Photoreversible solid state negative photochromism of N-(3,5-dichlorosalicylidene)-1-aminopyrene†
Abstract
N-(3,5-Dichlorosalicylidene)-1-aminopyrene (1) exhibits photoreversible negative photochromism. This colour change arises from the trans-keto to cis-keto interconversion upon irradiation at λ = 546 nm. The photogenerated cis-keto form of 1 is highly stable under ambient conditions and shows very negligible and slow thermal relaxation; it is photoreversible upon irradiation at λ = 450 nm.