Abstract
Dynamic covalent rearrangements of fluxional carbon cages, such as bullvalenes and barbaralanes, impart 'shapeshifting' molecular properties. Here, a series of five barbaralanes each interconvert dynamically between two constitutional isomers in solution, but resolve to single isomers upon crystallisation. Unexpectedly, the minor solution-phase isomers are resolved in two instances. Through dynamic NMR, crystallographic and DFT analyses, we show that the isomer observed in the solid state is not a direct consequence of the equilibrium distribution in solution or any specific noncovalent interactions. Rather, the dynamic preferential crystallisation is dictated by differences in molecular size and shape.
| Original language | English |
|---|---|
| Pages (from-to) | 8631-8636 |
| Number of pages | 6 |
| Journal | Chemical Science |
| Volume | 9 |
| Issue number | 46 |
| DOIs | |
| Publication status | Published - 2018 |
Bibliographical note
Funding Information:A. N. B. acknowledges an EPSRC DTG. J. S. acknowledges an Experientia Foundation Fellowship, Advanced Functional Nanorobots (CZ.02.1.01/0.0/0.0/15_003/0000444 nanced by the EFRR), and computational resources from the MSMT under the CESNET (LM2015042) and CERIT-Scientic Cloud (LM2015085) projects. B. M. C. and P. R. M. thank the EPSRC for funding (EP/ N029992/1). We thank Dr Mark Miller and Prof. Jon Steed for useful discussions. We are grateful to Dr David Apperley and Dr Raquel Belda-Vidal for assistance with NMR measurements.
Publisher Copyright:
© The Royal Society of Chemistry 2018.