Solid-state photochemical and photomechanical properties of molecular crystal nanorods composed of anthracene ester derivatives

摘要: A series of 9-anthroate esters that can form photoresponsive molecular crystal nanorods is prepared and their properties are investigated. All structures support a [4 + 4] photodimerization reaction lead to undergo photomechanical deformations without fragmentation. In order determine the molecular-level motions give rise nanorod response, anthracene-9-carboxylic acid tert-butyl ester studied in detail using X-ray diffraction solid-state NMR techniques. The monomer well-aligned within reacts photodimer according first-order kinetics. reacted dimer metastable intermediate slowly converts into low energy structure over course weeks. Based on single studies data, this likely composed has not yet undergone group rotations repacking necessary lower polymorph produced directly by crystallization from solution. Our results show response these nanostructures determined nonequilibrium states cannot be predicted based solely knowledge equilibrium reactant product structures.