Light-Driven Purification of Progesterone from Steroid Mixtures Using a Photoresponsive Metal-Organic Capsule.

Chemical separations are expensive, consuming 10-15% of humanity's global energy budget. Many current separation methods employ thermal energy for distillation, often through the combustion of carbon-containing fuels, or extractions and crystallizations from organic solvents, which must then be discarded or redistilled, with a substantial energetic cost. The direct use of renewable energy sources, such as light, could enable the development of novel separations processes, as is required for the transition away from fossil fuel use.

Secondary Bracing Ligands Drive Heteroleptic Cuboctahedral Pd Cage Formation.

The structural complexity of self-assembled metal-organic capsules can be increased by incorporating two or more different ligands into a single discrete product. Such complexity can be useful, by enabling larger, less-symmetrical, or more guests to be bound. Here we describe a rational design strategy for the use of subcomponent self-assembly to selectively prepare a heteroleptic cage with a large cavity volume (2631 Å) from simple, commercially available starting materials.

A three-shell supramolecular complex enables the symmetry-mismatched chemo- and regioselective bis-functionalization of C.

Molecular Russian dolls (matryoshkas) have proven useful for testing the limits of preparative supramolecular chemistry but applications of these architectures to problems in other fields are elusive. Here we report a three-shell, matryoshka-like complex-in which C sits inside a cycloparaphenylene nanohoop, which in turn is encapsulated inside a self-assembled nanocapsule-that can be used to address a long-standing challenge in fullerene chemistry, namely the selective formation of a particular fullerene bis-adduct. Spectroscopic evidence indicates that the ternary complex is sufficiently stable in solution for the two outer shells to affect the addition chemistry of the fullerene guest.

Highly selective encapsulation and purification of U-based C-EMFs within a supramolecular nanocapsule.

The ability of the tetragonal prismatic nanocapsule 1·(BArF) to selectively encapsulate U-based C EMFs from a soot mixture is reported, showing enhanced affinity for C-based EMFs over C-based EMFs. Molecular recognition driven by the electrostatic interactions between the host and guest is at the basis of the high selectivity observed for ellipsoidal C-based EMFs compared to spherical C-based EMFs. In addition, DFT analysis points towards an enhanced breathing adaptability of nanocapsule 1·(BArF) to C-based EMFs to further explain the selectivity observed when the host is used in the solid phase.

Purification of Uranium-based Endohedral Metallofullerenes (EMFs) by Selective Supramolecular Encapsulation and Release.

Supramolecular nanocapsule 1⋅(BArF) is able to sequentially and selectively entrap recently discovered U @C and unprecedented Sc CU@C , simply by soaking crystals of 1⋅(BArF) in a toluene solution of arc-produced soot. These species, selectively and stepwise absorbed by 1⋅(BArF) , are easily released, obtaining highly pure fractions of U @C and Sc CU@C in one step. Sc CU@C represents the first example of a mixed metal actinide-based endohedral metallofullerene (EMF).

Self-Assembled Cofacial Zinc-Porphyrin Supramolecular Nanocapsules as Tuneable O Photosensitizers.

We demonstrate the benefits of using cofacial Zn-porphyrins as structural synthons in coordination-driven self-assembled prisms to produce cage-like singlet oxygen ( O ) photosensitizers with tunable properties. In particular, we describe the photosensitizing and emission properties of palladium- and copper-based supramolecular capsules, and demonstrate that the nature of the bridging metal nodes in these discrete self-assembled prisms strongly influences O generation at the Zn-porphyrin centers. The Pd -based prism is a particularly robust photosensitizer, whereas the Cu self-assembled prism is a dormant photosensitizer that could be switched to a ON state upon disassembly of the suprastructure.

A Copper-based Supramolecular Nanocapsule that Enables Straightforward Purification of Sc N-based Endohedral Metallofullerene Soots.

A self-assembled Cu -based nanocapsule enables efficient and straightforward isolation of Sc N@C from arc-processed raw soot. The newly designed Cu -based supramolecular nanocapsule 5⋅(OTf) was used to effectively entrap fullerenes and endohedral metallofullerenes (EMFs) with different affinities depending on their size and shape. Moreover, we took advantage of the sharply different entrapment abilities of the 5⋅(OTf) cage in the solid state versus in solution to encapsulate all the species with the exception of Sc N@C (both I and D isomers), which remains pure in solution.