11]Anthrahelicene on TiO2 surfaces

Abstract

Helicenes are carbon-rich materials with an ordered structure that possess interesting and remarkable electronic, chiroptical, mechanical and magnetic properties either in bulk or as single molecule devices. We report on the first attempt to anchor and organize [11]anthrahelicene ([11]AH) molecules onto a metal oxide surface. Molecular structures obtained on the (110) and (011) faces of rutile titania are characterized using scanning probe microscopy. On the (110) surface, [11]AH molecules form islands that are comprised of small domains of two types that are mirror reflections of each other and have an ordered quasi-hexagonal lattice. In contrast, molecules form unordered clusters on the (011) surface. Single molecules on both faces are imaged with sub-molecular resolution.