Chinese scholars and overseas collaborators have made progress in molecular motor research

Figure Design and working principle of chemically driven unidirectional rotary molecular motor

With the support of the National Natural Science Foundation of China (Approval No.
: 21971267), Professor Depeng Zhao and collaborator Ben Feringa of Sun Yat-sen University reported that the use of chemical energy to drive molecular motors to achieve high unidirectional continuous rotation
.
The research results were published
in the journal Nature under the title "Intrinsically unidirectional chemically fuelled rotary molecular motors.
" Paper Link:

In nature, many complex molecular machines make up living organisms, in which molecular motors play a unique and important role, such as ATP synthetase
.
As an energy conversion device, artificial molecular motors have important application prospects in nano transportation, molecular pumps, intelligent materials, information storage and biomedical treatment
.
However, the high synthesis difficulty of chemical energy-driven artificial molecular motors, poor one-way and low energy utilization have led to slow
progress in related research.

Professor Zhao Depeng's team has long been committed to the research of
chemical energy molecular motors.
In the early work, the team proposed the idea of using dynamic covalent bonds to construct molecular motors, and developed a novel molecular motor system based on biphenyl structure, using orthogonal protection base strategy, and using condensation agents as fuel, achieving high unidirectional 360° rotation
。 However, in order to achieve the goal of "high unidirectional continuous rotation of chemical energy molecular motors", there are still the following challenges: 1) each step of the molecular motor rotation process needs to ensure high unidirectionality, while avoiding the reduction of one-way due to Brownian motion; 2) In order to ensure the continuity of the rotation of the molecular motor, the orthogonal protective base strategy must be abandoned, and the independent selectivity of the cyclization process must be realized through conformational control; 3) It must be in the same system, so that the series of steps of closing the loop - flipping - opening the ring occurs and has a similar reaction rate; 4) The reaction rate of chemical fuels and motors should be much higher than the hydrolysis rate of the fuel itself to reduce the background reaction and ensure high fuel utilization
.

In response to these challenges, Zhao Depeng's team cleverly used the two-hand center of the biphenyl skeleton sidechain to achieve simultaneous regulation of cyclization unidirectionality and ring flip unidirectionality, and realized the unidirectional rotation
of the chemical energy molecule motor under the non-protective base strategy.
The team clearly characterized the open ring state, ring unstable state and ring stable state of the molecular motor system by means of single crystal XRD, nuclear magnetic resonance spectroscopy, circular dichromatography, etc.
, and described the high unidirectional rotation process
of the molecular motor.
Through the desymmetry strategy, the 360° step-by-step rotation of the molecular motor is further demonstrated
.
In addition, the team also realized the addition of a single chemical fuel, which can make the molecular motor perform a continuous multi-step one-way rotation under the condition of "one pot" acid-base oscillation
.
It is also worth noting that the team also discovered the phenomenon of "dynamic dynamic hydrolysis" during the research process, and proposed the dynamic dynamic control phenomenon that exists during the continuous rotation of the molecular motor, which greatly improves the rotational one-way and fuel utilization
.
Finally, under mild conditions (35°C), a high unidirectional rotation
(7.
2*10⁷/1) of the chemically actuated molecular motor is achieved.
This achievement will provide new ideas and material basis
for the research of smart materials, biomimetic synthesis nanomachines and smart drugs.