Collaborative Research: Surface Coordination Chemistry: Toward Novel Functionality via Understanding Substrate Charge Transfer and Oxidation State

在这个由化学系大分子、超分子和纳米化学计划资助的项目中，中佛罗里达大学的Talat S.Rahman教授和加州大学河滨分校的Ludwig Bartels教授及其学生将结合扫描隧道显微镜和第一性原理电子结构计算来成像和了解金属表面金属配位网络的形成。他们将详细探索这些负载型金属配位中心的电子性质，以解决以下性质：(I)电荷转移(分子与底物之间、金属中心与底物之间、金属中心与底物之间)；(Ii)分子轨道的形状和能量及其与传统金属有机化学的关系。通过选择合适的衬底电子性质来调节金属中心和配体HOMO-LUMO能隙的有效氧化态，将为局部化学和几何环境的变化提供描述符。此外，将寻求定义表面上金属中心周围的配位几何的一般规则，并将测试具有特定几何形状(例如，三角形与正方形)的配位中心的稳定性条件。这个项目将为研究生、本科生和初级科学家提供最先进的建模和/或实验室经验，他们将学习化学合成、在各种金属表面上形成金属配位网络、成像和互补从头算电子结构计算的技术。该项目包括对金属表面配位化学的系统探索，这将为建立区别于支配溶液相金属有机化学的传统配位场和结晶场理论的规则提供框架。对系统的振动和磁特性以及色散力的特殊作用的研究将进一步增加拟议工作的价值。通过理论家的领导，这个项目肯定会创造系统的理解、更深的洞察力和更快的验证结果及其对其他系统的概括。拟议的工作预计将对工业方法和整个社会产生影响，因为它提供了以确定性方式进入金属协调网络的途径。对这种结构的控制将允许从原子到宏观尺度的连续表面图案化，这对于广泛的微电子、光电子和磁性应用来说应该被证明是重要的。这项工作还将为具有广泛的国家、国际和社会影响的教育和外联活动提供机会。

In this project, funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Prof. Talat S. Rahman of University of Central Florida and Prof. Ludwig Bartels of the University of California, Riverside, and their students will use a combination of scanning tunneling microscopy and first principles electronic structure calculations to image and understand the formation of metal coordination networks on a number of metallic surfaces. They will explore in detail electronic properties of these supported metal coordination centers to address properties such as (i) charge transfer (between molecule & substrate, metal-center & molecule, and metal-center & substrate), and (ii) shape and energetics of molecular orbitals and their relation to conventional metal organic chemistry. Tuning of the effective oxidation state of metal-centers and of ligand HOMO-LUMO gaps by suitable choice of the substrate electronic properties will provide descriptors for variation of the local chemical and geometrical environment. Furthermore, general rules that define the coordination geometry around metal-centers on surfaces will be sought and conditions for stability of coordination centers with specific geometry (e.g., triagonal vs. square) will be tested. Attention will also be paid to understanding the magnetic characteristics of metal coordination centers: metal-center/molecule/substrate combinations which conspire to produce stable magnetic networks will be pursued.This project will provide state of the art modeling and/or laboratory experiences for graduate and undergraduate students and junior scientists who will be learning the techniques of chemical synthesis, formation of metal coordination networks on various metallic surfaces, imaging, and complementary ab initio electronic structure calculations. The project consists of a systematic exploration of coordination chemistry at metal surfaces which will provide the framework for establishing the rules that distinguish it from conventional ligand field and crystal field theory, which govern solution-phase metal organic chemistry. Examination of vibrational and magnetic characteristics of the systems and the special role of dispersion forces will add further value to the proposed work. Through leadership by a theorist, this project is certain to create systematic understanding, deeper insights and faster validation of findings and their generalizations to other systems. The proposed work is expected to have impact on industrial methodologies and society at large by providing access to metal coordination networks in a deterministic fashion. Control of such structures will allow continuous surface patterning from the atomic to the macroscopic scale, which should prove important for a large range of microelectronic, optoelectronic and magnetic applications. The work will also provide opportunities for educational and outreach activities with proven broad national, international and societal impact.