Mixed Thiolate/Alkoxide Antimony Cages for Reversed-Bilayer Vesicle Self-Assembly and Dye Protection in Organic Media

A new two-step synthesis produces moisture-stable antimony and arsenic dithiothreitol cages. Structural analysis reveals that the Sb compounds self-assemble into reversed bilayers, consistent with pnictogen-bonded vesicle formation in organic media. The Sb assemblies more efficiently encapsulate and protect rhodamine B than the arsenic analogue or a topological mimic that lacks pnictogen-bonding capability. This work provides a synthetically accessible tool for partitioning organic media to allow for orthogonal reactivity.