Bis[4-(salicylideneamino)phenyl]methane.

The crystal structure of the title Schiff base {systematic name: 2,2'-[methylenedi-p-phenylenebis(nitrilomethylidyne)]diphenol}, C27H22N2O2, consists of intramolecularly hydrogen-bonded molecules interlinked by C-H...O hydrogen bonds [C...O = 3.426 (2) A and C-H...O = 152.7 (17) degrees ]. The molecule is in the enol form and is located on a twofold axis. The central methane C atom of the diphenylmethane motif is displaced from the aromatic ring planes. This effect is compared with previous results, which display an inverse correlation between the out-of-plane displacement and the C-C-C angle around the central methane C atom. In the title compound, the displacement is 0.124 (2) A and the C-C-C angle is 110.18 (19) degrees.