Theoretical Studies of Molecular Structure, Dynamics, and Reactivity at Liquid Interfaces
نام عام مواد
[Thesis]
نام نخستين پديدآور
Karnes, John Joseph
نام ساير پديدآوران
Benjamin, Ilan
وضعیت نشر و پخش و غیره
تاریخ نشرو بخش و غیره
2018
یادداشتهای مربوط به پایان نامه ها
کسي که مدرک را اعطا کرده
Benjamin, Ilan
امتياز متن
2018
یادداشتهای مربوط به خلاصه یا چکیده
متن يادداشت
Computational studies of liquid interfaces were performed to address a series of open questions across several distinct systems. Binary solvent mixtures of methanol and acetonitrile at the hydroxylated silica interface demonstrate that methanol, each molecule able to form two distinct hydrogen bonds with the silica surface, is energetically favored at the liquid/silica interface. The mechanism by which methanol displaces acetonitrile from the interface is a two-step process where the approaching methanol establishes itself at the surface with one hydrogen bond before ``locking'' into place when the second hydrogen is formed. Subtle differences in the induced ordering and structure of liquid methanol and ethanol at the silica interface make methanol's interfacial structure invisible to some nonlinear spectroscopic techniques while the similar, expected ordering is detected at the liquid ethanol/silica interface. This difference in spectroscopic response results from methanol's shorter alkyl tail being unable to span the interface at realistic silanol site densities. The function of \beta-cyclodextrin (\beta-CD) as inverse phase transfer catalyst in the reaction \ch{CN- + CH3(CH2)6CH2Br <-> CH3(CH2)6CH2CN + Br-} is studied in two contexts. Thermodynamic calculations on the formation and stability of the \beta-CD/1-bromooctane host/guest complex reveal the \beta-CD promotes transport of the organic reagent toward the nucleophile-rich aqueous phase. Using an empirical valence bond approach, \beta-CD is also shown to act as a conventional catalyst, reducing the free energy barrier to reaction when a model S_{\text{N}}
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