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Femtosecond Dynamics of Dioxygen – Picket‐Fence Cobalt Porphyrins: Ultrafast Release of O 2 and the Nature of Dative Bonding
Author(s) -
Steiger Beat,
Baskin J. Spencer,
Anson Fred C.,
Zewail Ahmed H.
Publication year - 2000
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/(sici)1521-3773(20000103)39:1<257::aid-anie257>3.0.co;2-3
Subject(s) - porphyrin , adduct , cobalt , femtosecond , photochemistry , nanosecond , chemistry , dative case , electron transfer , ultrashort pulse , crystallography , chemical physics , inorganic chemistry , organic chemistry , physics , optics , laser , linguistics , philosophy
The ultrafast release of O 2 from the O 2 adduct of picket‐fence cobalt porphyrin (see picture) has been probed in real time, and has a total reaction time of 2 ps, without subsequent recombination over several nanoseconds. The dynamics of this ultrafast release of O 2 shows that relaxation within the porphyrin system (200 fs) precedes porphyrin‐to‐metal electron transfer, but the latter occurs at an enhanced rate (500 fs as opposed to the more usual 1 – 2 ps) because of the dative bonding of cobalt and O 2 , which gives the adduct ground state significant Co III −O 2 − character.