Characterization of Molecular Arrangement of Long‐chain Ferrocenyl Derivatives Having Asymmetric Carbon by Method of Organized Molecular Films and Formation of Its Helical Nanofibers

Abstract

AbstractFormation of organized molecular film and helical nanofibers of ferrocene derivatives having R‐12‐hydroxystearyl chains with asymmetric carbon was investigated. The 12‐hydroxystearyl chain, which induces “thixotropy” due to the formation and breakage of intermolecular hydrogen bonds, was introduced into the ferrocenyl unit. The structure of this derivative as a monolayer on the water surface and its Langmuir‐Blodgett (LB) film properties were analyzed. The monolayer showed a two‐dimensional phase transition, corresponding to the formation of fibrous morphology. In the LB multilayers, intermolecular hydrogen bonding between hydroxyl groups at the 12‐position of the chain and crystalline packing was observed. Raman mapping revealed the difference in surface morphology of each derivative depending on the number of 12‐hydroxystearyl chains. The derivative having the single chain showed a right‐handed helical morphology in the film and this behavior is similar to those having two and three chains. In circular dichroism spectra, the film showed a positive Cotton effect. Since the helical chains easily entangle with each other to form a sponge‐like organization, it was expected that the solvent uptake was the origin of gelation induction to its contact solvent.