5-(Trifluoro­meth­oxy)isatin

M Schutte; C Pretorius; HG Visser; A Roodt

doi:10.1107/S1600536812044297

. 2012 Nov 28;68(Pt 12):o3472. doi: 10.1107/S1600536812044297

5-(Trifluoromethoxy)isatin

M Schutte ^a,^*, C Pretorius ^a, HG Visser ^a, A Roodt ^a

PMCID: PMC3589045 PMID: 23476281

Abstract

The title compound [systematic name: 5-(trifluoromethoxy)-1H-indole-2,3-dione], C₉H₄F₃NO₃, crystallized with two molecules in the asymmetric unit. Intermolecular N—H⋯O hydrogen bonds link the molecules to form layers parallel to the ab plane. In addition, π–π stacking interactions are observed with a centroid–centroid distance of 3.721 (1) Å. The near planarity of the two isatin ring systems is illustrated by by the maximum deviations of 0.023 (1) and 0.025 (1) Å for the N atom in each case.

Related literature

For similar structures and background information on isatin as a biological agent, see Schutte et al. (2012 ▶); Garden et al. (2006 ▶); Goldschmidt & Llewellyn (1950 ▶); Frolova et al. (1988 ▶); Wei et al. (2004 ▶); Palmer et al. (1987 ▶); Akkurt et al. (2006 ▶). For reaction kinetic data on similar structures, see: Schutte et al. (2011 ▶). graphic file with name e-68-o3472-scheme1.jpg

Experimental

Crystal data

C₉H₄F₃NO₃
M _r = 231.13
Monoclinic,
a = 14.329 (5) Å
b = 6.082 (5) Å
c = 20.401 (5) Å
β = 91.608 (5)°
V = 1777.2 (16) Å³
Z = 8
Mo Kα radiation
μ = 0.17 mm⁻¹
T = 100 K
0.51 × 0.18 × 0.10 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.152, T _max = 0.394
26198 measured reflections
4428 independent reflections
3513 reflections with I > 2σ(I)
R _int = 0.029

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.102
S = 1.04
4418 reflections
297 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.33 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT-Plus (Bruker, 2008 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Click here for additional data file.^{(23.1KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812044297/fy2072sup1.cif

e-68-o3472-sup1.cif^{(23.1KB, cif)}

Click here for additional data file.^{(212.1KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812044297/fy2072Isup2.hkl

e-68-o3472-Isup2.hkl^{(212.1KB, hkl)}

Click here for additional data file.^{(3.7KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536812044297/fy2072Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O4ⁱ	0.84 (2)	1.99 (2)	2.7615 (18)	152.8 (18)
N2—H2⋯O1ⁱⁱ	0.89 (2)	2.03 (2)	2.8776 (18)	157.4 (19)
N2—H2⋯O4ⁱⁱⁱ	0.89 (2)	2.55 (2)	2.9850 (18)	111.2 (16)
C16—H16⋯F3ⁱ	0.93	2.39	3.171 (2)	142
C18—H18⋯O2^iv	0.93	2.47	3.327 (3)	153

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

The University of the Free State, the Chemistry Department, the NRF and SASOL Ltd are acknowledged for funding.

supplementary crystallographic information

Comment

5-(Trifluoromethoxy)isatin crystallized in the P2₁/n spacegroup and with two independent molecules in the asymmetric unit. The use of 5-(trifluormethoxy)isatin forms part of a current study, where water soluble O,O'-donor bidentate ligands are coordinated to the rhenium tricarbonyl core in order to study the reactivity and activation of these potential radiopharmaceutical compounds. Previous studies have shown that the O,O'-bidenate ligands activate the Re(I) core to a great extent and we would like to explore this further (Schutte et al. (2011). The isatin molecule also has a variety of biological activities. It can act as an anticonvulsant agent, it has sedative effects but can also cause anxiety. Palmer et al., 1987; Goldschmidt & Llewellyn, 1950; Wei et al., 2004; Frolova et al., 1988; Akkurt et al., 2006). Due to its diverse pharmacological properties, a lot of interest has been shown in the isatin molecule and its derivatives. All bond lengths and angles compare well to the structure of N-benzylisatin reported by Schutte et al. (2012). Five intermolecular hydrogen interactions are observed in the structure (C—H···O, N—H···O and C—H···F) as well as π-π stacking with a centroid to centroid distance of 3.721 (1) Å. The molecules pack in a head to head fashion in alternating layers with the benzyl ring overlapping with the next molecules' pyrrolidinedione ring and vice versa. The π-π stacking and the packing in the unit cell are illustrated in Figure 2. The planarity of the ring systems, N1—C11—C12—C13—C14—C15—C16—C17—C18 and N2—C21—C22—C23—C24—C25—C26—C27—C28, are illustrated by very small deviations of all the atoms from these planes, with the largest deviations 0.023 (1) Å for N1 and 0.025 (1) for N2 respectively.

Experimental

5-(Trifluoromethoxy)isatin was dissolved in water (pH 4). The crystls were grown from a vapour diffusion setup with chloroform at 5 °C in a commercial refrigerator.