Video Experimental Relacionado
Updated: May 5, 2026
13:08
A Salt-Templated Synthesis Method for Porous Platinum-based Macrobeams and Macrotubes
Published on: May 18, 2020
8.9K
Cambios de fase inducidos por solventes y presión en dos estructuras orgánicas metálicas 3D basadas en glutarato de
Charl X Bezuidenhout1, Vincent J Smith1, Catharine Esterhuysen1
1Department of Chemistry and Polymer Science, University of Stellenbosch , Matieland 7602, South Africa.
Journal of the American Chemical Society
|April 1, 2017
Resumen
Dos marcos metálicos orgánicos flexibles (MOF) con pilares de glutarato de cobre cambian espontáneamente de fase al perder el disolvente, creando canales estrechos. Un MOF adsorbe selectivamente el CO2 volviendo a su forma de canal más amplio.
Área de la Ciencia:
- Ciencias de los materiales
- La cristalografía
- Ingeniería Química
Sus antecedentes:
- Las estructuras metálicas orgánicas (MOF) son materiales porosos avanzados con estructuras ajustables.
- Los MOF flexibles pueden exhibir transformaciones estructurales en respuesta a estímulos externos.
- Comprender la dinámica del marco es crucial para el diseño de MOF para aplicaciones específicas.
Objetivo del estudio:
- Investigar el comportamiento de fase de dos MOF isoreticulares basados en el glutarato con pilares flexibles.
- Caracterizar los cambios estructurales y su impacto en la porosidad.
- Explorar las propiedades y el mecanismo de absorción de CO2 de un MOF flexible.
Principales métodos:
- Difracción de rayos X monocristalino (SCXRD) para el análisis estructural.
- Mediciones de isoterma de sorción para estudios de absorción de gases.
- CO2 supercrítico para el aislamiento de estructuras incluidas en el gas.
- Simulaciones de modelado molecular para elucidar el mecanismo.
Principales resultados:
- Dos MOF, [Cu2 ((glu) 2 ((bpa)) ] y [Cu2 ((glu) 2 ((bpp)) ], sufren cambios de fase espontáneos a formas de canal estrecho al perder el disolvente.
- Las formas de canal estrecho exhiben volúmenes accesibles al disolvente significativamente reducidos.
- [Cu2 ((glu) 2 ((bpa)) muestra una isoterma de sorción de CO2 escalonada, lo que indica la transformación reversible a una forma de canal ancho bajo presión de CO2.
- SCXRD determinó las posiciones de las moléculas de CO2 dentro de los canales marco.
- El modelado molecular aclaró el mecanismo de cambio de fase y la energética asociada.
Conclusiones:
- Los MOF con capas pilares flexibles pueden presentar transformaciones estructurales significativas tras la eliminación del disolvente.
- El cambio de fase reversible en [Cu2 ((glu) 2 ((bpa)) ] permite una absorción selectiva de CO2.
- La comprensión de estos cambios estructurales dinámicos es clave para el diseño de MOF para aplicaciones de separación y almacenamiento de gases.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:54Ions as Acids and Bases
22.8K
Salts with Acidic Ions
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
22.8K
03:05Acid Strength and Molecular Structure
26.0K
Binary Acids and Bases
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with...
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with...
26.0K
03:45Formation of Complex Ions
18.8K
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
18.8K
02:51Metal-Ligand Bonds
19.3K
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...
19.3K
02:42Valence Bond Theory
8.9K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.9K
02:16Brønsted-Lowry Acids and Bases
20.0K
In 1923, the Brønsted–Lowry definition of acids and bases was proposed by Johannes Brønsted and Thomas Lowry. According to this theory, a Brønsted acid is defined as a species that donates a proton in a chemical reaction and gets converted to its conjugate base. A Brønsted base is defined as a species that accepts a proton in a chemical reaction and gets converted into its conjugate acid. These transfers of protons are caused by the displacement of electrons in these...
20.0K