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The Dewar Isomer of 1,2‐Dihydro‐1,2‐azaborinines: Isolation, Fragmentation, and Energy Storage
Author(s) -
Edel Klara,
Yang Xinyu,
Ishibashi Jacob S. A.,
Lamm Ashley N.,
MaichleMössmer Cäcilia,
Giustra Zachary X.,
Liu ShihYuan,
Bettinger Holger F.
Publication year - 2018
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/anie.201712683
Subject(s) - photoisomerization , chemistry , cyclobutadiene , photodissociation , matrix isolation , quantum yield , valence (chemistry) , photochemistry , isomerization , catalysis , ring (chemistry) , molecule , organic chemistry , fluorescence , physics , quantum mechanics
The photochemistry of 1,2‐dihydro‐1,2‐azaborinine derivatives was studied under matrix isolation conditions and in solution. Photoisomerization occurs exclusively to the Dewar valence isomers upon irradiation with UV light (>280 nm) with high quantum yield (46 %). Further photolysis with UV light (254 nm) results in the formation of cyclobutadiene and an iminoborane derivative. The thermal electrocyclic ring‐opening reaction of the Dewar valence isomer back to the 1,2‐dihydro‐1‐ tert ‐butyldimethylsilyl‐2‐mesityl‐1,2‐azaborinine has an activation barrier of (27.0±1.2) kcal mol −1 . In the presence of the Wilkinson catalyst, the ring opening occurs rapidly and exothermically (Δ H =(−48±1) kcal mol −1 ) at room temperature.