Macroscopic chirogenesis and photoinduced chiral motions enabled by selective accommodation of protic guests.

Symmetry breaking offers ideal platforms for understanding the emergence of chirality in bottom-up self-assembly. Here we show the chirogenesis induced by symmetry breaking by selective entrapping solvent guests and photoinduced motions in self-assembled matrices. In the absence of protic guests, the achiral nitro-conjugated cyanostilbenes self-assemble into macroscopic helices. When trace proton solvents are involved, hydrogen bonding anchors the molecular arrangement, suppressing symmetry breaking to form crystals. The topo-preference towards helices or achiral crystals is highly sensitive to protic guests including water, alcohols and acids. The packing nanopockets are indicated by single crystal structures, and we propose that whether these are filled determines the screw dislocations. On this basis, the photomechanical behavior is further realized by the [2 + 2] photodimerization of the stilbenes that induces crystal deformation, as well as the in-situ generation of macroscopic helices. The study presents a new strategy for precisely tuning symmetry breaking and photomechanical motion through guest accommodation, providing insights for understanding chirality emergence and the design of controllable light-driven dynamic crystals and molecular machines.