Surface solvation and hindered isomerization at the water/silica interface explored with second harmonic generation.
Surface solvation and hindered isomerization at the water/silica interface explored with second harmonic generation.
复制标题
通过二次谐波产生探索水/二氧化硅界面的表面溶剂化和受阻异构化。
DOI：
10.1063/1.5066451
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
R. Walker
中科院分区：
文献类型：
--
作者：
Grace E Purnell;R. Walker
共振增强二次谐波产生（SHG）光谱的香豆素152（C152）吸附在水-二氧化硅界面显示，C152的经验，局部介电环境比散装水的极性略强。这一结果与最近报道的时间分辨荧光实验和模拟结果相反，该实验和模拟结果表明，在强关联的亲水性固体表面，界面水具有类似烷烃的介电常数。两者合计，这些结果意味着，虽然在整个水-二氧化硅界面的静电场可能是大的，限制水动力学导致明显的非极性溶剂化行为类似于所经历的溶质在禁闭。共振增强的SHG光谱和时间分辨荧光C152吸附到水性疏水性二氧化硅表面表明，当水的氢键与二氧化硅表面的能力被消除，溶质的界面溶剂化和相应的能力，以photoisomerize收敛到一个中间极限类似的散装丙酮或甲醇中经历的。虽然水的结构和动力学在固-液界面已经得到了相当大的关注，下面给出的结果显示如何强大的溶剂-基质相互作用可以创建跨埋界面的溶质反应性的冲突图片。
Resonantly enhanced second harmonic generation (SHG) spectra of Coumarin 152 (C152) adsorbed at the water-silica interface show that C152 experiences a local dielectric environment slightly more polar than that of bulk water. This result stands in contrast to recently reported time-resolved fluorescence experiments and simulations that suggest an alkane-like permittivity for interfacial water at strongly associating, hydrophilic solid surfaces. Taken together, these results imply that while the static electric field across the aqueous-silica interface may be large, restricted water dynamics lead to apparent nonpolar solvation behavior similar to that experienced by solutes in confinement. Resonance-enhanced SHG spectra and time-resolved fluorescence of C152 adsorbed to aqueous-hydrophobic silica surfaces show that when water's ability to hydrogen bond with the silica surface is eliminated, a solute's interfacial solvation and corresponding ability to photoisomerize converge to an intermediate limit similar to that experienced in bulk acetone or methanol. While water structure and dynamics at solid-liquid interfaces have received considerable attention, results presented below show how strong solvent-substrate interactions can create conflicting pictures of solute reactivity across buried interfaces.
复杂的均质和异质荧光各向异性衰减：提高分析精度。
影响因子：
3.4
作者：
Bajzer,Z;Moncrieffe,MC;Penzar,I;Prendergast,FG
通讯作者：
Prendergast,FG