Chemistry and Electrochemistry of Molecule-Like Nanoparticles

北卡罗来纳大学教堂山分校的Royce W.Murray教授得到了分析和表面化学计划的支持，该计划研究金属纳米颗粒，重点是直径从3纳米到略低于1纳米的颗粒。重点是单层保护金属簇合物(MPC)的制备和表征的先进技术，MPC是通过保护硫酸盐配体的单层来稳定金属或类金属核心的化合物。在所研究的尺寸范围内的金属纳米颗粒位于块状金属和离散分子之间的过渡区域，并且表现出依赖于核尺寸和保护单分子膜的化学性质的性质。研究小组正在探索合成策略，以制备越来越小和更高度单分散的MPC，并使金属核心组成和配体功能基团(荧光团、氧化还原基团和分析上有用的结合位点)发生变化。分析方法正在开发中，特别关注于高效液相色谱分离和光学和电化学检测策略，以阐明MPC的尺寸分散性。不同大小的MPC的电子转移化学的能量学和动力学正在通过比较最大的MPC显示连续的电子荷电、较小的MPC显示量化的双层电荷和最小的核心MPC显示分子样的同/卢莫带隙来探索。我们还研究了配体交换反应和附着在金属核配体单分子膜上的荧光团的激发态行为。这项研究正在开发必要的工具来研究溶液中金属团簇的金属到分子的过渡区。这项工作在应用领域产生了影响，包括化学传感和开发用于电子电荷传输的纳米级管道。

Professor Royce W. Murray of the University of North Carolina at Chapel Hill is supported by the Analytical and Surface Chemistry program to investigate metal nanoparticles with emphasis on particles in the range from 3 nm to just below 1 nm in diameter. Focus is on advancing techniques for the preparation and characterization of monolayer-protected metal clusters (MPCs), compounds that have metal, or metal-like, cores stabilized by protecting monolayers of thiolate ligands. Metal nanoparticles in the size range targeted for study lie in the transition region between bulk metals and discrete molecules and exhibit properties that are dependent on both core size and the chemical nature of the protecting monolayer. The research team is exploring synthetic strategies for the preparation of MPCs that are increasingly smaller and more highly mono-disperse and enable variations in metal core composition and ligand functional groups (fluorophores, redox groups, and analytically useful binding sites). Analytical methods are being developed with special focus on high performance liquid chromatographic (HPLC) separations and tactics of optical and electrochemical detection that elucidate MPC size dispersity. The energetics and dynamics of electron transfer chemistry of differently sized MPCs are being explored through comparisons between responses of the largest MPCs that display a continuum of electronic charging, smaller MPCs that display quantized double layer charging and the smallest core MPCs that exhibit molecule-like homo/lumo band gaps. Ligand exchange reactions and the excited state behavior of fluorophores attached to the ligand monolayer of the metal core are also being investigated.This research is developing tools necessary to study the metal-to-molecule transition region of metal clusters in solution. The work has impact in application areas that include chemical sensing and the development of nanometer-scale conduits for electronic charge transport.