Ligand Dynamics and Chemistry on Locally Curved Metallic Nanoparticle Surfaces

在化学学部大分子、超分子和纳米化学项目的支持下，南卡罗来纳大学的王辉博士致力于对分子配体与纳米颗粒表面之间的动态相互作用以及表面曲率依赖的配体化学和光化学进行定量理解。无机核和有机配体壳是两种结构不同但相互作用强烈的组分，它们协同决定了纳米颗粒的光学、电子和催化性能。从该研究项目中获得的见解将作为一个核心知识框架，指导胶体纳米颗粒表面功能的合理优化，以实现催化、光催化、光子学、传感和生物医学的目标应用。该项目将为不同层次的学生创造宝贵的研究培训机会，并将进一步与外展活动发展相结合。具体来说，王博士将开发一个高度跨学科的纳米颗粒表面化学研究和教育项目，涉及研究生，本科生和高中生的广泛参与。此外，王博士和他的学生将与南卡罗莱纳的传统黑人学院和大学（HBCU）本尼迪克特学院合作，在研究和教育方面建立长期合作伙伴关系。此外，王小组将与南卡罗来纳大学电子显微镜中心密切合作，开发专门针对当地公立学校学生和南卡罗来纳州立科学博览会参与者的教育推广活动。实际上，所有化学合成的无机胶体纳米粒子，无论其尺寸、晶体结构和化学成分如何，都被一层薄薄的有机分子配体所覆盖。本研究项目包括对几种精心选择的纳米颗粒配体系统进行系统的比较研究，通过综合实验和计算研究，研究分子吸附在局部弯曲的金属纳米颗粒表面上的界面动力学和化学/光化学转化。王博士和他的研究团队将利用表面增强拉曼光谱（SERS）作为超灵敏的等离子体增强光谱工具，在多种配体吸附、解吸和交换条件下，定量地将界面配体动力学与详细的分子结构联系起来。SERS还将作为一种原位光谱工具，用于在化学和光化学反应过程中，实时精细旋转在结构定制的金属纳米颗粒表面上转化分子吸附物的详细结构演变。通过精心设计的SERS测量获得的热力学和动力学结果将进一步得到密度泛函理论计算的证实，以充分揭示纳米颗粒-吸附物相互作用的化学性质和纳米颗粒表面的局部曲率如何深刻影响各种表面结合配体分子的动态界面行为和化学/光化学反应活性，如有机硫醇、异氰化物化合物、末端炔和重氮衍生芳基配体。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Dr. Hui Wang of University of South Carolina aims at developing quantitative understanding of the dynamic interactions between molecular ligands and nanoparticle surfaces as well as surface curvature-dependent ligand chemistry and photochemistry. The inorganic cores and the organic ligand shells are two structurally distinct but strongly interplaying components that synergistically determine the collective optical, electronic, and catalytic properties of the nanoparticles. The insights to be gained from this research project will serve as a central knowledge framework that guides the rational optimization of the surface functionalities of colloidal nanoparticles toward targeted applications in catalysis, photocatalysis, photonics, sensing, and biomedicine. This project will create valuable research training opportunities for students at various levels and will be further integrated with outreach activity development. Specifically, Dr. Wang will develop a highly interdisciplinary research and education program on nanoparticle surface chemistry involving broad participation of graduate, undergraduate, and high school students. In addition, Dr. Wang and his students will collaborate with Benedict College, a Historically Black College and University (HBCU) in South Carolina, to develop a long-term partnership on both research and education. Furthermore, the Wang group will work closely with the Electron Microscopy Center at the University of South Carolina on developing educational outreach activities that specifically target the students from local public schools and the participants of the South Carolina State Science Fair.Virtually all chemically synthesized inorganic colloidal nanoparticles, regardless of their dimensions, crystalline structures, and chemical compositions, are coated with a thin layer of organic molecular ligands. This research project involves systematic comparative studies of several deliberately selected nanoparticle-ligand systems to investigate the interfacial dynamics and chemical/photochemical transformations of molecular adsorbates on locally curved metallic nanoparticle surfaces through integrated experimental and computational research efforts. Dr. Wang and his research team will utilize surface-enhanced Raman spectroscopy (SERS) as an ultrasensitive plasmon-enhanced spectroscopic tool to quantitatively correlate the interfacial ligand dynamics with detailed molecular structures under a diverse set of ligand adsorption, desorption, and exchange conditions. SERS will also be used as an in situ spectroscopic tool to fine-revolve detailed structural evolution of the transforming molecular adsorbates on structurally tailored metallic nanoparticle surfaces in real time during chemical and photochemical reactions. The thermodynamic and kinetic results obtained through deliberately designed SERS measurements will be further corroborated by density functional theory calculations to fully unravel how the chemical nature of nanoparticle-adsorbate interactions and the local curvature of nanoparticle surfaces profoundly influence the dynamic interfacial behaviors and the chemical/photochemical reactivities of various types of surface-bound ligand molecules, such as organothiols, isocyanide compounds, terminal alkynes, and diazonium-derived aryl ligands.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.