Reaction Tomography - Atomically Resolved Imaging of Chemical Transformations with Molecular Functionalized SPM Tips

在化学系化学测量和成像计划的支持下，加州大学伯克利分校的Fischer教授正在开发原子分辨成像技术，以增强可用于成像、操纵和光谱表征表面分子结构的反应性和自组装的分析工具。这一研究计划克服了原子分辨率扫描探针技术应用中面临的挑战，使这些技术更容易为研究人员所用，并更有能力回答有关分子体系的化学组成、电子结构和反应性的重大科学问题。所开发的工具和技术不仅能够以单原子分辨率识别未知化合物，而且对所有需要精确了解原子尺度过程的纳米科学领域都有影响。这包括在能源研究、分子电子学、分子识别和传感器技术等领域开发有益于社会的新应用。这个项目的核心是跨学科科学，通过综合研究和教育部分向所有级别的学生介绍，从K-12，从本科生到研究生。作为合成有机化学暑期培训计划的一部分，从加州州立大学东湾分校招募的本科生为建立一个公共可访问的图书馆做出了贡献，该图书馆收集吸附分子系统的原子分辨图像，作为K-12和本科教育工作者的资源。该研究项目的目标是开发扫描探针显微镜(SPM)技术，能够以比以前更高的空间分辨率和元素专一性来解析单个原子和分子成键构型。一类新的分子探针尖端是从多足和螯合配体衍生而来的，这些配体选择性地结合在电蚀刻SPM尖端的低配位过渡金属上。这些化学工程的探针尖端具有电子和振动可调的尖端配置，能够诱导元素与表面分子吸附的特定共价或非共价相互作用。该项目的重点是克服目前单分子扫描探针显微镜技术面临的三个重大挑战？实现了非平面分子结构中的原子分辨，实现了原子分辨的元素组成，并实现了键强度及其顺序的无失真表征。这里开发的SPM技术解决了单分子成像前沿的关键挑战，为发现和阐明表面促进反应机理铺平了道路，并提供了对常见化学转化最基本步骤的前所未有的详细洞察。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Fischer at the University of California, Berkeley, is developing atomically resolved imaging techniques that enhance the analytical tools available to image, manipulate, and spectroscopically characterize the reactivity and self-assembly of molecular structures on surfaces. This research program overcomes challenges faced in the application of atomic-resolution scanned probe techniques, and makes these techniques both more accessible to researchers and more capable of answering significant scientific questions regarding the chemical composition, electronic structure, and reactivity of molecular systems. The tools and techniques developed are not only be able to identify unknown compounds with single-atom resolution, but have an impact on all nanoscience areas that require precise knowledge of atomic-scale processes. This includes the development of new applications that benefit society in the areas of energy research, molecular-scale electronics, molecular recognition, and sensor technology. The interdisciplinary science that lies at the core of this project is introduced to students at all levels, from K-12, across the undergraduate to the graduate level via integrated research and educational components. Undergraduate students recruited from California State University East Bay as part of a summer training program in synthetic organic chemistry contribute to the establishment of a publicly accessible library for atomically-resolved images of adsorbed molecular systems that serve as a resource for K-12 and undergraduate educators. The goal of this research project is to develop scanned probe microscopy (SPM) techniques capable of resolving individual atoms and molecular bonding configurations with higher spatial resolution and elemental specificity than previously possible. A new class of molecular probe tips is derived from multipodand chelating ligands that selectively bind to low-coordinated transition metals lining the apex of electrically etched SPM tips. These chemically engineered probe tips feature electronically and vibrationally tunable apex configurations capable of inducing element specific covalent or non-covalent interactions with molecular adsorbates on surfaces. The project focuses on overcoming three significant challenges currently faced by single-molecule SPM techniques ? achieving atomic resolution in non-planar molecular structures, achieving atomically-resolved elemental composition, and achieving distortion-free characterization of bond strengths and their order. The SPM techniques developed herein address key challenges at the forefront of single molecule imaging, pave the way for the discovery and elucidation of surface facilitated reaction mechanisms, and provide an unprecedented detailed insight into the most elemental steps of common chemical transformations.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.