Video Experimental Relacionado
Updated: Jul 11, 2025
16:24
Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
18.7K
Dímetro de coordinación quiral térmico / mecanocrómico: formación de una estructura discreta conmutable y metastable
Kazuyoshi Takimoto1,2, Takumi Shimada1, Kazuhiko Nagura3
1Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
Journal of the American Chemical Society
|November 9, 2023
Resumen
Los complejos quirales de iridio (III) con ligandos de butilo-benzo[h]quinolina forman preferentemente dímeros homoquirales, lo que permite propiedades termo/mecanocrómicas conmutables en conjuntos supramoleculares discretos.
Área de la Ciencia:
- Química supramolecular
- Química de coordinación
- Materiales quirales
Sus antecedentes:
- La autoclasificación quiral se observa típicamente en polímeros extendidos, no en ensamblajes moleculares discretos.
- Esto limita el diseño de estructuras supramoleculares quirales conmutables y metastables.
- Los ensamblajes quirales discretos ofrecen potencial para nuevos materiales funcionales.
Objetivo del estudio:
- Investigar la autoclasificación quiral en complejos discretos de iridio.
- Para explorar la relación entre la quiralidad, la dimerización y el comportamiento termo- / mecano-crómico.
- Diseñar estructuras supramoleculares quirales discretas conmutables y metastables.
Principales métodos:
- Síntesis del complejo de iridio basado en butil-benzo[h]quinolina (Bu-Ir).
- Espectroscopia de radiación UV y RMN de temperatura variable para el estudio de la dimerización.
- Experimentos de cristalografía y molienda mecánica para evaluar la metestabilidad y el cambio de color.
Principales resultados:
- El complejo Bu-Ir muestra una fuerte preferencia por la formación de dímeros homoquirales (K_homo/K_hetero > 50).
- El dímero homoquiral es metastable y muestra termo-/mecano-cromatismo (de amarillo a rojo al moler).
- La dimerización implica la quiralidad helicoidal y los efectos estéricos combinados de los sustituyentes alquilo.
Conclusiones:
- El diseño racional de ensamblajes quirales discretos puede conducir a una fuerte autoclasificación quiral.
- El complejo de butilo-benzo[h]quinolina iridio (III) demuestra propiedades intercambiables y metastables.
- Estos hallazgos proporcionan información sobre la funcionalidad dinámica en los sistemas supramoleculares quirales.
Videos de Conceptos Relacionados
02:52Stereoisomerism
12.0K
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...
12.0K
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
02:33Stereoisomerism of Cyclic Compounds
8.9K
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,...
8.9K
02:30Chirality in Nature
13.5K
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.
13.5K
02:25Molecules with Multiple Chiral Centers
11.8K
Molecules that possess multiple chiral centers can afford a large number of stereoisomers. For instance, while some molecules like 2-butanol have one chiral center, defined as a tetrahedral carbon atom with four different substituents attached, several molecules like butane-2,3-diol have multiple chiral centers. A simple formula to predict the number of stereoisomers possible for a molecule with n chiral centers is 2n. However, there can be a lower number where some of the stereoisomers are...
11.8K
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