Assembly and photoinduced organization of mono- and oligopeptide molecules containing an azobenzene moiety

Assembled systems consisting of an azobenzene moiety as the photofunctional component and valyl units as the network backbone are investigated. The molecular ordering of these assemblies is examined by spectroscopy and theoretical calculations. The number of valyl units greatly influences the molecular order in the organized systems. Only N-(L-valyl-L-valyl-L-valyl)azobenzene-4-carboxamide (3) forms a complete beta-sheet structure in this artificial assembly. Upon photoirradiation, the azobenzene moieties isomerize completely, revealing the reversibility in the structural organization through the flexibility of the beta-sheet network in this system.