A Prospective Ultrafast Hemithioindigo Molecular Motor. Issue 6 (23rd April 2019)

• Record Type: Journal Article
• Authors: Schildhauer, Monika; Rott, Florian; Thumser, Stefan; Mayer, Peter; de Vivie‐Riedle, Regina; Dube, Henry
• Is Part Of: ChemPhotoChem. Volume 3:Issue 6(2019)
• Page Start: 365
• Page End: 371
• Publication Date: 2019-04-23
• Subjects: chromophores -- hemithioindigo -- molecular machines -- photochromism -- photoisomerization -- photoswitches; Photochemistry -- Periodicals; Periodicals; Electronic journals; 541.35
• DOI: 10.1002/cptc.201900074
• Languages: English
• ISSNs: 2367-0932

Abstract

Abstract: The maximum speed of light‐driven molecular motors is an important key‐property governing not only their overall performances but also many advanced functions. Currently, special emphasis lies on increasing the rate of unidirectional rotations to surpass natural systems and harness the full potential of artificial motors. Herein, we report a new molecular setup for a prospective light‐powered three‐step motor based on the hemithioindigo chromophore. Comprehensive quantum chemical treatment predicts a very low energy barrier for the only thermal ratcheting step in the unidirectional 360° rotation. Thus an ultrafast motion in the THz range could be possible with this motor at high light intensities and consequently a precise control of rotation speeds solely by light intensity variations could potentially be achieved. Experimental analyses using X‐ray crystallography and solution spectroscopy deliver first insights into the working mechanism and show that visible‐light photoswitching is feasible in both stable switching states. Additionally, significant alterations of the ground‐state energies can be induced by pH changes without hampering photoswitching capabilities. Abstract : Breakneck speed : A hemithioindigo‐based molecular setup for a prospective light‐powered three‐step motor is reported. Comprehensive quantum chemical treatment predicts only one thermal ratcheting step in the unidirectional 360° rotation. An ultrafast motion could therefore be possible with this motor as well as precise control of rotation speeds solely by light intensity variations. Experimental analyses show visible‐light photoswitching in both stable switching states.