Dynamics of flexible triplet biradicals
- Columbia Univ., New York, NY (USA)
A large number of thermal and photochemical reactions proceed via biradical intermediates. Typically, a biradical generated in the triplet state must first undergo intersystem crossing (ISC) to the singlet biradical before forming products. This presents one of the major challenges of photochemistry; to understand a reaction in which the molecule must hop from one potential energy surface to another. In this Account we are concerned with triplet-derived flexible chain biradicals, and Scheme I shows the important processes. A triplet precursor (e.g., an {sup 3}n, {pi}* ketone) cleaves with conservation of spin to produce a triplet biradical in a set of conformations where the radical centers are close together. Two processes ensue: ISC in a given conformation produces a singlet biradical in the same conformation, and internal rotation gives rise to chain dynamics, which changes the end-to-end distance.
- OSTI ID:
- 7196516
- Journal Information:
- Accounts of Chemical Research; (USA), Journal Name: Accounts of Chemical Research; (USA) Vol. 22:6; ISSN ACHRE; ISSN 0001-4842
- Country of Publication:
- United States
- Language:
- English
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Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
CHEMICAL REACTIONS
CHEMISTRY
DATA
DATA ANALYSIS
DECOMPOSITION
DYNAMICS
EXPERIMENTAL DATA
INFORMATION
MEASURING INSTRUMENTS
MEASURING METHODS
MECHANICS
NUMERICAL DATA
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOLYSIS
RADICALS