4-Phenethoxyaniline hemihydrate

The crystal structure of the title compound, C14H15NO·0.5H2O, features N—H⋯O and O—H⋯N hydrogen bonds between the amino group and water molecule of crystallization, which generate a chain along the c axis. The water molecule lies on a twofold rotation axis. A C—H⋯π interaction is observed between the phenyl and aniline rings. The angle between the mean planes of the phenyl rings is 72.51 (7)°.

The crystal structure of the title compound, C 14 H 15 NOÁ-0.5H 2 O, features N-HÁ Á ÁO and O-HÁ Á ÁN hydrogen bonds between the amino group and water molecule of crystallization, which generate a chain along the c axis. The water molecule lies on a twofold rotation axis. A C-HÁ Á Á interaction is observed between the phenyl and aniline rings. The angle between the mean planes of the phenyl rings is 72.51 (7) .

Related literature
For a similar hydrogen-bonding pattern in a related structure see Haider et al. (2011). The title compound is a precursor of diamine monomers, which are widely used for synthesis of polyimides (PIs), see: Ragosta et al. (2011). For the solubility of PIs, see: Chang et al. (2010). Reduced solubility is associated with intermolecular hydrogen-bonding chains and stiffness, see: Hsiao & Leu (2004); Liaw et al. (2005). Incorporation of bulky pendant groups such as substituted phenyl groups into a rigid PI backbone can enhance the solubility of PIs, see : Liaw et al. (2005) Table 1 Hydrogen-bond geometry (Å , ).

4-Phenethoxyaniline hemihydrate Toheed Akhter, Humaira Masood Siddiqi, Zareen Akhter and Vickie McKee Comment
The title compound is a precursor of diamine monomers which are widely used for synthesis of polyimides (PIs) (Ragosta et al., 2011). Solubility of PIs is considered as one of the key property when they are used for their specific application (Chang et al., 2010). Reduced solubility is associated with intermolecular hydrogen bonding chain and stiffness (Hsiao andLeu, 2004, Liaw et al., 2005). Incorporation of bulky pendant groups such as substituted phenyl groups into rigid PI backbone can enhance the solubility of PIs (Liaw et al., 2005, Li et al., 2007. Synthesis of the title compound is aimed for introducing pendant substituted phenyl group into PI backbone and thereby improving their solubility. Within the 1-amino-4-phenethoxybenzene molecule the two phenyl rings are tilted with respect to one another; the angle between the mean planes of the phenyl groups is 72.51 (7)° (Fig 1). The crystal structure is governed by hydrogen bonds between water molecule and the -NH 2 group (Table 1, Fig. 2) generating hydrogen bonded chains running parallel to the c axis (Fig. 2). There is also a C-H···π interaction (Fig 3).
Afterward solution of 1-fluoro-4-nitrobenzene in DMF was added drop wise and the reaction mixture was refluxed for 24 h at 393 K. After complete consumption of reactants, light yellow colour product was precipitated by pouring the reaction mixture into distilled water (500 mL). The crude product, after filtration and washing thoroughly with distilled water, was recrystallised from possible minimum volume of absolute ethanol. Yield was 81%.

Refinement
H atoms bonded to C atoms were inserted at calculated positions with C-H distances of 0.95 and 0.99 Å for aromatic and methylene C atoms, respectively. They were refined using a riding model with U iso (H) = 1.2U eq (C). H atoms bonded to O and N were located from difference maps and their coordinated refinded under geometric restraints, with U iso (H) = 1.5U eq (N or O).

Computing details
Data collection: APEX2 (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).    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 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. Freidel equivalents merged since the data do not permit determination of absolute configuration.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (