Back to Search
Start Over
Ultrafast dynamics in the power stroke of a molecular rotary motor
- Source :
- Nature Chemistry, Nature Chemistry, 4(7), 547-551. Nature Publishing Group
- Publication Year :
- 2012
- Publisher :
- Springer Science and Business Media LLC, 2012.
-
Abstract
- Light-driven molecular motors convert light into mechanical energy through excited-state reactions. Unidirectional rotary molecular motors based on chiral overcrowded alkenes operate through consecutive photochemical and thermal steps. The thermal (helix inverting) step has been optimized successfully through variations in molecular structure, but much less is known about the photochemical step, which provides power to the motor. Ultimately, controlling the efficiency of molecular motors requires a detailed picture of the molecular dynamics on the excited-state potential energy surface. Here, we characterize the primary events that follow photon absorption by a unidirectional molecular motor using ultrafast fluorescence up-conversion measurements with sub 50 fs time resolution. We observe an extraordinarily fast initial relaxation out of the Franck-Condon region that suggests a barrierless reaction coordinate. This fast molecular motion is shown to be accompanied by the excitation of coherent excited-state structural motion. The implications of these observations for manipulating motor efficiency are discussed.
- Subjects :
- Time Factors
Light
General Chemical Engineering
EXCITED-STATE
Molecular Dynamics Simulation
ACCELERATION
Spectrum Analysis, Raman
010402 general chemistry
Photochemistry
01 natural sciences
UNIDIRECTIONAL ROTATION
TORSIONAL DYNAMICS
Reaction coordinate
Quantitative Biology::Subcellular Processes
Molecular dynamics
Isomerism
PHOTOISOMERIZATION
Molecular motor
Absorption (electromagnetic radiation)
Mechanical energy
Fluorescent Dyes
ISOMERIZATION
Fluorenes
010405 organic chemistry
Chemistry
FEMTOSECOND
General Chemistry
CIS-STILBENE
0104 chemical sciences
Coherent control
Chemical physics
Potential energy surface
COHERENT-CONTROL
STRUCTURAL MODIFICATION
Excitation
Subjects
Details
- ISSN :
- 17554349 and 17554330
- Volume :
- 4
- Database :
- OpenAIRE
- Journal :
- Nature Chemistry
- Accession number :
- edsair.doi.dedup.....a3fea900e8afd586dbc250a7d76f7f5e