Video Experimental Relacionado
Updated: Aug 3, 2026
08:40
Gyroid Nickel Nanostructures from Diblock Copolymer Supramolecules
Published on: April 28, 2014
Fácil síntesis y caracterización de nuevos óxidos mesoporosos y mesorrelieves con estructuras tiroidales
Bozhi Tian1, Xiaoying Liu, Leonid A Solovyov
1Molecular Catalysis and Innovative Materials Lab, Department of Chemistry, Fudan University, Shanghai 200433, PR China.
Journal of the American Chemical Society
|January 22, 2004
Resumen
Los investigadores desarrollaron un método de post-síntesis solvotermal para crear sílice mesoporosa ordenada con canales ramificados. Esta técnica permite la fabricación de estructuras únicas de óxido metálico gyroidal con aplicaciones potenciales en la ciencia de los materiales.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Nanotecnología La nanotecnología es la nanotecnología.
- Química Química es la química.
Sus antecedentes:
- Los materiales de sílice mesoporosa ordenados son cruciales para la catálisis y la separación.
- El desarrollo de materiales con estructuras complejas y ordenadas como las redes tiroideales sigue siendo un desafío.
Objetivo del estudio:
- Introducir una estrategia de pos-síntesis solvotermal eficaz para la preparación de sílice mesoporosa ordenada con canales muy ramificados.
- Explorar las características estructurales y las aplicaciones potenciales de estos nuevos materiales de sílice y sus óxidos metálicos derivados.
Principales métodos:
- Se empleó la pos-síntesis solvotermal para crear la sílice mesoporosa.
- Se utilizó la digestión por microondas para eliminar las plantillas orgánicas, optimizando el tamaño de los poros y la superficie.
- Se utilizaron procedimientos de impregnación y termólisis para fabricar "negativos" de óxido metálico gyroidal a partir de las plantillas de sílice.
Principales resultados:
- La sílice mesoporosa exhibió una estructura giroidea doble cúbica (grupo espacial Ia-3d) con tamaños de poro ajustables (hasta 8,8 nm) y altas superficies (hasta 540 m2/g).
- Se propuso un modelo de transición de fase, atribuyendo la evolución estructural a un marco inorgánico flexible, alto contenido orgánico y no penetración de segmentos de óxido de polietileno.
- Los óxidos metálicos gyroidal fabricados (Co3O4, In2O3) muestran estructuras ordenadas a escala mesoscala y a escala atómica, influenciadas por la concentración de precursores.
Conclusiones:
- La estrategia de post-síntesis solvotermal es efectiva para crear sílice mesoporosa ordenada con canales ramificados y puede extenderse a materiales dopados y funcionalizados.
- La sílice mesoporosa preparada en 3D sirve como una plantilla versátil para la fabricación de óxidos metálicos tiroidales cristalinos ordenados.
- El estudio destaca la influencia de la cantidad de precursores en la estructura y la cristalinidad de los óxidos metálicos resultantes, ofreciendo información sobre los métodos de plantilla.
Videos de Conceptos Relacionados
02:51Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
02:34Structural Isomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
02:16Resonance and Hybrid Structures
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
01:26Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
01:28Structures of Carboxylic Acid Derivatives
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...