New Conjugated Bis(AZO) Mesogens with “Push-PULL” Substituents
摘要:
Two series of conjugated bis( azo) compounds with "push'' ( alkoxy, acyloxy) and "pull'' ( nitro) substituents at the end positions were synthesized and their thermal behavior investigated. Smectic A and nematic mesophases were observed over long temperature intervals. Surprisingly, photoirradiation of these compounds does not give detectable amounts of the expected photoisomerized isomers.