Chemical adsorption of molecules to nanomaterials imparts thermodynamic and kinetic variations to molecular reactivity. However, these differences are challenging to measure or predict and thus are frequently overlooked in nanomaterial/molecular interfacial systems. In this study, interfacial attachment of an azobenzene derivative to ZrO₂ nanoparticle thin films more than doubles the azobenzene thermal isomerization rate and decreases the extent of photoisomerization by up to a factor of 3 compared to that of fluid solution. The magnitude of these changes can be controlled by selectively anchoring either the cis or trans isomer of azobenzene to the ZrO₂ film. Furthermore, the coadsorption of the sterically hindering molecule chenodeoxycholic acid to a ZrO₂ thin film previously treated with cis-azobenzene results in a decreased extent of isomerization that mimics the trans-azobenzene anchored ZrO₂ film. Accordingly, steric hindrance of the azobenzene isomerization at the interface is implicated as an explanation for the observed variations in the reaction dynamics.

中文翻译：

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ZrO ₂纳米薄膜上固定的偶氮苯衍生物的分子内异构化反应的控制

分子对纳米材料的化学吸附使分子反应性具有热力学和动力学变化。然而，这些差异难以测量或预测，因此在纳米材料/分子界面系统中经常被忽略。在这项研究中，偶氮苯衍生物与ZrO ₂纳米颗粒薄膜的界面结合使偶氮苯的热异构化速率增加了一倍以上，并且光异构化的程度降低了多达3倍（与流体溶液相比）。这些变化的幅度可以通过将偶氮苯的顺式或反式异构体选择性锚定到ZrO ₂上来控制电影。此外，空间阻碍分子鹅去氧胆酸对预先用顺式-偶氮苯处理的ZrO ₂薄膜的共吸附导致模仿反式-偶氮苯锚定的ZrO ₂膜的异构化程度降低。因此，暗示了在界面处的偶氮苯异构化的空间位阻，作为所观察到的反应动力学变化的解释。