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Photoinduced Nitrene, Carbene, and Atomic Oxygen Transfer Reactions Starting from the Corresponding Pyridinium N‐, C‐, and O‐ Ylides
Author(s) -
Strub Henri,
Strehler Christiane,
Streith Jacques
Publication year - 1987
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19871200318
Subject(s) - chemistry , carbene , photochemistry , pyridinium , nitrene , reactive intermediate , singlet state , fragmentation (computing) , ground state , triplet state , photodissociation , oxygen , molecule , medicinal chemistry , excited state , organic chemistry , catalysis , physics , quantum mechanics , nuclear physics , operating system , computer science
Ultraviolet irradiation of the pyridinium ylides 1,2 and 3 led to fragmentation of the exocyclic polar bonds, as well as to skeletal rearrangements. The photoinduced fragmentation processes gave the corresponding pyridines and highly reactive intermediates, i. e. Ethoxycarbonylitrene, Dicyanocarbene and atomic oxygen (oxene), respectively. Trapping of the reactive intermediates by alkanes and alkenes permitted the determination of their spin multiplicity. Ethoxycarbonylnitrene was in its triplet ground state at the moment of its formation. Dicyanocarbene occurred as a mixture of singlet and triplet, as determined by dilution experiments with variable amounts of alkenes. As to atomic oxygen, all collected data point to its formation in solution in its triplet ground state.