Strengthening of the intramolecular O⋯H⋯N hydrogen bonds in Schiff bases as a result of steric repulsion

Three ortho hydroxy Schiff bases 2-(N-methyl-α-iminoethyl)-phenol (I), 2-(N-benzyl-α-iminoethyl)-phenol (II) and 2-(N-benzyl-α-iminopropyl)-phenol (III) were synthesised in which the hydrogen atoms in C–C(H)N group were replaced by an alkyl substituent. The crystal structures were determined and ab...

Full description

Saved in:
Bibliographic Details
Published in:Journal of molecular structure 1999-06, Vol.484 (1-3), p.75-89
Main Authors: Filarowski, Aleksander, Głowiaka, Tadeusz, Koll, Aleksander
Format: Article
Language:English
Subjects:
Ab initio
Crystal structure
Hydrogen bonds
Schiff bases
Steric repulsion
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Three ortho hydroxy Schiff bases 2-(N-methyl-α-iminoethyl)-phenol (I), 2-(N-benzyl-α-iminoethyl)-phenol (II) and 2-(N-benzyl-α-iminopropyl)-phenol (III) were synthesised in which the hydrogen atoms in C–C(H)N group were replaced by an alkyl substituent. The crystal structures were determined and ab initio calculations at the B3LYP/6-31G** basis set were performed. One of the shortest known O–H⋯N hydrogen bonds were found with O⋯N distance equal to 2.459(3), 2.497(3) and 2.494(3) Å, respectively in I, II and III. Steric repulsion of substituted alkyl results in this unusual strengthening of the hydrogen bonds. FT-IR spectra in solution and in the solid state in function of the temperature were determined. Strong influence of the temperature on the character of the hydrogen bond was observed.
ISSN:0022-2860
1872-8014
DOI:10.1016/S0022-2860(98)00660-7