Cohesion in Coordination Chemistry

配位化学中的内聚力

基本信息

批准号：
258769765
负责人：
Professor Dr. Stefan Grimme
金额：
--
依托单位：
Mulliken Center for Theoretical Chemistry
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/258769765?language=en
关键词：
Cohesion Coordination Chemistry

项目摘要

This collaborative work addresses the issues of cohesion in coordination and organometallic chemistry fostered by a mutual effort in experimental and theoretical investigations of the role of predominantly non-covalent interactions (NCIs) in reactions involving d-block transition metals where intramolecular London dispersion forces are suspected to be essential to their stabilization. For years, NCIs have been overlooked in coordination chemistry. Recent research shows that accounting for the effect of these interactions was essential to produce a physically correct assessment of the importance of metals ligand retinue on association energies and on relative stabilities of intermediates. It is expected that in coordination reactions involving ligand-metal bond formation, as encountered in catalytic processes, remote organic fragments contribute to the ligand-metal association energy by way of a significant dispersion term. Recent advances in dispersion-corrected DFT (namely DFT-D3) renders the investigation of reactions involving large (100-200 atoms) transition metal complexes possible in the gas, solution, and the solid state. This constitutes a new framework for improving further the general understanding of reaction kinetic profiles, regio, chemo and stereoselectivities. However, two pitfalls remain. The first one is the lack of comprehensive accurate thermodynamic data for ligand-metal binding that could serve as standard for the evaluation of quantum chemical (QC) methods. The second, intimately bound to the improvement of the former, is rooted in the known limitations of continuum-based solvation models. The project proposes a solution based on the investigation of elementary reactions by means of isotherm titration calorimetry, a technique that allows the accurate measure of enthalpies of reactions as low as 1 kcal/mol. It targets the study of known transition metal reactions. Acquisition of thermodynamic information by ITC is to be confronted to the assessment of the same thermochemistry by theoretical methods based on DFT-D3 and coupled-cluster type wave function theory (WFT) in order to elaborate a new benchmark reference. The critical goal of this confrontation of theory with experiment is to evaluate on a systematic basis the performance of contemporary QC methods particularly for reactions occurring in solution. Further research will be focused on the joint experimental/theoretical assessment of the nature and strength of non-covalent interactions involved in so-called hemichelation by a systematic investigation of the thermochemistry of ligand interaction with hemichelates. Further research will target the synthesis of new cases of hemichelates bearing different electron-unsaturated metal centers.

这项协作工作解决了协调和有机金属化学方面的凝聚力问题，这是通过在涉及涉及D-Block过渡金属的反应中的主要非共价相互作用（NCIS）的作用中的实验和理论研究中促进的，在该反应中，涉及伦敦内部分子分散力对于稳定而言至关重要。多年来，NCI在协调化学方面一直被忽略。最近的研究表明，考虑这些相互作用的影响对于对金属配体对缔合能量和中间体的相对稳定性的重要性进行物理上正确评估至关重要。可以预期，在涉及配体 - 金属键形成的配位反应中，正如催化过程中遇到的那样，远程有机碎片通过大量分散术语有助于配体 - 金属缔合能量。分散校正的DFT（即DFT-D3）的最新进展使涉及气体，溶液和固态中可能大的（100-200个原子）过渡金属络合物的反应研究。这构成了一个新的框架，以进一步改善对反应动力学谱，regio，化学和立体选择性的一般理解。但是，仍然存在两个陷阱。第一个是缺乏可以作为评估量子化学方法（QC）方法的标准的配体 - 金属结合的全面的热力学数据。第二，与前者的改进密切相关，植根于已知的基于连续的溶剂化模型的局限性。该项目提出了一种基于通过等温滴定量热法对基本反应研究的解决方案，该技术允许对低至1 kcal/mol的反应的准确度量。它针对已知过渡金属反应的研究。 ITC对热力学信息的获取应通过基于DFT-D3和耦合群集类型波函数理论（WFT）的理论方法来评估相同的热化学，以详细阐述新的基准标准。与实验对抗的这种对抗的关键目标是在系统的基础上评估当代QC方法的性能，尤其是对于解决方案中发生的反应。进一步的研究将集中在通过对与半理群体配体相互作用的热化学相互作用的系统研究，对参与所谓的半偏度的非共价相互作用的性质和强度的联合实验/理论评估。进一步的研究将针对带有不同电子不饱和金属中心的新的半精灵病例的合成。