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Photo- and Thermal-Induced Multistructural Transformation of 2-Phenylazolyl Chelate Boron Compounds
- Source :
- Journal of the American Chemical Society. 135:3407-3410
- Publication Year :
- 2013
- Publisher :
- American Chemical Society (ACS), 2013.
-
Abstract
- The new N,C-chelate boron compounds B(2-phenylazolyl)Mes2 [Mes = mesityl; azolyl = benzothiazolyl (1a), 4-methylthiazolyl (2a), benzoxazolyl (3a), benzimidazolyl (4a)] undergo an unprecedented multistructural transformation upon light irradiation or heating, sequentially producing isomers b, c, d, and e. The dark isomers b generated by photoisomerization of a undergo a rare thermal intramolecular H-atom transfer (HAT), reducing the azole ring and generating new isomers c, which are further transformed into isomers d. Remarkably, isomers d can be converted to their diastereomers e quantitatively by heating, and e can be converted back to d by irradiation at 300 nm. The structures of isomers 1d and 1e were established by X-ray diffraction. The unusual HAT reactivity can be attributed to the geometry of the highly energetic isomers b and the relatively low aromaticity of the azole rings. The boryl unit plays a key role in the reversible interconversion of d and e, as shown by mechanistic pathways established through DFT and TD-DFT calculations.
- Subjects :
- Azoles
Boron Compounds
Models, Molecular
Photoisomerization
chemistry.chemical_element
Crystallography, X-Ray
Ring (chemistry)
Photochemistry
Biochemistry
Medicinal chemistry
Catalysis
Colloid and Surface Chemistry
Reactivity (chemistry)
Boron
Chelating Agents
chemistry.chemical_classification
Molecular Structure
Temperature
Diastereomer
Aromaticity
General Chemistry
Photochemical Processes
chemistry
Intramolecular force
Quantum Theory
Azole
Subjects
Details
- ISSN :
- 15205126 and 00027863
- Volume :
- 135
- Database :
- OpenAIRE
- Journal :
- Journal of the American Chemical Society
- Accession number :
- edsair.doi.dedup.....be73fe159ede4f3c02d47972afc5fb34