Interfacial Forces and Novel Self-Assembled Surface Structures

本提案中的研究探讨了在界面处发生的一些基本过程。 所谓界面，我们指的是物质的两个不同相之间的连接：这里是液-固界面。 固液界面上发生的事件是许多化学过程的基础，实际上往往主导着许多化学过程，这些化学过程既有学术意义，也有实际意义。 例如，大宗和精细化学品的工业合成;医疗设备中生物分子的检测;以及许多环境过程都可以在固液界面发生。本研究的一个主题是手性分子的检测和分离。 手性分子有两种形式，它们实际上是彼此的镜像。 这两种形式具有相同的物理特性，因此难以检测。 然而，如果它们与另一个手性分子接触，它们的反应就不同了。 手性分子不仅仅具有学术意义：几乎所有的生物系统都是由它们控制的。 因此，许多药物分子是手性的。 例如，用于治疗哮喘的药物沙丁胺醇或ventolin（TM）有两种手性形式，称为R-和S-对映体，并且由50/50混合物组成。 R-对映体是活性形式，而S-对映体被一些人认为会产生许多与药物相关的副作用。 这种行为与许多药理学物质有关，因此开发检测和分离手性分子的方法非常重要。 我们的研究重点是了解在称为手性色谱的过程中分离手性分子的R和S版本的基本结构-性质关系。 ** 我们的第二个研究主题涉及一种以前未被认识到的使用自组装过程修饰表面的方法：在这里，一个无序的分子系统自发地演变成一个有序的结构，在这种情况下，表面上的单层分子。 我们的目标分子被称为N-杂环卡宾，或NHC。 这类分子已经知道了一段时间，并且经常被发现作为各种催化剂的组分。 但我们发现，它也可能用于在Au和潜在的其他金属上形成自组装单层，并可以深刻改变金属的性质-包括在光学，微电子和检测技术中的潜在应用。 此外，我们已经发现，碳-金属结合的基于NHC的单层可能比该领域中基于硫-金属化学键的当前最先进技术稳定得多。 基于NHC的自组装系统目前还是一个很大的未知数，但它有可能彻底改变许多技术。 在这项研究中，我们打算专注于NHC自组装过程的基本方面，以及NHC膜如何用于取代生物医学检测技术中的硫基化学，称为表面等离子体共振。总之，界面化学是各种过程的基础，如化合物混合物的纯化、生物分子的检测以及新的光子和电子器件的生产。 我们将解决的问题，将通知这些问题的新方法，因为我们专注于两个表面上的自组装和方法探索发生在这些表面的化学相互作用的新系统的发展。 在任何时候，五名博士生和一名本科生将从事这项研究，为政府或企业实验室，商业或学术界的职业生涯做准备。

The research in this proposal explores some of the fundamental processes that take place at interfaces. By interface, we mean the junction between two different phases of matter: here, the liquid-solid interface. The events that take place at solid-liquid interfaces are fundamental to, and indeed often dominate, many chemical processes that are of both academic and practical interest. For example, industrial synthesis of both bulk and fine chemicals; detection of biological molecules in medical devices; and many environmental processes can all take place at a solid-liquid interface.**One theme in this research is the detection and separation of chiral molecules. A chiral molecule is one which comes in two forms, which are literally mirror images of one another. The two forms have the same physical properties and so are difficult to detect. However, they react differently if they come into contact with another chiral molecule. Chiral molecules have more than academic interest: just about all biological systems are dominated by them. Consequently, many drug molecules are chiral. For example, the drug salbutamol, or ventolin(TM), used to treat asthma, comes in two chiral forms, referred to as the R- and S-enantiomer, and consists of a 50/50 mixture. The R-enantiomer is the active form, while the S-enantiomer is thought by some to produce many of the side effects associated with the drug. Such behaviour is associated with many pharmacological substances, and therefore developing means of detecting and separating chiral molecules is of great importance. Our research focuses on understanding the fundamental structure-property relationships that underlie the separation of the R and S versions of chiral molecules in a process known as chiral chromatography. **Our second research theme involves a previously unrecognized means of modifying surfaces using a process of self-assembly: here, a disordered system of molecules spontaneously evolves into an ordered structure, in this case a single layer (monolayer) of molecules at a surface. Our target class of molecule is called an N-heterocyclic carbene, or NHC. This class of molecule has been known for some time, and is often found as a component of various catalysts. But we have found that it may also be used to form a self-assembled monolayer on Au and potentially other metals, and can profoundly change the properties of the metal - including potential applications in optics, microelectronics and detection technologies. Furthermore, we have found that the carbon-metal bound NHC-based monolayers are potentially far more stable than the current state-of-the-art technologies in this area, which are based on a sulfur-metal chemical bond. NHC-based self-assembled systems are currently a big unknown, but ones which have the potential to revolutionize a number of technologies. In this research, we are intending to focus on both the fundamental aspects of the NHC self-assembly process, and also how an NHC film can be used to replace the sulfur-based chemistry in a biomedical detection technology known as surface plasmon resonance.**In summary, interfacial chemistry underlies processes as diverse as purifying mixtures of compounds, the detection of biomolecules, and the production of new photonic and electronic devices. We will address questions that will inform new approaches to these problems as we focus on both the development of new systems of self-assembly on surfaces and methodologies exploring the chemical interactions taking place at these surfaces. At any time, five PhD students and one undergraduate will be engaged in this research, preparing for careers in government or corporate laboratories, business or academia.