Two Molecular Spheres: Viruses form highly symmetrical coat structures, capsids, through the assembly of multiple lower-symmetry protein precursors. Recently, chemists have sought to emulate this process on a smaller scale, relying on the assembly of organic molecular struts and metal ions, rather than proteins. Sun et al. (p. 1144 , published online 29 April; see the Perspective by Stefankiewicz and Sanders ) now demonstrate that a mixture of palladium ions and V-shaped bridging ligands can self-assemble into a hollow, nearly spherical polyhedron with 24 vertices and a central diameter of 4 nanometers. The assembly process was highly sensitive to the ligand angle; a subtle average decrease generated instead a smaller 12-vertex product.

Significance: Defining unique properties of anomalous molecular entities is one of the most important roles of chemistry. Revealed by discovery of carbon nanotubes, rolled sheets of graphitic carbons are among such molecular structures possessing unique chirality. Although the chirality in nanotubes is attracting renewed interest in physical science, our understanding as well as exploration of its utilities is still in its infancy due to scarcity of chiral congeners with discrete structures. In this paper, chirality-originated properties of tubular molecules have been disclosed. The chirality in the cylindrical molecular structure results in chiral double helices in crystals and in extremely large dissymmetry factors associated with circularly polarized light. Cylinder chirality would be characteristic features to be explored in materials science of tubular structures.

The distinct properties of fluorous phases are practically useful for separation, purification, and reaction control in organic synthesis. Here, we report the formation of a liquid-like fluorous droplet, composed of 24 perfluoroalkyl chains confined in the interior of a 5-nanometer-sized, roughly spherical shell that spontaneously assembled in solution from 12 palladium ions and 24 bridging ligands. Crystallographic analysis confirmed the rigid shell framework and amorphous interior. Perfluoroalkanes can dissolve in this well-defined fluorous phase, whereas they can hardly dissolve in a surrounding polar organic solution, and their solubility (up to ∼eight perfluoroalkane molecules per spherical complex) can be finely controlled by tuning the length of perfluoroalkyl chains tethered to the shell.

Toward nanotubes with periodic gaps: Carbon nanotubes consist of a continuous array of benzene rings fused along their edges. It is not straightforward to excise regular fragments in a top-down fashion to produce periodic gaps. Sun et al. showcase the beginnings of a bottom-up strategy toward this end. They used borylations and catalytic cross-coupling chemistry to prepare a discrete cylindrical carbon compound composed of 40 benzene rings bonded to one another at the 1, 3, and 5 positions to leave regular void spaces in the walls. Catenation of multiple similar segments could ultimately lead to an extended nanotube with periodic wall defects. Science , this issue p. 151