Giant strain geared to transformable H-bonded network in compressed ß-D-mannose.

Networks of OH···O bonds in sugars and H2O ices are hardly affected by temperature, but transform under pressure. Such a transition at 1.95 GPa in ß-D-mannose induces strong strain, non-destructive for the single crystal and easily visible in its shape deformation. This transition occurs at the lowest pressure of all sugars investigated at high pressure so far. The giant strain propagates perpendicular to the clearly visible zero-strain planes. The transition reconstructs the 3-dimensional pattern of OH···O hydrogen bonds, changes the conformation of molecules and preserves the space-group symmetry, like the analogous transitions of α-D-glucose and D-sucrose. However, new repulsing O···O contacts have been generated at high pressure in D-mannose only.

Generation of a Multicomponent Library of Disulfide Donor-Acceptor Architectures Using Dynamic Combinatorial Chemistry.

We describe here the generation of new donor-acceptor disulfide architectures obtained in aqueous solution at physiological pH. The application of a dynamic combinatorial chemistry approach allowed us to generate a large number of new disulfide macrocyclic architectures together with a new type of [2]catenanes consisting of four distinct components. Up to fifteen types of structurally-distinct dynamic architectures have been generated through one-pot disulfide exchange reactions between four thiol-functionalized aqueous components. The distribution of disulfide products formed was found to be strongly dependent on the structural features of the thiol components employed. This work not only constitutes a success in the synthesis of topologically- and morphologically-complex targets, but it may also open new horizons for the use of this methodology in the construction of molecular machines.

Selective C70 encapsulation by a robust octameric nanospheroid held together by 48 cooperative hydrogen bonds.

Self-assembly of multiple building blocks via hydrogen bonds into well-defined nanoconstructs with selective binding function remains one of the foremost challenges in supramolecular chemistry. Here, we report the discovery of a enantiopure nanocapsule that is formed through the self-assembly of eight amino acid functionalised molecules in nonpolar solvents through 48 hydrogen bonds. The nanocapsule is remarkably robust, being stable at low and high temperatures, and in the presence of base, presumably due to the co-operative geometry of the hydrogen bonding motif. Thanks to small pore sizes, large internal cavity and sufficient dynamicity, the nanocapsule is able to recognize and encapsulate large aromatic guests such as fullerenes C60 and C70. The structural and electronic complementary between the host and C70 leads to its preferential and selective binding from a mixture of C60 and C70.