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A Combined Experimental and Theoretical Study on the Isomers of 2,3,4,5-Tetracarba-nido-Hexaborane(6) Derivatives and Their Photophysical Properties.
- Source :
-
Chemistry - A European Journal . 1/2/2015, Vol. 21 Issue 1, p210-218. 9p. - Publication Year :
- 2015
-
Abstract
- Building upon our ongoing studies on the highyield synthetic route to 2,3,4,5-tetracarba-1,6-nido hexaborane derivative 5, we continue to explore the chemistry of this system to isolate a range of perphenylated C4B2-type carborane isomers. As a result, the photolysis of 5 for an elongated period yielded 6, which exhibits an intense luminescence upon excitation with a UV lamp (λex=366 nm). In contrast, the conversion of 5 under thermal conditions (microwave heating) generated the isomer 7, which does not show any luminescence. The structural disparity among the three isomers 5-7 is the position of the butadiene moiety with respect to the C4B2-carborane cage as deduced from single-crystal X-ray diffraction analyses. In an attempt to generate the classical structural motif of 5, an equimolar amount of KOtBu was added to a THF solution of 5, which immediately provided the boratacyclopentadiene derivative 8 in good yield. The observed rearrangement reactions were further investigated by quantum chemical calculations to suggest a plausible reaction pathway. According to the DFT calculations, the energetically favored reaction mechanism most likely involves tricyclic transition states and classical intermediate structures. In addition, the fluorescence emission properties of 6 were investigated in solution as well as in the solid state. [ABSTRACT FROM AUTHOR]
- Subjects :
- *ISOMERIZATION
*ISOMERS
*EXCITATION spectrum
*ISOMERASES
*MOLECULAR physics
Subjects
Details
- Language :
- English
- ISSN :
- 09476539
- Volume :
- 21
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Chemistry - A European Journal
- Publication Type :
- Academic Journal
- Accession number :
- 102210942
- Full Text :
- https://doi.org/10.1002/chem.201405017