Prototypes of molecular motors based on star-shaped organometallic ruthenium complexes

Abstract

This tutorial review presents our strategy to control the rotation in a molecular rotary motor, and the family of star-shaped ruthenium complexes designed to perform such a task. The molecules have a piano-stool structure with a "stator" meant to be grafted on a surface, and a "rotor" bearing redox-active groups, so that addressing the molecule with nano-electrodes would trigger rotation.

Switchable molecule-based materials for micro- and nanoscale actuating applications: Achievements and prospects

“…Another important point we must mention at the beginning is that the exciting and also very challenging field of single molecule machines is not covered by the present review, the interested reader can find details on this approach in Refs. [6][7][8][9][10][11][12]. Here we focus on materials based on molecular switches.…”

Toward unidirectional switches: 2-(2-Hydroxyphenyl)pyridine and 2-(2-methoxyphenyl)pyridine derivatives as pH-triggered pivots

“…One important requirement for the construction of a molecular motor is that at least one movement of the motor proceeds unidirectionally. Such a unidirectional movement was already realized for rotations around N–N [29] and C–C [19–20 22,30–31] double bonds, around C–C single bonds [21,32–36], mechanical bonds [37–38] and in metal complexes [39–48]. A system for which unidirectional movement was realized, by making use of two different concepts, is the 2,2′-bipyridine unit [32,34–35].…”

Unidirectional rotary motion in achiral molecular motors

“…Key to performing mechanical tasks is control over the directionality of rotary motion, as is seen with ATPase-mediated transport 35 , flagella-based bacterial swimming 36 and the rotation of microscopic objects at the liquid crystal-air interface by directional rotation of a chiral nematic phase 37 . Leigh and co-workers noted that having chirality embedded in a molecule is not a prerequisite for directionality in a motor system when a specific sequence of chemical steps can be used to induce the rotary motion, as shown for a mechanically interlocked motor 38,39 . In a surface-mounted motor by Vives et al, despite the use of an achiral molecule, the entire system is non-symmetric, which thus governs directionality 40 . To enable autonomous directional movement and avoid an equal probability of clockwise and anticlockwise rotation around a single rotary axle connecting rotor and stator, our synthetic rotary motors [41][42][43] rely on the chirality of the system.…”