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Updated: May 9, 2025

Förster Resonance Energy Transfer Measurements in Living Plant Cells
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在一个受体-受体异质二极体中,可逆兴奋状态电子转移

Jesper Dahl Jensen1, Shayan Louie2, Yanmei He1,3

  • 1Nano-Science Center & Department of Chemistry, University of Copenhagen Universitetsparken 5, DK-2100 Copenhagen Ø Denmark bwl@chem.ku.dk.

Chemical science
|May 2, 2025
PubMed
概括

研究人员开发了一种新型的二化物 (PDI) 和aza dioxa triangulenium (ADOTA) 双. 这个系统表现出独特的,可逆的兴奋状态电子转移,受溶剂极性影响.

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Photochemical Electrocyclic Reactions: Stereochemistry

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
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Thermal Electrocyclic Reactions: Stereochemistry

The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
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Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...
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