Related Experiment Video
Updated: May 16, 2026
Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
E pluribus unum: isolation, structure determination, network analysis and DFT studies of a single metastable
1Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang Pauli Strasse 10, 8093 Zürich, Switzerland.
Abstract:
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.
More Related Videos
Related Concept Videos
02:33Stereoisomerism of Cyclic Compounds
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
01:16Structure of Conjugated Dienes
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
02:16Resonance and Hybrid Structures
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
01:24Mass Spectrum: Interpretation
01:13¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.