Ethyl 2-amino-4-methyl­thio­phene-3-carboxyl­ate

Khanum, G.; Fatima, A.; Sharma, P.; Srivastava, S.K.; Butcher, R.J.

doi:10.1107/S2414314621003515

organic compounds

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ISSN: 2414-3146

Volume 6| Part 4| April 2021| x210351

https://doi.org/10.1107/S2414314621003515

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Ethyl 2-amino-4-methylthiophene-3-carboxylate

Ghazala Khanum,^a Aysha Fatima,^a Pooja Sharma,^a S. K. Srivastava ^a and Ray J. Butcher ^b ^*

^aSchool of Studies in Chemistry, Jiwaji University, Gwalior 474011, India, and ^bDepartment of Chemistry, Howard University, 525 College Street NW, Washington DC 20059, USA
^*Correspondence e-mail: rbutcher99@yahoo.com

Edited by M. Bolte, Goethe-Universität Frankfurt, Germany (Received 31 March 2021; accepted 1 April 2021; online 9 April 2021)

The title compound, C₈H₁₁NO₂S, crystallizes with two molecules, A and B, in the asymmetric unit. Each molecule features an intramolecular N—H⋯O hydrogen bond and the same H atom is also involved in an intermolecular N—H⋯S bond to generate A + B dimers. Further N—H⋯O hydrogen bonds link the dimers into a [010] chain.

Keywords: crystal structure; 2-aminothiophene derivative; hydrogen bonding.

CCDC reference: 2074848

Structure description

Thiophene derivatives have been reported to exhibit a broad spectrum of biological properties such as anti-inflammatory, antidepressant, antimicrobial and anticonvulsant activities (Molvi et al., 2007 ; Ashalatha et al., 2007 ; Rai et al., 2008 ). Thiophene derivatives are found to be active as allosteric enhancers at the adenosine A1 receptor, which has been linked to antiarrhythmic and antilipolytic activity (Cannito et al.,1990 ; Lütjens et al., 2003 ; Göblyös & Ijzerman, 2009 ; Nikolakopoulos et al., 2006 ). Thiophenes also possess properties that are suitable for functional materials, such as field effect transistors (MacDiarmid, 2001 ; Kraft, 2001 ) and organic light-emitting diodes (Akcelrud, 2003 ; Perepichka et al., 2005 ) because of their reversible oxidation occurring at low potentials (Nessakh et al., 1995 ; van Haare et al., 1995 ) and their semiconductor-like behaviour obtained upon p-doping (Roncali et al., 2005 ).

Many 2-,3-aminothiophene derivatives have been prepared so far and the structures of more than 25 of them have been published (see, e.g.: Çoruh et al., 2003 ; Nirmala et al., 2005 ; Bourgeaux & Skene, 2007 ; Akkurt et al., 2008 ; Zhang & Jiao, 2010 ; Ghorab et al., 2012 ). Crystal structures of several thiophenes have been determined in which different functional groups are attached in place of NH₂ at the 2-position of the ring (Yan & Liu, 2007 ; Mukhtar et al., 2012 ; de Oliveira et al., 2012 ; Mabkhot et al., 2013 ; Kaur et al., 2014 ). Compounds are known in which the replacement of NH₂ group by iodine resulted in a cyclomer by the association of two monomers through a weak intermolecular CN⋯I Lewis acid–base interaction (Moncol et al., 2007 ). In the crystal structure of another compound, which is a derivative of piperidine containing aminothiophenes, a dimer is formed by the intermolecular C—H⋯S interaction between the piperidine and thiophene rings (Al-Adiwish et al., 2012 ).

We report herein the synthesis, characterization and crystal structure of the title compound, 2-amino-4-methylthiophene-3-carboxylate (1) (Fig. 1), which crystallizes in the triclinic space group P $[\overline{1}]$ with four molecules in the unit cell (Z′ = 2). The two molecules in the asymmetric unit are labelled as A and B. In both A and B, the thiophene ring and the directly attached atoms are all coplanar within experimental error [for A: the r.m.s. deviation of the thiophene moiety is 0.003 (1) Å with N1, C5, and C6 at 0.044 (3), 0.005 (3) and 0.011 (3) Å, respectively; for B the r.m.s. deviation is 0.001 (1) Å with N1, C5 and C6 at 0.009 (4), 0.009 (4), and 0.003 (3) Å, respectively]. For A the dihedral angle between the thiophene ring and the NH₂ substituent is 12.5 (18)° while for the C7, O1 and O2 moiety, this angle is 1.65 (10)°, indicating that this group is almost exactly coplanar with the ring. For B the corresponding values are 11 (2) and 2.1 (2)°.

Figure 1
Diagram showing the two molecules A and B with atom labelling. R₂³(6) interactions involving the NH₂ and S moieties with a bifurcated hydrogen bond from H1BA to S1A and O1B links the A and B molecules. Hydrogen bonds are shown with dashed lines. Atomic displacement parameters are at the 30% probability level.

A search for structures containing a 2-amino-thiophene-3-carboxylate moiety gave 45 hits, two of which are particularly relevant to the current reported structure, viz. ethyl 2-amino-4-isobutylthiophene-3-carboxylate (KIKPIE; Liao et al., 2007 ) and ethyl 2-amino-4-phenylthiophen-3-carboxylate (VIWPUM; Dufresne & Skene, 2010 ). The only difference between these structures and that of 1 is in the substituent at the 3-position on the ring which are 2-methylpropyl and phenyl for KIKPIE (Liao et al., 2007) and VIWPUM (Dufresne & Skene, 2010). In both cases the metrical parameters are similar as well as the planarity of the substituents.

As far as the packing of the molecules is concerned, there is both intra- and intermolecular hydrogen bonding. This links the molecules into a C₄²(12) chain in the b-axis direction (Etter et al., 1990 ). In addition, there are R₂³(6) interactions involving the NH₂ and S moieties with a bifurcated hydrogen bond from H1BA to S1A and O1B, which links the A and B molecules (Table 1, Figs. 2 and 3).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1B—H1BA⋯O1B	0.82 (3)	2.14 (3)	2.734 (3)	130 (2)
N1B—H1BB⋯O1Aⁱ	0.87 (3)	2.10 (3)	2.946 (3)	163 (2)
N1A—H1AA⋯S1Bⁱⁱ	0.83 (3)	3.07 (3)	3.819 (2)	151 (2)
N1A—H1AA⋯O1A	0.83 (3)	2.14 (3)	2.736 (3)	129 (2)
N1A—H1AB⋯O1B	0.86 (3)	2.05 (3)	2.897 (3)	165 (2)
C7A—H7AA⋯S1Aⁱⁱⁱ	0.97	3.02	3.736 (3)	131
Symmetry codes: (i) ; (ii) x, y+1, z; (iii) .

Figure 2
Diagram showing both intra- and intermolecular hydrogen bonding, which links the molecules into a C₄²(12) chain in the b-axis direction, and R₂³(6) interactions involving the NH₂ and S moieties with a bifurcated hydrogen bond from H1BA to S1A and O1B which links the A and B molecules. Hydrogen bonds are shown with dashed lines. Atomic displacement parameters are at the 30% probability level.

Figure 3
Packing diagram viewed along the a axis. Hydrogen bonds are shown with dashed lines.

Synthesis and crystallization

The title compound (ethyl 2-amino-4-methylthiophene-3-carboxylate) (1) was prepared by the procedure described in the literature (Zhang et al., 2010). A mixture of acetone (0.5 mmol) and ethylcyanoacetate (0.5 mmol) in absolute ethanol (2 ml) was added to a solution of elemental S (0.5 mmol) and diethylamine (0.5 mmol) in absolute ethanol (2 ml) and stirred constantly for 3 h at 50°C. The reaction completion was confirmed by using pre-coated silica gel 60 F254 MERCK (20×20 cm). The reaction mixture was quenched with ice-cold water and extracted with ethyl acetate. The organic layer was separated, dried over anhydrous sodium sulfate and concentrated. The crude product was purified using silica gel column chromatography (100–200 mesh) using hexane/ethyl acetate (7:3) mixture solution. Yellow crystals were obtained by slow evaporation of a saturated solution in ethyl acetate and the crystals were used for X-ray diffraction studies. Compound 1: Yield: (85%). m.p. 76–79°C. ¹H NMR (400 MHz, CDCl₃) δ 6.07 (s, 2H), 5.82 (s, 1H), 4.29 (q, J = 7.1 Hz, 2H), 2.28 (s, 3H), 1.35 (t, J = 7.1 Hz, 3H). ¹³C NMR (400 MHz, CDCl₃) δ 166.13, 164.17, 136.71, 106.72, 102.85, 59.54, 18.40, 14.40. ESI–MS: m/z calculated for C₈H₁₁NO₂S 185.05; found [M + H]+ 186.15.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₈H₁₁NO₂S
M_r	185.24
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	293
a, b, c (Å)	7.664 (3), 9.876 (3), 13.018 (5)
α, β, γ (°)	91.602 (12), 104.301 (13), 101.729 (13)
V (Å³)	931.7 (6)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.31
Crystal size (mm)	0.48 × 0.35 × 0.12

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996 )
T_min, T_max	0.565, 0.747
No. of measured, independent and observed [I > 2σ(I)] reflections	27589, 5636, 3845
R_int	0.062
(sin θ/λ)_max (Å⁻¹)	0.714

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.057, 0.168, 1.03
No. of reflections	5636
No. of parameters	237
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.62, −0.39
Computer programs: APEX2 (Bruker, 2005 ), SAINT (Bruker, 2002 ), SHELXT (Sheldrick 2015 a), SHELXL2018/3 (Sheldrick, 2015b) and SHELXTL (Sheldrick 2008 ).

Structural data

CCDC reference: 2074848

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314621003515/bt4112sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314621003515/bt4112Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314621003515/bt4112Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXT (Sheldrick 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: SHELXTL (Sheldrick 2008); software used to prepare material for publication: SHELXTL (Sheldrick 2008).

Ethyl 2-amino-4-methylthiophene-3-carboxylate top

Crystal data top

C₈H₁₁NO₂S	Z = 4
M_r = 185.24	F(000) = 392
Triclinic, P1	D_x = 1.321 Mg m⁻³
a = 7.664 (3) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.876 (3) Å	Cell parameters from 9004 reflections
c = 13.018 (5) Å	θ = 2.6–30.7°
α = 91.602 (12)°	µ = 0.31 mm⁻¹
β = 104.301 (13)°	T = 293 K
γ = 101.729 (13)°	Plate, colourless
V = 931.7 (6) Å³	0.48 × 0.35 × 0.12 mm

Data collection top

Bruker APEXII CCD diffractometer	3845 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.062
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	θ_max = 30.5°, θ_min = 2.1°
T_min = 0.565, T_max = 0.747	h = −10→10
27589 measured reflections	k = −14→14
5636 independent reflections	l = −18→18

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.057	Hydrogen site location: mixed
wR(F²) = 0.168	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ²(F_o²) + (0.0812P)² + 0.2238P] where P = (F_o² + 2F_c²)/3
5636 reflections	(Δ/σ)_max < 0.001
237 parameters	Δρ_max = 0.62 e Å⁻³
0 restraints	Δρ_min = −0.39 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.

Refinement. The structure was solved with SHELXT (Sheldrick, 2015a) and refined with SHELXL2018/3 (Sheldrick 2015b). The amine hydrogen atoms were refined isotropically while the C-bound H atoms were included in calculated positions and treated as riding, with C—H = 0.95–0.98 Å, and with 1.2U_eq(C) for H atoms.

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

	x	y	z	U_iso*/U_eq
S1A	0.57912 (8)	0.63040 (5)	0.90873 (4)	0.05608 (17)
O1A	0.5956 (2)	1.07513 (14)	0.82938 (11)	0.0598 (4)
O2A	0.77241 (18)	1.13164 (13)	0.99478 (10)	0.0469 (3)
N1A	0.4678 (3)	0.7995 (2)	0.76263 (15)	0.0611 (5)
H1AA	0.478 (4)	0.878 (3)	0.741 (2)	0.074 (8)*
H1AB	0.420 (4)	0.728 (3)	0.718 (2)	0.067 (7)*
C1A	0.5667 (3)	0.79097 (18)	0.86174 (15)	0.0434 (4)
C2A	0.6638 (2)	0.89702 (17)	0.93919 (13)	0.0394 (4)
C3A	0.7481 (2)	0.84624 (19)	1.03824 (14)	0.0429 (4)
C4A	0.7121 (3)	0.7062 (2)	1.03180 (17)	0.0535 (5)
H4AA	0.754788	0.655468	1.088165	0.064*
C5A	0.8619 (3)	0.9325 (2)	1.13746 (16)	0.0580 (5)
H5AA	0.899385	0.872987	1.191859	0.087*
H5AB	0.790195	0.990278	1.160998	0.087*
H5AC	0.969117	0.989811	1.123237	0.087*
C6A	0.6715 (2)	1.03954 (17)	0.91494 (14)	0.0400 (4)
C7A	0.7865 (3)	1.27623 (18)	0.97679 (16)	0.0501 (4)
H7AA	0.664931	1.297311	0.957187	0.060*
H7AB	0.845948	1.299239	0.919940	0.060*
C8A	0.8989 (3)	1.3566 (2)	1.07851 (18)	0.0607 (5)
H8AA	0.910249	1.454059	1.070404	0.091*
H8AB	1.019220	1.335704	1.096380	0.091*
H8AC	0.839418	1.331695	1.134225	0.091*
S1B	0.35148 (12)	0.08122 (6)	0.57884 (5)	0.0809 (3)
O1B	0.3541 (2)	0.53445 (14)	0.63773 (11)	0.0620 (4)
O2B	0.2205 (2)	0.52307 (14)	0.46392 (11)	0.0538 (3)
N1B	0.4376 (3)	0.2976 (2)	0.72151 (14)	0.0639 (5)
H1BA	0.451 (3)	0.381 (3)	0.7357 (18)	0.057 (7)*
H1BB	0.484 (4)	0.242 (3)	0.765 (2)	0.076 (8)*
C1B	0.3661 (3)	0.25098 (19)	0.61927 (15)	0.0474 (4)
C2B	0.2967 (3)	0.32322 (18)	0.53404 (13)	0.0425 (4)
C3B	0.2320 (3)	0.2374 (2)	0.43493 (16)	0.0564 (5)
C4B	0.2549 (5)	0.1078 (3)	0.4495 (2)	0.0824 (8)
H4BA	0.221258	0.038177	0.394211	0.099*
C5B	0.1488 (4)	0.2818 (3)	0.32835 (17)	0.0748 (7)
H5BA	0.121058	0.205434	0.275478	0.112*
H5BB	0.234517	0.357479	0.311217	0.112*
H5BC	0.037419	0.311113	0.329922	0.112*
C6B	0.2961 (3)	0.46767 (18)	0.55163 (14)	0.0424 (4)
C7B	0.2082 (3)	0.6659 (2)	0.47361 (19)	0.0609 (5)
H7BA	0.330234	0.725322	0.498848	0.073*
H7BB	0.136218	0.679395	0.523229	0.073*
C8B	0.1157 (4)	0.6988 (3)	0.3643 (2)	0.0809 (8)
H8BA	0.089268	0.789501	0.367982	0.121*
H8BB	0.002774	0.631283	0.336545	0.121*
H8BC	0.195895	0.696714	0.318332	0.121*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1A	0.0707 (4)	0.0344 (2)	0.0629 (3)	0.0106 (2)	0.0173 (3)	0.0055 (2)
O1A	0.0810 (10)	0.0432 (7)	0.0456 (7)	0.0181 (7)	−0.0054 (7)	0.0073 (6)
O2A	0.0547 (8)	0.0354 (6)	0.0441 (7)	0.0084 (5)	0.0020 (6)	0.0059 (5)
N1A	0.0846 (14)	0.0431 (9)	0.0456 (9)	0.0128 (9)	0.0003 (9)	−0.0027 (8)
C1A	0.0497 (10)	0.0369 (8)	0.0453 (9)	0.0108 (7)	0.0141 (8)	0.0038 (7)
C2A	0.0404 (9)	0.0366 (8)	0.0414 (8)	0.0088 (7)	0.0103 (7)	0.0065 (6)
C3A	0.0425 (9)	0.0434 (9)	0.0450 (9)	0.0116 (7)	0.0128 (7)	0.0109 (7)
C4A	0.0631 (12)	0.0458 (10)	0.0543 (11)	0.0166 (9)	0.0144 (9)	0.0176 (8)
C5A	0.0635 (13)	0.0579 (12)	0.0444 (10)	0.0124 (10)	−0.0012 (9)	0.0109 (9)
C6A	0.0428 (9)	0.0378 (8)	0.0400 (8)	0.0115 (7)	0.0091 (7)	0.0055 (6)
C7A	0.0621 (12)	0.0345 (8)	0.0500 (10)	0.0116 (8)	0.0062 (9)	0.0055 (7)
C8A	0.0653 (13)	0.0454 (10)	0.0605 (13)	0.0052 (9)	0.0021 (10)	−0.0021 (9)
S1B	0.1329 (7)	0.0398 (3)	0.0631 (4)	0.0278 (3)	0.0053 (4)	0.0040 (2)
O1B	0.0879 (11)	0.0431 (7)	0.0452 (7)	0.0163 (7)	−0.0015 (7)	−0.0043 (6)
O2B	0.0696 (9)	0.0449 (7)	0.0446 (7)	0.0190 (6)	0.0046 (6)	0.0083 (6)
N1B	0.0985 (16)	0.0499 (10)	0.0380 (8)	0.0265 (10)	−0.0011 (9)	0.0056 (8)
C1B	0.0601 (11)	0.0383 (8)	0.0419 (9)	0.0129 (8)	0.0077 (8)	0.0040 (7)
C2B	0.0492 (10)	0.0395 (8)	0.0360 (8)	0.0107 (7)	0.0052 (7)	0.0015 (6)
C3B	0.0707 (13)	0.0495 (10)	0.0404 (9)	0.0104 (9)	0.0015 (9)	−0.0040 (8)
C4B	0.128 (2)	0.0480 (12)	0.0570 (13)	0.0180 (14)	0.0015 (14)	−0.0132 (10)
C5B	0.1004 (19)	0.0743 (15)	0.0386 (10)	0.0216 (14)	−0.0035 (11)	−0.0068 (10)
C6B	0.0463 (9)	0.0398 (8)	0.0399 (8)	0.0107 (7)	0.0074 (7)	0.0050 (7)
C7B	0.0672 (13)	0.0447 (10)	0.0700 (14)	0.0180 (9)	0.0105 (11)	0.0160 (9)
C8B	0.0828 (18)	0.0716 (16)	0.0840 (18)	0.0226 (14)	0.0055 (14)	0.0366 (14)

Geometric parameters (Å, º) top

S1A—C4A	1.727 (2)	S1B—C4B	1.715 (3)
S1A—C1A	1.7277 (19)	S1B—C1B	1.716 (2)
O1A—C6A	1.220 (2)	O1B—C6B	1.217 (2)
O2A—C6A	1.330 (2)	O2B—C6B	1.333 (2)
O2A—C7A	1.440 (2)	O2B—C7B	1.437 (2)
N1A—C1A	1.340 (3)	N1B—C1B	1.337 (3)
N1A—H1AA	0.83 (3)	N1B—H1BA	0.82 (3)
N1A—H1AB	0.86 (3)	N1B—H1BB	0.87 (3)
C1A—C2A	1.386 (3)	C1B—C2B	1.389 (2)
C2A—C6A	1.444 (2)	C2B—C6B	1.440 (2)
C2A—C3A	1.445 (2)	C2B—C3B	1.443 (3)
C3A—C4A	1.350 (3)	C3B—C4B	1.339 (3)
C3A—C5A	1.495 (3)	C3B—C5B	1.495 (3)
C4A—H4AA	0.9300	C4B—H4BA	0.9300
C5A—H5AA	0.9600	C5B—H5BA	0.9600
C5A—H5AB	0.9600	C5B—H5BB	0.9600
C5A—H5AC	0.9600	C5B—H5BC	0.9600
C7A—C8A	1.492 (3)	C7B—C8B	1.502 (3)
C7A—H7AA	0.9700	C7B—H7BA	0.9700
C7A—H7AB	0.9700	C7B—H7BB	0.9700
C8A—H8AA	0.9600	C8B—H8BA	0.9600
C8A—H8AB	0.9600	C8B—H8BB	0.9600
C8A—H8AC	0.9600	C8B—H8BC	0.9600

C4A—S1A—C1A	91.37 (9)	C4B—S1B—C1B	91.28 (11)
C6A—O2A—C7A	117.21 (14)	C6B—O2B—C7B	117.81 (16)
C1A—N1A—H1AA	116.2 (19)	C1B—N1B—H1BA	116.5 (17)
C1A—N1A—H1AB	122.2 (17)	C1B—N1B—H1BB	118.1 (18)
H1AA—N1A—H1AB	120 (2)	H1BA—N1B—H1BB	124 (2)
N1A—C1A—C2A	128.91 (17)	N1B—C1B—C2B	128.53 (18)
N1A—C1A—S1A	119.95 (15)	N1B—C1B—S1B	120.36 (15)
C2A—C1A—S1A	111.12 (14)	C2B—C1B—S1B	111.12 (14)
C1A—C2A—C6A	119.56 (16)	C1B—C2B—C6B	119.66 (16)
C1A—C2A—C3A	112.69 (15)	C1B—C2B—C3B	112.43 (17)
C6A—C2A—C3A	127.75 (16)	C6B—C2B—C3B	127.92 (17)
C4A—C3A—C2A	111.36 (17)	C4B—C3B—C2B	111.01 (19)
C4A—C3A—C5A	122.25 (18)	C4B—C3B—C5B	122.6 (2)
C2A—C3A—C5A	126.40 (16)	C2B—C3B—C5B	126.34 (19)
C3A—C4A—S1A	113.46 (15)	C3B—C4B—S1B	114.16 (17)
C3A—C4A—H4AA	123.3	C3B—C4B—H4BA	122.9
S1A—C4A—H4AA	123.3	S1B—C4B—H4BA	122.9
C3A—C5A—H5AA	109.5	C3B—C5B—H5BA	109.5
C3A—C5A—H5AB	109.5	C3B—C5B—H5BB	109.5
H5AA—C5A—H5AB	109.5	H5BA—C5B—H5BB	109.5
C3A—C5A—H5AC	109.5	C3B—C5B—H5BC	109.5
H5AA—C5A—H5AC	109.5	H5BA—C5B—H5BC	109.5
H5AB—C5A—H5AC	109.5	H5BB—C5B—H5BC	109.5
O1A—C6A—O2A	121.81 (16)	O1B—C6B—O2B	121.96 (17)
O1A—C6A—C2A	124.29 (16)	O1B—C6B—C2B	124.56 (17)
O2A—C6A—C2A	113.89 (15)	O2B—C6B—C2B	113.46 (16)
O2A—C7A—C8A	106.65 (16)	O2B—C7B—C8B	106.1 (2)
O2A—C7A—H7AA	110.4	O2B—C7B—H7BA	110.5
C8A—C7A—H7AA	110.4	C8B—C7B—H7BA	110.5
O2A—C7A—H7AB	110.4	O2B—C7B—H7BB	110.5
C8A—C7A—H7AB	110.4	C8B—C7B—H7BB	110.5
H7AA—C7A—H7AB	108.6	H7BA—C7B—H7BB	108.7
C7A—C8A—H8AA	109.5	C7B—C8B—H8BA	109.5
C7A—C8A—H8AB	109.5	C7B—C8B—H8BB	109.5
H8AA—C8A—H8AB	109.5	H8BA—C8B—H8BB	109.5
C7A—C8A—H8AC	109.5	C7B—C8B—H8BC	109.5
H8AA—C8A—H8AC	109.5	H8BA—C8B—H8BC	109.5
H8AB—C8A—H8AC	109.5	H8BB—C8B—H8BC	109.5

C4A—S1A—C1A—N1A	−177.88 (18)	C4B—S1B—C1B—N1B	−179.6 (2)
C4A—S1A—C1A—C2A	0.54 (15)	C4B—S1B—C1B—C2B	0.33 (19)
N1A—C1A—C2A—C6A	−2.3 (3)	N1B—C1B—C2B—C6B	−0.3 (3)
S1A—C1A—C2A—C6A	179.41 (13)	S1B—C1B—C2B—C6B	179.78 (15)
N1A—C1A—C2A—C3A	177.8 (2)	N1B—C1B—C2B—C3B	179.7 (2)
S1A—C1A—C2A—C3A	−0.5 (2)	S1B—C1B—C2B—C3B	−0.3 (2)
C1A—C2A—C3A—C4A	0.1 (2)	C1B—C2B—C3B—C4B	0.0 (3)
C6A—C2A—C3A—C4A	−179.77 (18)	C6B—C2B—C3B—C4B	180.0 (2)
C1A—C2A—C3A—C5A	−179.96 (18)	C1B—C2B—C3B—C5B	179.7 (2)
C6A—C2A—C3A—C5A	0.2 (3)	C6B—C2B—C3B—C5B	−0.3 (4)
C2A—C3A—C4A—S1A	0.3 (2)	C2B—C3B—C4B—S1B	0.2 (3)
C5A—C3A—C4A—S1A	−179.62 (16)	C5B—C3B—C4B—S1B	−179.5 (2)
C1A—S1A—C4A—C3A	−0.52 (17)	C1B—S1B—C4B—C3B	−0.3 (3)
C7A—O2A—C6A—O1A	0.9 (3)	C7B—O2B—C6B—O1B	−0.2 (3)
C7A—O2A—C6A—C2A	−179.88 (16)	C7B—O2B—C6B—C2B	178.22 (17)
C1A—C2A—C6A—O1A	0.7 (3)	C1B—C2B—C6B—O1B	0.4 (3)
C3A—C2A—C6A—O1A	−179.46 (18)	C3B—C2B—C6B—O1B	−179.5 (2)
C1A—C2A—C6A—O2A	−178.48 (15)	C1B—C2B—C6B—O2B	−177.98 (17)
C3A—C2A—C6A—O2A	1.4 (3)	C3B—C2B—C6B—O2B	2.1 (3)
C6A—O2A—C7A—C8A	177.71 (17)	C6B—O2B—C7B—C8B	−179.07 (18)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1B—H1BA···O1B	0.82 (3)	2.14 (3)	2.734 (3)	130 (2)
N1B—H1BB···O1Aⁱ	0.87 (3)	2.10 (3)	2.946 (3)	163 (2)
N1A—H1AA···S1Bⁱⁱ	0.83 (3)	3.07 (3)	3.819 (2)	151 (2)
N1A—H1AA···O1A	0.83 (3)	2.14 (3)	2.736 (3)	129 (2)
N1A—H1AB···O1B	0.86 (3)	2.05 (3)	2.897 (3)	165 (2)
C7A—H7AA···S1Aⁱⁱⁱ	0.97	3.02	3.736 (3)	131

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

Funding information

RJB wishes to acknowledge NSF award 1205608, Partnership for Reduced Dimensional Materials, for partial funding of this research.

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