Video Experimental Relacionado
Updated: Jul 6, 2026
10:51
The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Un complejo monometálico de elementos f de dinitrógeno: (C5Me5) 3U(eta1-N2)
William J Evans1, Stosh A Kozimor, Joseph W Ziller
1Department of Chemistry, University of California, Irvine, CA 92697-2025, USA. wevans@uci.edu
Journal of the American Chemical Society
|November 20, 2003
Resumen
Los complejos de uranio estéricamente obstaculizados muestran una reactividad diferente con los ligandos. (C5Me5) 3U reacciona con N2, mientras que menos obstaculizado (C5Me4H) 3U coordina THF, destacando los efectos estéricos en la química de los elementos f.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Química del Uranio La Química del Uranio
- Reactividad de los ligandos.
Sus antecedentes:
- Los complejos de uranio con ligandos ciclopentadienilo son claves en la química de los elementos f.
- Comprender la coordinación y la reactividad de los ligandos es crucial para desarrollar nuevos materiales a base de uranio.
- El obstáculo estérico alrededor del centro del metal influye significativamente en la reactividad.
Objetivo del estudio:
- Para comparar la reactividad de estérico abarrotado (C5Me5) 3U y menos abarrotado (C5Me4H) 3U con diferentes ligandos.
- Para investigar el comportamiento de coordinación de tetrahidrofurano (THF) y dinitrógeno (N2) con estos complejos de uranio.
- Para dilucidar el papel de la masa estérica en la determinación de las vías de reacción.
Principales métodos:
- Síntesis y caracterización de complejos de uranio.
- Estudios de reacción con tetrahidrofurano (THF) y dinitrógeno (N2) en condiciones variables.
- Análisis espectroscópico (por ejemplo, espectroscopia de infrarrojos) y cristalografía de rayos X para determinar las estructuras y la unión del producto.
Principales resultados:
- Tetrahidrofurano (THF) las coordenadas a la menos abarrotado (C5Me4H) 3U, formando (C5Me4H) 3U (THF).
- La apertura del anillo de THF ocurre con el estérico abarrotado (C5Me5) 3U.U.
- El dinitrógeno (N2) a 80 psi reacciona con (C5Me5) 3U para formar (C5Me5) 3U(eta1-N2), caracterizado por la longitud del enlace U-N y la frecuencia de estiramiento N2.
- Sólo la (C5Me4H) 3U no reaccionada se aisló bajo 80 psi de N2, lo que indica que no hay reacción o coordinación.
Conclusiones:
- El obstáculo estérico en los complejos de uranio ciclopentadienilo dicta su reactividad hacia los ligandos comunes y no tradicionales.
- (C5Me5) 3U exhibe una reactividad única con N2 debido a su naturaleza abarrotada.
- (C5Me4H) 3U muestra una coordinación preferente con THF, lo que demuestra el impacto de la accesibilidad estérica en la elección del ligando.
Videos de Conceptos Relacionados
03:26Electron Configuration of Multielectron Atoms
The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the 3s orbital, giving a 1s22s22p63s1 configuration. The electrons occupying the outermost shell orbital(s) (highest value of n) are called valence electrons, and those occupying the inner shell orbitals are called core electrons. Since the core electron shells correspond to noble gas electron configurations, we can abbreviate electron...
02:54Coordination Compounds and Nomenclature
In most main group element compounds, the valence electrons of the isolated atoms combine to form chemical bonds that satisfy the octet rule. For instance, the four valence electrons of carbon overlap with electrons from four hydrogen atoms to form CH4. The one valence electron leaves sodium and adds to the seven valence electrons of chlorine to form the ionic formula unit NaCl (Figure 1a). Transition metals do not normally bond in this fashion. They primarily form coordinate covalent bonds, a...
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...
02:42Valence Bond Theory
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...
01:19Complexation Equilibria: The Chelate Effect
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
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...