1-Tetra­decyl­indoline-2,3-dione

Mamari, K.; Zouihri, H.; Essassi, E.M.; Ng, S.W.

doi:10.1107/S1600536810018258

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 66| Part 6| June 2010| Page o1410

https://doi.org/10.1107/S1600536810018258

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1-Tetradecylindoline-2,3-dione

Khalil Mamari,^a Hafid Zouihri,^b El Mokhtar Essassi ^a and Seik Weng Ng ^c ^*

^aLaboratoire de Chimie Organique Hétérocyclique, Pôle de Compétences Pharmacochimie, Université Mohammed V-Agdal, BP 1014 Avenue Ibn Batout, Rabat, Morocco, ^bCNRST Division UATRS, Angle Allal Fassi/FAR, BP 8027 Hay Riad, Rabat, Morocco, and ^cDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: seikweng@um.edu.my

(Received 15 May 2010; accepted 17 May 2010; online 22 May 2010)

In the title N-alkyl isatin, C₂₂H₃₃NO₂, the isatin moiety is planar (r.m.s. deviation = 0.03 Å). The tetradecyl substituent has all torsion angles in an antiperiplanar conformation.

Related literature

For background to N-substituted isatins and their derivatives, see: Bouhfid et al. (2008 ). For the crystal structures of two N-alkyl isatins, see: Miehe et al. (2003 ); Naumov et al. (2002 ).

Experimental

Crystal data

C₂₂H₃₃NO₂
M_r = 343.49
Monoclinic, P 2₁ /c
a = 27.6647 (8) Å
b = 4.7055 (1) Å
c = 15.7583 (5) Å
β = 103.635 (1)°
V = 1993.54 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 200 K
0.18 × 0.16 × 0.11 mm

Data collection

Bruker X8 APEXII diffractometer
23477 measured reflections
5172 independent reflections
3532 reflections with I > 2σ(I)
R_int = 0.042

Refinement

R[F² > 2σ(F²)] = 0.065
wR(F²) = 0.222
S = 1.11
5172 reflections
226 parameters
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810018258/bt5273sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810018258/bt5273Isup2.hkl

checkCIF report

Comment top

N-Substituted isatins (Bouhfid et al., 2008) represent a large family of heterocyclic compounds reported to show a wide range of useful medicinal activities. These are readily synthesized by the reaction of isatin and an alkyl halide in the presence of a catalyst. The title tetradecyl derivative (Scheme I, Fig. 1) has a particarly long hydrocarbon chain; the chain adopts a extended zigzag conformation.

The crystal structures of only few N-substituted isatins have been reported; these have only short hydrocarbon chains, e.g., methyl isatin (Miehe et al., 2003) and ethyl isatin (Naumov et al., 2002).

Related literature top

For background to N-substituted isatins and their derivatives, see: Bouhfid et al. (2008). For the crystal structures of two N-alkyl isatins, see: Miehe et al. (2003); Naumov et al. (2002).

Experimental top

To a solution of isatin (1 g, 6.8 mmol) dissolved in DMF(50 ml) was added 1-bromotetradecane (1.87 g, 6.8 mmol), potassium carbonate (1 g, 7.4 mmol) and a catalytic quantity of tetra-n-butylammonium bromide.The mixture was stirred for 48 h; the reaction was monitored by thin layer chromatography. The mixture was filtered and the solvent removed under vacuum. The solid that was obtained was recrystallized from ethanol to afford the title compound as orange crystals in 80% yield.

Structure description top

For background to N-substituted isatins and their derivatives, see: Bouhfid et al. (2008). For the crystal structures of two N-alkyl isatins, see: Miehe et al. (2003); Naumov et al. (2002).

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

Fig. 1. Anisotropic displacement ellipsoid plot (Barbour, 2001) of the title compound at the 70% probability level; hydrogen atoms are drawn as spheres of arbitrary radius.

1-Tetradecylindoline-2,3-dione top

Crystal data top

C₂₂H₃₃NO₂	F(000) = 752
M_r = 343.49	D_x = 1.144 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4926 reflections
a = 27.6647 (8) Å	θ = 2.6–28.7°
b = 4.7055 (1) Å	µ = 0.07 mm⁻¹
c = 15.7583 (5) Å	T = 200 K
β = 103.635 (1)°	Irregular block, orange
V = 1993.54 (10) Å³	0.18 × 0.16 × 0.11 mm
Z = 4

Data collection top

Bruker X8 APEXII diffractometer	3532 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.042
Graphite monochromator	θ_max = 28.8°, θ_min = 2.3°
φ and ω scans	h = −37→37
23477 measured reflections	k = −6→5
5172 independent reflections	l = −21→21

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)] = 0.065	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.222	H-atom parameters constrained
S = 1.11	w = 1/[σ²(F_o²) + (0.098P)² + 1.1616P] where P = (F_o² + 2F_c²)/3
5172 reflections	(Δ/σ)_max = 0.001
226 parameters	Δρ_max = 0.27 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₂₂H₃₃NO₂	V = 1993.54 (10) Å³
M_r = 343.49	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 27.6647 (8) Å	µ = 0.07 mm⁻¹
b = 4.7055 (1) Å	T = 200 K
c = 15.7583 (5) Å	0.18 × 0.16 × 0.11 mm
β = 103.635 (1)°

Data collection top

Bruker X8 APEXII diffractometer	3532 reflections with I > 2σ(I)
23477 measured reflections	R_int = 0.042
5172 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.065	0 restraints
wR(F²) = 0.222	H-atom parameters constrained
S = 1.11	Δρ_max = 0.27 e Å⁻³
5172 reflections	Δρ_min = −0.21 e Å⁻³
226 parameters

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

	x	y	z	U_iso*/U_eq
O1	0.46046 (6)	1.1884 (4)	0.43051 (11)	0.0487 (5)
O2	0.38053 (7)	0.7712 (5)	0.36601 (11)	0.0524 (5)
N1	0.37452 (6)	0.7894 (4)	0.50944 (11)	0.0309 (4)
C1	0.39707 (7)	0.9506 (4)	0.58407 (12)	0.0263 (4)
C2	0.38674 (7)	0.9454 (5)	0.66525 (13)	0.0312 (4)
H2	0.3623	0.8214	0.6780	0.037*
C3	0.41379 (8)	1.1306 (5)	0.72815 (14)	0.0352 (5)
H3	0.4073	1.1327	0.7847	0.042*
C4	0.44969 (8)	1.3112 (5)	0.71059 (15)	0.0376 (5)
H4	0.4672	1.4355	0.7548	0.045*
C5	0.46031 (7)	1.3115 (5)	0.62847 (14)	0.0339 (5)
H5	0.4852	1.4326	0.6160	0.041*
C6	0.43356 (7)	1.1305 (4)	0.56570 (12)	0.0282 (4)
C7	0.43501 (7)	1.0834 (5)	0.47474 (13)	0.0339 (5)
C8	0.39388 (8)	0.8608 (5)	0.43985 (14)	0.0352 (5)
C9	0.33228 (7)	0.5996 (5)	0.50282 (16)	0.0354 (5)
H9A	0.3371	0.4853	0.5569	0.042*
H9B	0.3306	0.4673	0.4534	0.042*
C10	0.28326 (7)	0.7629 (5)	0.48906 (15)	0.0342 (5)
H10A	0.2832	0.8755	0.5421	0.041*
H10B	0.2808	0.8974	0.4399	0.041*
C11	0.23799 (7)	0.5690 (5)	0.46968 (15)	0.0341 (5)
H11A	0.2405	0.4329	0.5185	0.041*
H11B	0.2377	0.4583	0.4161	0.041*
C12	0.18917 (7)	0.7341 (5)	0.45715 (15)	0.0346 (5)
H12A	0.1886	0.8336	0.5123	0.042*
H12B	0.1880	0.8803	0.4115	0.042*
C13	0.14296 (7)	0.5478 (5)	0.43108 (15)	0.0347 (5)
H13A	0.1440	0.4011	0.4765	0.042*
H13B	0.1433	0.4492	0.3757	0.042*
C14	0.09459 (7)	0.7159 (5)	0.41929 (15)	0.0359 (5)
H14A	0.0941	0.8117	0.4750	0.043*
H14B	0.0939	0.8651	0.3748	0.043*
C15	0.04810 (7)	0.5345 (5)	0.39165 (15)	0.0364 (5)
H15A	0.0487	0.3850	0.4361	0.044*
H15B	0.0485	0.4391	0.3358	0.044*
C16	0.00019 (7)	0.7038 (5)	0.38033 (15)	0.0373 (5)
H16A	−0.0003	0.8538	0.3361	0.045*
H16B	−0.0001	0.7987	0.4363	0.045*
C17	−0.04666 (7)	0.5241 (5)	0.35234 (15)	0.0376 (5)
H17A	−0.0463	0.3745	0.3967	0.045*
H17B	−0.0463	0.4288	0.2965	0.045*
C18	−0.09460 (7)	0.6944 (5)	0.34082 (16)	0.0377 (5)
H18A	−0.0948	0.7913	0.3965	0.045*
H18B	−0.0951	0.8430	0.2961	0.045*
C19	−0.14159 (7)	0.5157 (6)	0.31364 (16)	0.0386 (5)
H19A	−0.1415	0.4188	0.2579	0.046*
H19B	−0.1411	0.3672	0.3583	0.046*
C20	−0.18930 (8)	0.6862 (6)	0.30219 (16)	0.0390 (5)
H20A	−0.1894	0.7831	0.3579	0.047*
H20B	−0.1897	0.8348	0.2575	0.047*
C21	−0.23622 (8)	0.5095 (6)	0.27508 (17)	0.0447 (6)
H21A	−0.2358	0.3606	0.3196	0.054*
H21B	−0.2363	0.4133	0.2192	0.054*
C22	−0.28379 (8)	0.6818 (7)	0.2641 (2)	0.0543 (7)
H22A	−0.3126	0.5554	0.2469	0.081*
H22B	−0.2850	0.8263	0.2188	0.081*
H22C	−0.2844	0.7747	0.3195	0.081*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0391 (9)	0.0730 (13)	0.0381 (9)	0.0013 (9)	0.0171 (7)	0.0179 (9)
O2	0.0500 (10)	0.0715 (13)	0.0335 (9)	0.0075 (10)	0.0056 (7)	−0.0139 (8)
N1	0.0226 (8)	0.0361 (10)	0.0329 (9)	−0.0005 (7)	0.0045 (7)	−0.0041 (7)
C1	0.0209 (8)	0.0309 (10)	0.0261 (9)	0.0024 (8)	0.0035 (7)	0.0019 (8)
C2	0.0268 (9)	0.0377 (11)	0.0301 (10)	−0.0018 (9)	0.0087 (8)	0.0045 (8)
C3	0.0351 (11)	0.0438 (13)	0.0269 (10)	0.0039 (10)	0.0078 (8)	0.0003 (9)
C4	0.0347 (11)	0.0366 (12)	0.0382 (11)	−0.0014 (10)	0.0023 (9)	−0.0041 (9)
C5	0.0246 (9)	0.0355 (11)	0.0398 (11)	−0.0036 (9)	0.0041 (8)	0.0047 (9)
C6	0.0222 (9)	0.0337 (11)	0.0287 (9)	0.0030 (8)	0.0060 (7)	0.0067 (8)
C7	0.0256 (9)	0.0451 (13)	0.0314 (10)	0.0094 (9)	0.0073 (8)	0.0121 (9)
C8	0.0297 (10)	0.0450 (13)	0.0301 (10)	0.0104 (10)	0.0055 (8)	−0.0007 (9)
C9	0.0223 (9)	0.0332 (11)	0.0478 (12)	−0.0004 (9)	0.0026 (8)	−0.0053 (9)
C10	0.0227 (9)	0.0297 (11)	0.0475 (12)	−0.0006 (8)	0.0030 (9)	−0.0047 (9)
C11	0.0208 (9)	0.0342 (11)	0.0450 (12)	0.0001 (8)	0.0032 (8)	−0.0041 (9)
C12	0.0217 (9)	0.0344 (11)	0.0457 (12)	0.0001 (8)	0.0036 (8)	−0.0026 (9)
C13	0.0208 (9)	0.0390 (12)	0.0423 (11)	−0.0007 (9)	0.0035 (8)	−0.0028 (9)
C14	0.0218 (9)	0.0404 (12)	0.0443 (12)	0.0005 (9)	0.0056 (8)	−0.0012 (10)
C15	0.0220 (9)	0.0432 (13)	0.0425 (12)	−0.0004 (9)	0.0044 (9)	−0.0026 (10)
C16	0.0225 (9)	0.0424 (13)	0.0456 (12)	0.0003 (9)	0.0055 (9)	−0.0017 (10)
C17	0.0225 (9)	0.0447 (13)	0.0439 (12)	−0.0001 (9)	0.0042 (9)	−0.0038 (10)
C18	0.0211 (9)	0.0437 (13)	0.0460 (12)	0.0001 (9)	0.0032 (9)	−0.0012 (10)
C19	0.0228 (9)	0.0474 (14)	0.0442 (12)	0.0003 (9)	0.0050 (9)	−0.0048 (10)
C20	0.0237 (10)	0.0454 (13)	0.0458 (12)	0.0004 (10)	0.0042 (9)	−0.0012 (10)
C21	0.0277 (11)	0.0535 (15)	0.0508 (14)	−0.0028 (11)	0.0052 (10)	−0.0085 (12)
C22	0.0246 (11)	0.0702 (19)	0.0649 (17)	−0.0010 (12)	0.0045 (11)	−0.0017 (15)

Geometric parameters (Å, º) top

O1—C7	1.207 (2)	C13—H13A	0.9900
O2—C8	1.211 (3)	C13—H13B	0.9900
N1—C8	1.371 (3)	C14—C15	1.519 (3)
N1—C1	1.415 (3)	C14—H14A	0.9900
N1—C9	1.455 (3)	C14—H14B	0.9900
C1—C2	1.375 (3)	C15—C16	1.520 (3)
C1—C6	1.399 (3)	C15—H15A	0.9900
C2—C3	1.397 (3)	C15—H15B	0.9900
C2—H2	0.9500	C16—C17	1.523 (3)
C3—C4	1.384 (3)	C16—H16A	0.9900
C3—H3	0.9500	C16—H16B	0.9900
C4—C5	1.393 (3)	C17—C18	1.523 (3)
C4—H4	0.9500	C17—H17A	0.9900
C5—C6	1.381 (3)	C17—H17B	0.9900
C5—H5	0.9500	C18—C19	1.522 (3)
C6—C7	1.460 (3)	C18—H18A	0.9900
C7—C8	1.549 (3)	C18—H18B	0.9900
C9—C10	1.529 (3)	C19—C20	1.519 (3)
C9—H9A	0.9900	C19—H19A	0.9900
C9—H9B	0.9900	C19—H19B	0.9900
C10—C11	1.521 (3)	C20—C21	1.516 (3)
C10—H10A	0.9900	C20—H20A	0.9900
C10—H10B	0.9900	C20—H20B	0.9900
C11—C12	1.530 (3)	C21—C22	1.520 (3)
C11—H11A	0.9900	C21—H21A	0.9900
C11—H11B	0.9900	C21—H21B	0.9900
C12—C13	1.524 (3)	C22—H22A	0.9800
C12—H12A	0.9900	C22—H22B	0.9800
C12—H12B	0.9900	C22—H22C	0.9800
C13—C14	1.527 (3)

C8—N1—C1	110.78 (17)	H13A—C13—H13B	107.8
C8—N1—C9	123.48 (18)	C15—C14—C13	113.71 (19)
C1—N1—C9	125.31 (17)	C15—C14—H14A	108.8
C2—C1—C6	121.43 (19)	C13—C14—H14A	108.8
C2—C1—N1	128.04 (18)	C15—C14—H14B	108.8
C6—C1—N1	110.53 (16)	C13—C14—H14B	108.8
C1—C2—C3	117.06 (19)	H14A—C14—H14B	107.7
C1—C2—H2	121.5	C14—C15—C16	113.3 (2)
C3—C2—H2	121.5	C14—C15—H15A	108.9
C4—C3—C2	122.05 (19)	C16—C15—H15A	108.9
C4—C3—H3	119.0	C14—C15—H15B	108.9
C2—C3—H3	119.0	C16—C15—H15B	108.9
C3—C4—C5	120.3 (2)	H15A—C15—H15B	107.7
C3—C4—H4	119.8	C15—C16—C17	113.7 (2)
C5—C4—H4	119.8	C15—C16—H16A	108.8
C6—C5—C4	118.04 (19)	C17—C16—H16A	108.8
C6—C5—H5	121.0	C15—C16—H16B	108.8
C4—C5—H5	121.0	C17—C16—H16B	108.8
C5—C6—C1	121.07 (18)	H16A—C16—H16B	107.7
C5—C6—C7	131.52 (19)	C16—C17—C18	113.6 (2)
C1—C6—C7	107.41 (18)	C16—C17—H17A	108.8
O1—C7—C6	131.3 (2)	C18—C17—H17A	108.8
O1—C7—C8	123.5 (2)	C16—C17—H17B	108.8
C6—C7—C8	105.27 (16)	C18—C17—H17B	108.8
O2—C8—N1	126.5 (2)	H17A—C17—H17B	107.7
O2—C8—C7	127.5 (2)	C19—C18—C17	113.9 (2)
N1—C8—C7	105.93 (17)	C19—C18—H18A	108.8
N1—C9—C10	111.84 (18)	C17—C18—H18A	108.8
N1—C9—H9A	109.2	C19—C18—H18B	108.8
C10—C9—H9A	109.2	C17—C18—H18B	108.8
N1—C9—H9B	109.2	H18A—C18—H18B	107.7
C10—C9—H9B	109.2	C20—C19—C18	113.7 (2)
H9A—C9—H9B	107.9	C20—C19—H19A	108.8
C11—C10—C9	112.80 (18)	C18—C19—H19A	108.8
C11—C10—H10A	109.0	C20—C19—H19B	108.8
C9—C10—H10A	109.0	C18—C19—H19B	108.8
C11—C10—H10B	109.0	H19A—C19—H19B	107.7
C9—C10—H10B	109.0	C21—C20—C19	114.0 (2)
H10A—C10—H10B	107.8	C21—C20—H20A	108.8
C10—C11—C12	112.39 (18)	C19—C20—H20A	108.8
C10—C11—H11A	109.1	C21—C20—H20B	108.8
C12—C11—H11A	109.1	C19—C20—H20B	108.8
C10—C11—H11B	109.1	H20A—C20—H20B	107.7
C12—C11—H11B	109.1	C20—C21—C22	113.6 (2)
H11A—C11—H11B	107.9	C20—C21—H21A	108.8
C13—C12—C11	113.66 (19)	C22—C21—H21A	108.8
C13—C12—H12A	108.8	C20—C21—H21B	108.8
C11—C12—H12A	108.8	C22—C21—H21B	108.8
C13—C12—H12B	108.8	H21A—C21—H21B	107.7
C11—C12—H12B	108.8	C21—C22—H22A	109.5
H12A—C12—H12B	107.7	C21—C22—H22B	109.5
C12—C13—C14	112.95 (19)	H22A—C22—H22B	109.5
C12—C13—H13A	109.0	C21—C22—H22C	109.5
C14—C13—H13A	109.0	H22A—C22—H22C	109.5
C12—C13—H13B	109.0	H22B—C22—H22C	109.5
C14—C13—H13B	109.0

C8—N1—C1—C2	178.1 (2)	C1—N1—C8—C7	2.6 (2)
C9—N1—C1—C2	5.4 (3)	C9—N1—C8—C7	175.52 (18)
C8—N1—C1—C6	−1.6 (2)	O1—C7—C8—O2	−2.9 (4)
C9—N1—C1—C6	−174.36 (18)	C6—C7—C8—O2	175.9 (2)
C6—C1—C2—C3	0.9 (3)	O1—C7—C8—N1	178.6 (2)
N1—C1—C2—C3	−178.8 (2)	C6—C7—C8—N1	−2.7 (2)
C1—C2—C3—C4	−0.4 (3)	C8—N1—C9—C10	−94.4 (2)
C2—C3—C4—C5	−0.5 (3)	C1—N1—C9—C10	77.5 (3)
C3—C4—C5—C6	0.9 (3)	N1—C9—C10—C11	172.23 (18)
C4—C5—C6—C1	−0.4 (3)	C9—C10—C11—C12	179.29 (19)
C4—C5—C6—C7	178.9 (2)	C10—C11—C12—C13	175.77 (19)
C2—C1—C6—C5	−0.5 (3)	C11—C12—C13—C14	179.72 (19)
N1—C1—C6—C5	179.22 (19)	C12—C13—C14—C15	178.93 (19)
C2—C1—C6—C7	−179.99 (19)	C13—C14—C15—C16	179.85 (19)
N1—C1—C6—C7	−0.3 (2)	C14—C15—C16—C17	179.82 (19)
C5—C6—C7—O1	1.0 (4)	C15—C16—C17—C18	−179.84 (19)
C1—C6—C7—O1	−179.6 (2)	C16—C17—C18—C19	−179.47 (19)
C5—C6—C7—C8	−177.6 (2)	C17—C18—C19—C20	−179.98 (19)
C1—C6—C7—C8	1.8 (2)	C18—C19—C20—C21	180.0 (2)
C1—N1—C8—O2	−176.0 (2)	C19—C20—C21—C22	179.8 (2)
C9—N1—C8—O2	−3.1 (3)

Experimental details

Crystal data
Chemical formula	C₂₂H₃₃NO₂
M_r	343.49
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	200
a, b, c (Å)	27.6647 (8), 4.7055 (1), 15.7583 (5)
β (°)	103.635 (1)
V (Å³)	1993.54 (10)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.07
Crystal size (mm)	0.18 × 0.16 × 0.11

Data collection
Diffractometer	Bruker X8 APEXII diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	23477, 5172, 3532
R_int	0.042
(sin θ/λ)_max (Å⁻¹)	0.677

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.065, 0.222, 1.11
No. of reflections	5172
No. of parameters	226
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.27, −0.21

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2010).

Acknowledgements

We thank Université Mohammed V-Agdal and the University of Malaya for supporting this study.

References

Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191. CrossRef CAS Google Scholar
Bouhfid, R., Joly, N., Ohmani, F., Essassi, E. M., Massoui, M. & Martin, P. (2008). Lett. Org. Chem. pp. 3–7. Google Scholar
Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Miehe, G., Süsse, P., Kupcik, V., Egert, E., Nieger, M., Kunz, G., Gerke, R., Knieriem, B., Niemeyer, M. & Lüttke, W. (2003). Angew. Chem. Int. Ed. Engl. 30, 964–967. CSD CrossRef Web of Science Google Scholar
Naumov, P., Anastasova, F., Drew, M. G. B. & Ng, S. W. (2002). Bull. Chem. Technol. Macedon. 21, 165–169. CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43. Submitted. Google Scholar