INTRAMOLECULAR HYDROGEN-BONDS AND HYDROGEN-BONDED SYSTEMS IN DI-SCHIFF BASES OF 4-METHYL-ISOPHTHALALDEHYDE WITH 4-SUBSTITUTED ANILINES

Three di-Schiff bases of 2-hydroxy-5-methyl-isophthalaldehyde with 4-R -anilines (R=H, CH3, OCH3) and their 1:1 complexes with HClO4 were stu died by FT-IR, H-1, and C-13 NMR spectroscopy in acetonitrile and [H-2 (3)]acetonitrile solutions, respectively, In di-Schiff bases intramole cular OH ... N hydrogen bonds have been detected; however, they show n o proton polarizability. Hydrogen-bonded systems with fast proton fluc tuation and large proton polarizability have been found in the 1:1 com plexes of di-Schiff bases with HClO4. (C) 1998 Elsevier Science B.V.