Crystal structure of N,N′-dibenzyl-3,3′-di­meth­oxy­benzidine

The title compound, (systematic name: N,N′-dibenzyl-3,3′-dimeth­oxy-1,1′-biphenyl-4,4′-di­amine), C(28)H(28)N(2)O(2), was synthesized by the reduction of a Schiff base prepared via a condensation reaction between o-dianisidine and benzaldehyde under acidic conditions. The mol­ecule lies on a crystallographic inversion centre so that the asymmetric unit contains one half-mol­ecule. The biphenyl moiety compound is essentially planar. Two intra­molecular N—H⋯O hydrogen bonds occur. The dihedral angle between the terminal phenyl and phenyl­ene rings of a benzidine unit is 48.68 (6)°. The methyl­ene C atom of the benzyl group is disordered over two sets of sites, with occupancy ratio 0.779 (18):0.221 (18). In the crystal, mol­ecules are connected by hydrogen bonding between o-dianisidine O atoms and H atoms of the terminal benzyl groups, forming a one-dimensional ladder-like structure. In the data from DFT calculations, the central biphenyl showed a twisted conformation.