Video Experimental Relacionado
Updated: Mar 24, 2026
08:22
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
7.4K
Cromóforos energéticos: iniciación láser de baja energía en complejos explosivos de Fe (II) Tetrazina
Thomas W Myers1, Josiah A Bjorgaard1, Kathryn E Brown1
1M Division, ‡Theoretical Division, §W Division, and ∥Chemistry Division, Los Alamos National Laboratory , P.O. Box 1663, Los Alamos, New Mexico 87545, United States.
Journal of the American Chemical Society
|March 18, 2016
Resumen
Los investigadores desarrollaron nuevos complejos de coordinación de hierro que son explosivos más seguros y más sensibles. Estos nuevos materiales, iniciados por láseres infrarrojos cercanos, ofrecen umbrales de energía más bajos y una sensibilidad reducida al impacto y la fricción en comparación con el PETN.
Área de la Ciencia:
- Química inorgánica
- Ciencias de los materiales
- Química Física
Sus antecedentes:
- Los explosivos secundarios son materiales energéticos cruciales.
- El PETN es un explosivo secundario de referencia, pero tiene limitaciones en el manejo y la iniciación.
- El desarrollo de explosivos más seguros y más fáciles de iniciar es un objetivo clave de la investigación.
Objetivo del estudio:
- Síntesis y caracterización de nuevos complejos de coordinación de hierro estable en el aire.
- Investigar el potencial de estos complejos como explosivos secundarios con propiedades de iniciación ajustables.
- Comparar sus características de seguridad e iniciación con las del PETN.
Principales métodos:
- Síntesis de complejos de Fe (II) con los ligandos de tetrazina y triazol-tetrazina.
- Caracterización mediante técnicas espectroscópicas y electroquímicas.
- Teoría funcional de densidad dependiente del tiempo (TD-DFT) para modelar propiedades.
- Iniciación con láser y ensayo de sensibilidad mecánica.
Principales resultados:
- Síntesis y caracterización exitosas de complejos de Fe (II) estables en el aire.
- Estos complejos presentan umbrales de energía de iniciación láser más bajos que el PETN.
- Se ha demostrado una sensibilidad significativamente menor al impacto y a la fricción en comparación con el PETN.
- Modelado TD-DFT correlacionado con modificaciones de la estructura electrónica con propiedades ópticas sintonizables (bandas MLCT).
Conclusiones:
- Los complejos de tetrazina Fe (II) desarrollados representan una nueva clase de explosivos secundarios.
- Ofrecen una combinación sin precedentes de sensibilidad mecánica reducida y umbrales de iniciación láser más bajos.
- El ajuste de las bandas de transferencia de carga de metal-ligando en el infrarrojo cercano permite un manejo más seguro y la iniciación del láser NIR, superando el rendimiento de PETN.
Videos de Conceptos Relacionados
01:26Photochemical Electrocyclic Reactions: Stereochemistry
2.4K
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
2.4K
01:25Deactivation Processes: Jablonski Diagram
2.2K
Luminescence, the emission of light by a substance that has absorbed energy, is a process that involves the interaction of molecules with light. The energy-level diagram, or Jablonski diagram, is a graphical representation of these interactions, illustrating the various states and transitions a molecule can undergo. In a typical Jablonski diagram, the lowest horizontal line represents the ground-state energy of the molecule, which is usually a singlet state. This state represents the energies...
2.2K
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.8K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.8K
03:02Colors and Magnetism
14.5K
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...
14.5K
01:20Atomic Emission Spectroscopy: Overview
4.2K
Atomic emission spectroscopy (AES) is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted from excited atoms. In AES, atoms in a sample are excited to higher energy levels by thermal energy from high-temperature sources, such as plasma, arcs, or sparks. When these excited atoms return to lower energy states, they emit light at specific wavelengths characteristic of each element. The resulting atomic emission spectrum, which consists of...
4.2K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
49.5K
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 the dxy,...
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 the dxy,...
49.5K