N,N′-Bis(diphenylmethyl)benzene-1,4-diamine

The complete molecule of the title compound, C32H28N2, is generated by crystallographic inversion symmetry. The dihedral angles between the central aromatic ring and the pendant adjacent rings are 61.37 (16) and 74.20 (14)°. The N—H group does not participate in hydrogen bonds and there are no aromatic π–π stacking interactions in the crystal.

The complete molecule of the title compound, C 32 H 28 N 2 , is generated by crystallographic inversion symmetry. The dihedral angles between the central aromatic ring and the pendant adjacent rings are 61.37 (16) and 74.20 (14) . The N-H group does not participate in hydrogen bonds and there are no aromaticstacking interactions in the crystal.

Related literature
The reduction of the Schiff-base was as described in Higuchi et al. (2003) and Higuchi et al. (2000). For the use of dendrimers in the formation of new types of organic-metallic hybrid materials, see: Kim et al. (2005); for drug generation, see: Basavaraj et al. (2009). For related structures, see: Ge & Ng (2006); Yang et al. (2007); Xia et al. (2007). Data were collected and processed according to Coles & Gale (2012

Comment
Bis-amine compounds are essential building blocks to produce branched or dendritic polymers. Dendrimers are an interesting class of materials which are based on bis-aromatic imine and amine precursors. These polymeric materials have attracted increasing attention due to their functional coordination groups, which can trap many metal ions or metal clusters within the voids in the dendrimers. This can lead to the formation of new types of organic-metallic hybrid nanomaterials (Kim et al., 2005). Furthermore, the polyvalent nature of dendrimers is a key factor in generating a new class of drugs with much improved and acceptable pharmacokinetic profiles (Basavaraj et al., 2009). This paper reports on a new addition to the bis-amine compounds and its chemical and physical features.
The compound, with a molar mass of 440.56 g mol -1 , crystallizes in a monoclinic crystal structure with a space group notation of P2 1 /n and had a calculated density of 1.250 g cm -3 . The asymmetric unit consists of half the molecule, the molecule is completed by inversion symmetry. Infrared spectra indicates typical absorbance bands of the functional phenyl group and amine -C=N group at 1570 and 1620 cm -1 , respectively. The positive ES mass spectrum of the bisamine showed a parent ion peak at m/z = 441.2362 (M+H)+, corresponding to C 32 H 28 N 2 , for which the required value = 440.2252.
The precipitate was removed by filtration, and then the filtrate was concentrated. The Schiff-base product (yield: 1.83 g, 91%) was isolated by silica gel uniplate chromatography with an eluent mixture of hexane:ethylacetate; 9:1, Rf = 0.25.

Refinement
Data were collected and processed according to Coles & Gale (2012). Hydrogen atoms were placed in geometrically calculated positions and included as part of a riding model with U iso values set at 1.2 times U eq of the parent atom.

Figure 1
The structure of the title compound displacement ellipsoids drawn at the 50% probability level. Symmetry code: (i) 1 -x, 1 -y, -z. 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. 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq N1 0.44891 (