A new monoclinic polymorph of 3-diethyl­amino-4-(4-meth­oxy­phen­yl)-1,1-dioxo-4H-1λ6,2-thia­zete-4-carbonitrile

Orlando, A.M.; Lo Presti, L.; Soave, R.

doi:10.1107/S1600536810027558

organic compounds

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ISSN: 2056-9890

Volume 66| Part 8| August 2010| Pages o2032-o2033

https://doi.org/10.1107/S1600536810027558

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A new monoclinic polymorph of 3-diethylamino-4-(4-methoxyphenyl)-1,1-dioxo-4H-1λ⁶,2-thiazete-4-carbonitrile

Ahmed M. Orlando,^a Leonardo Lo Presti ^a ^* and Raffaella Soave ^b

^aDipartimento di Chimica Fisica ed Elettrochimica, Universitá degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy, and ^bConsiglio Nazionale delle Ricerche, Istituto di Scienze e Tecnologie Molecolari, Via Golgi 19, 20133 Milano, Italy
^*Correspondence e-mail: leonardo.lopresti@unimi.it

(Received 16 June 2010; accepted 12 July 2010; online 17 July 2010)

A new monoclinic form of the title compound, C₁₄H₁₇N₃O₃S, has been found upon slow crystallization from water. Another monoclinic form of the compound was obtained previously from a mixture of dichloromethane and diethyl ether [Clerici et al. (2002 ). Tetrahedron, 58, 5173–5178]. Both phases crystallize in space group P2₁/n with one molecule in the asymmetric unit. The formally single exocyclic C—N bond that connects the –NEt₂ unit with the thiazete ring is considerably shorter than the adjacent, formally double, endocyclic C=N bond. This is likely to be due to the extended conjugated system between the electron-donor diethylammine fragment and the electron-withdrawing sulfonyl group. In the newly discovered polymorph, the methoxy group is rotated by almost 180° around the phenyl–OCH₃ bond, resulting in a different molecular conformation.

Related literature

For the synthesis of the title compound and the crystal structure of the other polymorph, see: Clerici et al. (2002). For a related structure, see: Clerici et al. (1996 ). For the biological activity of β-sultam derivatives, see: Barwick et al. (2008 ) and references therein.

Experimental

Crystal data

C₁₄H₁₇N₃O₃S
M_r = 307.37
Monoclinic, P 2₁ /n
a = 8.3853 (17) Å
b = 17.554 (4) Å
c = 10.458 (2) Å
β = 95.07 (3)°
V = 1533.4 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.22 mm⁻¹
T = 293 K
0.18 × 0.16 × 0.16 mm

Data collection

Bruker APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ) T_min = 0.855, T_max = 0.947
16661 measured reflections
2814 independent reflections
1949 reflections with I > 2σ(I)
R_int = 0.043

Refinement

R[F² > 2σ(F²)] = 0.037
wR(F²) = 0.102
S = 1.01
2814 reflections
258 parameters
All H-atom parameters refined
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Data collection: SMART (Bruker, 2005 ); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2010 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810027558/nk2045sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810027558/nk2045Isup2.hkl

checkCIF report

Comment top

The title compound, (I), a thiazete 1,1 dioxo derivative containing a four-membered heterocycle, exhibits a marked similarity with the β-sultamic functionality, which is the key component of promising antibiotic drugs (Barwick et al., 2008). A new monoclinic polymorph of (I) (hereinafter, phase B: Fig. 1, Table 1) was found upon slow recrystallization from water of a little amount of the phase A, originally obtained from a CH₂Cl₂:Et₂O mixture (Clerici et al., 2002). Both polymorphs share the same space group, P2₁/n, with one molecule in the asymmetric unit. On average, bond lengths and angles are very similar between the two forms, while the molecular conformations are different. The most important dissimilarity resides in the dihedral angles involving the phenyl-OCH₃ single bond, which is rotated by ~180° in the form B with respect to form A (Fig. 2). In both crystal forms the formally single exocyclic C9–N1 bond connecting the –NEt₂ moiety to the thiazete ring is considerably shorter (phase B: 1.307 (3) Å; phase A: 1.318 (3) Å) than the adjacent, formally double, endocyclic C9=N2 bond (phase B: 1.331 (3) Å; phase A: 1.327 (3) Å). A possible explanation resides in the existence of an extended π conjugated system between the electron-donor diethylammine fragment and the electron-withdrawing sulfonyl group. This conjecture is supported by the values of the C–N1–C angles, which in both phases range from ~118° to ~122° and are compatible with a formally sp² tertiary nitrogen atom. Very similar bond distances within the thiazete group have been reported by Clerici et al. (1996) for a chemically related derivative of (I). On geometrical grounds, no relevant intermolecular hydrogen bonds have been found in both phases.

Related literature top

For the synthesis of the title compound and the crystal structure of the other polymorph, see: Clerici et al. (2002). For a related structure, see: Clerici et al. (1996). For the biological activity of β-sultam derivatives, see: Barwick et al. (2008) and references therein.

Experimental top

The compound (I) was synthesized using the procedure reported by Clerici et al. (2002). Part of the material obtained from dichloromethane and diethyl ether (phase A) was dissolved in distilled water and crystallized by slow solvent evaporation at room temperature. After roughly 7 days, very small colorless crystals with the same habit (prism) as the most common phase A appeared. Only the X-ray analysis revealed that in fact a new polymorph (phase B) was obtained.

Structure description top

For the synthesis of the title compound and the crystal structure of the other polymorph, see: Clerici et al. (2002). For a related structure, see: Clerici et al. (1996). For the biological activity of β-sultam derivatives, see: Barwick et al. (2008) and references therein.

Computing details top

Data collection: SMART (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2010); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. Molecular structure of (I), with the non-H atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Least-squares overlay scheme of the asymmetric units of (I) within phase B (this work, carbon backbone in gray) and phase A (Clerici et al., 2002; carbon backbone in green). Hydrogen atoms omitted for clarity.

3-diethylamino-4-(4-methoxyphenyl)-1,1-dioxo-4H-1λ⁶,2-thiazete- 4-carbonitrile top

Crystal data top

C₁₄H₁₇N₃O₃S	F(000) = 648
M_r = 307.37	D_x = 1.331 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2885 reflections
a = 8.3853 (17) Å	θ = 2.3–21.6°
b = 17.554 (4) Å	µ = 0.22 mm⁻¹
c = 10.458 (2) Å	T = 293 K
β = 95.07 (3)°	Prism, colourless
V = 1533.4 (5) Å³	0.18 × 0.16 × 0.16 mm
Z = 4

Data collection top

Bruker APEX CCD area-detector diffractometer	2814 independent reflections
Radiation source: fine-focus sealed tube	1949 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.043
ω scans	θ_max = 25.4°, θ_min = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −10→10
T_min = 0.855, T_max = 0.947	k = −21→21
16661 measured reflections	l = −12→12

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: structure-invariant direct methods
R[F² > 2σ(F²)] = 0.037	Hydrogen site location: difference Fourier map
wR(F²) = 0.102	All H-atom parameters refined
S = 1.01	w = 1/[σ²(F_o²) + (0.0446P)² + 0.4078P] where P = (F_o² + 2F_c²)/3
2814 reflections	(Δ/σ)_max < 0.001
258 parameters	Δρ_max = 0.16 e Å⁻³
0 restraints	Δρ_min = −0.31 e Å⁻³

Crystal data top

C₁₄H₁₇N₃O₃S	V = 1533.4 (5) Å³
M_r = 307.37	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 8.3853 (17) Å	µ = 0.22 mm⁻¹
b = 17.554 (4) Å	T = 293 K
c = 10.458 (2) Å	0.18 × 0.16 × 0.16 mm
β = 95.07 (3)°

Data collection top

Bruker APEX CCD area-detector diffractometer	2814 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2007)	1949 reflections with I > 2σ(I)
T_min = 0.855, T_max = 0.947	R_int = 0.043
16661 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.037	0 restraints
wR(F²) = 0.102	All H-atom parameters refined
S = 1.01	Δρ_max = 0.16 e Å⁻³
2814 reflections	Δρ_min = −0.31 e Å⁻³
258 parameters

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.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
S1	0.46791 (6)	0.19850 (4)	0.39836 (6)	0.0569 (2)
O1	0.1824 (2)	0.00687 (9)	−0.10877 (14)	0.0636 (5)
O2	0.57694 (19)	0.19314 (11)	0.51054 (16)	0.0758 (5)
O3	0.53410 (19)	0.20903 (10)	0.27881 (16)	0.0724 (5)
N1	0.0608 (2)	0.20205 (10)	0.44220 (16)	0.0472 (4)
N2	0.3156 (2)	0.25469 (11)	0.41859 (19)	0.0611 (5)
N3	0.3384 (3)	0.02616 (14)	0.5764 (2)	0.0739 (6)
C1	0.2489 (4)	−0.06433 (17)	−0.1428 (3)	0.0698 (8)
C2	0.2106 (2)	0.03021 (12)	0.01541 (19)	0.0458 (5)
C3	0.2867 (3)	−0.01266 (14)	0.1123 (2)	0.0521 (6)
C4	0.3129 (3)	0.01743 (13)	0.2346 (2)	0.0491 (5)
C5	0.1573 (3)	0.10253 (13)	0.0415 (2)	0.0497 (5)
C6	0.1842 (3)	0.13239 (13)	0.1623 (2)	0.0474 (5)
C7	0.2636 (2)	0.09019 (11)	0.26096 (18)	0.0395 (5)
C8	0.3043 (2)	0.12520 (12)	0.39177 (19)	0.0425 (5)
C9	0.2122 (2)	0.19738 (12)	0.42216 (19)	0.0448 (5)
C10	0.3242 (2)	0.06955 (14)	0.4954 (2)	0.0496 (5)
C11	−0.0148 (3)	0.27758 (15)	0.4525 (3)	0.0599 (7)
C12	−0.0724 (4)	0.3089 (2)	0.3236 (3)	0.0769 (8)
C13	−0.0377 (3)	0.13436 (15)	0.4614 (2)	0.0553 (6)
C14	−0.0494 (4)	0.1173 (2)	0.6015 (3)	0.0780 (9)
H1A	0.226 (3)	−0.0650 (17)	−0.234 (3)	0.105 (10)*
H1B	0.201 (3)	−0.1077 (16)	−0.096 (3)	0.085 (9)*
H1C	0.364 (3)	−0.0633 (15)	−0.122 (2)	0.081 (9)*
H3	0.317 (3)	−0.0621 (14)	0.100 (2)	0.066 (7)*
H4	0.367 (2)	−0.0118 (12)	0.299 (2)	0.055 (6)*
H5	0.100 (2)	0.1321 (12)	−0.027 (2)	0.055 (6)*
H6	0.153 (3)	0.1815 (13)	0.176 (2)	0.056 (7)*
H11A	−0.101 (3)	0.2705 (13)	0.502 (2)	0.068 (7)*
H11B	0.064 (3)	0.3094 (15)	0.495 (2)	0.078 (9)*
H12A	−0.122 (3)	0.3602 (18)	0.334 (3)	0.095 (9)*
H12B	−0.152 (4)	0.2716 (19)	0.279 (3)	0.114 (12)*
H12C	0.016 (4)	0.3143 (15)	0.271 (3)	0.088 (9)*
H13A	−0.139 (3)	0.1458 (12)	0.4177 (19)	0.053 (6)*
H13B	0.008 (2)	0.0906 (13)	0.4177 (19)	0.052 (6)*
H14A	−0.113 (4)	0.073 (2)	0.613 (3)	0.126 (12)*
H14B	−0.094 (3)	0.1583 (18)	0.642 (3)	0.095 (10)*
H14C	0.062 (4)	0.1065 (18)	0.653 (3)	0.116 (12)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0428 (3)	0.0691 (4)	0.0599 (4)	−0.0149 (3)	0.0108 (3)	−0.0137 (3)
O1	0.0840 (12)	0.0642 (11)	0.0414 (9)	0.0047 (9)	−0.0024 (8)	−0.0079 (8)
O2	0.0492 (9)	0.1081 (15)	0.0690 (11)	−0.0171 (9)	−0.0014 (8)	−0.0233 (10)
O3	0.0624 (10)	0.0883 (13)	0.0705 (11)	−0.0220 (9)	0.0270 (9)	−0.0068 (10)
N1	0.0434 (10)	0.0506 (11)	0.0489 (10)	−0.0011 (8)	0.0116 (8)	−0.0073 (8)
N2	0.0559 (12)	0.0537 (12)	0.0755 (14)	−0.0126 (9)	0.0162 (10)	−0.0154 (10)
N3	0.0798 (15)	0.0884 (17)	0.0534 (13)	0.0113 (13)	0.0047 (11)	0.0129 (12)
C1	0.092 (2)	0.0672 (19)	0.0505 (17)	−0.0020 (17)	0.0059 (15)	−0.0149 (14)
C2	0.0466 (12)	0.0514 (13)	0.0392 (12)	−0.0049 (10)	0.0033 (9)	−0.0013 (10)
C3	0.0619 (14)	0.0448 (14)	0.0492 (13)	0.0077 (11)	0.0032 (10)	−0.0051 (11)
C4	0.0510 (13)	0.0524 (14)	0.0428 (13)	0.0089 (11)	−0.0011 (10)	0.0024 (11)
C5	0.0563 (13)	0.0506 (14)	0.0417 (12)	0.0046 (11)	0.0010 (10)	0.0066 (11)
C6	0.0517 (13)	0.0415 (13)	0.0495 (14)	0.0046 (10)	0.0072 (10)	0.0021 (11)
C7	0.0355 (10)	0.0430 (12)	0.0405 (11)	−0.0034 (9)	0.0066 (8)	−0.0013 (9)
C8	0.0371 (11)	0.0492 (13)	0.0415 (12)	−0.0022 (9)	0.0054 (9)	−0.0042 (10)
C9	0.0437 (11)	0.0491 (13)	0.0422 (12)	−0.0050 (10)	0.0064 (9)	−0.0074 (10)
C10	0.0447 (12)	0.0619 (15)	0.0421 (13)	0.0007 (11)	0.0040 (10)	−0.0062 (12)
C11	0.0602 (16)	0.0581 (16)	0.0635 (17)	0.0092 (13)	0.0169 (13)	−0.0099 (13)
C12	0.083 (2)	0.073 (2)	0.077 (2)	0.0205 (18)	0.0162 (17)	0.0058 (17)
C13	0.0408 (13)	0.0619 (16)	0.0640 (16)	−0.0094 (11)	0.0095 (11)	−0.0148 (13)
C14	0.085 (2)	0.078 (2)	0.077 (2)	−0.0188 (19)	0.0353 (18)	−0.0019 (17)

Geometric parameters (Å, º) top

S1—O3	1.4241 (17)	C5—C6	1.369 (3)
S1—O2	1.4252 (18)	C5—H5	0.98 (2)
S1—N2	1.642 (2)	C6—C7	1.391 (3)
S1—C8	1.878 (2)	C6—H6	0.92 (2)
O1—C2	1.362 (2)	C7—C8	1.511 (3)
O1—C1	1.426 (3)	C8—C10	1.457 (3)
N1—C9	1.307 (3)	C8—C9	1.532 (3)
N1—C13	1.471 (3)	C11—C12	1.496 (4)
N1—C11	1.478 (3)	C11—H11A	0.94 (2)
N2—C9	1.331 (3)	C11—H11B	0.95 (3)
N3—C10	1.138 (3)	C12—H12A	1.00 (3)
C1—H1A	0.96 (3)	C12—H12B	1.02 (3)
C1—H1B	1.01 (3)	C12—H12C	0.97 (3)
C1—H1C	0.97 (3)	C13—C14	1.508 (4)
C2—C3	1.373 (3)	C13—H13A	0.95 (2)
C2—C5	1.381 (3)	C13—H13B	0.99 (2)
C3—C4	1.384 (3)	C14—H14A	0.95 (4)
C3—H3	0.92 (2)	C14—H14B	0.93 (3)
C4—C7	1.377 (3)	C14—H14C	1.06 (3)
C4—H4	0.94 (2)

O3—S1—O2	117.38 (11)	C10—C8—C7	113.72 (18)
O3—S1—N2	113.77 (11)	C10—C8—C9	115.25 (17)
O2—S1—N2	112.54 (11)	C7—C8—C9	116.52 (17)
O3—S1—C8	113.38 (10)	C10—C8—S1	113.39 (14)
O2—S1—C8	113.47 (10)	C7—C8—S1	114.70 (13)
N2—S1—C8	80.92 (9)	C9—C8—S1	78.81 (12)
C2—O1—C1	117.5 (2)	N1—C9—N2	127.0 (2)
C9—N1—C13	122.43 (19)	N1—C9—C8	126.87 (18)
C9—N1—C11	119.8 (2)	N2—C9—C8	106.11 (17)
C13—N1—C11	117.72 (19)	N3—C10—C8	179.4 (2)
C9—N2—S1	93.77 (15)	N1—C11—C12	111.7 (2)
O1—C1—H1A	102.2 (18)	N1—C11—H11A	106.2 (15)
O1—C1—H1B	111.1 (15)	C12—C11—H11A	110.1 (15)
H1A—C1—H1B	115 (2)	N1—C11—H11B	106.1 (16)
O1—C1—H1C	109.3 (16)	C12—C11—H11B	111.2 (16)
H1A—C1—H1C	109 (2)	H11A—C11—H11B	111 (2)
H1B—C1—H1C	110 (2)	C11—C12—H12A	109.8 (16)
O1—C2—C3	124.6 (2)	C11—C12—H12B	108.9 (18)
O1—C2—C5	115.63 (19)	H12A—C12—H12B	111 (2)
C3—C2—C5	119.7 (2)	C11—C12—H12C	110.2 (17)
C2—C3—C4	119.9 (2)	H12A—C12—H12C	109 (2)
C2—C3—H3	122.2 (15)	H12B—C12—H12C	108 (2)
C4—C3—H3	117.9 (15)	N1—C13—C14	112.2 (2)
C7—C4—C3	120.9 (2)	N1—C13—H13A	104.7 (13)
C7—C4—H4	120.0 (13)	C14—C13—H13A	112.1 (13)
C3—C4—H4	119.1 (13)	N1—C13—H13B	108.5 (12)
C6—C5—C2	120.3 (2)	C14—C13—H13B	110.8 (12)
C6—C5—H5	120.4 (12)	H13A—C13—H13B	108.2 (17)
C2—C5—H5	119.3 (12)	C13—C14—H14A	111 (2)
C5—C6—C7	120.7 (2)	C13—C14—H14B	110.7 (19)
C5—C6—H6	118.4 (14)	H14A—C14—H14B	109 (3)
C7—C6—H6	120.8 (14)	C13—C14—H14C	113.6 (17)
C4—C7—C6	118.55 (19)	H14A—C14—H14C	106 (3)
C4—C7—C8	120.69 (18)	H14B—C14—H14C	106 (3)
C6—C7—C8	120.64 (19)

O3—S1—N2—C9	116.10 (15)	N2—S1—C8—C10	−116.78 (16)
O2—S1—N2—C9	−107.28 (15)	O3—S1—C8—C7	−1.80 (19)
C8—S1—N2—C9	4.46 (13)	O2—S1—C8—C7	−139.02 (15)
C1—O1—C2—C3	−5.7 (3)	N2—S1—C8—C7	110.27 (16)
C1—O1—C2—C5	174.0 (2)	O3—S1—C8—C9	−116.00 (13)
O1—C2—C3—C4	178.3 (2)	O2—S1—C8—C9	106.78 (13)
C5—C2—C3—C4	−1.5 (3)	N2—S1—C8—C9	−3.94 (12)
C2—C3—C4—C7	−0.1 (3)	C13—N1—C9—N2	−171.6 (2)
O1—C2—C5—C6	−177.87 (19)	C11—N1—C9—N2	5.4 (3)
C3—C2—C5—C6	1.9 (3)	C13—N1—C9—C8	11.5 (3)
C2—C5—C6—C7	−0.8 (3)	C11—N1—C9—C8	−171.5 (2)
C3—C4—C7—C6	1.2 (3)	S1—N2—C9—N1	176.98 (19)
C3—C4—C7—C8	−174.95 (19)	S1—N2—C9—C8	−5.62 (17)
C5—C6—C7—C4	−0.7 (3)	C10—C8—C9—N1	−66.9 (3)
C5—C6—C7—C8	175.38 (19)	C7—C8—C9—N1	70.2 (3)
C4—C7—C8—C10	−28.1 (3)	S1—C8—C9—N1	−177.6 (2)
C6—C7—C8—C10	155.89 (18)	C10—C8—C9—N2	115.7 (2)
C4—C7—C8—C9	−165.80 (18)	C7—C8—C9—N2	−107.2 (2)
C6—C7—C8—C9	18.2 (3)	S1—C8—C9—N2	5.00 (15)
C4—C7—C8—S1	104.7 (2)	C9—N1—C11—C12	85.4 (3)
C6—C7—C8—S1	−71.3 (2)	C13—N1—C11—C12	−97.4 (3)
O3—S1—C8—C10	131.15 (16)	C9—N1—C13—C14	96.4 (3)
O2—S1—C8—C10	−6.06 (19)	C11—N1—C13—C14	−80.6 (3)

Experimental details

Crystal data
Chemical formula	C₁₄H₁₇N₃O₃S
M_r	307.37
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	293
a, b, c (Å)	8.3853 (17), 17.554 (4), 10.458 (2)
β (°)	95.07 (3)
V (Å³)	1533.4 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.22
Crystal size (mm)	0.18 × 0.16 × 0.16

Data collection
Diffractometer	Bruker APEX CCD area-detector
Absorption correction	Multi-scan (SADABS; Bruker, 2007)
T_min, T_max	0.855, 0.947
No. of measured, independent and observed [I > 2σ(I)] reflections	16661, 2814, 1949
R_int	0.043
(sin θ/λ)_max (Å⁻¹)	0.603

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.037, 0.102, 1.01
No. of reflections	2814
No. of parameters	258
H-atom treatment	All H-atom parameters refined
Δρ_max, Δρ_min (e Å⁻³)	0.16, −0.31

Computer programs: SMART (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2010).

Selected bond lengths (Å) top

S1—N2	1.642 (2)	N1—C9	1.307 (3)
S1—C8	1.878 (2)	N2—C9	1.331 (3)

Acknowledgements

Thanks are due to Professor Riccardo Destro (Università degli Studi di Milano) for thoughtful discussions and to Professor Francesca Clerici (Università degli Studi di Milano) for providing the crystal. Dr Laura Loconte (Università degli Studi di Milano) and Mr Pietro Colombo (Consiglio Nazionale delle Ricerche) are also to be thanked for technical assistance. Financial support by the Italian MIUR (fondi PUR 2008) is also gratefully appreciated.

References

Barwick, M., Abu-Izneid, T. & Novak, I. (2008). J. Phys. Chem. 112, 10993–10997. CrossRef CAS Google Scholar
Brandenburg, K. (2010). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2005). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2007). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Clerici, F., Galletti, F., Pocar, D. & Roversi, P. (1996). Tetrahedron, 52, 7183–7199. CSD CrossRef CAS Web of Science Google Scholar
Clerici, F., Gelmi, M. L., Soave, R. & Lo Presti, L. (2002). Tetrahedron, 58, 5173–5178. Web of Science CSD CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar

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