Hydrogen bonded Schiff bases; di-anil of 2-hydroxy-5-methyl-isophthaldehyde

Structural and spectroscopic properties of solid dianil of 2-hydroxy-5-meth yl-isophthaldehyde have been investigated. This is a Schiff base containing intramolecular O-H ... N hydrogen bonding. Single crystal X-ray diffractio n shows that the possibly equivalent hard structural parameters (bond lengt hs and the valence angles) of the title molecule are hardly differentiated by an asymmetric hydrogen bonding and different conformations of the anil w ings. C-13 MAS NMR results are more sensitive and they clearly show the inf luence of [O-H ... N] hydrogen bonding on the chemical shifts of the centra l ring carbon atoms. (C) 1999 Elsevier Science B.V. All rights reserved.