Crystal structure of (E)-1-{2-[(5,5-dimethyl-1,3,2-dioxaphosphinan-2-yl)oxy]naphthalen-1-yl}-N-(4-fluorophenyl)methanimine

In the title compound, the six-membered ring which includes the P atom has a chair conformation and three O atoms are bonded in a trigonal–pyramidal manner to the P atom. In the crystal, molecules are linked via C—H⋯π interactions, forming slabs lying parallel to (10).

In the title compound, C 22 H 21 FNO 3 P, a 1,3,2-dioxaphosphinan-2-yloxy derivative, three O atoms are bonded in a trigonal-pyramidal manner to the P atom. The exocyclic P-O bond is significantly longer than the two endocyclic P-O bonds, viz. 1.6678 (12) Å compared to 1.6046 (13) and 1.6096 (12) Å . The sixmembered ring which includes the P atom has a chair conformation. The fluorophenyl ring is inclined to the naphthalene ring system by 24.42 (7) . In the crystal, molecules are linked via C-HÁ Á Á interactions, forming slabs lying parallel to (101).

Chemical context
Many phosphorus and/or nitrogen based ligands bind strongly to transition metals and they offer a wide range of properties and basicities due to the large variety of accessible substituents (Crabtree, 2005;Joslin et al., 2012;Kuehl, 2005;Tolman, 1977). The title compound is an example of a phosphorusnitrogen bidentate ligand. Complexation experiments with such ligands could result in the isolation of mono-or binuclear complexes (van den Beuken et al., 1997). Examples of bidentate ligands with phosphorus and nitrogen donor groups bonded to transition metals have been shown to be effective cross-coupling catalysts (Hayashi & Kumada, 1985). The present work is a continuation of the investigation into the synthesis and study of more bi-and tri-cyclic, penta-and hexa-coordinated phosphoranes to form anionic, neutral and zwitterionic compounds (Said et al. 1996;Timosheva et al. 2006;Kumara Swamy & Kumar, 2006).

Structural commentary
The molecular structure of the title compound, Fig. 1 (13) and 1.6096 (12) Å ]. The sixmembered ring which includes the phosphorus atom has a chair conformation. The fluorophenyl ring is inclined to the naphthalene ring system by 24.42 (7) . The molecule has an E conformation about the C N bond (Fig. 1).

Figure 1
The molecular structure of the title compound, showing the atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
A view along the b axis of the crystal packing of the title compound showing the HÁ Á ÁC contacts (dashed lines) of the C-HÁ Á Á weak interactions (see Table 1 for details).
naphthalene-2-ol in 10 ml of dry dichloromethane. The mixture was refluxed under a slow flow of nitrogen for 4 h. The solvent was reduced to 5 ml under vacuum and 3 ml of dry n-hexane were added to afford the title compound as a paleyellow crystalline solid (yield 2.07 g, 86%; m.p. 401-405 K

(I)
Crystal data

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Reflections were merged by SHELXL according to the crystal class for the calculation of statistics and refinement. _reflns_Friedel_fraction is defined as the number of unique Friedel pairs measured divided by the number that would be possible theoretically, ignoring centric projections and systematic absences.