Fig. 2: Typical cases of local reactivity control for small-molecule chemistry in coacervates.
From: Recent advances in coacervate protocells from passive catalysts to chemically programmable systems
a Formulation reweights the medium. Interpolyelectrolyte complexes (PDADMAC/PAA) provide a productive window for the Knoevenagel condensation: (I) reaction and coacervate droplets schematic; (II) time-resolved UV–vis shows faster product build-up with coacervate droplets than in buffer (inset, absorbance–time trace). Reproduced with permission33. Copyright 2025, Royal Society of Chemistry. b Coacervate droplets engulf hydrophobic reactants as embedded organic microdroplets. At the coacervate/organic interface, a PAA-rich layer interacts with the thiazolium precatalyst to generate the NHC in situ, enabling base-free Stetter C-C coupling and yielding higher conversion/selectivity than in water or THF—an interface-driven effect beyond simple concentration. Reproduced with permission36. Copyright 2025, American Chemical Society. c In-phase photophysics as an antenna. TPPS/DEAE–dextran coacervates assemble TPPS into porphyrin J-aggregates and enrich iodide (I⁻) in the dense phase. Upon visible irradiation (hν), excited TPPS transfers energy to ³O₂ to generate ¹O₂, which oxidizes I⁻ to I₃⁻, resulting in enhanced photocatalytic iodide oxidation (stepwise scheme). Reproduced with permission37. Copyright 2022, Royal Society of Chemistry. d Hydrophobic subcompartments act as microreactors. DNA protocells doped with a PEG-based amphiphilic block copolymer (forming hydrophobic subcompartments) localize and accelerate a self-reporting retro-Diels–Alder reaction: a protected dansylfuran pro-fluorophore undergoes retro-DA cleavage in the presence of a nucleophilic catalyst (e.g., DMAP: 4-dimethylaminopyridine) to release fluorescent dansylfuran. (I) design schematic; (II) fluorescence at 570 nm vs time inside the polymer-doped protocells versus plain protocells (inset, initial-slope comparison), showing faster, compartment-localized product build-up in the hydrophobic domains. Reproduced with permission39. Copyright 2023, American Chemical Society. e Definition of the “red-line” boundary (loss of acceleration). Bright-field images (scale bar, 10 μm): (1) no LLPS (homogeneous), (2) stable coacervate droplets, (3) incipient aggregation, (4) solid-like aggregates. Crossing this boundary corresponds to stronger interactions and increased microviscosity/immobilization, which reduces molecular exchange and diminishes catalytic gains. Reproduced with permission41. Copyright 2024, Springer Nature.
