En Route to Surface-Bound Electric Field-Driven Molecular Motors

Abstract

Four caltrop-shaped molecules that might be useful as surface-bound electric field-driven molecular motors have been synthesized. The caltrops are comprised of a pair of electron donor-acceptor arms and a tripod base. The molecular arms are based on a carbazole or oligo(phenylene ethynylene) core with a strong net dipole. The tripod base uses a silicon atom as its core. The legs of the tripod bear sulfur-tipped bonding units, as acetyl-protected benzylic thiols, for bonding to a gold surface. The geometry of the tripod base allows the caltrop to project upward from a metallic surface after self-assembly. Ellipsometric studies show that self-assembled monolayers of the caltrops are formed on Au surfaces with molecular thicknesses consistent with the desired upright-shaft arrangement. As a result, the zwitterionic molecular arms might be controllable when electric fields are applied around the caltrops, thereby constituting field-driven motors.

The Synthesis and One‐ and Two‐Photon Optical Properties of Dipolar, Quadrupolar and Octupolar Donor–Acceptor Molecules Containing Dimesitylboryl Groups

“…4-Ethynyl-N,N-dimethylaniline, [39] 4-ethynyl-N,N-di(4-tolyl)aniline, [40] 3,6-diethynyl-N-n-butyl-carbazole [41] and tris(4-ethynylphenyl)amine [42] were prepared according to literature procedures. The synthesis of 4-(4-ethynylphenylethynyl)-N,Ndimethylaniline will be reported in detail in a forthcoming paper on extended linear arylene ethynylenes.…”

Luminescent acetylthiol derivative tripodal osmium(II) and iridium(III) complexes: Spectroscopy in solution and on surfaces

“…From these results it is evident that multiple anchoring groups would lead to a better stability of the formed monolayers. Therefore, more recently, bipyridine derivatives containing tripodal-type ligands bearing anchoring groups at each leg of the tripod have been designed by a few research groups [34,[37][38][39]. Following the same rationale we have designed rigid tripodal complexes of Ru, Os, and Ir with acetylthiol terminal groups.…”

A 16-bit parallel processing in a molecular assembly

“…Several novel nanomachines have been realized over the last two decades by rearranging the constituent atoms of nature's building blocks, namely proteins (11,12), DNA (13), and other compounds (14)(15)(16)(17). Researchers have sought to increase the number of versatile instructions and generate multiple operations by increasing the complexity of design via diverse assembly routes.…”