Light-driven brake stops molecular machines

Molecular machines (either synthetic or biological) are defined as molecules or groups of molecules that perform mechanical-like movements in response to certain stimuli (light, electricity, or chemical energy).

Jul 1st, 2008

Molecular machines (either synthetic or biological) are defined as molecules or groups of molecules that perform mechanical-like movements in response to certain stimuli (light, electricity, or chemical energy). Because a braking system is important for any moving object, researchers at National Taiwan University and Academia Sinica (both in Taipei, Taiwan) have developed the first light-driven, room-temperature molecular brake.

Based on nuclear magnetic resonance (NMR) studies, spectral simulations, and molecular modeling, it is possible to calculate the rotation rate of the rigid pentiptycene group, a four-bladed wheel structure that can exhibit two different motion states (trans-1 and cis-1). In dichloromethane solution at 298 K, the pentiptycene wheel freely rotates in a trans-1 state but slows by nine orders of magnitude in the cis-1 state. The two states can be switched by using different wavelengths of light (306 and 254 nm) due to the wavelength-sensitive dinitrostyryl group within the pentiptycene. This molecular “brake” could be attached to other molecular machines in solution to effectively control or stop their motion as a function of illumination wavelength. Contact Jye-Shane Yang at jsyang@ntu.edu.tw.

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