Zhang Yiqing, Blum Suzanne A
Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States.
J Org Chem. 2025 Aug 22;90(33):11883-11889. doi: 10.1021/acs.joc.5c01297. Epub 2025 Aug 13.
Fluorescence lifetime imaging microscopy (FLIM) enabled identification of three-phase emulsions during a cross-coupling reaction in water, offering insight into their features and factors driving their formation. Droplet morphology was influenced by surfactant choice, ionic strength through phosphate concentration, and evolution of the reaction medium composition. Spatially resolved, subdroplet imaging characterized two organic phases, with one exhibiting preferential localization of the palladium catalyst. Anisotropy and solvatochromic polarity measurements indicated that the palladium-catalyst-containing organic-droplet core exhibited higher viscosity than the organic shell, whereas the polarity of the two organic phases was indistinguishable within the solvatochromic detection capability. The presence of three-phase emulsions correlated with overall formulation and with faster rates of product generation. These findings provide insight for composition-droplet structure relationships toward optimizing aqueous-phase organic reactions and advancing synthetic organic chemistry in water.
荧光寿命成像显微镜（FLIM）能够在水中的交叉偶联反应过程中识别三相乳液，从而深入了解其特征以及驱动其形成的因素。液滴形态受表面活性剂选择、通过磷酸盐浓度体现的离子强度以及反应介质组成的演变影响。空间分辨的亚液滴成像表征了两个有机相，其中一个显示出钯催化剂的优先定位。各向异性和溶剂化显色极性测量表明，含钯催化剂的有机液滴核心的粘度高于有机壳层，而在溶剂化显色检测能力范围内，两个有机相的极性无法区分。三相乳液的存在与整体配方以及更快的产物生成速率相关。这些发现为优化水相有机反应和推动水中合成有机化学发展的组成 - 液滴结构关系提供了见解。
