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Triplet excited states of nitronaphthalenes. III. 1,4‐dinitronaphthalene
Author(s) -
Capellos C.,
Suryanarayanan K.
Publication year - 1976
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550080408
Subject(s) - chemistry , flash photolysis , photochemistry , excited state , intramolecular force , ultrafast laser spectroscopy , triplet state , solvent , absorption (acoustics) , hydride , reactivity (psychology) , hydrogen atom abstraction , hydrogen , atomic physics , molecule , stereochemistry , kinetics , organic chemistry , laser , reaction rate constant , medicine , physics , quantum mechanics , acoustics , alternative medicine , pathology , optics
Nanosecond flash photolysis of 1,4‐dinitronaphthalene (1,4‐DNO 2 N) in aerated and deaerated solvents shows a transient species with absorption maximum at 545 nm. The maximum of the transient absorption is independent of solvent polarity and its lifetime seems to be a function of the hydrogen donor efficiency of the solvent. The transient absorption is attributed to the lowest excited triplet state of 1,4‐DNO 2 N. The reactivity of this state for hydrogen abstraction from tributyl tin hydride (Bu 3 SnH), K q = 3.8 × 10 8 M −1 sec, is almost equal to that of nitrobezene triplet state which has been characterized as an n → π* state. Based on spectroscopic and kinetic evidence obtained in the present work, the triplet state of 1,4‐DNO 2 N behaves as an n → π* state in nonpolar solvents, while in polar solvents the state is predominantly n → π* with a small amount of intramolecular charge transfer character.