A Light-Driven Constitutional Pump

Achieving high degrees of nonequilibrium in dynamic covalent chemistry remains a major challenge for emulating energy-dissipative, biomimetic constitutional behaviors based on reversible covalent bond reorganization. At the molecular level, the central difficulty lies in maximizing the kinetic asymmetry introduced by energy-driven auxiliary pathways over thermally equilibrating dynamic covalent reactions, whose microscopic reversibility and rapid equilibration intrinsically limit its amplification. Here we report a light-driven constitutional pump that addresses this limitation by embedding a unidirectional, kinetically dominant pathway onto a reversible dynamic covalent metathesis reaction, enabling the system to reach high degrees of nonequilibrium under continuous irradiation. This pumping mechanism is encoded at the molecular design level through conjugative coupling between a diarylethene photoswitch and a polar olefin moiety, which simultaneously enables photonic gating to suppress reverse pathways and generates a high-energy photoisomer intermediate that imposes a strong kinetic preference. As a result, the reaction network is efficiently driven toward a nonequilibrium steady state (NESS), exhibiting pronounced constitutional selection while remaining fully reversible upon removal of the light input. This work establishes a new strategy for approaching highly nonequilibrium dynamic covalent systems and lays the groundwork for the development of life-like nonequilibrium matter.