2-(Mesitylmethylsulfanyl)pyridine N-oxide–18-crown-6 (2/1)

In the title compound, 2C15H17NOS·C12H24O6, the asymmetric unit consists of one N-oxide derivative and one-half of the 18-crown-6 ether, which lies on an inversion centre. In the crown ether, the O—C—C—O torsion angles indicate a gauche conformation of the ethyleneoxy units, while the C—O—C—C torsion angles indicate planarity of these segments. In the N-oxide unit, the dihedral angle between the pyridine and benzene rings is 85.88 (12)°. The crystal packing is stabilized by weak C—H⋯O hydrogen bonds and C—H⋯π interactions.

In the title compound, 2C 15 H 17 NOSÁC 12 H 24 O 6 , the asymmetric unit consists of one N-oxide derivative and one-half of the 18-crown-6 ether, which lies on an inversion centre. In the crown ether, the O-C-C-O torsion angles indicate a gauche conformation of the ethyleneoxy units, while the C-O-C-C torsion angles indicate planarity of these segments. In the N-oxide unit, the dihedral angle between the pyridine and benzene rings is 85.88 (12) . The crystal packing is stabilized by weak C-HÁ Á ÁO hydrogen bonds and C-HÁ Á Á interactions.
BRDN thanks the University Grants Commission, India, for a Teacher Fellowship.   (Lobana & Bhatia, 1989;Symons et al.,1985). These compounds are also found to be involved in DNA strand scission under physiological conditions (Katsuyuki et al., 1991;Bovin et al.1992). Pyridine N-oxides bearing a sulfur group in position 2 display significant antimicrobial activity (Leonard et al.,1955). In view of the importance of N-oxides, we have previously reported the crystal structures of N-oxide derivatives (Jebas et al., 2005;Ravindran Durai Nayagam et al., 2008). As an extension of our work on these derivatives, we report here the crystal structure of the title compound ( Fig. 1).
The asymmetric unit of the title compound consists of one mono(1-oxopyridine 2-sulfanylmethyl)mesitylene molecule and one-half of a 18-crown 6-ether molecule, the other half being inversion related. The bond lengths and angles of the N-oxide moiety agree well with those observed in other N-oxide derivatives reported earlier (Jebas et al., 2005;Ravindran et al., 2008). The N-O bond length is in good agreement with the mean value of 1.304 (15) Å reported in the literature for pyridine N-oxides (Allen et al.,1987).
The oxopyridinium and benzene rings are planar to within ±0.006 (2) Å and ±0.012 (2) Å, respectively, and they form a dihedral angle of 85.88 (12)°, indicating that both the rings are perpendicular to each other. Atom O7 deviates from the plane of the pyridinium ring by 0.006 (2) Å.
The compound formed was filtered off and dried. The compound was recrystallized from a chloroform-methanol (1: Refinement H atoms were positioned geometrically [C-H = 0.93 (aromatic), 0.96 Å (methyl) and 0.97 Å (methylene)] and refined using a riding model, with U iso (H) = 1.2-1.5U eq (C). Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering scheme. Atoms labelled with the suffix A are generated by the symmetry operation (-x, 1-y, 1-z).