Light-Driven Constitutional Pump Powers Far-From-Equilibrium Dynamic-Covalent Behavior

28 February 2025, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Accessing non-equilibrium states in dynamic covalent chemistry (DCC) remains fundamentally challenged by microscopic reversibility and rapid equilibration. Drawing inspiration by the kinetic asymmetry mechanisms prevalent in living organisms, we introduce a light-driven constitutional pump that establishes a unidirectional kinetic pathway beyond intrinsic equilibria, that autonomously driving a dynamic covalent C=C/C=N metathesis reaction far from equilibrium. This pump operates through a kinetic ratchet mechanism under single-wavelength photonic control: (1) photocyclization of a diarylethene-based Knoevenagel derivative generates a high-energy photoisomer (ΔG = 22.5 kcal/mol), (2) irreversible covalent metathesis (K > 10^16) releases stored chemical potential, and (3) a photon-energy-gated ring-opening reaction enforces pathway unidirectionality. The resulting strong directional bias drives the system to a non-equilibrium steady state (NESS), achieving a 28-fold amplification of the equilibrium constant while preserving closed-system reversibility. Integrated into polymer networks, this pump enables spatiotemporal control over crosslink density, producing photo-adaptamers with non-equilibrium modulus switching. Unlike catalytic approaches, this platform achieves kinetic control by elevating the energy of intermediates through photonic programming, establishing DCC as a versatile toolbox for designing life-inspired adaptive materials.

Keywords

dynamic covalent chemistry
non-equilibrium
constitutional dynamic chemistry
diarylethenes

Supplementary materials

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detailed synthetic methods and characterization data
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