The Experts below are selected from a list of 9543 Experts worldwide ranked by ideXlab platform
Ben L. Feringa - One of the best experts on this subject based on the ideXlab platform.
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unidirectional Rotary Motion in a metal organic framework
Nature Nanotechnology, 2019Co-Authors: Wojciech Danowski, Diederik Roke, Sander J. Wezenberg, Thomas Van Leeuwen, Shaghayegh Abdolahzadeh, Wesley R Browne, Ben L. FeringaAbstract:Overcrowded alkene-based light-driven molecular motors are able to perform large-amplitude repetitive unidirectional rotations. Their behaviour is well understood in solution. However, Brownian Motion precludes the precise positioning at the nanoscale needed to harness cooperative action. Here, we demonstrate molecular motors organized in crystalline metal-organic frameworks (MOFs). The motor unit becomes a part of the organic linker (or strut), and its spatial arrangement is elucidated through powder and single-crystal X-ray analyses and polarized optical and Raman microscopies. We confirm that the light-driven unidirectional rotation of the motor units is retained in the MOF framework and that the motors can operate in the solid state with similar Rotary speed (rate of thermal helix inversion) to that in solution. These 'moto-MOFs' could in the future be used to control dynamic function in crystalline materials.
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light gated rotation in a molecular motor functionalized with a dithienylethene switch
Angewandte Chemie, 2018Co-Authors: Diederik Roke, Constantin Stuckhardt, Wojciech Danowski, Sander J. Wezenberg, Ben L. FeringaAbstract:: A multiphotochromic hybrid system is presented in which a light-driven overcrowded alkene-based molecular Rotary motor is connected to a dithienylethene photoswitch. Ring closing of the dithienylethene moiety, using an irradiation wavelength different from the wavelength applied to operate the molecular motor, results in inhibition of the Rotary Motion as is demonstrated by detailed 1 H-NMR and UV/Vis experiments. For the first time, a light-gated molecular motor is thus obtained. Furthermore, the excitation wavelength of the molecular motor is red-shifted from the UV into the visible-light region upon attachment of the dithienylethene switch.
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supramolecularly directed Rotary Motion in a photoresponsive receptor
Nature Communications, 2018Co-Authors: Sander J. Wezenberg, Ben L. FeringaAbstract:Stimuli-controlled Motion at the molecular level has fascinated chemists already for several decades. Taking inspiration from the myriad of dynamic and machine-like functions in nature, a number of strategies have been developed to control Motion in purely synthetic systems. Unidirectional Rotary Motion, such as is observed in ATP synthase and other motor proteins, remains highly challenging to achieve. Current artificial molecular motor systems rely on intrinsic asymmetry or a specific sequence of chemical transformations. Here, we present an alternative design in which the rotation is directed by a chiral guest molecule, which is able to bind non-covalently to a light-responsive receptor. It is demonstrated that the Rotary direction is governed by the guest chirality and hence, can be selected and changed at will. This feature offers unique control of directional rotation and will prove highly important in the further development of molecular machinery.
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artificial muscle like function from hierarchical supramolecular assembly of photoresponsive molecular motors
Nature Chemistry, 2018Co-Authors: Jiawen Chen, Franco Kingchi Leung, Takashi Kajitani, Erik Van Der Giessen, Takanori Fukushima, Marc C. A. Stuart, Ben L. FeringaAbstract:A centimetre-long string formed by the hierarchical self-assembly of a photoresponsive amphiphilic molecular motor — composed of 95 wt% of water — undergoes muscle-like contraction. Under irradiation, Rotary Motion at the molecular level is amplified through non-covalent interactions to sustain a fast macroscopic mechanical Motion of large amplitude.
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locked synchronous rotor Motion in a molecular motor
Science, 2017Co-Authors: Peter Stacko, Jos C M Kistemaker, Muchieh Chang, Edwin Otten, Thomas Van Leeuwen, Ben L. FeringaAbstract:Biological molecular motors translate their local directional Motion into ordered movement of other parts of the system to empower controlled mechanical functions. The design of analogous geared systems that couple Motion in a directional manner, which is pivotal for molecular machinery operating at the nanoscale, remains highly challenging. Here, we report a molecular Rotary motor that translates light-driven unidirectional Rotary Motion to controlled movement of a connected biaryl rotor. Achieving coupled Motion of the distinct parts of this multicomponent mechanical system required precise control of multiple kinetic barriers for isomerization and synchronous Motion, resulting in sliding and rotation during a full Rotary cycle, with the motor always facing the same face of the rotor.
Bernard Feringa - One of the best experts on this subject based on the ideXlab platform.
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unidirectional Rotary Motion in achiral molecular motors
Nature Chemistry, 2015Co-Authors: Jos C M Kistemaker, Peter Stacko, Johan Visser, Bernard FeringaAbstract:Avoiding equal probability for clockwise and anticlockwise rotation is essential for the function of molecular motors, and both biological and synthetic systems take advantage of chirality to control the Rotary direction. Now it has been shown, by integrating two rotor moieties in a symmetric meso motor design, that light-driven unidirectional Rotary Motion can be achieved in an achiral system.
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unidirectional Rotary Motion in a liquid crystalline environment color tuning by a molecular motor
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Richard A Van Delden, Nagatoshi Koumura, Noboyuki Harada, Bernard FeringaAbstract:Life could not exist without Motion induced by a variety of molecular motors. The construction of artificial motors by chemical synthesis, which can power Motions that lead to macroscopic detectable effects in a system, is a major endeavor in contemporary science. To move toward this goal, a host–guest system, composed of a nematic liquid crystal film doped with a chiral light-driven molecular motor, is assembled. Irradiation of the film results in unidirectional Rotary Motion of the molecular motor, which induces a Motion of the mesogenic molecules leading to a molecular reorganization and, as a consequence, a change in the color of the film. In this way, by control of the Rotary Motion at the molecular level, color tuning over the entire visible spectrum is achieved. These findings demonstrate that a molecular motor can exert a visually observable macroscopic change in a material.
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light driven monodirectional molecular rotor
Nature, 1999Co-Authors: Nagatoshi Koumura, R W J Zijlstra, R A Van Delden, Nobuyuki Harada, Bernard FeringaAbstract:Attempts to fabricate mechanical devices on the molecular level1,2 have yielded analogues of rotors3, gears4, switches5, shuttles6,7, turnstiles8 and ratchets9. Molecular motors, however, have not yet been made, even though they are common in biological systems10. Rotary Motion as such has been induced in interlocked systems11,12,13 and directly visualized for single molecules14, but the controlled conversion of energy into unidirectional Rotary Motion has remained difficult to achieve. Here we report repetitive, monodirectional rotation around a central carbon–carbon double bond in a chiral, helical alkene, with each 360° rotation involving four discrete isomerization steps activated by ultraviolet light or a change in the temperature of the system. We find that axial chirality and the presence of two chiral centres are essential for the observed monodirectional behaviour of the molecular motor. Two light-induced cis-trans isomerizations are each associated with a 180° rotation around the carbon–carbon double bond and are each followed by thermally controlled helicity inversions, which effectively block reverse rotation and thus ensure that the four individual steps add up to one full rotation in one direction only. As the energy barriers of the helicity inversion steps can be adjusted by structural modifications, chiral alkenes based on our system may find use as basic components for ‘molecular machinery’ driven by light.
Jos C M Kistemaker - One of the best experts on this subject based on the ideXlab platform.
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locked synchronous rotor Motion in a molecular motor
Science, 2017Co-Authors: Peter Stacko, Jos C M Kistemaker, Muchieh Chang, Edwin Otten, Thomas Van Leeuwen, Ben L. FeringaAbstract:Biological molecular motors translate their local directional Motion into ordered movement of other parts of the system to empower controlled mechanical functions. The design of analogous geared systems that couple Motion in a directional manner, which is pivotal for molecular machinery operating at the nanoscale, remains highly challenging. Here, we report a molecular Rotary motor that translates light-driven unidirectional Rotary Motion to controlled movement of a connected biaryl rotor. Achieving coupled Motion of the distinct parts of this multicomponent mechanical system required precise control of multiple kinetic barriers for isomerization and synchronous Motion, resulting in sliding and rotation during a full Rotary cycle, with the motor always facing the same face of the rotor.
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a chemically powered unidirectional Rotary molecular motor based on a palladium redox cycle
Nature Chemistry, 2016Co-Authors: Beatrice S L Collins, Jos C M Kistemaker, Edwin Otten, Ben L. FeringaAbstract:Control of Motion at the molecular level is an integral requirement for the development of future nanoscale machinery. Now, governed by the fundamental reactivity principles of organometallic chemistry, a biaryl rotor is shown to exhibit 360° unidirectional Rotary Motion driven by the conversion of two simple fuels.
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unidirectional Rotary Motion in achiral molecular motors
Nature Chemistry, 2015Co-Authors: Jos C M Kistemaker, Peter Stacko, Johan Visser, Bernard FeringaAbstract:Avoiding equal probability for clockwise and anticlockwise rotation is essential for the function of molecular motors, and both biological and synthetic systems take advantage of chirality to control the Rotary direction. Now it has been shown, by integrating two rotor moieties in a symmetric meso motor design, that light-driven unidirectional Rotary Motion can be achieved in an achiral system.
Michael M. Pollard - One of the best experts on this subject based on the ideXlab platform.
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reversing the direction in a light driven Rotary molecular motor
Nature Chemistry, 2011Co-Authors: Nopporn Ruangsupapichat, Syuzanna R Harutyunyan, Michael M. Pollard, Ben L. FeringaAbstract:Biological Rotary motors can alter their mechanical function by changing the direction of Rotary Motion. Now, researchers have designed a synthetic light-driven Rotary motor in which the direction of rotation can be reversed on command by changing the chirality of the molecular motor through base-induced epimerization.
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reversing the direction in a light driven Rotary molecular motor
Nature Chemistry, 2011Co-Authors: Nopporn Ruangsupapichat, Syuzanna R Harutyunyan, Michael M. Pollard, Ben L. FeringaAbstract:Biological Rotary motors can alter their mechanical function by changing the direction of Rotary Motion. Achieving a similar reversal of direction of rotation in artificial molecular motors presents a fundamental stereochemical challenge: how to change from clockwise to anticlockwise Motion without compromising the autonomous unidirectional Rotary behaviour of the system. A new molecular motor with multilevel control of Rotary Motion is reported here, in which the direction of light-powered rotation can be reversed by base-catalysed epimerization. The key steps are deprotonation and reprotonation of the photochemically generated less-stable isomers during the 360° unidirectional Rotary cycle, with complete inversion of the configuration at the stereogenic centre. The ability to change directionality is an essential step towards mechanical molecular systems with adaptive functional behaviour.
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a reversible unidirectional molecular Rotary motor driven by chemical energy
Science, 2005Co-Authors: Stephen P Fletcher, Michael M. Pollard, Frederic Dumur, Ben L. FeringaAbstract:With the long-term goal of producing nanometer-scale machines, we describe here the unidirectional Rotary Motion of a synthetic molecular structure fueled by chemical conversions. The basis of the rotation is the movement of a phenyl rotor relative to a naphthyl stator about a single bond axle. The sense of rotation is governed by the choice of chemical reagents that power the motor through four chemically distinct stations. Within the stations, the rotor is held in place by structural features that limit the extent of the rotor's Brownian Motion relative to the stator.
M Moallem - One of the best experts on this subject based on the ideXlab platform.
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a piezoelectric energy harvester for Rotary Motion applications design and experiments
IEEE-ASME Transactions on Mechatronics, 2013Co-Authors: Farbod Khameneifar, Siamak Arzanpour, M MoallemAbstract:This paper investigates the analysis and design of a vibration-based energy harvester for Rotary Motion applications. The energy harvester consists of a cantilever beam with a tip mass and a piezoelectric ceramic attached along the beam that is mounted on a rotating shaft. Using this system, mechanical vibration energy is induced in the flexible beam due to the gravitational force applied to the tip mass while the hub is rotating. The piezoelectric transducer is used to convert the induced mechanical vibration energy into electricity. The equations of Motion of the flexible structure are utilized along with the physical characteristics of the piezoelectric transducer to derive expressions for the electrical power. Furthermore, expressions for the optimum load resistance and maximum output power are obtained and validated experimentally using PVDF and PZT transducers. The results indicate that a maximum power of 6.4 mW at a shaft speed of 138 rad/s can be extracted by using a PZT transducer with dimensions 50.8 mm × 38.1 mm × 0.13 mm. This amount of power is sufficient to provide power for typical wireless sensors such as accelerometers and strain gauges.
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modeling and analysis of a piezoelectric energy scavenger for Rotary Motion applications
Journal of Vibration and Acoustics, 2011Co-Authors: Farbod Khameneifar, M Moallem, Siamak ArzanpourAbstract:This paper presents modeling and analysis of a piezoelectric mounted Rotary flexible beam that can be used as an energy scavenger for Rotary Motion applications. The energy harvester system consists of a piezoelectric bimorph cantilever beam with a tip mass mounted on a rotating hub. Assuming Euler-Bernoulli beam equations and considering the effect of a piezoelectric transducer, equations of Motion are derived using the Lagrangian approach followed by relationships describing the harvested power. The equations provide a quantitative description of how the hub acceleration and gravity due to the tip mass contribute power to the energy harvester. In particular, expressions describing optimum load resistance and the maximum power that can be harvested using the proposed system are derived. Numerical simulations are performed to show the performance of the harvester by obtaining tip velocities and electrical output voltages for a range of electrical load resistances and rotational speeds. It is shown that by proper sizing and parameter selection, the proposed system can supply enough energy for operating wireless sensors in rotating mechanisms such as tires and turbines.
