Video Experimental Relacionado
Updated: Jun 28, 2025
07:24
Hyperspectral Imaging as a Tool to Study Optical Anisotropy in Lanthanide-Based Molecular Single Crystals
Published on: April 14, 2020
17.1K
Transferencia de quiralidad inducida por cristalización en complejos de azaheliceno conformacionalmente flexibles con
Pingyu Jiang1, Alexander S Mikherdov2, Hajime Ito1,2
1Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan.
Journal of the American Chemical Society
|April 16, 2024
Resumen
Estabilizar la quiralidad dinámica en moléculas flexibles es un desafío. Este estudio demuestra la transferencia de quiralidad inducida por la cristalización en los complejos de oro, mejorando la estabilidad y la luminiscencia polarizada circularmente (CPL).
Área de la Ciencia:
- Química orgánica
- Química supramolecular
- Ciencias de los materiales
Sus antecedentes:
- Los sistemas π flexibles y retorcidos pueden exhibir quiralidad, pero la racemicidad es un desafío.
- La transferencia de quiralidad de un auxiliar quiral es un método prometedor para estabilizar la homoquiralidad.
- Los azahelicenos son una clase de moléculas con quiralidad dinámica que son difíciles de estabilizar.
Objetivo del estudio:
- Desarrollar un nuevo enfoque para estabilizar la quiralidad dinámica en especies de azaheliceno flexibles.
- Investigar la transferencia de quiralidad intermolecular inducida por la cristalización en complejos de oro.
- Explorar el impacto de la transferencia de quiralidad en las propiedades de la luminiscencia polarizada circular (CPL).
Principales métodos:
- Síntesis de complejos de oro con azaheliceno (dibenzo[c,g]carbazole y benzo[c]carbazole) y ligandos quirales de carbenos N-heterocíclicos (NHC).
- Cristalización de los complejos de oro para inducir la transferencia de quiralidad intermolecular.
- Caracterización de las estructuras cristalinas y propiedades CPL de los complejos.
Principales resultados:
- La cristalización suprimió la quiralidad dinámica y estabilizó la homoquiralidad en dibenzocarbazoles azahelicenos a través de la conjunción intermolecular con los ligandos quirales NHC.
- En los complejos benzo[c]carbazoles, la transferencia de quiralidad inducida por la cristalización creó quiralidad en el ligando inicialmente achiral.
- La cristalización activó y mejoró significativamente las propiedades de CPL, con factores de disimetría de luminiscencia de 5 a 10 veces más altos en complejos con transferencia de quiralidad.
Conclusiones:
- La transferencia de quiralidad intermolecular inducida por cristalización es una estrategia efectiva para estabilizar la quiralidad dinámica en azahelicenos flexibles.
- Este enfoque no solo estabiliza la quiralidad existente, sino que también puede inducir la quiralidad en las fracciones achirales.
- El método mejora significativamente las propiedades de CPL, ofreciendo potencial para aplicaciones en materiales quirales y optoelectrónica.
Videos de Conceptos Relacionados
01:26Photochemical Electrocyclic Reactions: Stereochemistry
1.8K
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
1.8K
02:30Chirality in Nature
13.4K
Chirality is the most intriguing yet essential facet of nature, governing life’s biochemical processes and precision. It can be observed from a snail shell pattern in a macroscopic world to an amino acid, the minutest building block of life. Most of the snails around the world have right-coiled shells because of the intrinsic chirality in their genes. All the amino acids present in the human body exist in an enantiomerically pure state, except for glycine - the sole achiral amino acid.
13.4K
02:05Prochirality
3.8K
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...
3.8K
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
5.7K
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
5.7K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.0K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.0K
02:52Stereoisomerism
11.9K
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...
11.9K