N-(2-{[7-(2-Anilinoethoxy)-3,6-dibromonaphthalen-2-yl]oxy}ethyl)aniline

In the title compound, C26H24Br2N2O2, the central naphthalene system carries two Br atoms and two –CH2CH2NHC6H5 substituents. The phenyl rings of the latter residues are inclined at 74.17 (17) and 51.4 (2)° with respect to the naphthalene ring system. Each alkyl chain adopts a fully extended all-cis conformation with respect to the naphthalene and phenyl rings [N—C—C—O torsion angles = 68.6 (4) and 60.5 (4)°]. In the crystal, one of the N—H groups forms bifurcated N—H⋯(Br,O) hydrogen bonds, which link the molecules into inversion-related dimers. The centrosymmetric dimers are aggregated via pairs of C—H⋯π interactions into sheets parallel to (110).


Qian-Shou Zong and Jian-Yi Wu Comment
Open-chain crown ethers are flexible ligands which offer many advantages in extraction and analysis (ion-selective electrodes) of the rare earth ions (Zhang et al., 2002;Qin et al., 2003;Chandan, Ved, Kumar, 2008;Liou et al., 2011). With suitable substitution at the terminal groups, these molecules can recognize anions or cations and may can also form stable complexes with them (Chandan, Ved, Niraj et al., 2008). In particular, the open-chain crown ethers containing amide groups possess suitable molecular structure for this chemistry: a chain with inflexible terminal groups. Therefore, they are excellent reagents for activating ion-selective electrodes and for extraction of rare earth ions (Tan et al., 1986). In the present work, we designed and synthesized a new and doubly functionalised open-chain crown ether ligand with terminal phenylamine groups, and its crystal structure was determined by X-ray diffraction methods.
As shown in Fig. 1, the naphthalene ring of the molecule contains two -CH 2 CH 2 NHC 6 H 5 residues and two bromo atoms. The N2-containing -CH 2 CH 2 NHC 6 H 5 residue is nearly planar with a maximum deviation of 0.065 (9) Å [for atom C23] from the mean plane of its constituent atoms. However, the other residue [having the N1 atom] is less planar with a maximum deviation of 0.18 (6) Å for the C26 atom. The naphthalene ring system (C7-C16) is oriented with respect to the phenyl rings of the N1-and N2-residues at 74.17 (17) Table 1). These centrosymmetric dimers are further aggregated via pairs of C-H···π interactions into twodimensional sheets parallel to (1 1 0) (Fig. 3).

Experimental
To a 50 mL two-necked round-bottom flask equipped with a magnetic stirring bar, a thermometer and a dropping funnel was added 3,6-dibromo-2,7-di((N-phenylacetamide)oxy)naphthalene (1.20 g, 2 mmol), sodium borohydride (0.8 g, 22 mmol) and anhydrous tetrahydrofuran (20 mL). The mixture was cooled to 273 K and boron trifluoride etherate (48 %, 4 mL) was added drop-wise via a dropping funnel, while maintaining the temperature at 273 K. After complete addition, the reaction mixture was stirred for one additional hour at 273 K to allow completion of the reaction and then was quenched by drop-wise addition of aqueous NaOH (1 M, 10 mL) while keeping the temperature below 278 K. The tetrahydrofuran was removed under under reduced pressure and the remains were extracted with CH 2 Cl 2 (3×15 mL). The organic layers were combined and washed with water (10 mL) and then dried over anhydrous Na 2 SO 4 . The solvent was evaporated under reduced pressure to give the title compound as a white solid (1.10 g, 98% yield). Single crystals suitable for X-ray diffraction were obtained by recrystallizing the crude product from its chloroform solution and slow

Refinement
All H atoms were placed in idealized positions (C-H = 0.93-0.97 Å and N-H = 0.86 Å) and refined as riding atoms with U iso (H) = 1.2U eq (C or N).

Figure 1
The molecular structure of the title compound, with displacement ellipsoids at the 30% probability level.   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.48 e Å −3 Δρ min = −0.60 e Å −3 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.