Open AccessRelation between photochromic properties and molecular structures in salicylideneaniline crystals
Author(s) -
Johmoto Kohei,
Ishida Takashi,
Sekine Akiko,
Uekusa Hidehiro,
Ohashi Yuji
Publication year - 2012
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
eISSN - 1600-5740
pISSN - 0108-7681
DOI - 10.1107/s0108768112010993
Subject(s) - photochromism , dihedral angle , aniline , chemistry , steric effects , benzene , crystallography , schiff base , photochemistry , stereochemistry , hydrogen bond , molecule , organic chemistry
The crystal structures of the salicylideneaniline derivatives N ‐salicylidene‐4‐ tert ‐butyl‐aniline (1), N ‐3,5‐di‐ tert ‐butyl‐salicylidene‐3‐methoxyaniline (2), N ‐3,5‐di‐ tert ‐butyl‐salicylidene‐3‐bromoaniline (3), N ‐3,5‐di‐ tert ‐butyl‐salicylidene‐3‐chloroaniline (4), N ‐3,5‐di‐ tert ‐butyl‐salicylidene‐4‐bromoaniline (5), N ‐3,5‐di‐ tert ‐butyl‐salicylidene‐aniline (6), N ‐3,5‐di‐ tert ‐butyl‐salicylidene‐4‐carboxyaniline (7) and N ‐salicylidene‐2‐chloroaniline (8) were analyzed by X‐ray diffraction analysis at ambient temperature to investigate the relationship between their photochromic properties and molecular structures. A clear correlation between photochromism and the dihedral angle of the two benzene rings in the salicylideneaniline derivatives was observed. Crystals with dihedral angles less than 20° were non‐photochromic, whereas those with dihedral angles greater than 30° were photochromic. Crystals with dihedral angles between 20 and 30° could be either photochromic or non‐photochromic. Inhibition of the pedal motion by intra‐ or intermolecular steric hindrance, however, can result in non‐photochromic behaviour even if the dihedral angle is larger than 30°.