CAREER: Stable Carbenes as Surface Anchoring Groups

麻省理工学院的Jeremiah A. Johnson教授获得了“大分子、超分子和纳米化学计划”的一项奖励，他对几个纳米大小的粒子（纳米粒子）的表面进行了化学修饰，以使它们在不同的功能上更有用。广泛的现代技术，如电子、诊断系统、传感器、药物递送剂等，都依赖于纳米颗粒表面的可控、坚固的分子层涂层，这些分子层将以特定的方式与其他分子发生反应；这被称为表面功能化。令人惊讶的是，表面功能化的化学方法数量相对较少，在大多数应用中只涉及少数反应，而且每种方法都有局限性。因此，生产和使用单层功能单层的新方法可能会对广泛的技术产生巨大影响。本项目的研究重点是开发特定的碳族（活性碳化合物）作为纳米颗粒单层表面修饰的新方法。这种碳烯化学提供了一个潜在的理想组合，强表面键合和合成的多功能性，有可能成为不同现代纳米颗粒技术的理想平台。这项研究包括对nhc层形成的基础研究，以及这项技术在电子和药物输送方面的应用。这项CAREER提案研究正在与一项外展计划相结合，该计划的重点是在小学和高中举办纳米科学日和科学博览会。本提案旨在开发可寻址的n -杂环碳烯（anhc）作为制造新型金属-有机界面的通用配体。这一目标是通过三个研究重点来实现的：(1)在不同基质上形成薄膜的背景下，正在合成和研究具有不同立体体积和反应性的anhc库；(2) ANHC表面引发聚合的范围正在扩大，包括各种半导体聚合物和其他聚合物纳米结构；(3)利用扫描隧道显微镜断结（STMBJ）技术研究了双- nhcs和金属-有机ANHC导线的电子特性。所提出的ANHC的合成多样性，在广泛的衬底上形成ANHC单层并随后功能化这些单层的能力，以及形成导电ANHC-金属界面的潜力，使所提出的研究成为各种表面改性应用的平台技术。此外，这项研究的结果将被整合到一个全面的教育计划中，包括麻省理工学院和校外研究生、本科、高中和初等教育的课程开发。

Professor Jeremiah A. Johnson at the Massachusetts Institute of Technology is supported by an award from the Macromolecular, Supramolecular and Nanochemistry Program to chemically modify the surfaces of several-nanometer-sized particles (nanoparticles) in order to make them more useful for different functions. A broad range of modern technologies, e.g., electronics, diagnostic systems, sensors, drug delivery agents, etc., rely on controlled, robust coating of the nanoparticle surface with layers of molecules that will react in particular ways with other molecules; this is called surface functionalization. It is quite surprising that chemical methods for surface functionalization are relatively few in number, involving only a handful of reactions for most applications, and each of these methods has limitations. As a result, new approaches to produce and use single layers of functional monolayers could drastically impact a wide range of technologies. The research in this project focuses on the development of particular carbene families (reactive carbon compounds) as a new way of making single-layer surface modifications of nanoparticles. This carbene chemistry offers a potentially ideal combination of strong surface bonding and synthetic versatility with the potential to be the ideal platform for different modern nanoparticle technologies. The research encompasses fundamental studies of NHC-layer formation, as well as applications of this technology to electronics and drug delivery. This CAREER proposal research is being integrated with an outreach program focused on the development of a Nanoscience Day and science fair at an elementary and high school. This proposal seeks to develop addressable N-heterocyclic carbenes (ANHCs) as versatile ligands for the fabrication of novel metal-organic interfaces. This goal is being pursued through three research thrusts: (1) a library of ANHCs with varied steric bulk and reactivity is being synthesized and studied in the context of film formation on various substrates; (2) the scope of surface-initiated polymerization from ANHC surfaces is being expanded to include a variety of semiconducting polymers and other polymeric nanostructures; (3) the electronic properties of bis-NHCs and metal-organic ANHC wires is being studied using the scanning tunneling microscopy break junction (STMBJ) technique. The synthetic diversity of the proposed ANHCs, the ability to form ANHC monolayers on a wide array of substrates and subsequently functionalize those monolayers, and the potential to form conductive ANHC-metal interfaces makes the proposed research a platform technology for a variety of surface modification applications. Furthermore, the results of this research are being integrated with a comprehensive education plan that includes course development within MIT and extramural graduate, undergraduate, high school, and elementary education.