Crystal structure of 2-{(R)-[1-(4-bromo­phen­yl)eth­yl]imino­meth­yl}-4-(phenyl­diazen­yl)phenol, a chiral photochromic Schiff base

The title chiral photochromic Schiff base compound, C(21)H(18)BrN(3)O, was synthesized from (R)-(+)-1-(4-bromo­phen­yl)ethyl­amine and the salicyl­aldehyde of an azo­benzene derivative. The mol­ecule corresponds to the phenol–imine tautomer, the C=N and N—C bond distances being 1.285 (3) and 1.470 (3) Å, respectively. The diazenyl group adopts a trans form, with an N=N distance of 1.256 (3) Å. The hy­droxy group is involved in intra­molecular O—H⋯N hydrogen bonding. In the crystal, C—H⋯π inter­actions consolidate the crystal packing of one-dimensional chains, which exhibits short inter­molecular Br⋯C contacts of 3.400 (3) Å.