On-Surface Translational Activity of Porphyrin Chromophore Molecules

Translational activity of molecules on a metal surface is an important area of study due to its relevance to the field of molecular motors and machines. Here, we study molecular motions of a planarized porphyrin molecule, a so-called ‘nanocar’, on a clean Au(111) surface, driven by applying a bias voltage from a tip of scanning tunneling microscopy (STM) at low temperature. The molecular design strategy involves on-surface cyclodehydrogenation to planarize the nanocar precursor molecule 5-(9-anthryl)-15-(9,9’-bianthryl)-10,20-bis(trifluoromethyl) porphyrinatocopper(II) under the concept of superlubricity leading us to assign the nickname ‘Slider-Spider’ to this nano-sportscar. The resulting planar nanocar molecule was stimulated to move a distance of 1054 nm (including 54 turns) during a 24 h period leading to victory for the NIMS Tsukuba Team in the 2nd Nanocar Race. The molecule had excellent stability and could be operated as a nanocar for 24 h under remote control at 10,211 km (Toulouse in France–Tsukuba in Japan) by using a scanning probe system at subnanometer scale.