Shape-selective crystallisation of fluxional carbon cages. Issue 46 (7th November 2018)

• Record Type: Journal Article
• Authors: Bismillah, Aisha N.; Sturala, Jiri; Chapin, Brette M.; Yufit, Dmitry S.; Hodgkinson, Paul; McGonigal, Paul R.
• Is Part Of: Chemical science. Volume 9:Issue 46(2018)
• Page Start: 8631
• Page End: 8636
• Publication Date: 2018-11-07
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8sc04303e
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Overall molecular shape, rather than any specific noncovalent interactions, controls the preferential crystallisation of shapeshifting barbaralane isomers from dynamic mixtures. 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.