5,5′-Dimethoxy-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethylidyne)]diphenol

The asymmetric unit of the title Schiff base compound, C21H26N2O4, consists of four crystallographically independent molecules, viz. A, B, C and D. The A and D, and the B and C molecules are related by a pseudo-inversion centre, and the remaining pairs of molecules differ in the orientations of one of the methoxy groups. In each independent molecule, intramolecular O-H center dot center dot center dot N hydrogen bonds generate two S(6) ring motifs. The dihedral angles between the benzene rings in molecules A, B, C and D are 65.86 (19), 50.41 (19), 68.59 (19) and 50.85 (19)degrees, respectively. In the crystal structure, molecules are linked by C-H center dot center dot center dot O hydrogen bonds, forming R-2(2)(8) dimers. In addition, weak C-H center dot center dot center dot pi interactions are observed.