Video Experimental Relacionado
Updated: Jun 5, 2026
10:33
An Electrochemical Cholesteric Liquid Crystalline Device for Quick and Low-Voltage Color Modulation
Published on: February 27, 2019
Interacciones intercromofóricas en oligómeros conjugados π quirales tipo X: un estudio óptico lineal y no lineal
David Cornelis1, Edith Franz, Inge Asselberghs
1Laboratory for Molecular Electronics and Photonics, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
Journal of the American Chemical Society
|January 8, 2011
Resumen
Los oligómeros ligados al binaftaleno quiral exhiben interacciones a través del espacio, mejorando las propiedades ópticas no lineales. Este diseño facilita la transferencia de carga entre las unidades ricas en electrones y pobres en electrones en los nuevos sistemas π-conjugados.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Ciencia de los materiales Ciencia de los materiales.
- Química supramolecular de las moléculas.
Sus antecedentes:
- Los oligómeros π-conjugados son cruciales para la electrónica orgánica.
- El control de las interacciones intermoleculares en los oligómeros es clave para ajustar las propiedades.
- Las unidades de binaftaleno ofrecen un andamio quiral para organizar sistemas conjugados.
Objetivo del estudio:
- Para presentar un concepto novedoso de oligómeros conjugados π organizados de tipo X, quirales, unidos por una tenaza de binaftaleno.
- Para investigar las interacciones a través del espacio entre estos oligómeros en estados neutros y oxidados.
- Para explorar las propiedades ópticas no lineales de los derivados heteroacoplados de binaftaleno.
Principales métodos:
- Síntesis de oligómeros quirales, tipo X organizados y conjugados con π.
- Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN).
- Voltametría de pulso cíclico y diferencial.
- UV-vis, dicroísmo circular (CD) y espectroscopia de emisión.
- Las mediciones de la dispersión de Hyper-Rayleigh (HRS).
Principales resultados:
- Los oligómeros están muy cerca unos de otros, influyendo unos en otros a través del espacio.
- Interacciones a través del espacio confirmadas por varias técnicas espectroscópicas.
- Las derivadas heteroacopladas (BN1-2, BN1-3) muestran una hiperpolarizabilidad no lineal mejorada de segundo orden (β).
- Pruebas directas de transferencia de carga a través del espacio entre oligómeros de tipo p y tipo n en BN1-3 y BN1-2.
Conclusiones:
- La pinza de binaftaleno organiza eficazmente los oligómeros conjugados con π.
- Las interacciones a través del espacio impactan significativamente las propiedades electrónicas y ópticas.
- Los sistemas heteroacoplados diseñados demuestran potencial para aplicaciones ópticas no lineales avanzadas.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:24Properties of Enantiomers and Optical Activity
It is essential to understand the difference between chiral and achiral interactions and the implications thereof in optical activity and their applications. Just as our feet, which are chiral, interact uniquely with chiral objects, such as a pair of shoes, but identically with achiral socks, enantiomers of a molecule exhibit different properties only when they interact with other chiral media. An example of a significant implication from this facet is the phenomenon known as optical activity,...
02:52Stereoisomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
02:05Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
02:33Stereoisomerism of Cyclic Compounds
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:27¹H NMR: Long-Range Coupling
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.