmetry code: −x + 1, −y + 1, −z). There is an additional intermolecular C20—H20B⋯π(imidazole ring) interaction of 3.03 Å (symmetry code: −x + 1, y + $[{1\over 2}]$ , −z + $[{1\over 2}]$ ) which strengthens the crystalline arrangement of (3).

Figure 4
(a) The crystal packing diagram of (3)

along the direction of the ab plane. (b) A detailed view of the formation of the $[R_{2}^{2}]$ (8) hydrogen-bonding motif and the π–π stacking interactions. [Where is the origin in part (a)?]

As can be seen, the structures of (2) and (3) have similar parameters around the silyl–amine bond, but while (3) is a dimer formed by classical hydrogen bonding, the structure of (2) is a helix supported by nonclassical interactions.

Supporting information

CCDC references: 1416509; 1416508

Crystal structure: contains datablocks 2, 3, global. DOI: 10.1107/S2053229615014503/fn3201sup1.cif

Structure factors: contains datablock 2. DOI: 10.1107/S2053229615014503/fn32012sup2.hkl

Structure factors: contains datablock 3. DOI: 10.1107/S2053229615014503/fn32013sup3.hkl

Supporting information file. DOI: 10.1107/S2053229615014503/fn32012sup4.cml

Supporting information file. DOI: 10.1107/S2053229615014503/fn32013sup5.cml

Introduction top

2-Mercaptobenzimidazole (1) (see Scheme 1) is a planar molecule with two substitutable acidic H atoms. The N atoms of this molecule have demonstrated the ability to form Lewis acid–base coordination compounds. Under basic conditions, the corresponding salt of (1) has been shown to react with p-block elements (O'Sullivan & Wallis, 1972).

The 2-mercaptobenzimidazole heterocycle has been found in compounds with biological activity, such as progesterone agonists (Zhang et al., 2007). Antinematode activity was evaluated for (1H-benzimidazol-2-yl)thioacetylpiperazine (Mavrova et al., 2010), while 2-alkylthiobenzimidazole with a β-lactam ring presented antibacterial and antifungal activities (Desai & Desai, 2006). Isomeric 2-methylmercaptobenzimidazole compounds were synthesized as acyclic analogues of the HIV-1 RT inhibitor ring system (Gardiner & Loyns, 1995). More recently, isoxazole–mercaptobenzimidazole hybrids presented analgesic and anti-inflammatory activities (Kankala et al., 2013). Furthermore, the benzimidazole fragment has had a wide range of biological activities reported, such as antifungal, antibacterial, vasodilator, spasmodic, anti-ulcer (Akkurt et al., 2012), antimicrobial (De Almeida et al., 2007), antihistamine (Mor et al., 2004), neutropic (Bakhareva et al., 1996) and analgesic (Anandarajagopal et al., 2010). Additionally, alkylsilyl-substituted benzimidazole has shown in vitro cytotoxicity. 1-[3-(Trimethylsilyl)propyl]benzimidazole inhibits carcinoma S180 tumour (Lukevics et al., 2001). In 2012, 1-{[dimethyl(phenyl)silyl]methyl}-3-(2-phenylethyl)-1-benzimidazol-3-ium bromide monohydrate was synthetsized and its crystal structure elucidated (Akkurt et al., 2012). Silylated compounds are stable at low temperatures and, in some cases, under atmospheric conditions. Aminosilanes are soluble in nonpolar solvents, while the presence of trimethylsilyl groups increases the volatility of the organic fragments, most of which can be distilled without decomposition and, sometimes, even crystallized (Ghose & Gilchrist, 1991). Alkoxysilanes, thiosilanes and aminosilanes are stable at low temperatures, while the latter become unstable under atmospheric conditions (Colvin, 1981).

Experimental top

All reagents were purchased from Aldrich and used as received. All solvents were dried before use. ¹H NMR (300.13185 MHz) and ¹³C NMR (75.47564 MHz) analyses in CDCl₃ were performed on a Bruker 300 MHz spectrometer, using TMS as the internal reference. Chemical shifts (δ) are reported in p.p.m. IR spectra were recorded on a Perkin–Elmer FT–IR 1600 spectrophotometer in the 4000–400 cm^-1 range. Elemental analyses were performed in a Thermofinniga Flash 112 instrument under standard conditions.

Synthesis and crystallization top

Compound (2) was obtained by mixing 1H-benzimidazole-2(3H)-thione (0.5 g, 3.3 mmol) and chlorotrimethylsilane (0.89 ml, 75.9 mg, 6.9 mmol) in triethylamine (15 ml). The reaction was kept under constant stirring and reflux for 6 h. The resulting compound was a yellow liquid (yield 92%, 1.87 g) which solidified after 24 h. Crystals of (2) suitable for X-ray diffraction were collected. Spectroscopic analysis: m/z (intensity, %): 294 (M⁺, 100), 206 (25), 150 (11); IR (KBr, ν_max, cm^-1): 1623 (C═ N), 1514 and 1470 (N—C—S), 1181 (Si—N), 714 and 710 (Si—C); ¹H NMR (C₆D₆/THF, 1:1, δ, p.p.m.): AA'BB' 7.26 (m, H4, H7), 7.04 (m, H5, H6), 0.73 (s, H_Me); ¹³C NMR (δ, p.p.m.): 182.3, (C2), 112.2 (C4, C7), 122.6 (C5, C6), 2.5 (C_Me). Elemental analysis, calculated for C₁₃H₂₂N₂SSi₂: C 53.01, H 7.53, N 9.51, S 10.89%; found: C 53.03, H 7.60, N 9.60, S 10.69%.

Compound (3) was obtained from the partial hydrolysis of (2); both (2) and (3) are readily hydrolysed under atmospheric conditions. This compound was not analysed by spectroscopic techniques. However, crystals of (3) suitable for X-ray diffraction were obtained from a hexane solution and a single crystal immersed in oil was analysed.

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 1. H atoms were included in geometrically calculated positions, riding on the C or N atom to which they were bonded. C—H distances were restrained to 0.93 (aromatic) or 0.96 Å (methyl) and the N—H bond length was restrained to 0.86 Å. H-atom displacement parameters were set at U_iso(H) = 1.5U_eq(C) for methyl H atoms and at 1.2U_eq(C,N) otherwise.

Results and discussion top

Compound (2) crystallizes in the orthorhombic space group P2₁2₁2₁. The average N1—Si1—Me_10,11,12 angle is 109.0 (2)° and the average N1—Si1—Me_13,14,15 angle is 109.1 (2)°. The Si—N distances of 1.809 (3) and 1.803 (3) Å are slightly longer than those reported previously for 1,3-bis(trimethylsilyl)imidazolidin-2-one [1.739 (7) Å] and 4-methyl-1,3-bis(trimethylsilyl)imidazolidin-2-one [1.745 (3) Å] (Szalay et al.,2005), which might be caused by the difference in electronegativity between O and S atoms.

Compound (3) crystallizes with two independent molecules in the asymmetric unit in the monoclinic space group P2₁/c. The average N1—Si1—Me_20,21,22 angle is 108.49 (12)° and average N11—Si2—Me_23,24,25 angle is 108.66 (12)°. The Si—N distances are 1.817 (2) and 1.804 (2) Å.

Overall, compounds (2) and (3) have very similar structures, which are shown in Figs. 1 and 2, respectively. Selected bond lengths and angles are listed in Tables 2 and 3, respectively. The average C—Si bond length for both compounds is 1.847 (3) Å and the average C—Si—C angle is 109.5 (2)°, in agreement with sp³ hybridization on the Si atoms. These values agree with those in similar structures reported previously (Wagler et al., 2010).

The C═S distances for compounds (2) and (3) range from 1.669 (4) to 1.675 (2) Å. The average N_1,3—C2═S1 angle is 125.0 (3)° for (2) and the average N_1,11—C_2,12═S12 angle is 126.9 (18)° for (3). These angles agree with the sp²-hybridization of the C and S atoms, typical of thiourea groups (Wagler et al., 2010). The S atom of (3) has a slight displacement from the benzimidazole molecular plane of 0.007 (1) Å, whereas in (2) the S atom is out of the plane by 0.155 (2) Å. This displacement could be caused by noncovalent intramolecular interactions between the S-atom nucleus and both Si atoms or the methyl H atoms and the S atom. Compound (2) presents four noncovalent C—H···S interactions (Table 4), with C···S distances ranging from 2.77 to 2.96 Å and angles ranging from 122 to 125°, which amount to less than the sum of the van der Waals radii of S and H atoms (3.25 Å; [Standard reference?]).

Another noncovalent intramolecular interaction (Table 5) was observed in (3), viz. C21—H21···S1, with a C···S distance of 2.83 Å and an angle of 125.5°, similar to that observed in (2).

Comparing the structures of (2) and (3), it becomes obvious that the fused rings in (2) are not completely flat. Specifically, the thiourea unit composed of atoms N1/C2/N3/S1 is offset from the molecular plane defined by the benzene ring. This is a consequence of the intramolecular C—H···S noncovalent interactions present in the system.

Fig. 3(a) shows the spiral arrangement of (2), which forms a linking interaction between molecules through the imidazole ring (C10—H10A···Cg1 = 2.94 Å; Cg1 is the centroid of the imidazole ring) and the benzene ring [C10—H10B···Cg2 = 2.83 Å; Cg2 is the centroid of the benzene ring at (x - 1/2, -y + 3/2, -z)]. These interactions form a helicoidal repeat unit of 10.03 Å, which extends along the crystallographic a axis. Fig. 3(b) presents the helix overlap of this system. A third interaction, C13—H13···π(x + 1/2, -y + 1/2, -z), has a C···π distance of 2.77 Å, which further supports the helicoidal arrangement.

Molecules A and B of (3) are auto-assembled by N—H···S [N3—H3···S2 = 2.52 Å and N13—H13···S1 = 2.45 Å; symmetry code (1 - x, 1 - y, -z)] interactions. This arrangement forms a cyclical system with an R₂²(8) hydrogen-bonding pattern (Bernstein et al., 1995) (Fig. 4). Furthermore, π–π interactions between the imidazole and benzene rings are observed in the dimerization of the compound and extend along [Should this be in?] the ab plane (Fig. 4). The distance between the ring centroids in these interactions is 3.64 Å [symmetry code (-x + 1, -y + 1, -z)]. Another similar arrangement propagates in the opposite direction [A plane does not have a direction] of this plane, as shown in Fig. 4. There is an additional intermolecular C20—H20B···π(imidazole ring) interaction of 3.03 Å [symmetry code (-x + 1, y + 1/2, -z + 1/2)] which strengthens the crystalline arrangement of (3).

Final sentence to tie the paper together, highlighting the differences between the compounds?

Computing details top

For both compounds, data collection: COLLECT (Nonius, 2000); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: XPMA (Zsolnai, 1997); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

Figures top

	Fig. 1. The molecular structure of compound (2), showing the atom-numbering scheme. Displacement ellipsoids are shown at the 30% probability level.
	Fig. 2. The molecular structure of compound (3), showing the atom-numbering scheme. Displacement ellipsoids are shown at the 30% probability level.
	Fig. 3. (a) The spiral arrangement for (2) and (b) the overlap of the helix along the direction of the a axis.
	Fig. 4. (a) The crystal packing diagram of (3), along the direction of the ab plane. (b) A detailed view of the formation of the R²₂(8) hydrogen-bonding motif and the π–π stacking interactions. [Where is the origin in part (a)?]

(2) 1,3-Bis(trimethylsilyl)-1H-benzimidazole-2(3H)-thione top

Crystal data top

C₁₃H₂₂N₂SSi₂	D_x = 1.131 Mg m⁻³
M_r = 294.56	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 600 reflections
a = 10.0302 (3) Å	θ = 20–25°
b = 10.6172 (3) Å	µ = 0.31 mm⁻¹
c = 16.2428 (6) Å	T = 293 K
V = 1729.74 (10) Å³	Prism, colourless
Z = 4	0.25 × 0.20 × 0.10 × 0.15 (radius) mm
F(000) = 632

Data collection top

Nonius Kappa CCD area-detector diffractometer	3889 independent reflections
Radiation source: fine-focus sealed tube	2472 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.064
Detector resolution: 3 pixels mm^-1	θ_max = 27.4°, θ_min = 3.8°
ω scans	h = −12→12
Absorption correction: for a sphere Interpolation using Int. Tables Vol. C (1992) p. 523, Table 6.3.3.3, for values of muR in the range 0–2.5, and Int. Tables Vol. II (1959) p. 302, Table 5.3.6 B, for muR in the range 2.6–10.0. The interpolation procedure of Dwiggins (1975) is used with some modification.	k = −12→13
T_min = 0.861, T_max = 0.862	l = −20→20
15678 measured reflections

Refinement top

Refinement on F²	H-atom parameters constrained
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0297P)² + 0.4977P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.048	(Δ/σ)_max < 0.001
wR(F²) = 0.104	Δρ_max = 0.17 e Å⁻³
S = 1.01	Δρ_min = −0.20 e Å⁻³
3889 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
164 parameters	Extinction coefficient: 0.008 (2)
0 restraints	Absolute structure: Flack x parameter determined using 838 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
Hydrogen site location: inferred from neighbouring sites	Absolute structure parameter: 0.01 (7)

Crystal data top

C₁₃H₂₂N₂SSi₂	V = 1729.74 (10) Å³
M_r = 294.56	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 10.0302 (3) Å	µ = 0.31 mm⁻¹
b = 10.6172 (3) Å	T = 293 K
c = 16.2428 (6) Å	0.25 × 0.20 × 0.10 × 0.15 (radius) mm

Data collection top

Nonius Kappa CCD area-detector diffractometer	3889 independent reflections
Absorption correction: for a sphere Interpolation using Int. Tables Vol. C (1992) p. 523, Table 6.3.3.3, for values of muR in the range 0–2.5, and Int. Tables Vol. II (1959) p. 302, Table 5.3.6 B, for muR in the range 2.6–10.0. The interpolation procedure of Dwiggins (1975) is used with some modification.	2472 reflections with I > 2σ(I)
T_min = 0.861, T_max = 0.862	R_int = 0.064
15678 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.048	H-atom parameters constrained
wR(F²) = 0.104	Δρ_max = 0.17 e Å⁻³
S = 1.01	Δρ_min = −0.20 e Å⁻³
3889 reflections	Absolute structure: Flack x parameter determined using 838 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
164 parameters	Absolute structure parameter: 0.01 (7)
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.

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

	x	y	z	U_iso*/U_eq
Si1	0.40978 (12)	0.83025 (11)	0.87960 (8)	0.0615 (3)
Si2	0.81188 (12)	1.15207 (13)	0.98310 (9)	0.0735 (4)
S1	0.68527 (14)	0.98333 (17)	0.83494 (7)	0.0965 (6)
N1	0.5113 (3)	0.9147 (3)	0.95331 (19)	0.0481 (8)
N3	0.6713 (3)	1.0480 (3)	0.99562 (19)	0.0522 (8)
C9	0.5940 (4)	1.0147 (4)	1.0649 (2)	0.0514 (9)
C8	0.4962 (4)	0.9315 (3)	1.0387 (2)	0.0485 (9)
C7	0.4107 (4)	0.8755 (4)	1.0949 (3)	0.0668 (12)
H7	0.3466	0.8178	1.0780	0.080*
C2	0.6206 (4)	0.9823 (4)	0.9296 (2)	0.0525 (9)
C4	0.6060 (5)	1.0450 (5)	1.1472 (3)	0.0802 (15)
H4	0.6718	1.1003	1.1652	0.096*
C5	0.5186 (6)	0.9917 (7)	1.2017 (3)	0.1007 (19)
H5	0.5237	1.0128	1.2572	0.121*
C6	0.4237 (6)	0.9077 (6)	1.1759 (3)	0.0923 (17)
H6	0.3667	0.8717	1.2145	0.111*
C14	0.9616 (4)	1.0580 (6)	0.9550 (4)	0.0990 (19)
H14A	1.0367	1.1132	0.9482	0.148*
H14B	0.9802	0.9982	0.9978	0.148*
H14C	0.9452	1.0140	0.9043	0.148*
C12	0.3532 (5)	0.9393 (5)	0.7986 (3)	0.1019 (19)
H12A	0.2994	0.8944	0.7596	0.153*
H12B	0.3015	1.0057	0.8230	0.153*
H12C	0.4292	0.9747	0.7711	0.153*
C13	0.7699 (6)	1.2751 (5)	0.9077 (5)	0.134 (3)
H13A	0.8447	1.3306	0.9010	0.201*
H13B	0.7488	1.2367	0.8559	0.201*
H13C	0.6945	1.3222	0.9270	0.201*
C11	0.5048 (7)	0.6943 (5)	0.8405 (4)	0.122 (2)
H11A	0.4515	0.6490	0.8013	0.184*
H11B	0.5849	0.7234	0.8143	0.184*
H11C	0.5274	0.6397	0.8855	0.184*
C10	0.2582 (5)	0.7739 (6)	0.9326 (4)	0.114 (2)
H10A	0.2031	0.7288	0.8943	0.172*
H10B	0.2830	0.7190	0.9770	0.172*
H10C	0.2097	0.8446	0.9540	0.172*
C15	0.8462 (6)	1.2293 (6)	1.0833 (4)	0.124 (2)
H15A	0.9209	1.2852	1.0775	0.186*
H15B	0.7693	1.2765	1.1002	0.186*
H15C	0.8662	1.1664	1.1239	0.186*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Si1	0.0585 (7)	0.0565 (7)	0.0696 (8)	−0.0086 (6)	−0.0095 (6)	−0.0071 (6)
Si2	0.0477 (6)	0.0730 (8)	0.0999 (10)	−0.0160 (6)	−0.0084 (7)	0.0001 (7)
S1	0.0760 (8)	0.1618 (15)	0.0517 (6)	−0.0372 (10)	0.0097 (6)	0.0012 (8)
N1	0.0434 (16)	0.0495 (18)	0.052 (2)	−0.0058 (14)	0.0010 (15)	0.0006 (14)
N3	0.0455 (16)	0.0559 (19)	0.055 (2)	−0.0098 (14)	−0.0040 (16)	−0.0011 (15)
C9	0.045 (2)	0.061 (2)	0.048 (2)	0.008 (2)	−0.0043 (18)	−0.0040 (19)
C8	0.043 (2)	0.051 (2)	0.052 (2)	0.0071 (18)	0.0027 (19)	0.0041 (18)
C7	0.055 (2)	0.074 (3)	0.072 (3)	0.004 (2)	0.013 (2)	0.013 (2)
C2	0.046 (2)	0.062 (2)	0.050 (2)	−0.0074 (18)	−0.0001 (17)	0.003 (2)
C4	0.065 (3)	0.115 (4)	0.061 (3)	0.004 (3)	−0.011 (2)	−0.017 (3)
C5	0.082 (4)	0.175 (6)	0.046 (3)	0.023 (4)	0.002 (3)	−0.003 (4)
C6	0.073 (3)	0.142 (5)	0.061 (3)	0.012 (4)	0.014 (3)	0.021 (3)
C14	0.050 (3)	0.129 (5)	0.118 (5)	−0.004 (3)	−0.001 (3)	0.002 (4)
C12	0.105 (4)	0.103 (4)	0.098 (4)	−0.024 (3)	−0.045 (3)	0.018 (3)
C13	0.096 (4)	0.095 (4)	0.212 (8)	−0.027 (3)	−0.011 (5)	0.063 (5)
C11	0.139 (5)	0.100 (4)	0.129 (5)	0.029 (4)	−0.026 (5)	−0.054 (4)
C10	0.085 (4)	0.126 (5)	0.132 (5)	−0.057 (4)	−0.011 (4)	0.001 (4)
C15	0.098 (4)	0.127 (5)	0.148 (6)	−0.045 (4)	−0.001 (4)	−0.057 (4)

Geometric parameters (Å, º) top

Si1—N1	1.809 (3)	C5—H5	0.9300
Si1—C11	1.842 (5)	C6—H6	0.9300
Si1—C12	1.842 (5)	C14—H14A	0.9600
Si1—C10	1.847 (5)	C14—H14B	0.9600
Si2—N3	1.803 (3)	C14—H14C	0.9600
Si2—C13	1.839 (6)	C12—H12A	0.9600
Si2—C15	1.854 (6)	C12—H12B	0.9600
Si2—C14	1.861 (5)	C12—H12C	0.9600
S1—C2	1.669 (4)	C13—H13A	0.9600
N1—C2	1.366 (4)	C13—H13B	0.9600
N1—C8	1.406 (5)	C13—H13C	0.9600
N3—C2	1.376 (5)	C11—H11A	0.9600
N3—C9	1.412 (5)	C11—H11B	0.9600
C9—C4	1.381 (5)	C11—H11C	0.9600
C9—C8	1.387 (5)	C10—H10A	0.9600
C8—C7	1.387 (5)	C10—H10B	0.9600
C7—C6	1.366 (7)	C10—H10C	0.9600
C7—H7	0.9300	C15—H15A	0.9600
C4—C5	1.369 (7)	C15—H15B	0.9600
C4—H4	0.9300	C15—H15C	0.9600
C5—C6	1.370 (8)

N1—Si1—C11	109.0 (2)	C5—C6—H6	119.2
N1—Si1—C12	109.53 (19)	Si2—C14—H14A	109.5
C11—Si1—C12	113.9 (3)	Si2—C14—H14B	109.5
N1—Si1—C10	108.4 (2)	H14A—C14—H14B	109.5
C11—Si1—C10	109.4 (3)	Si2—C14—H14C	109.5
C12—Si1—C10	106.4 (3)	H14A—C14—H14C	109.5
N3—Si2—C13	109.4 (2)	H14B—C14—H14C	109.5
N3—Si2—C15	108.5 (2)	Si1—C12—H12A	109.5
C13—Si2—C15	108.2 (3)	Si1—C12—H12B	109.5
N3—Si2—C14	109.3 (2)	H12A—C12—H12B	109.5
C13—Si2—C14	113.7 (3)	Si1—C12—H12C	109.5
C15—Si2—C14	107.7 (3)	H12A—C12—H12C	109.5
C2—N1—C8	107.3 (3)	H12B—C12—H12C	109.5
C2—N1—Si1	121.7 (3)	Si2—C13—H13A	109.5
C8—N1—Si1	130.9 (3)	Si2—C13—H13B	109.5
C2—N3—C9	106.9 (3)	H13A—C13—H13B	109.5
C2—N3—Si2	120.8 (3)	Si2—C13—H13C	109.5
C9—N3—Si2	132.3 (2)	H13A—C13—H13C	109.5
C4—C9—C8	120.5 (4)	H13B—C13—H13C	109.5
C4—C9—N3	131.7 (4)	Si1—C11—H11A	109.5
C8—C9—N3	107.7 (3)	Si1—C11—H11B	109.5
C7—C8—C9	120.6 (4)	H11A—C11—H11B	109.5
C7—C8—N1	131.4 (4)	Si1—C11—H11C	109.5
C9—C8—N1	107.9 (3)	H11A—C11—H11C	109.5
C6—C7—C8	117.9 (5)	H11B—C11—H11C	109.5
C6—C7—H7	121.1	Si1—C10—H10A	109.5
C8—C7—H7	121.1	Si1—C10—H10B	109.5
N1—C2—N3	110.1 (3)	H10A—C10—H10B	109.5
N1—C2—S1	125.1 (3)	Si1—C10—H10C	109.5
N3—C2—S1	124.8 (3)	H10A—C10—H10C	109.5
C5—C4—C9	118.3 (5)	H10B—C10—H10C	109.5
C5—C4—H4	120.8	Si2—C15—H15A	109.5
C9—C4—H4	120.8	Si2—C15—H15B	109.5
C4—C5—C6	121.1 (5)	H15A—C15—H15B	109.5
C4—C5—H5	119.5	Si2—C15—H15C	109.5
C6—C5—H5	119.5	H15A—C15—H15C	109.5
C7—C6—C5	121.6 (5)	H15B—C15—H15C	109.5
C7—C6—H6	119.2

C11—Si1—N1—C2	70.3 (4)	C2—N1—C8—C7	−172.9 (4)
C12—Si1—N1—C2	−55.0 (4)	Si1—N1—C8—C7	10.2 (6)
C10—Si1—N1—C2	−170.7 (3)	C2—N1—C8—C9	2.8 (4)
C11—Si1—N1—C8	−113.2 (4)	Si1—N1—C8—C9	−174.1 (3)
C12—Si1—N1—C8	121.5 (4)	C9—C8—C7—C6	1.8 (6)
C10—Si1—N1—C8	5.8 (4)	N1—C8—C7—C6	177.1 (4)
C13—Si2—N3—C2	59.4 (4)	C8—N1—C2—N3	−3.7 (4)
C15—Si2—N3—C2	177.2 (4)	Si1—N1—C2—N3	173.6 (2)
C14—Si2—N3—C2	−65.7 (4)	C8—N1—C2—S1	175.3 (3)
C13—Si2—N3—C9	−121.0 (4)	Si1—N1—C2—S1	−7.5 (5)
C15—Si2—N3—C9	−3.2 (4)	C9—N3—C2—N1	3.1 (4)
C14—Si2—N3—C9	113.9 (4)	Si2—N3—C2—N1	−177.2 (2)
C2—N3—C9—C4	174.9 (5)	C9—N3—C2—S1	−175.9 (3)
Si2—N3—C9—C4	−4.8 (7)	Si2—N3—C2—S1	3.9 (5)
C2—N3—C9—C8	−1.2 (4)	C8—C9—C4—C5	−0.5 (7)
Si2—N3—C9—C8	179.1 (3)	N3—C9—C4—C5	−176.2 (4)
C4—C9—C8—C7	−1.3 (6)	C9—C4—C5—C6	1.7 (8)
N3—C9—C8—C7	175.3 (3)	C8—C7—C6—C5	−0.6 (8)
C4—C9—C8—N1	−177.6 (4)	C4—C5—C6—C7	−1.2 (9)
N3—C9—C8—N1	−1.0 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C11—H11B···S1	0.96	2.96	3.564 (7)	122
C12—H12C···S1	0.96	2.77	3.415 (5)	125
C13—H13B···S1	0.96	2.79	3.423 (7)	125
C14—H14C···S1	0.96	2.86	3.480 (5)	123

(3) 1-Trimethylsilyl-1H-benzimidazole-2(3H)-thione top

Crystal data top

C₁₀H₁₄N₂SSi	F(000) = 944
M_r = 222.38	D_x = 1.204 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.8057 (2) Å	Cell parameters from 60 reflections
b = 15.8032 (4) Å	θ = 20–25°
c = 15.8658 (5) Å	µ = 0.33 mm⁻¹
β = 93.859 (1)°	T = 293 K
V = 2453.01 (11) Å³	Block, colourless
Z = 8	0.20 × 0.20 × 0.15 × 0.15 (radius) mm

Data collection top

Nonius Kappa CCD area-detector diffractometer	5554 independent reflections
Radiation source: fine-focus sealed tube	3199 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.096
Detector resolution: 3 pixels mm^-1	θ_max = 27.5°, θ_min = 2.1°
ω scans	h = −12→12
Absorption correction: for a sphere Interpolation using Int. Tables Vol. C (1992) p. 523, Table 6.3.3.3, for values of muR in the range 0–2.5, and Int. Tables Vol.II (1959) p. 302, Table 5.3.6 B, for muR in the range 2.6–10.0. The interpolation procedure of Dwiggins (1975) is used with some modification.	k = −20→20
T_min = 0.861, T_max = 0.862	l = −20→19
29355 measured reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.049	H-atom parameters constrained
wR(F²) = 0.138	w = 1/[σ²(F_o²) + (0.0633P)² + 0.2886P] where P = (F_o² + 2F_c²)/3
S = 1.00	(Δ/σ)_max = 0.021
5554 reflections	Δρ_max = 0.21 e Å⁻³
259 parameters	Δρ_min = −0.24 e Å⁻³

Crystal data top

C₁₀H₁₄N₂SSi	V = 2453.01 (11) Å³
M_r = 222.38	Z = 8
Monoclinic, P2₁/c	Mo Kα radiation
a = 9.8057 (2) Å	µ = 0.33 mm⁻¹
b = 15.8032 (4) Å	T = 293 K
c = 15.8658 (5) Å	0.20 × 0.20 × 0.15 × 0.15 (radius) mm
β = 93.859 (1)°

Data collection top

Nonius Kappa CCD area-detector diffractometer	5554 independent reflections
Absorption correction: for a sphere Interpolation using Int. Tables Vol. C (1992) p. 523, Table 6.3.3.3, for values of muR in the range 0–2.5, and Int. Tables Vol.II (1959) p. 302, Table 5.3.6 B, for muR in the range 2.6–10.0. The interpolation procedure of Dwiggins (1975) is used with some modification.	3199 reflections with I > 2σ(I)
T_min = 0.861, T_max = 0.862	R_int = 0.096
29355 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.049	0 restraints
wR(F²) = 0.138	H-atom parameters constrained
S = 1.00	Δρ_max = 0.21 e Å⁻³
5554 reflections	Δρ_min = −0.24 e Å⁻³
259 parameters

Special details top

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

	x	y	z	U_iso*/U_eq
S1	0.82440 (7)	0.33390 (5)	−0.08409 (5)	0.0743 (3)
Si1	0.72585 (7)	0.27663 (5)	0.10559 (5)	0.0593 (2)
N1	0.62117 (19)	0.33350 (12)	0.02544 (12)	0.0516 (5)
N3	0.5713 (2)	0.40073 (13)	−0.09430 (13)	0.0567 (5)
H3	0.5788	0.4220	−0.1437	0.068*
C2	0.6702 (3)	0.35663 (16)	−0.05052 (16)	0.0540 (6)
C4	0.3314 (3)	0.44625 (17)	−0.06900 (19)	0.0649 (7)
H4	0.3138	0.4750	−0.1197	0.078*
C5	0.2354 (3)	0.44054 (19)	−0.0107 (2)	0.0740 (8)
H5	0.1501	0.4652	−0.0222	0.089*
C6	0.2631 (3)	0.3988 (2)	0.0649 (2)	0.0743 (8)
H6	0.1958	0.3966	0.1035	0.089*
C7	0.3879 (3)	0.35996 (18)	0.08536 (18)	0.0656 (7)
H7	0.4053	0.3319	0.1365	0.079*
C8	0.4853 (2)	0.36489 (15)	0.02638 (16)	0.0515 (6)
C9	0.4568 (2)	0.40705 (15)	−0.04922 (16)	0.0518 (6)
C20	0.7631 (3)	0.17130 (18)	0.06240 (19)	0.0724 (8)
H20A	0.6952	0.1317	0.0782	0.109*
H20B	0.8517	0.1529	0.0846	0.109*
H20C	0.7618	0.1745	0.0019	0.109*
C21	0.8813 (3)	0.3392 (2)	0.1347 (2)	0.0952 (11)
H21A	0.8557	0.3931	0.1566	0.143*
H21B	0.9320	0.3475	0.0856	0.143*
H21C	0.9371	0.3094	0.1770	0.143*
C22	0.6279 (4)	0.2639 (3)	0.19972 (19)	0.0971 (12)
H22A	0.6846	0.2378	0.2441	0.146*
H22B	0.5496	0.2288	0.1861	0.146*
H22C	0.5983	0.3183	0.2181	0.146*
S2	0.41465 (7)	0.49235 (5)	0.27755 (4)	0.0645 (2)
Si2	0.25642 (8)	0.35791 (5)	0.40605 (5)	0.0638 (2)
N11	0.17856 (19)	0.44585 (13)	0.34850 (13)	0.0530 (5)
N13	0.15541 (19)	0.54650 (13)	0.25194 (13)	0.0542 (5)
H13	0.1744	0.5824	0.2137	0.065*
C12	0.2474 (2)	0.49487 (15)	0.29285 (15)	0.0498 (6)
C14	−0.0965 (3)	0.57291 (19)	0.25713 (19)	0.0715 (8)
H14	−0.1033	0.6156	0.2167	0.086*
C15	−0.2088 (3)	0.5458 (2)	0.2971 (2)	0.0868 (10)
H15	−0.2932	0.5711	0.2841	0.104*
C16	−0.1981 (3)	0.4822 (3)	0.3559 (2)	0.0965 (11)
H16	−0.2762	0.4644	0.3810	0.116*
C17	−0.0746 (3)	0.4436 (2)	0.3789 (2)	0.0837 (10)
H17	−0.0689	0.4008	0.4192	0.100*
C18	0.0396 (2)	0.47021 (17)	0.34055 (16)	0.0563 (6)
C19	0.0272 (2)	0.53378 (17)	0.27982 (16)	0.0549 (6)
C23	0.2899 (5)	0.2784 (2)	0.3261 (3)	0.1273 (15)
H23A	0.3674	0.2955	0.2964	0.191*
H23B	0.2113	0.2732	0.2870	0.191*
H23C	0.3085	0.2249	0.3531	0.191*
C24	0.4101 (4)	0.3910 (3)	0.4689 (3)	0.1213 (16)
H24A	0.4233	0.3552	0.5177	0.182*
H24B	0.3999	0.4486	0.4867	0.182*
H24C	0.4878	0.3865	0.4355	0.182*
C25	0.1363 (3)	0.3166 (3)	0.4803 (2)	0.1084 (13)
H25	0.1828	0.2770	0.5181	0.163*
H25B	0.0617	0.2887	0.4494	0.163*
H25C	0.1017	0.3625	0.5122	0.163*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0615 (4)	0.0868 (6)	0.0762 (5)	0.0191 (4)	0.0171 (3)	0.0267 (4)
Si1	0.0585 (4)	0.0614 (5)	0.0576 (4)	0.0110 (3)	0.0009 (3)	0.0068 (3)
N1	0.0481 (11)	0.0519 (12)	0.0544 (12)	0.0052 (9)	0.0019 (9)	0.0042 (10)
N3	0.0563 (12)	0.0593 (13)	0.0539 (12)	0.0033 (10)	−0.0012 (10)	0.0097 (10)
C2	0.0541 (14)	0.0513 (15)	0.0561 (15)	0.0025 (11)	0.0001 (11)	0.0025 (12)
C4	0.0563 (16)	0.0571 (17)	0.0787 (19)	0.0055 (13)	−0.0155 (14)	−0.0023 (14)
C5	0.0488 (16)	0.0658 (18)	0.106 (2)	0.0088 (13)	−0.0080 (16)	−0.0126 (17)
C6	0.0494 (16)	0.081 (2)	0.094 (2)	0.0030 (14)	0.0121 (15)	−0.0082 (18)
C7	0.0565 (16)	0.0690 (18)	0.0720 (18)	0.0012 (13)	0.0105 (13)	−0.0003 (14)
C8	0.0479 (14)	0.0443 (13)	0.0614 (15)	−0.0002 (11)	−0.0029 (11)	−0.0041 (12)
C9	0.0470 (14)	0.0442 (14)	0.0632 (15)	−0.0010 (10)	−0.0046 (11)	−0.0055 (11)
C20	0.0755 (19)	0.0620 (18)	0.080 (2)	0.0176 (14)	0.0106 (15)	0.0116 (15)
C21	0.081 (2)	0.101 (3)	0.098 (2)	0.0015 (19)	−0.0279 (18)	−0.003 (2)
C22	0.103 (2)	0.123 (3)	0.068 (2)	0.044 (2)	0.0187 (17)	0.0232 (19)
S2	0.0470 (4)	0.0746 (5)	0.0727 (5)	0.0043 (3)	0.0094 (3)	0.0152 (4)
Si2	0.0542 (4)	0.0568 (5)	0.0798 (5)	−0.0029 (3)	−0.0002 (4)	0.0199 (4)
N11	0.0459 (11)	0.0509 (12)	0.0621 (12)	−0.0029 (9)	0.0030 (9)	0.0092 (10)
N13	0.0502 (12)	0.0541 (13)	0.0586 (12)	−0.0003 (10)	0.0058 (9)	0.0118 (10)
C12	0.0482 (13)	0.0468 (14)	0.0540 (14)	−0.0013 (11)	0.0011 (11)	0.0000 (11)
C14	0.0561 (17)	0.081 (2)	0.0753 (19)	0.0097 (14)	−0.0088 (14)	0.0132 (16)
C15	0.0458 (16)	0.115 (3)	0.099 (2)	0.0122 (17)	0.0009 (15)	0.012 (2)
C16	0.0466 (17)	0.135 (3)	0.109 (3)	0.0011 (18)	0.0124 (16)	0.030 (2)
C17	0.0556 (17)	0.100 (3)	0.096 (2)	−0.0059 (16)	0.0103 (15)	0.0340 (19)
C18	0.0456 (14)	0.0609 (16)	0.0620 (15)	−0.0030 (12)	0.0008 (11)	0.0045 (13)
C19	0.0461 (14)	0.0594 (16)	0.0587 (15)	−0.0018 (11)	−0.0003 (11)	0.0020 (12)
C23	0.173 (4)	0.061 (2)	0.149 (4)	0.020 (2)	0.021 (3)	0.001 (2)
C24	0.077 (2)	0.158 (4)	0.124 (3)	−0.029 (2)	−0.032 (2)	0.056 (3)
C25	0.080 (2)	0.116 (3)	0.129 (3)	−0.001 (2)	0.011 (2)	0.069 (3)

Geometric parameters (Å, º) top

S1—C2	1.676 (3)	S2—C12	1.675 (2)
Si1—N1	1.817 (2)	Si2—N11	1.804 (2)
Si1—C22	1.841 (3)	Si2—C24	1.827 (3)
Si1—C20	1.846 (3)	Si2—C23	1.830 (4)
Si1—C21	1.850 (3)	Si2—C25	1.841 (3)
N1—C2	1.377 (3)	N11—C12	1.384 (3)
N1—C8	1.423 (3)	N11—C18	1.413 (3)
N3—C2	1.348 (3)	N13—C12	1.350 (3)
N3—C9	1.374 (3)	N13—C19	1.375 (3)
N3—H3	0.8600	N13—H13	0.8600
C4—C5	1.366 (4)	C14—C15	1.375 (4)
C4—C9	1.394 (3)	C14—C19	1.388 (4)
C4—H4	0.9300	C14—H14	0.9300
C5—C6	1.380 (4)	C15—C16	1.371 (5)
C5—H5	0.9300	C15—H15	0.9300
C6—C7	1.388 (4)	C16—C17	1.383 (4)
C6—H6	0.9300	C16—H16	0.9300
C7—C8	1.384 (4)	C17—C18	1.375 (4)
C7—H7	0.9300	C17—H17	0.9300
C8—C9	1.384 (3)	C18—C19	1.392 (3)
C20—H20A	0.9600	C23—H23A	0.9600
C20—H20B	0.9600	C23—H23B	0.9600
C20—H20C	0.9600	C23—H23C	0.9600
C21—H21A	0.9600	C24—H24A	0.9600
C21—H21B	0.9600	C24—H24B	0.9600
C21—H21C	0.9600	C24—H24C	0.9600
C22—H22A	0.9600	C25—H25	0.9600
C22—H22B	0.9600	C25—H25B	0.9600
C22—H22C	0.9600	C25—H25C	0.9600

N1—Si1—C22	108.72 (12)	N11—Si2—C24	111.21 (15)
N1—Si1—C20	107.62 (12)	N11—Si2—C23	105.51 (15)
C22—Si1—C20	109.24 (16)	C24—Si2—C23	113.3 (2)
N1—Si1—C21	109.12 (13)	N11—Si2—C25	109.27 (13)
C22—Si1—C21	108.81 (18)	C24—Si2—C25	106.95 (19)
C20—Si1—C21	113.23 (16)	C23—Si2—C25	110.6 (2)
C2—N1—C8	107.39 (19)	C12—N11—C18	107.40 (19)
C2—N1—Si1	122.00 (16)	C12—N11—Si2	123.12 (16)
C8—N1—Si1	130.56 (17)	C18—N11—Si2	128.88 (17)
C2—N3—C9	110.7 (2)	C12—N13—C19	110.6 (2)
C2—N3—H3	124.6	C12—N13—H13	124.7
C9—N3—H3	124.6	C19—N13—H13	124.7
N3—C2—N1	107.9 (2)	N13—C12—N11	107.9 (2)
N3—C2—S1	125.48 (19)	N13—C12—S2	125.02 (19)
N1—C2—S1	126.65 (18)	N11—C12—S2	127.12 (18)
C5—C4—C9	117.1 (3)	C15—C14—C19	117.0 (3)
C5—C4—H4	121.4	C15—C14—H14	121.5
C9—C4—H4	121.4	C19—C14—H14	121.5
C4—C5—C6	121.1 (3)	C16—C15—C14	121.0 (3)
C4—C5—H5	119.5	C16—C15—H15	119.5
C6—C5—H5	119.5	C14—C15—H15	119.5
C5—C6—C7	122.2 (3)	C15—C16—C17	121.9 (3)
C5—C6—H6	118.9	C15—C16—H16	119.1
C7—C6—H6	118.9	C17—C16—H16	119.1
C8—C7—C6	117.1 (3)	C18—C17—C16	118.3 (3)
C8—C7—H7	121.5	C18—C17—H17	120.9
C6—C7—H7	121.5	C16—C17—H17	120.9
C9—C8—C7	120.3 (2)	C17—C18—C19	119.4 (2)
C9—C8—N1	107.1 (2)	C17—C18—N11	133.3 (3)
C7—C8—N1	132.6 (2)	C19—C18—N11	107.3 (2)
N3—C9—C8	107.0 (2)	N13—C19—C14	130.8 (2)
N3—C9—C4	130.9 (3)	N13—C19—C18	106.8 (2)
C8—C9—C4	122.2 (3)	C14—C19—C18	122.4 (2)
Si1—C20—H20A	109.5	Si2—C23—H23A	109.5
Si1—C20—H20B	109.5	Si2—C23—H23B	109.5
H20A—C20—H20B	109.5	H23A—C23—H23B	109.5
Si1—C20—H20C	109.5	Si2—C23—H23C	109.5
H20A—C20—H20C	109.5	H23A—C23—H23C	109.5
H20B—C20—H20C	109.5	H23B—C23—H23C	109.5
Si1—C21—H21A	109.5	Si2—C24—H24A	109.5
Si1—C21—H21B	109.5	Si2—C24—H24B	109.5
H21A—C21—H21B	109.5	H24A—C24—H24B	109.5
Si1—C21—H21C	109.5	Si2—C24—H24C	109.5
H21A—C21—H21C	109.5	H24A—C24—H24C	109.5
H21B—C21—H21C	109.5	H24B—C24—H24C	109.5
Si1—C22—H22A	109.5	Si2—C25—H25	109.5
Si1—C22—H22B	109.5	Si2—C25—H25B	109.5
H22A—C22—H22B	109.5	H25—C25—H25B	109.5
Si1—C22—H22C	109.5	Si2—C25—H25C	109.5
H22A—C22—H22C	109.5	H25—C25—H25C	109.5
H22B—C22—H22C	109.5	H25B—C25—H25C	109.5

C22—Si1—N1—C2	176.3 (2)	C24—Si2—N11—C12	56.7 (3)
C20—Si1—N1—C2	−65.5 (2)	C23—Si2—N11—C12	−66.5 (2)
C21—Si1—N1—C2	57.8 (2)	C25—Si2—N11—C12	174.5 (2)
C22—Si1—N1—C8	−1.1 (3)	C24—Si2—N11—C18	−133.4 (3)
C20—Si1—N1—C8	117.1 (2)	C23—Si2—N11—C18	103.4 (3)
C21—Si1—N1—C8	−119.6 (2)	C25—Si2—N11—C18	−15.6 (3)
C9—N3—C2—N1	−0.4 (3)	C19—N13—C12—N11	0.8 (3)
C9—N3—C2—S1	179.14 (18)	C19—N13—C12—S2	−179.11 (18)
C8—N1—C2—N3	0.6 (3)	C18—N11—C12—N13	−0.5 (3)
Si1—N1—C2—N3	−177.32 (16)	Si2—N11—C12—N13	171.28 (16)
C8—N1—C2—S1	−178.90 (19)	C18—N11—C12—S2	179.38 (19)
Si1—N1—C2—S1	3.2 (3)	Si2—N11—C12—S2	−8.8 (3)
C9—C4—C5—C6	1.0 (4)	C19—C14—C15—C16	−0.8 (5)
C4—C5—C6—C7	−0.7 (5)	C14—C15—C16—C17	1.3 (6)
C5—C6—C7—C8	0.2 (4)	C15—C16—C17—C18	−0.5 (6)
C6—C7—C8—C9	0.0 (4)	C16—C17—C18—C19	−0.7 (5)
C6—C7—C8—N1	−180.0 (3)	C16—C17—C18—N11	179.8 (3)
C2—N1—C8—C9	−0.6 (2)	C12—N11—C18—C17	179.6 (3)
Si1—N1—C8—C9	177.06 (17)	Si2—N11—C18—C17	8.5 (5)
C2—N1—C8—C7	179.3 (3)	C12—N11—C18—C19	0.1 (3)
Si1—N1—C8—C7	−3.0 (4)	Si2—N11—C18—C19	−171.09 (18)
C2—N3—C9—C8	0.0 (3)	C12—N13—C19—C14	178.8 (3)
C2—N3—C9—C4	−180.0 (3)	C12—N13—C19—C18	−0.7 (3)
C7—C8—C9—N3	−179.6 (2)	C15—C14—C19—N13	−179.9 (3)
N1—C8—C9—N3	0.4 (2)	C15—C14—C19—C18	−0.4 (4)
C7—C8—C9—C4	0.4 (4)	C17—C18—C19—N13	−179.2 (3)
N1—C8—C9—C4	−179.7 (2)	N11—C18—C19—N13	0.4 (3)
C5—C4—C9—N3	179.1 (3)	C17—C18—C19—C14	1.2 (4)
C5—C4—C9—C8	−0.8 (4)	N11—C18—C19—C14	−179.2 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3···S2ⁱ	0.86	2.52	3.374 (2)	170
N13—H13···S1ⁱ	0.86	2.45	3.282 (2)	164
C21—H21B···S1	0.96	2.83	3.480 (4)	126

Symmetry code: (i) −x+1, −y+1, −z.

Experimental details

	(2)	(3)
Crystal data
Chemical formula	C₁₃H₂₂N₂SSi₂	C₁₀H₁₄N₂SSi
M_r	294.56	222.38
Crystal system, space group	Orthorhombic, P2₁2₁2₁	Monoclinic, P2₁/c
Temperature (K)	293	293
a, b, c (Å)	10.0302 (3), 10.6172 (3), 16.2428 (6)	9.8057 (2), 15.8032 (4), 15.8658 (5)
α, β, γ (°)	90, 90, 90	90, 93.859 (1), 90
V (Å³)	1729.74 (10)	2453.01 (11)
Z	4	8
Radiation type	Mo Kα	Mo Kα
µ (mm⁻¹)	0.31	0.33
Crystal size (mm)	0.25 × 0.20 × 0.10 × 0.15 (radius)	0.20 × 0.20 × 0.15 × 0.15 (radius)

Data collection
Diffractometer	Nonius Kappa CCD area-detector diffractometer	Nonius Kappa CCD area-detector diffractometer
Absorption correction	For a sphere Interpolation using Int. Tables Vol. C (1992) p. 523, Table 6.3.3.3, for values of muR in the range 0–2.5, and Int. Tables Vol. II (1959) p. 302, Table 5.3.6 B, for muR in the range 2.6–10.0. The interpolation procedure of Dwiggins (1975) is used with some modification.	For a sphere Interpolation using Int. Tables Vol. C (1992) p. 523, Table 6.3.3.3, for values of muR in the range 0–2.5, and Int. Tables Vol.II (1959) p. 302, Table 5.3.6 B, for muR in the range 2.6–10.0. The interpolation procedure of Dwiggins (1975) is used with some modification.
T_min, T_max	0.861, 0.862	0.861, 0.862
No. of measured, independent and observed [I > 2σ(I)] reflections	15678, 3889, 2472	29355, 5554, 3199
R_int	0.064	0.096
(sin θ/λ)_max (Å⁻¹)	0.648	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.048, 0.104, 1.01	0.049, 0.138, 1.00
No. of reflections	3889	5554
No. of parameters	164	259
H-atom treatment	H-atom parameters constrained	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.20	0.21, −0.24
Absolute structure	Flack x parameter determined using 838 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)	?
Absolute structure parameter	0.01 (7)	?

Computer programs: COLLECT (Nonius, 2000), DENZO and SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL2014 (Sheldrick, 2015), XPMA (Zsolnai, 1997).

Selected geometric parameters (Å, º) for (2) top

Si1—N1	1.809 (3)	Si2—C13	1.839 (6)
Si1—C11	1.842 (5)	Si2—C15	1.854 (6)
Si1—C12	1.842 (5)	Si2—C14	1.861 (5)
Si1—C10	1.847 (5)	S1—C2	1.669 (4)
Si2—N3	1.803 (3)

N1—Si1—C11	109.0 (2)	N3—Si2—C14	109.3 (2)
N1—Si1—C12	109.53 (19)	C13—Si2—C14	113.7 (3)
C11—Si1—C12	113.9 (3)	C15—Si2—C14	107.7 (3)
N1—Si1—C10	108.4 (2)	C2—N1—Si1	121.7 (3)
C11—Si1—C10	109.4 (3)	C8—N1—Si1	130.9 (3)
C12—Si1—C10	106.4 (3)	C2—N3—Si2	120.8 (3)
N3—Si2—C13	109.4 (2)	C9—N3—Si2	132.3 (2)
N3—Si2—C15	108.5 (2)	N1—C2—S1	125.1 (3)
C13—Si2—C15	108.2 (3)	N3—C2—S1	124.8 (3)

C11—Si1—N1—C2	70.3 (4)	C14—Si2—N3—C9	113.9 (4)
C12—Si1—N1—C2	−55.0 (4)	Si2—N3—C9—C4	−4.8 (7)
C10—Si1—N1—C2	−170.7 (3)	Si2—N3—C9—C8	179.1 (3)
C11—Si1—N1—C8	−113.2 (4)	Si1—N1—C8—C7	10.2 (6)
C12—Si1—N1—C8	121.5 (4)	Si1—N1—C8—C9	−174.1 (3)
C10—Si1—N1—C8	5.8 (4)	Si1—N1—C2—N3	173.6 (2)
C13—Si2—N3—C2	59.4 (4)	C8—N1—C2—S1	175.3 (3)
C15—Si2—N3—C2	177.2 (4)	Si1—N1—C2—S1	−7.5 (5)
C14—Si2—N3—C2	−65.7 (4)	Si2—N3—C2—N1	−177.2 (2)
C13—Si2—N3—C9	−121.0 (4)	C9—N3—C2—S1	−175.9 (3)
C15—Si2—N3—C9	−3.2 (4)	Si2—N3—C2—S1	3.9 (5)

Hydrogen-bond geometry (Å, º) for (2) top

D—H···A	D—H	H···A	D···A	D—H···A
C11—H11B···S1	0.96	2.96	3.564 (7)	122.4
C12—H12C···S1	0.96	2.77	3.415 (5)	125.1
C13—H13B···S1	0.96	2.79	3.423 (7)	124.6
C14—H14C···S1	0.96	2.86	3.480 (5)	123.3

Selected geometric parameters (Å, º) for (3) top

S1—C2	1.676 (3)	S2—C12	1.675 (2)
Si1—N1	1.817 (2)	Si2—N11	1.804 (2)
Si1—C22	1.841 (3)	Si2—C24	1.827 (3)
Si1—C20	1.846 (3)	Si2—C23	1.830 (4)
Si1—C21	1.850 (3)	Si2—C25	1.841 (3)

N1—Si1—C22	108.72 (12)	N11—Si2—C24	111.21 (15)
N1—Si1—C20	107.62 (12)	N11—Si2—C23	105.51 (15)
C22—Si1—C20	109.24 (16)	C24—Si2—C23	113.3 (2)
N1—Si1—C21	109.12 (13)	N11—Si2—C25	109.27 (13)
C22—Si1—C21	108.81 (18)	C24—Si2—C25	106.95 (19)
C20—Si1—C21	113.23 (16)	C23—Si2—C25	110.6 (2)
C2—N1—Si1	122.00 (16)	C12—N11—Si2	123.12 (16)
C8—N1—Si1	130.56 (17)	C18—N11—Si2	128.88 (17)
N3—C2—S1	125.48 (19)	N13—C12—S2	125.02 (19)
N1—C2—S1	126.65 (18)	N11—C12—S2	127.12 (18)

C22—Si1—N1—C2	176.3 (2)	C24—Si2—N11—C12	56.7 (3)
C20—Si1—N1—C2	−65.5 (2)	C23—Si2—N11—C12	−66.5 (2)
C21—Si1—N1—C2	57.8 (2)	C25—Si2—N11—C12	174.5 (2)
C22—Si1—N1—C8	−1.1 (3)	C24—Si2—N11—C18	−133.4 (3)
C20—Si1—N1—C8	117.1 (2)	C23—Si2—N11—C18	103.4 (3)
C21—Si1—N1—C8	−119.6 (2)	C25—Si2—N11—C18	−15.6 (3)
C9—N3—C2—S1	179.14 (18)	C19—N13—C12—S2	−179.11 (18)
Si1—N1—C2—N3	−177.32 (16)	Si2—N11—C12—N13	171.28 (16)
C8—N1—C2—S1	−178.90 (19)	C18—N11—C12—S2	179.38 (19)
Si1—N1—C2—S1	3.2 (3)	Si2—N11—C12—S2	−8.8 (3)
Si1—N1—C8—C9	177.06 (17)	Si2—N11—C18—C17	8.5 (5)
Si1—N1—C8—C7	−3.0 (4)	Si2—N11—C18—C19	−171.09 (18)

Hydrogen-bond geometry (Å, º) for (3) top

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3···S2ⁱ	0.86	2.52	3.374 (2)	170.0
N13—H13···S1ⁱ	0.86	2.45	3.282 (2)	164.4
C21—H21B···S1	0.96	2.83	3.480 (4)	125.5

Symmetry code: (i) −x+1, −y+1, −z.

Acknowledgements

JPM is grateful for Scholarship CVU 269487. Financial support by CONACyT (grant No. 130381) and CINVESTAV, México, is acknowledged.

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Volume 71| Part 9| September 2015| Pages 788-792

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