Bioinspired Nanofluidic Temperate Synthesis

ConspectusThe development of new methodologies for efficient and selective catalysis under mild, green conditions is critical in synthetic chemistry. While nanoconfined catalysis has emerged as a powerful way for modulating reaction pathways, existing systems lack continuously interconnected confined channels and fail to achieve precise control over the size and length of these channels, making it difficult to achieve rapid reaction at room temperature, along with difficulty in achieving ∼100% conversion and ∼100% selectivity. Learning from nature may provide a solution to this challenge. As natural catalysts, enzymes demonstrate remarkable efficiency and selectivity to certain reactions with ultralow-energy-consumption (UEC) features. Recently, a fundamental question has emerged in life sciences: how do living systems achieve UEC features in highly efficient biological processes, particularly biosynthesis? To achieve bionic UEC temperate synthesis, we propose a concept of "bioinspired nanofluidic temperate synthesis". The core innovation lies in the synergistic integration of several bioinspired design elements: (1) the precise control of channel size (interlayer spacing or pore size) to a scale comparable to molecular dimensions, which promotes the formation of "ultrafast ordered molecular fluid" and enhances reactant confinement; (2) strategic incorporation of tailored catalytic sites (e.g., Lewis and Brønsted acid, Lewis base) on the channel wall to selectively activate substrate; (3) rational incorporation of binding sites (e.g., graphitic domains, oxygen vacancies (V_O)) on the channel wall to facilitate absorption of reactants. The engineered nanochannel mimics the function of an enzyme's active site and its surrounding pocket, enabling reactions to proceed along energetically favorable pathways under mild conditions. Our experimental implementation of this concept has validated its transformative potential. Stereoregulated polymerizations have been achieved using zinc porphyrin metal-organic framework membranes featuring 1D nanochannels. Utilizing 2D GO-based membranes, we have achieved high-performance flow reaction at ambient temperature, achieving ∼100% conversion and ∼100% selectivity for diverse reactions, including Knoevenagel condensation, esterification, and ring-opening reactions. Using transitional metal oxide membranes, we have achieved ∼100% conversion and ∼100% selectivity in the synthesis of acetate ester flavors and in benzylamine coupling reactions. Despite significant progress, there are still challenges to learn from the process of DNA replication resonantly driven by adenosine triphosphate releasing photons, and to develop a new reaction type, which uses low-energy photons at a specific frequency to break specific chemical bonds in a resonant manner. The rational design of active sites, fine-tuning of channel sizes, development of in situ/operando characterization methods, and application of external fields remain underexplored. This account summarizes recent progress in bioinspired nanofluidic membrane reactors and outlines future directions toward sustainable flow synthesis.