4-(4-Methoxyphenyl)naphtho[2,3-b]thiophene

In the title compound, C19H14OS, the naphthothiophene moiety is almost planar except for the S atom of the five-membered ring, which is situated 0.047 (6) Å out of the C4 plane (with an r.m.s. deviation of fitted atoms = 0.0009 Å). The dihedral angle between the naphthothiophene plane and the attached methoxyphenyl ring is 67.6 (2)°. In the crystal, a C—H⋯π interaction is observed between a methoxyphenyl C—H group and the outer benzene ring of the naphthothiophene moiety. The five-membered ring of the naphthothiophene moiety is disordered, with the S and opposite non-fused C atom approximately exchanging positions, with a site-occupancy factors of 0.808 (3) and 0.187 (3).

In the title compound, C 19 H 14 OS, the naphthothiophene moiety is almost planar except for the S atom of the fivemembered ring, which is situated 0.047 (6) Å out of the C 4 plane (with an r.m.s. deviation of fitted atoms = 0.0009 Å ). The dihedral angle between the naphthothiophene plane and the attached methoxyphenyl ring is 67.6 (2) . In the crystal, a C-HÁ Á Á interaction is observed between a methoxyphenyl C-H group and the outer benzene ring of the naphthothiophene moiety. The five-membered ring of the naphthothiophene moiety is disordered, with the S and opposite non-fused C atom approximately exchanging positions, with a site-occupancy factors of 0.808 (3) and 0.187 (3).
Cg is the centroid of the of C5-C10 ring.
Data collection: APEX2 (Bruker, 2004); cell refinement: APEX2 and SAINT (Bruker, 2004); data reduction: SAINT and XPREP (Bruker, 2004); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97.   1 shows the ORTEP representation of the molecular structure of the title compound with atoms at the 40% probability level. The five membered ring of the naphtho-thiophene moiety is disordered with sulfur (S1) and carbon (C2) approximately exchanging positions. The two portions of the moiety were assigned variable occupancy factors during refinement with sum of their occupancies restrained as 1 resulting in a refined s.o.f. ratio of 81% and 19%. In the naphtho thiophene moiety, S1 of the five membered ring in the major component is observed 0.047 (6) Å out of the (C1-C4) plane (0.058 (7) Å for the minor component). The latter atoms show a r.m.s. deviation of 0.0009 Å or 0.009 Å for the major and minor component, respectively. The dihedral angle between the mean plane of the naphtho-thiophene moiety and the methoxy-phenyl ring is 67.6 (2)°. Fig. 2 shows the packing of molecules in the unit cell. There is a C-H···π interaction between H17 (symmcode: 1.5 − x, −0.5 + y, 1.5 − z) and the phenyl ring (C5-C10). The distance between the H atom and centroid of the phenyl ring is 2.822 Å. Except for this C-H···π interaction, the packing is featureless.

Refinement
As S1 and C2 are disordered, refinement is carried out with a second component for the thiophene ring with atoms C2′, C1′, S1′ located near S1, C1 and C2, respectively. Disordered pairs of the same sites were restrained to have same thermal parameter. The distance C3-S1′ was restrained to be 1.70 Å. Similarily, distances C1-C2′ and C2′-C12 were restrained to be around 1.4 Å and 1.52 Å during the refinement. The two components were assigned variable occupancy factors during refinement with the sum of their occupancies restrained as 1 resulting in a refined s.o.f. ratio of 81% and 19%. H atoms were constrained as riding atoms with d(C-H) = 0.93 Å and U iso (H) = 1.2U eq (C) for aromatic CH groups and 0.96 Å and U iso (H) = 1.5U eq (C) for the methyl group.

Figure 1
ORTEP plot of the title compound with thermal ellipsoids drawn at the 40% probability level.

Figure 2
Molecular packing diagram. C-H···π interactions are shown as dotted lines. 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (