This website uses cookies to give you the best user experience. If you continue
without changing your settings we'll assume you are happy to receive all RSC cookies.
You can change your cookie settings by navigating to our Privacy and Cookies page and following the instructions. These instructions
are also obtainable from the privacy link at the bottom of any RSC page.
E pluribus unum: isolation, structure determination, network analysis and DFT studies of a single metastable structure from a shapeshifting mixture of 852 bullvalene structural isomers
Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang Pauli Strasse 10, 8093 Zürich, Switzerland
E-mail: bode@org.chem.ethz.ch
Org. Biomol. Chem., 2013,11, 1306-1317
DOI:
10.1039/C2OB26954F
Received
07 Oct 2012,
Accepted
07 Nov 2012
First published online
09 Nov 2012
Bullvalene is an organic molecule that spontaneously undergoes Cope rearrangements, resulting in a reconfiguration of its carbon framework. During our study of oligosubstituted bullvalenes, which are structurally dynamic shapeshifting molecules, we found that we could isolate one metastable isomer from the interconverting population of 1680 constitutional isomers (852 structures if enantiomeric pairs are counted once). The preferential formation and unexpected stability of this isomer led to many questions, which we have addressed in this report. (1) What is its structure? (2) How many rearrangements are required to form this isomer from the initial bullvalene structure? (3) Why is it the preferred isomer? (4) What is the role of the substituents in its energetic preference? Our answers required synthesis, HPLC isolation, NMR characterizations, network construction and analysis, and computational (DFT) studies. The results of these efforts revealed the remarkable interconversion network of bullvalene rearrangements. The formation of this metastable isomer is preferred by both thermodynamic and kinetic factors and the ester substituent amplifies the energy difference between various structural isomers of oligosubstituted bullvalenes. The shapeshifting nature of oligosubstituted bullvalene is a useful and unusual property that has many potential applications. Insights into their rearrangements, energy landscape and substituent effect will be important knowledge for the development of these molecules towards materials, sensors and biologically active compounds.
Fetching data from CrossRef. This may take some time to load.
Organic & Biomolecular Chemistry
- Information Point