1,8-Bis(4-fluorobenzoyl)naphthalen-2,7-diyl dimethanesulfonate

The molecule of the title compound, C26H18F2O8S2, lies across a crystallographic twofold rotation axis. The benzene rings of the 4-fluorobenzoyl groups make dihedral angles of 78.93 (12)° with the naphthalene ring system. An intramolecular C—H⋯π interaction occurs. In the crystal, a number of C—H⋯O interactions link the molecules, forming a three-dimensional structure.

The molecule of the title compound, C 26 H 18 F 2 O 8 S 2 , lies across a crystallographic twofold rotation axis. The benzene rings of the 4-fluorobenzoyl groups make dihedral angles of 78.93 (12) with the naphthalene ring system. An intramolecular C-HÁ Á Á interaction occurs. In the crystal, a number of C-HÁ Á ÁO interactions link the molecules, forming a three-dimensional structure. 173 parameters H-atom parameters constrained Á max = 0.29 e Å À3 Á min = À0.33 e Å À3 Table 1 Hydrogen-bond geometry (Å , ).

Related literature
Cg is the centroid of the C8-C13 ring. Symmetry codes: (i) Àx; y; Àz þ 1 2 ; (ii) Àx; Ày þ 2; Àz þ 1; (iii) Àx þ 1; Ày þ 2; Àz þ 1; (iv) Àx þ 1 2 ; y þ 1 2 ; Àz þ 1 2 . In the course of our study on electrophilic aromatic aroylation of 2,7-dimethoxynaphthalene, peri-aroylnaphthalene compounds have proven to be formed regioselectively with the aid of suitable acidic mediators (Okamoto & Yonezawa, 2009;Okamoto et al., 2011). Under these circumstances, the authors have stimulated the X-ray crystal structural study of Accordingly, to the best of our knowledge, these molecules have essentially the same non-coplanar features, namely: The aroyl groups at the 1,8-positions of the naphthalene ring are bonded in an almost perpendicular fashion and oriented in opposite directions (anti-orientation), but the benzene ring moieties of the aroyl groups tilt slightly toward the exo sides of the naphthalene ring. Recently, the authors have described the crystal structures of 1,8-diaroylated 2,7-dimethoxynaphthalene analogues, in which the two aroyl groups are situated in the same direction (syn-orientation), that is, 2,7- The authors then investigated the correlation between the aroyl groups and the neighbouring groups in the spatial organization of 1,8-diaroylnaphthalenes. In the crystal structure of 1,8-bis(4-fluorobenzoyl)-2,7-diphenoxynaphthalene [(4-fluorophenyl)[8-(4-fluorobenzoyl)-2,7-diphenoxynaphthalen-1-yl]methanone; Hijikata et al., 2012], two phenoxy groups are asymmetrically situated with respect to the adjacent aroyl groups. One phenoxy group is horizontal to the aroyl group, whereas another phenoxy group leans toward the naphthalene ring. As a part of our continuous study on the molecular structures of this kind of homologous molecules, the crystal structure of title compound is presented herein.
The molecule of the title compound lies across a crystallographic 2-fold axis, Fig. 1, so that the asymmetric unit contains one-half of the molecule. Thus, the two aroyl groups are situated in an anti orientation and twisted away from the naphthalene ring. The benzene ring of the aroyl group make a dihedral angle of 78.93 (12) ° with the naphthalene ring. The dihedral angle between the benzene rings of the aroyl groups is 21.55 (15) °. There are two intramolecular C-H···π interactions in the molecule involving one methyl H atom (H14A) of the methanesulfonyl group and the phenyl ring of the 4-fluorobenzoyl group ( Fig. 1 and Table 1).
In the crystal, the ketonic carbonyl oxygen atom (O1) and the sulfonyl oxygen atom (O4) are involved in C-H···O interactions ( Fig. 2 and Table 1). These interactions contribute to the stabilization of the packing and lead to the formation a three-dimensional structure ( Fig. 2  Experimental 1,8-bis(4-fluorobenzoyl)-2,7-dihydroxynaphthalene (1.0 mmol, 404 mg), methanesulfonyl chloride (2.4 mmol, 487 mg), pyridine (10.0 mmol, 791 mg), and methylene chloride (2.5 ml) were placed in a 10 ml flask. The mixture was stirred at room temperature for 24 h. After the reaction, the mixture was extracted with CHCl 3 . The combined extracts were washed with 2 M aqueous HCl followed by washing with brine. The organic layers thus obtained were dried over anhydrous MgSO 4 . The solvent was removed under reduced pressure to give cake. The crude product was purified by recrystallization from AcOEt-hexane (v/v= 2:1) [55% isolated yield; M.p. 507.4 K], giving colourless block-like crystals.
Spectroscopic data for the title compound are available in the archived CIF.

Refinement
All H atoms were placed in calculated positions and treated as riding on their parent atoms: C-H = 0.95 (aromatic C-H), 0.98 (methyl) and U iso (H) = 1.2U eq (aromatic C, methyl C). The positions of methyl H atoms were rotationally optimized.  The molecular structure of title molecule, with atom labelling. showing The displacement ellipsoids are drawn at the 50% probability level. The intramolecular C-H···π interactions are shown as a dashed lines (see Table 1 for details; symmetry code: (i) -x+1, y, -z+1/2).  A partial crystal packing diagram of title compound. The C-H···O interactions are shown as dashed lines (see Table 1 for details). Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.