Designing light-driven rotary molecular motors

Abstract

The ability to induce and amplify motion at the molecular scale has seen tremendous progress ranging from simple molecular rotors to responsive materials. In the two decades since the discovery...

Design and Nonadiabatic Photoisomerization Dynamics Study of a Three-Stroke Light-Driven Molecular Rotary Motor

“…Although some outstanding developments on photon-only molecular motors [ 18 , 19 , 21 , 22 ] have been achieved from a computational perspective, Feringa et al pointed out very recently that these molecules are often highly challenging to synthesize in experiment [ 24 ]. Designing a light-driven molecular motor with fewer operational steps based on synthesized molecular systems may be an effective way.…”

“…The presence of THI steps hinders the rotation of LDMRMs at lower temperatures and also limits the rotation speed and unidirectionality of the LDMRMs [ 14 , 16 , 17 , 18 , 19 , 20 ]. Therefore, reducing the THI steps is an ongoing research challenge [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. On the theory side, by introducing a chiral hydrogen bond environment, García-Iriepa et al [ 18 ] proposed a two-stroke photon-only LDMRM, which was predicted to complete the unidirectional rotation with only two photochemical steps (no thermal steps are involved in the mechanism).…”

Controlling rotary motion of molecular motors based on oxindole

“…40,41 The computed thermochemistry suggests that motors 1-9 will follow the unidirectional rotation cycle as is typical for oxindole motors and other overcrowded alkene-based motors. 15,40,41 The simulated UV-Vis spectra (see Table 1, ESI and Table S15 †) for the stable states of motors 1-9 in all solvents (DMSO, CH 2 Cl 2 and MeOH) exhibit broad bands with absorption maxima centred between 370-450 nm, extending further into the visible region (up to >600 nm in the case of E S -3). For the corresponding metastable states, the absorption maxima are red-shifted by around 30-50 nm, due to both a destabilisation of the HOMOs of the metastable states in comparison to the HOMOs of the stable states, and a stabilisation of the LUMOs of the metastable states in comparison to that of the stable states (Fig.…”

“…12 Since the first light-driven unidirectional rotary molecular motor presented by our group in 1999, 13 a vast amount of research has been carried out on overcrowded alkene-based molecular motors. 14,15 They are now highly tuneable actuators which can be tailored to diverse purposes in a multitude of different fields, such as smart materials, [16][17][18] catalysis [19][20][21] and biomedical applications. [22][23][24][25] Synthetic modification can fine-tune the properties of molecular motors towards these purposes, for example altering their rotational speed or quantum efficiency.…”

“…[22][23][24][25] Synthetic modification can fine-tune the properties of molecular motors towards these purposes, for example altering their rotational speed or quantum efficiency. 15 Potentially harmful UV light is commonly used to excite unfunctionalised overcrowded alkenes, 15,26 hence, a substantial research effort currently aims to shift the absorption wavelength of molecular motors towards the visible region of the electromagnetic spectrum. This goal can be achieved through integration of extended π-systems, [27][28][29] push-pull substituents 30,31 and photosensitisers.…”