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Shape-selective crystallisation of fluxional carbon cages.

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.

SUBMITTER: Bismillah AN

PROVIDER: S-EPMC6301275 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature

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Shape-selective crystallisation of fluxional carbon cages.

Bismillah Aisha N AN Sturala Jiri J Chapin Brette M BM Yufit Dmitry S DS Hodgkinson Paul P McGonigal Paul R PR

Chemical science 20181022 46

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 ...[more]

PMID: 30647882

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