Video Experimental Relacionado
Updated: May 15, 2025
05:47
Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts
Published on: August 7, 2018
7.6K
Complejos de carbono ciclometalizado con estados de transferencia de carga de energía más baja accesibles con luz
Spencer T Burton1, Gyunhee Lee1, Curtis E Moore1
1Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43214, United States.
Journal of the American Chemical Society
|April 10, 2025
Resumen
Los nuevos complejos de cobalto (III) son prometedores como sensibilizantes para la energía solar y la catálisis fotorredóxica. El complejo 3, un complejo heteroleptico Co ((III), demuestra una transferencia de carga fotoinducida eficiente utilizando luz verde.
Área de la Ciencia:
- Química de coordinación
- La fotofísica
- Ciencias de los materiales
Sus antecedentes:
- Los complejos de cobalto (III) se exploran por su potencial en la conversión de energía solar y la catálisis fotorredóxica.
- La comprensión de las propiedades fotofísicas de los complejos de cobalto ciclometalizados es crucial para el desarrollo de sensibilizadores eficientes.
Objetivo del estudio:
- Para sintetizar y caracterizar nuevos complejos cis-[Co(ppy) 2 ((L) ]PF6, donde L es un ligando de diimina (bpy, fen o DAP).
- Investigar sus propiedades fotofísicas y evaluar su potencial como sensibilizadores para la energía solar y la catálisis fotorredóxica.
- Explorar la relación entre el diseño estructural y las propiedades del estado excitado para los fotosensibilizadores d6.
Principales métodos:
- Síntesis y caracterización de tres complejos de cobalto: cis-[Co(ppy) 2 ((bpy) ]PF6 (1), cis-[Co(ppy) 2 ((phen) ]PF6 (2) y cis-[Co(ppy) 2 ((DAP) ]PF6 (3).
- Investigaciones de las propiedades fotofísicas, incluida la espectroscopia de absorción y la espectroscopia de absorción transitoria.
- Estudios computacionales para analizar las interacciones orbitales moleculares y las estructuras electrónicas.
- Experimentos fotocatalíticos que incluyen la reducción del metilviólogo.
Principales resultados:
- Los cálculos revelaron fuertes interacciones orbitales Co (dπ) /ppy (π), lo que condujo a un HOMO localizado en Co (dπ) y un LUMO en el ligando diimine.
- El complejo 3 exhibió una amplia banda de absorción de transferencia de carga de metal/ligando a ligando (ML-LCT) con un máximo de 507 nm, que se extiende más allá de 600 nm.
- La excitación de la transición 1ML-LCT condujo a un estado excitado 3ML-LCT con vidas de 3,0 ps, 4,6 ps y 42 ps para los complejos 1, 2 y 3, respectivamente.
- El complejo 3 redujo con éxito el metilviólogo tras la irradiación con luz de 505 nm, demostrando su actividad fotocatalítica.
Conclusiones:
- Los complejos sintetizados de cobalto (III) poseen propiedades fotofísicas sintonizables influenciadas por el ligando de diimina.
- El complejo 3 es el primer complejo heteroleptico molecular Co ((III) reportado que combina ciclometalización con un ligando de diimina, con estados de ML-LCT bajos capaces de transferencia de carga fotoinducida con luz verde.
- El diseño estructural del complejo 3 representa un avance significativo en el desarrollo de fotosensibilizadores d6 basados en metales abundantes en tierra para aplicaciones de energía sostenible.
![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
Videos de Conceptos Relacionados
03:02Colors and Magnetism
11.4K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
11.4K
02:42Valence Bond Theory
8.4K
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...
8.4K
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
02:58Crystal Field Theory - Octahedral Complexes
25.8K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
25.8K
03:45Formation of Complex Ions
23.0K
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...
23.0K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
40.8K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...
40.8K