1,3-Bis[(4-methylbenzylidene)aminooxy]propane

The title bisoxime compound, C19H22N2O2, synthesized by the reaction of 4-methyl-2-hydroxybenzaldehyde with 1,3-bis(aminooxy)propane in ethanol, adopts a V-shaped conformation. The dihedral angle between the rings is 84.59 (3)°. The molecule is disposed about a crystallographic twofold rotation axis, with one C atom lying on the axis. In the crystal, molecules are packed by C—H⋯π(Ph) interactions, forming chains.

The title bisoxime compound, C 19 H 22 N 2 O 2 , synthesized by the reaction of 4-methyl-2-hydroxybenzaldehyde with 1,3-bis-(aminooxy)propane in ethanol, adopts a V-shaped conformation. The dihedral angle between the rings is 84.59 (3) . The molecule is disposed about a crystallographic twofold rotation axis, with one C atom lying on the axis. In the crystal, molecules are packed by C-HÁ Á Á(Ph) interactions, forming chains.

Experimental
Cg1 is the centroid of the C4-C9 ring.

Comment
Much interest has been focused on bisoxime compounds, in which the large electronegativity of O atoms is expected to affect strongly the electronic properties of the nitrogen atoms, and exhibit high stability against imine metathesis reactions (Akine et al., 2005). Some of them or their metal complexes are used in wide field due to their variety of applications, especially for catalysis and biological processes, magnetism, and supramolecular architectures (Atwood et al., 2001;Yeap et al., 2008;Dong et al., 2008). Herein, the synthesis and structure of 4,4'-dimethyl-1,3-[propenedioxybis(nitrilomethylidyne)]dibenzene (I) is reported (Fig. 1).
The single-crystal structure of (I) is built up by discrete C 19 H 22 N 2 O 2 molecules, in which all bond lengths are in normal ranges. The title compound adopts a V-shaped configuration with the dihedral angle between the two halves of the molecule is 85.82 (3)°. The molecules are disposed about a crystallographic two-fold rotation axis. This structure is similar to that observed in our previously reported salen-type bisoxime compounds . The packing of the molecule is controlled by C-H···π(Ph) interactions linking molecules into infinite supramolecular structure along b axis.
Colorless needle-like single crystals suitable for X-ray diffraction studies were obtained after about four weeks by slow evaporation from an acetonitrile solution of (I).

Refinement
Non-H atoms were refined anisotropically. H atoms were treated as riding atoms with distances C-H = 0.96 Å (CH 3 ), 0.97 Å (CH 2 ),0.93 Å (CH) and U iso (H) = 1.2 U eq (C). Fig. 1 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 Rfactors(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.