Triethylammonium (S)-(−)-O-[1-(2-naphthyl)ethyl] (4-methoxyphenyl)dithiophosphonate

The crystal structure of the title compound, C6H16N+·C19H18O2PS2 −, consists of the dithiophosphonate anions and the triethylammonium cations, which are linked by N—H⋯S hydrogen bonds and weak C—H⋯O hydrogen bonds. In the anion, the benzene ring is oriented with respect to the naphthalene ring system at a dihedral angle of 24.92 (5)°. In the crystal, weak C—H⋯π interactions also occur.

The crystal structure of the title compound, C 6 H 16 N + Á-C 19 H 18 O 2 PS 2 À , consists of the dithiophosphonate anions and the triethylammonium cations, which are linked by N-HÁ Á ÁS hydrogen bonds and weak C-HÁ Á ÁO hydrogen bonds. In the anion, the benzene ring is oriented with respect to the naphthalene ring system at a dihedral angle of 24.92 (5) . In the crystal, weak C-HÁ Á Á interactions also occur.

Related literature
For dithiophosphorus compounds and their complexes, see: Heiduc et al. (2006); Karakuş et al. (2007); Gataulina et al. (2008). For the roles of dithiophosphorus compounds in agricultural, industrial and medicinal products such as additives to lubricant oils, solvent extraction reagents for metals, floatation agents for minerals, pesticides and insecticides, see: Thomas et al. (2001); Gray et al. (2003). For the synthetic routes reported for dithiophosphorus-type ligands, see: Alberti et al. (2007). For the preparation of ferrocenyl and aryldithiophosphonates and their complexes with a range of transition metals, see: Gray et al. (2004). For bond-length data, see: Allen et al. (1987 Table 1 Hydrogen-bond geometry (Å , ).

D-HÁ
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009 (Heiduc et al., 2006;Karakuş et al., 2007;Gataulina et al., 2008). They have been utilized in agricultural, industrial and medicinal products such as additive to lubricant oils, solvent extraction reagents for metals, floatation agents for minerals, pectidites and insecticides (Thomas et al., 2001;Gray et al., 2003). For example, tin diphenyldithiophosphinato complexes show an antiproliferation activity towards certain leukaemia cells (Gray et al., 2003). In general, dithiophosphorus type ligands are not commercially available, but a few synthetic routes were reported in the literature (Alberti et al., 2007). When compared to the other dithiophosphorus derivatives, there is very limited research on dithiophosphonates in the last century, due to the difficulties in sythesizing these compounds. Recently, ferrocenyl and aryldithiophosphonates and their complexes with a range of transition metals were prepared by Woolins et al. (Gray et al., 2003;Gray et al., 2004). The present study was undertaken to ascertain the crystal structure of the title compound to contribute to this relatively less developed area.
The title compound consists of a dithiophosphonate bridged napthylethyl and methoxyphenyl groups and a triethylammonium moiety linked by a C-H···O hydrogen bond (Table 1 and Fig. 1), where the bond lengths are close to standard values (Allen et al., 1987).
An examination of the deviations from the least-squares planes through individual rings shows that rings A (C1-C6), B (C10-C13/C18/C19) and C (C13-C18) are planar. The naphthalene group, containing the rings B and C are also nearly planar [with a maximum deviation of -0.022 (2) Å for atom C13] with a dihedral angle of B/C = 1.67 (7)°. Ring A is oriented with respect to the planar naphthalene group at a dihedral angle of 24.92 (5)°.
In the crystal, C-H···O and N-H···S hydrogen bonds link the molecules into chains along [100] (Table 1 and Fig. 2).

Refinement
H1 atom is located in a difference Fourier synthesis and refined isotropically. The C-bound H-atoms were positioned geometrically with C-H = 0.93, 0.98, 0.97 and 0.96 Å, for aromatic, methine, methylene and methyl H-atoms, respectively, supplementary materials sup-2 and constrained to ride on their parent atoms, with U iso (H) = k × U eq (C), where k = 1.5 for methyl H-atoms and k = 1.2 for all other H-atoms. Fig. 1. The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. C-H···O hydrogen bond is shown as dashed line.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
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 > 2sigma(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.