2,4-Diethyl­thioxanthen-9-one

Ge Liu

doi:10.1107/S1600536809006308

. 2009 Feb 28;65(Pt 3):o613. doi: 10.1107/S1600536809006308

2,4-Diethylthioxanthen-9-one

Ge Liu ^a,^*

PMCID: PMC2968468 PMID: 21582265

Abstract

The asymmetric unit of the title compound, C₁₇H₁₆OS, contains two crystallographically independent molecules, one of which is nearly planar, the outer rings making dihedral angles of 1.51 (3) and 1.09 (3)° with the central ring. In the crystal structure, weak intermolecular C—H⋯O hydrogen bonds link molecules into chains parallel to the a axis. π–π Contacts between the thioxanthone rings [centroid–centroid distances = 3.798 (3) and 3.781 (3) Å] may further stabilize the structure.

Related literature

For general background, see: Fouassier et al. (1995 ▶); Roffey (1997 ▶). For a related structure, see: Bearson et al. (1996 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₇H₁₆OS
M _r = 268.37
Triclinic,
a = 9.5403 (19) Å
b = 11.083 (2) Å
c = 13.807 (3) Å
α = 77.19 (3)°
β = 87.72 (3)°
γ = 79.35 (3)°
V = 1399.0 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.22 mm⁻¹
T = 294 K
0.15 × 0.12 × 0.10 mm

Data collection

Rigaku R-AXIS RAPID-S diffractometer
Absorption correction: none
12071 measured reflections
4920 independent reflections
3346 reflections with I > 2σ(I)
R _int = 0.041

Refinement

R[F ² > 2σ(F ²)] = 0.064
wR(F ²) = 0.138
S = 1.07
4920 reflections
344 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 1998 ▶); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809006308/hk2627sup1.cif

e-65-0o613-sup1.cif^{(25.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809006308/hk2627Isup2.hkl

e-65-0o613-Isup2.hkl^{(241KB, hkl)}

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
C14—H14A⋯O2ⁱ	0.93	2.54	3.334 (3)	143
C32—H32A⋯O1ⁱⁱ	0.93	2.61	3.466 (3)	154

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

Acknowledgments

The author thanks Chifeng University for supporting this work.

supplementary crystallographic information

Comment

Thioxanthone derivatives are good photoinitiators with excellent capabilities in UV-curing materials. They have been widely used in UV-curing applications because they absorb at a longer UV wavelength and have a faster photocuring speed than other photoinitiators. They have been introduced in processes such as printing inks, surface coatings, microelectronics and photoresists (Fouassier et al., 1995; Roffey, 1997). We report herein the crystal structure of the title compound.

The asymmetric unit of the title compound contains two crystallographically independent molecules (Fig. 1), in which the bond lengths (Allen et al., 1987) and angles are generally within normal ranges. Rings A (S1/C1-C5), B (C4-C9), C (C2/C3/C14-C17) and D (S2/C18-C22), E (C19/C20/C23-C26), F (C21/C22/C31-C34) are, of course, planar, and they are oriented at dihedral angles of A/B = 1.51 (3), A/C = 1.09 (3), B/C = 2.54 (3) ° and D/E = 2.95 (3), D/F = 2.85 (3), E/F = 5.75 (3) °. So, rings A, B and C are nearly coplanar.

In the crystal structure, weak intermolecular C-H···O hydrogen bonds (Table 1) link the molecules into chains parallel to the a-axis (Fig. 2), in which they may be effective in the stabilization of the structure. The π-π contacts between the thioxanthone rings, Cg1—Cg2ⁱ and Cg4—Cg4ⁱⁱ [symmetry codes: (i) -x, -y, 2 - z; (ii) 1 - x, 1 - y, 1 - z, where Cg1, Cg2 and Cg4 are centroids of the rings A (S1/C1-C5), B (C4-C9) and D (S2/C18-C22), respectively] may further stabilize the structure, with centroid-centroid distances of 3.798 (3) and 3.781 (3) Å, respectively.

Experimental

The title compound was prepared by the literature method (Bearson et al., 1996). Crystals suitable for X-ray analysis were obtained by dissolving the title compound (80.5 mg, 0.3 mmol) in ethanol (10 ml) and evaporating ethanol slowly at room temperature for about 10 d.