Crystal structure of 1-ethyl-3-(2-oxo-1,3-di­thiol-4-yl)quinoxalin-2(1H)-one

Chrysochos, N.; Schulzke, C.

doi:10.1107/S2056989018007892

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Volume 74| Part 7| July 2018| Pages 901-904

https://doi.org/10.1107/S2056989018007892

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Crystal structure of 1-ethyl-3-(2-oxo-1,3-dithiol-4-yl)quinoxalin-2(1H)-one

Nicolas Chrysochos ^a and Carola Schulzke ^a ^*

^aInstitut für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, 4 Felix-Hausdorff-Strasse, 17487 Greifswald, Germany
^*Correspondence e-mail: carola.schulzke@uni-greifswald.de

Edited by V. Khrustalev, Russian Academy of Sciences, Russia (Received 2 May 2018; accepted 28 May 2018; online 8 June 2018)

The title compound I, C₁₃H₁₀N₂O₂S₂, crystallizes in the monoclinic space group C2/c with eight molecules in the unit cell. Excluding for the ethyl substituent, the molecule of I adopts a nearly coplanar conformation (r.m.s. deviations is 0.058 Å), which is supported by the intramolecular C—H⋯O hydrogen-bonding interaction between the two ring systems [C⋯O = 2.859 (3) Å]. In the crystal, the molecules form dimeric associates via two bifurcated C—H⋯O hydrogen-bonding interactions between an ene hydrogen atom and a carbonyl functional group of an adjacent molecule [C⋯O = 3.133 (3) Å] and vice versa. The crystal structure is further stabilized by a three-dimensional network of weak hydrogen bonds between one molecule and six adjacent molecules as well as offset π–π stacking. The combination of the quinoxaline 2(1H)-one moiety with the dithiocarbonate moiety extends the aromaticity of the quinoxaline scaffold towards the substituent as well as influencing the π-system of the quinoxaline. The title compound is the direct precursor for a dithiolene ligand mimicking the natural cofactor ligand molybdopterin.

Keywords: crystal structure; quinoxalin; ene-dithiocarbonate; carbonodithioate; hydrogen bonding interaction; molybdopterin.

CCDC reference: 1845671

1. Chemical context

Non-innocent dithiolenes and their role as interesting ligand systems were discovered in the early 1960s. As a result of their unusual redox and structural characteristics and those of their metal complexes, they immediately attracted considerable scientific interest (Schrauzer & Mayweg, 1962 ). Initially, dithiolene systems were studied predominantly in the context of electronic and photonic conductors (Wudl et al., 1972 ; Ferraris et al., 1973 ). Later, metal dithiolene complexes found application in the purification and separation of olefins (Wang & Stiefel, 2001 ). In the early 1980s Rajagopalan and co-workers discovered and characterized the natural molybdopterin ligand (mpt) in the active sites of enzymes. Mpt is present in nearly all molybdenum enzymes and all tungsten enzymes and binds the respective central metal by a dithiolene moiety. As these enzymes are ubiquitous to all kingdoms of life, this brought dithiolene chemistry again to the focus of scientific attention (Johnson et al., 1980 ; Johnson & Rajagopalan, 1982 ; Kramer et al., 1987 ). Quinoxaline constitutes a widely exploited platform in the development of pharmaceuticals (Shi et al., 2018 ). The title compound is a dithiolene ligand precursor, which can be used for the synthesis of molybdopterin cofactor model complexes bearing quinoxaline substituents. The target dithiolene ligand replicates the pyrazine moiety of mpt in its half-reduced form and in addition contains an oxofunction in the position of the pyran ring of the natural product. By itself it is an interesting example of an extended π-system involving (by resonance) three different heteroatoms (N, O and S).

2. Structural commentary

The title molecule I crystallizes in the monoclinic space group C2/c with Z = 8. The quinoxaline ring system [C4–C11, N1, N2; largest deviation from plane = 0.041 (2) Å for C5] and the dithiolene ring [C1–C3, S1, S2; largest deviation from plane = 0.012 (1) Å for C3)], which are connected by the C3—C4 bond [length = 1.465 (3) Å], are essentially coplanar, with an angle of only 4.89 (12)° between the two planes (Fig. 1). This planitarity is supported by intramolecular hydrogen bonding between the dithiolene hydrogen atom and the quinoxaline carbonyl oxygen atom [C2—H2⋯O2 with D⋯A = 2.859 (3) Å; Table 1]. Only the alkyl substituent C12—C13 subtends out of the planar geometry with an N1—C12—C13 torsion angle of 112.78 (18)°. While the N1—C12 bond [amine nitrogen and ethyl substituent; 1.475 (3) Å] is of explicit single-bond character, all other N—C distances are decidedly shorter, ranging from 1.296 (3) Å for the, according to the chemical structure, double bond of imine nitrogen (N2=C4) to 1.392 (3) Å for the amine nitrogen-to-benzene ring formal single bond (N1—C6). The longest C—C bond of the benzene ring is the one that is shared with the N-heterocycle [C6—C11, 1.411 (3) Å]. This, together with the adjacent N—C bonds [N1—C6, 1.392 (3) Å and C11—N2, 1.374 (3) Å] being significantly shorter than single bonds indicates resonance throughout the entire quinoxaline substituent. The C=O bond [1.212 (3) Å] of the carbonodithioate moiety is slightly shorter than the carbonyl C=O bond [1.232 (3) Å] of the quinoxaline substituent, suggesting that the latter might be involved to a small extent in resonance effects of the π-system, whereas the former is not. The C2=C3 double bond of the ene-dithiocarbonate moiety is at 1.341 (3) Å slightly longer than the average value for C=C double bonds of 1.331 (9) Å (Allen et al., 1995 ), which again may be due to participation in resonance effects throughout the entire molecule. The deviation from the average value of 1.751 (17) Å for S—Csp² bonds (Allen et al., 1995) of the S1—C2 bond [1.724 (2) Å] is substantial enough to suggest that the resonance effects extend up to this bond to which partial double-bond character can be assigned. All other C—S bonds concur with typical single bonds.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2⋯O2	0.95 (2)	2.30 (3)	2.859 (3)	117.2 (19)
C2—H2⋯O2ⁱ	0.95 (2)	2.44 (2)	3.133 (3)	129 (2)
C7—H7⋯O1ⁱⁱ	0.95	2.51	3.272 (3)	138
C9—H9⋯S2ⁱⁱⁱ	0.95	2.99	3.652 (3)	128
C12—H12A⋯O2^iv	0.99	2.69	3.367 (3)	126
Symmetry codes: (i) -x, -y+2, -z+1; (ii) $[x, -y+1, z+{\script{1\over 2}}]$ ; (iii) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]$ ; (iv) x, y-1, z.

Figure 1
The molecular structure of 1-ethyl-3-(2-oxo-1,3-dithiol-4yl-)quinoxalin-2(1H)-one showing the atom labelling, 50% probability displacement ellipsoids and the intramolecular non-classical hydrogen bond (dashed line).

By bidirectional intermolecular hydrogen bonding, the title compound crystallizes as dimeric associate with the same donor and acceptor roles for both monomers [C2—H2⋯O2(−x, −y + 2, −z + 1) and O2⋯H2—C2(−x, −y + 2, −z + 1); D⋯A = 3.133 (3) Å]. Here, the exact same atoms are involved as in the intramolecular hydrogen bond mentioned above. The respective hydrogen atom H2 is therefore bound to the ene carbon atom C2 and hydrogen bonded to the carbonyl oxygen (O2) of the quinoxaline moiety of the same molecule as well as that of the adjacent molecule (Fig. 2, left). There are only two crystal sructures of very closely related systems reported in the literature. In one (A), the quinoxalin substituent of the present molecule is replaced by a coumarine (Ghosh et al., 2016 ). In the other (B), the ene-dithiocarbonate is replaced by an aminothiazole (Mamedov et al., 2005 ). The metrical parameters in both structures are, as far as comparable, very similar to the ones observed here. Notable differences comprise (i) a slightly stronger resonance involvement of the thiazole in B compared to the ene-dithiocarbonate while the quinoxalin carbonyl and amine functions are embraced to a lesser extent and (ii) an overall weaker resonance in A, in which the benzene ring C—C distances are all very similar (i.e. strongly resonant) whereas all other distances are of more pronounced single- and double-bond character and of less aromatic character.

Figure 2
Crystal packing and intra- and intermolecular hydrogen-bonding interactions yielding the dimeric associates viewed along b (left) and hydrogen bonding contacts of an individual molecule to six adjacent molecules (right) (Mercury; Macrae et al., 2006

3. Supramolecular features

In the crystal, the associated dimers are linked by (partly rather weak) C—H⋯O and C—H⋯S hydrogen-bonding interactions, forming a three-dimensional network (Fig. 2, Table 1). In the three-dimensional network, each molecule forms hydrogen-bonding interactions to six surrounding molecules. These are donor interactions involving C2 [C2—H2⋯O2(−x, −y + 2, −z + 1); D⋯A = 3.133 (3) Å], C7 [C7—H7⋯O1(x, −y + 1, z + $[{1\over 2}]$ ); D⋯A = 3.272 (3) Å], C9 [C9—H9⋯S2(−x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z + 1); D⋯A = 3.652 (3) Å], C12 [C12—H12A⋯O2(x, y − 1, z); D⋯A = 3.367 (3) Å] and acceptor interactions involving S2 [S2⋯H9—C9(−x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z + 1)], O2 [O2⋯H2—C2(−x, −y + 2, −z + 1), O2⋯H12A—C12(x, y–1, z)] and O1 [O1⋯H7—C7(x, −y + 1, z − $[{1\over 2}]$ )]. Even though there are coplanar alignments of layers, only offset π–π stacking was observed with centroid–centroid distances of 3.587 (3) Å between the benzene ring of one molecule and the pyrazine ring of a molecule in the layer above or below.

4. Synthesis and crystallization

The title compound, 1-ethyl-3-(2-oxo-1,3-dithiol-4yl-)quinoxalin-2(1H)-one was synthesized based on a reported literature procedure (Mamedov et al., 2005). The compound was synthesized in five steps starting from o-phenylenediamine. The last step in the synthetical pathway was carried out via an acid-catalysed Tchugaeff ring closure reaction, which led to the formation of the dithiolene ring.

Synthesis of 1-ethyl-3-(2-oxo-1,3-dithiol-4yl-)quinoxalin-2(1H)-one: To a solution of S-2-(4-ethyl-3-oxo-4-dihydroquinoxalin-2-yl)-2-oxo-ethyl o-isopropyl carbonodithioate (11.180 g, 31.9 mmol) in 250 ml DCM/Et₂O 1:1 at ambient temperature, H₂SO₄ (25.50 ml) was added. The reaction mixture was stirred at room temperature for 2h. After that, the reaction was quenched by addition of 250 ml of ice and the mixture was stirred for 30 min. The organic phase was washed with brine and water 3 × 250 ml. The solvent was reduced to 10 ml in vacuo and the greenish precipitate was filtered off and washed on the filter with cold acetone 3 × 50 ml. The title compound was obtained as a greenish-white powder. Single crystals suitable for X-ray analysis were obtained by slow diffusion of solvents with chloroform and Et₂O Yield: 1.85g (20%).

¹H NMR (300MHz, CD₃Cl) δ 8.79 ppm (s, 1H), 7.87 ppm (m, 1H), 7.61 ppm (m, 1H), 7.4 ppm (m, 1H), 4.39 ppm (q, J = 7.2Hz, 2H), 1.42 ppm (t, J = 7.3Hz, 3H). ¹³C NMR (300MHz, CD₃Cl) δ 152.54 ppm, 144.75 ppm, 133.25 ppm, 132.58 ppm, 131.14 ppm, 130.32 ppm, 126.98 ppm, 124.00 ppm, 113.47 ppm, 37.47 ppm, 12.20 ppm. IR (KBr pellet): (ν cm⁻¹) = 3495 (br), 1734 (w), 1646 (sst), 1601 (st), 1579 (st), 1535 (st), 1463 (st), 1383 (w), 1280 (st), 1248 (w), 1216 (w), 1173 (st), 1128 (w), 1087 (w), 1045 (w), 950 (w), 892 (st), 868 (w), 825 (st), 785 (w), 758 (st), 631 (w), 554 (w), 529 (w), 467 (w), 432 (w). APCI–MS (m/s) = 291 (M⁺ + H⁺). Analysis calculated for C₁₃H₁₀N₂O₂S₂: C, 53.78; H 3.47; N 9.65; S 22.09. Found: C, 53.41; H 3.25; N 9.86; S 22.32.

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The hydrogen atom of the dithiolene unit (H2) was refined freely without any constraints or restraints. All other C-bound hydrogen atoms were attached in calculated positions and treated as riding: C—H = 0.98 Å with U_iso(H) = 1.5U_eq(C) for the methyl group, C—H = 0.99 Å with U_iso(H) = 1.2U_eq(C) for the methylene group and C—H = 0.95 Å with U_iso(H) = 1.2U_eq(C) for the aromatic atoms.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₃H₁₀N₂O₂S₂
M_r	290.35
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	170
a, b, c (Å)	25.531 (6), 4.8522 (10), 20.861 (4)
β (°)	107.81 (3)
V (Å³)	2460.4 (10)
Z	8
Radiation type	Mo Kα
μ (mm⁻¹)	0.43
Crystal size (mm)	0.48 × 0.46 × 0.04

Data collection
Diffractometer	Stoe IPDS 2T
Absorption correction	Numerical (X-RED32 and X-SHAPE; Stoe & Cie, 2010 )
T_min, T_max	0.680, 0.887
No. of measured, independent and observed [I > 2σ(I)] reflections	10078, 2599, 2052
R_int	0.107
(sin θ/λ)_max (Å⁻¹)	0.633

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.113, 1.03
No. of reflections	2599
No. of parameters	177
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.39, −0.44
Computer programs: X-AREA (Stoe & Cie, 2010), SIR92 (Altomare et al., 1994 ), SHELXL2016/6 (Sheldrick, 2015 ), XP in SHELXTL (Sheldrick, 2008 ), Mercury (Macrae et al., 2006 ) and CIFTAB (Sheldrick, 2013 ).

Supporting information

CCDC reference: 1845671

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989018007892/kq2022sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989018007892/kq2022Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989018007892/kq2022Isup3.cml

checkCIF report

Computing details top

Data collection: X-AREA (Stoe & Cie, 2010); cell refinement: X-AREA (Stoe & Cie, 2010); data reduction: X-AREA (Stoe & Cie, 2010); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL2016/6 (Sheldrick, 2015); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006); software used to prepare material for publication: CIFTAB (Sheldrick, 2013) and Mercury (Macrae et al.,, 2006).

1-Ethyl-3-(2-oxo-1,3-dithiol-4-yl)quinoxalin-2(1H)-one top

Crystal data top

C₁₃H₁₀N₂O₂S₂	F(000) = 1200
M_r = 290.35	D_x = 1.568 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 25.531 (6) Å	Cell parameters from 10798 reflections
b = 4.8522 (10) Å	θ = 3.4–53.5°
c = 20.861 (4) Å	µ = 0.43 mm⁻¹
β = 107.81 (3)°	T = 170 K
V = 2460.4 (10) Å³	Platelet, green
Z = 8	0.48 × 0.46 × 0.04 mm

Data collection top

Stoe IPDS2T diffractometer	2599 independent reflections
Radiation source: fine-focus sealed tube	2052 reflections with I > 2σ(I)
Detector resolution: 6.67 pixels mm^-1	R_int = 0.107
ω scans	θ_max = 26.7°, θ_min = 1.7°
Absorption correction: numerical (X-Red32 and X-Shape; Stoe & Cie, 2010)	h = −32→32
T_min = 0.680, T_max = 0.887	k = −6→6
10078 measured reflections	l = −26→23

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.043	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.113	w = 1/[σ²(F_o²) + (0.0557P)² + 1.3022P] where P = (F_o² + 2F_c²)/3
S = 1.03	(Δ/σ)_max < 0.001
2599 reflections	Δρ_max = 0.39 e Å⁻³
177 parameters	Δρ_min = −0.44 e Å⁻³

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	0.06586 (2)	1.17332 (13)	0.38431 (3)	0.02924 (17)
S2	0.16189 (2)	0.80790 (12)	0.43550 (3)	0.02882 (17)
O1	0.14629 (7)	1.1274 (4)	0.32955 (8)	0.0379 (4)
O2	0.04198 (6)	0.7134 (3)	0.56260 (8)	0.0296 (4)
N1	0.09576 (7)	0.3591 (4)	0.61708 (9)	0.0233 (4)
N2	0.16734 (7)	0.4593 (4)	0.54239 (9)	0.0242 (4)
C1	0.12850 (9)	1.0512 (5)	0.37418 (11)	0.0290 (5)
C2	0.06873 (9)	0.9742 (5)	0.45374 (11)	0.0258 (5)
C3	0.11163 (9)	0.8032 (5)	0.47709 (11)	0.0237 (4)
C4	0.12261 (8)	0.6022 (5)	0.53199 (10)	0.0229 (4)
C5	0.08324 (8)	0.5692 (5)	0.57104 (10)	0.0236 (4)
C6	0.14444 (8)	0.2091 (5)	0.63101 (11)	0.0231 (4)
C7	0.15922 (9)	0.0081 (5)	0.68143 (11)	0.0263 (5)
H7	0.135972	−0.028724	0.708326	0.032*
C8	0.20757 (9)	−0.1364 (5)	0.69197 (11)	0.0278 (5)
H8	0.217320	−0.273223	0.726147	0.033*
C9	0.24248 (9)	−0.0852 (5)	0.65328 (12)	0.0296 (5)
H9	0.275622	−0.187017	0.661099	0.036*
C10	0.22885 (9)	0.1124 (5)	0.60399 (11)	0.0273 (5)
H10	0.252595	0.147249	0.577626	0.033*
C11	0.17997 (9)	0.2633 (5)	0.59235 (11)	0.0237 (4)
C12	0.05590 (9)	0.2972 (5)	0.65349 (12)	0.0269 (5)
H12A	0.054369	0.095209	0.659446	0.032*
H12B	0.018905	0.359079	0.625995	0.032*
C13	0.07039 (10)	0.4352 (6)	0.72202 (12)	0.0353 (6)
H13A	0.108738	0.394349	0.747326	0.053*
H13B	0.046176	0.365385	0.746832	0.053*
H13C	0.065600	0.634974	0.716145	0.053*
H2	0.0387 (10)	0.987 (5)	0.4716 (12)	0.028 (6)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0263 (3)	0.0320 (3)	0.0296 (3)	0.0039 (2)	0.0086 (2)	0.0057 (2)
S2	0.0273 (3)	0.0336 (3)	0.0300 (3)	0.0057 (2)	0.0152 (2)	0.0046 (2)
O1	0.0404 (9)	0.0485 (11)	0.0299 (9)	0.0037 (8)	0.0181 (7)	0.0084 (8)
O2	0.0251 (8)	0.0323 (9)	0.0348 (9)	0.0061 (7)	0.0143 (6)	0.0034 (7)
N1	0.0206 (8)	0.0250 (9)	0.0262 (9)	−0.0011 (7)	0.0099 (7)	−0.0010 (8)
N2	0.0206 (8)	0.0252 (9)	0.0282 (9)	0.0001 (7)	0.0096 (7)	−0.0013 (8)
C1	0.0287 (11)	0.0313 (12)	0.0272 (11)	0.0004 (10)	0.0089 (9)	0.0011 (10)
C2	0.0228 (10)	0.0296 (12)	0.0260 (10)	−0.0002 (9)	0.0087 (8)	0.0003 (10)
C3	0.0221 (10)	0.0253 (11)	0.0245 (10)	−0.0006 (8)	0.0085 (8)	−0.0029 (9)
C4	0.0220 (10)	0.0239 (10)	0.0237 (10)	−0.0003 (8)	0.0083 (8)	−0.0029 (9)
C5	0.0202 (10)	0.0262 (11)	0.0251 (10)	−0.0015 (9)	0.0081 (8)	−0.0037 (9)
C6	0.0200 (10)	0.0228 (10)	0.0260 (10)	−0.0005 (8)	0.0065 (8)	−0.0038 (9)
C7	0.0268 (10)	0.0262 (11)	0.0269 (11)	−0.0030 (9)	0.0096 (8)	−0.0009 (9)
C8	0.0293 (11)	0.0238 (11)	0.0277 (11)	0.0007 (9)	0.0048 (9)	0.0018 (9)
C9	0.0255 (11)	0.0278 (12)	0.0340 (12)	0.0065 (9)	0.0067 (9)	−0.0016 (10)
C10	0.0223 (10)	0.0315 (12)	0.0287 (11)	0.0016 (9)	0.0088 (8)	−0.0022 (10)
C11	0.0226 (10)	0.0243 (10)	0.0247 (10)	−0.0009 (8)	0.0077 (8)	−0.0021 (9)
C12	0.0226 (10)	0.0282 (11)	0.0357 (12)	−0.0010 (9)	0.0173 (9)	0.0010 (10)
C13	0.0362 (12)	0.0401 (14)	0.0366 (13)	−0.0039 (11)	0.0215 (10)	−0.0032 (11)

Geometric parameters (Å, º) top

S1—C2	1.724 (2)	C6—C11	1.411 (3)
S1—C1	1.778 (2)	C7—C8	1.378 (3)
S2—C3	1.755 (2)	C7—H7	0.9500
S2—C1	1.758 (2)	C8—C9	1.395 (3)
O1—C1	1.212 (3)	C8—H8	0.9500
O2—C5	1.232 (3)	C9—C10	1.371 (3)
N1—C5	1.370 (3)	C9—H9	0.9500
N1—C6	1.392 (3)	C10—C11	1.403 (3)
N1—C12	1.475 (3)	C10—H10	0.9500
N2—C4	1.296 (3)	C12—C13	1.519 (3)
N2—C11	1.374 (3)	C12—H12A	0.9900
C2—C3	1.341 (3)	C12—H12B	0.9900
C2—H2	0.95 (2)	C13—H13A	0.9800
C3—C4	1.465 (3)	C13—H13B	0.9800
C4—C5	1.483 (3)	C13—H13C	0.9800
C6—C7	1.399 (3)

C2—S1—C1	96.00 (11)	C6—C7—H7	120.1
C3—S2—C1	95.93 (11)	C7—C8—C9	121.1 (2)
C5—N1—C6	122.51 (18)	C7—C8—H8	119.4
C5—N1—C12	117.57 (17)	C9—C8—H8	119.4
C6—N1—C12	119.91 (18)	C10—C9—C8	119.9 (2)
C4—N2—C11	119.18 (18)	C10—C9—H9	120.1
O1—C1—S2	123.50 (19)	C8—C9—H9	120.1
O1—C1—S1	123.48 (19)	C9—C10—C11	120.2 (2)
S2—C1—S1	113.02 (13)	C9—C10—H10	119.9
C3—C2—S1	118.16 (17)	C11—C10—H10	119.9
C3—C2—H2	124.3 (15)	N2—C11—C10	118.85 (19)
S1—C2—H2	117.4 (15)	N2—C11—C6	121.32 (19)
C2—C3—C4	129.5 (2)	C10—C11—C6	119.8 (2)
C2—C3—S2	116.86 (17)	N1—C12—C13	112.79 (18)
C4—C3—S2	113.64 (15)	N1—C12—H12A	109.0
N2—C4—C3	115.80 (19)	C13—C12—H12A	109.0
N2—C4—C5	124.1 (2)	N1—C12—H12B	109.0
C3—C4—C5	120.11 (19)	C13—C12—H12B	109.0
O2—C5—N1	121.94 (19)	H12A—C12—H12B	107.8
O2—C5—C4	123.6 (2)	C12—C13—H13A	109.5
N1—C5—C4	114.42 (18)	C12—C13—H13B	109.5
N1—C6—C7	122.65 (19)	H13A—C13—H13B	109.5
N1—C6—C11	118.2 (2)	C12—C13—H13C	109.5
C7—C6—C11	119.16 (19)	H13A—C13—H13C	109.5
C8—C7—C6	119.8 (2)	H13B—C13—H13C	109.5
C8—C7—H7	120.1

C3—S2—C1—O1	−178.3 (2)	N2—C4—C5—N1	−4.3 (3)
C3—S2—C1—S1	1.57 (15)	C3—C4—C5—N1	174.71 (18)
C2—S1—C1—O1	179.1 (2)	C5—N1—C6—C7	175.2 (2)
C2—S1—C1—S2	−0.82 (15)	C12—N1—C6—C7	−3.6 (3)
C1—S1—C2—C3	−0.6 (2)	C5—N1—C6—C11	−4.9 (3)
S1—C2—C3—C4	−176.09 (18)	C12—N1—C6—C11	176.29 (19)
S1—C2—C3—S2	1.9 (3)	N1—C6—C7—C8	178.9 (2)
C1—S2—C3—C2	−2.1 (2)	C11—C6—C7—C8	−0.9 (3)
C1—S2—C3—C4	176.21 (16)	C6—C7—C8—C9	0.3 (3)
C11—N2—C4—C3	−178.92 (19)	C7—C8—C9—C10	0.2 (4)
C11—N2—C4—C5	0.1 (3)	C8—C9—C10—C11	0.0 (3)
C2—C3—C4—N2	178.4 (2)	C4—N2—C11—C10	−179.0 (2)
S2—C3—C4—N2	0.4 (3)	C4—N2—C11—C6	1.9 (3)
C2—C3—C4—C5	−0.7 (4)	C9—C10—C11—N2	−179.8 (2)
S2—C3—C4—C5	−178.67 (16)	C9—C10—C11—C6	−0.7 (3)
C6—N1—C5—O2	−174.7 (2)	N1—C6—C11—N2	0.3 (3)
C12—N1—C5—O2	4.1 (3)	C7—C6—C11—N2	−179.8 (2)
C6—N1—C5—C4	6.6 (3)	N1—C6—C11—C10	−178.7 (2)
C12—N1—C5—C4	−174.59 (18)	C7—C6—C11—C10	1.2 (3)
N2—C4—C5—O2	177.0 (2)	C5—N1—C12—C13	−96.3 (2)
C3—C4—C5—O2	−4.0 (3)	C6—N1—C12—C13	82.5 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O2	0.95 (2)	2.30 (3)	2.859 (3)	117.2 (19)
C2—H2···O2ⁱ	0.95 (2)	2.44 (2)	3.133 (3)	129 (2)
C7—H7···O1ⁱⁱ	0.95	2.51	3.272 (3)	138
C9—H9···S2ⁱⁱⁱ	0.95	2.99	3.652 (3)	128
C12—H12A···O2^iv	0.99	2.69	3.367 (3)	126

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

Acknowledgements

Generous financial support from the European Research Council (project MocoModels) is gratefully acknowledged.

Funding information

Funding for this research was provided by: FP7 Ideas: European Research Council (grant No. 281257 to Carola Schulzke).

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