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Synthesis of covalently bonded molecular nano-architectures on surfaces modeled from first principles

根据第一原理在表面上合成共价键合分子纳米结构

基本信息

批准号：
187085969
负责人：
Professor Dr. Wolf Gero Schmidt
金额：
--
依托单位：
Arbeitsgruppe Theoretische Materialphysik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2011
资助国家：
德国
起止时间：
2010-12-31 至 2012-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/187085969?language=en
关键词：
Synthesis covalently bonded molecular nano

项目摘要

A wide variety of highly regular supramolecular architectures, based on noncovalent bonds, has been realized on single crystal metal surfaces over the past decade. Many potential applications, e.g., in bottom-up device technology, however, require a thermal and chemical stability that can only be provided by covalent bonding. In response to this need a number of attempts to fabricate covalently interlinked polymeric networks on single crystal metal surfaces have recently been made. Thereby it was noted that some reactions known from 3D chemistry occur differently when the reaction partners are confined to two dimensions and in some cases entirely novel reaction pathways were reported. Here we propose density-functional theory (DFT) calculations in order to explore in detail the influence of the surface on the thermodynamics and kinetics of chemical reactions. In particular we aim at identifying and exploring systems, where the substrate acts simultaneously as a template and a catalyst, as they seem especially promising for controllable reactions at surfaces. Thereby we focus on prototypical examples such as surface-supported tautomerization of pyrimidine groups, Ullmann couplings, imidization condensation of amines and anhydrides, esterification between boronic acid and diol groups, imine formation from aldehydes and amines, and the reaction of activated porphyrins on metal substrates. Various potential mechanisms like steric hindrances, electron transfer and screening effects, chemical interactions with the substrate as well as the direct involvement of substrate atoms in the reaction will be investigated for the coin metal (111), (110), and (001) surfaces in order to establish chemical trends and arrive at a deep and thorough understanding of the covalent synthesis at surfaces.

在过去的十年中，在单晶金属表面上已经实现了各种基于非共价键的高度规则的超分子结构。许多潜在的应用，例如，然而，在自下而上器件技术中，需要热稳定性和化学稳定性，这只能通过共价键合来提供。为了满足这一需要，最近已经进行了许多在单晶金属表面上制造共价互连的聚合物网络的尝试。因此，人们注意到，当反应伙伴被限制在二维时，从3D化学已知的一些反应以不同的方式发生，并且在某些情况下，报道了全新的反应途径。在这里，我们提出了密度泛函理论（DFT）计算，以详细探索的热力学和化学反应动力学的表面的影响。特别是，我们的目标是识别和探索系统，其中基板同时作为模板和催化剂，因为它们似乎特别有希望在表面的可控反应。因此，我们专注于原型的例子，如表面支持的嘧啶基团的互变异构化，乌尔曼耦合，胺和酸酐的亚胺化缩合，硼酸和二醇基团之间的酯化反应，从醛和胺形成亚胺，以及活化的卟啉在金属基底上的反应。各种潜在的机制，如空间位阻，电子转移和屏蔽效应，与基板的化学相互作用，以及基板原子在反应中的直接参与将被调查的硬币金属（111），（110）和（001）表面，以建立化学趋势，并达到在表面的共价合成的深入和彻底的理解。