Video Experimental Relacionado
Updated: Jun 29, 2026
10:52
Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Fotoinducción de un movimiento de traslación rápido y reversible en una lanzadera molecular unida por hidrógeno
A M Brouwer1, C Frochot, F G Gatti
1Laboratory of Organic Chemistry, University of Amsterdam, Nieuwe Achtergracht 129, NL-1018 WS Amsterdam, Netherlands.
Science (New York, N.Y.)
|March 17, 2001
Resumen
Un nuevo rotaxano utiliza un pulso láser para conducir un macrociclo entre dos estaciones. Este movimiento de tipo pistón impulsado por energía es reversible y se monitorea mediante espectroscopia de absorción óptica.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- La fotoquímica es la fotoquímica.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Los rotaxanos son máquinas moleculares con aplicaciones potenciales en nanotecnología.
- El control del movimiento molecular es crucial para el desarrollo de materiales funcionales avanzados.
Objetivo del estudio:
- Para describir un sistema de rotaxano capaz de movimiento direccional inducido por la luz.
- Para monitorear cuantitativamente y caracterizar el proceso de traducción submolecular.
Principales métodos:
- Utilizó un pulso láser de nanosegundos para iniciar la fotoexcitación.
- Se empleó la espectroscopia de absorción óptica transitoria para observar el movimiento molecular en tiempo real.
- Investigó la influencia del medio circundante en la dinámica del traslado.
Principales resultados:
- Se ha demostrado el traslado reversible de un macrociclo entre dos estaciones de enlace de hidrógeno.
- Cuantificó el tiempo de traslado hacia adelante (aprox. 1 microsegundo) y el tiempo de retorno (aprox. 100 microsegundos) en acetonitrilo a temperatura ambiente.
- Confirmó la naturaleza ciclable y impulsada por la energía del proceso.
Conclusiones:
- El rotaxano estudiado funciona como un pistón impulsado por energía, controlado por luz.
- La espectroscopia de absorción óptica transitoria es efectiva para el monitoreo del movimiento submolecular rápido.
- El sistema exhibe propiedades adecuadas para aplicaciones de maquinaria molecular.
Videos de Conceptos Relacionados
00:26Hydrogen Bonds
Hydrogen BondsHydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has a partial negative charge. The other is a hydrogen atom that has bonded with another electronegative atom and has a partial positive charge.Hydrogen Bonds Control the World!Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are...
01:13Induced-fit Model
Most chemical reactions in cells require enzymes—biological catalysts that speed up the reaction without being consumed or permanently changed. They reduce the activation energy needed to convert the reactants into products. Enzymes are proteins, that usually work by binding to a substrate—a reactant molecule that they act upon.
Enzymes exhibit substrate specificity, meaning that they can only bind to certain substrates. This is mainly determined by the shape and chemical characteristics of...
Enzymes exhibit substrate specificity, meaning that they can only bind to certain substrates. This is mainly determined by the shape and chemical characteristics of...
01:37Energy to Drive Translocation
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
01:16Thermal Sigmatropic Reactions: Overview
Sigmatropic rearrangements are a class of pericyclic reactions in which a σ bond migrates from one part of a π system to another. These are intramolecular rearrangements where the total number of σ and π bonds remain unchanged.
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
01:17Chemical Shift: Internal References and Solvent Effects
In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...