Light-driven rotary molecular motors on gold nanoparticles.

We report the synthesis of unidirectional light-driven rotary molecular motors based on chiral overcrowded alkenes and their immobilisation on the surface of gold nanoparticles through two anchors. Using a combination of (1)H and (13)C NMR, UV/Vis and CD spectroscopy, we show that these motors preserve their photochemical and thermal behaviour after they have been attached to gold nanoparticles. Furthermore, we describe the synthesis of (2)H- and (13)C-labelled derivatives that were used to verify the unidirectionality of the rotary cycle of these motors both in solution and while grafted to gold nanoparticles. Taken together, these data support the conclusion that these motors maintain their unidirectional rotary cycle when grafted to the surface of small (ca. 2 nm) gold nanoparticles. Thus, continuous irradiation of the system under appropriate conditions leads to unidirectional rotation of the upper half of the molecules relative to the entire nanoparticle.