Investigations of potential energy surfaces and reaction mechanisms in organic chemistry, radical chemistry , and material chemistry
Title: Investigations of potential energy surfaces and reaction mechanisms in organic chemistry, radical chemistry , and material chemistry
SNIC Project: SNIC 2021/5-213
Project Type: SNIC Medium Compute
Principal Investigator: Peter Dinér <diner@kth.se>
Affiliation: Kungliga Tekniska högskolan
Duration: 2021-05-01 – 2022-05-01
Classification: 10405 10407
Homepage: https://www.kth.se/che/orgkem/research/diner/peter-diner-associate-professor-docent-1.417177
Keywords:

Abstract

This projects aims to use computational chemistry to better understand reaction mechanisms in organic chemistry. By the use of density functional theory calculation, a better understanding of the structure and reactivity of reactants, intermediates, and product leads to insight in the development of new reactions in organic chemistry. The reactions that will be studied include radical species in photoredox catalysed reactions, transition states of polymerisation processes and supramolecular structures in gels. In the first project, we will utilise DFT calculation to investigate the potential energy surface of photoredox-based chemistry. In photoredox catalysis, light is used to generate radical species that react in a selective manner. In order to understand the reactivity of the elusive radicals (that are transient in there nature and are difficult to detect experimentally), we will optimise the radical species and transition states using DFT and from these results correlate with the reactivity that we observe experimentally. Since the molecules we will investigate are open-shell radical species it is important to verify that the metods we use are consistent, which usually take a lot of effort and computational demand. Examples of reaction that will be investigated is photoredox catalysed functionalization of carbohydrates and photoredox catalysed syntheses of spiro-compounds. The second project of this proposal relates to the catalytic reactivity of cyclic carbonates and how the reactivity changes with different ring sizes. The overall gaol with this project is to produce sustainable polymers that can replace fossil-based plastics and this project is a collaboration between my group and Assoc. Prof. Karin Odelius. The computational challenge of this project is the conformational flexibility of the large macrocyclic carbonate substrates. In order to model the reactivity, a large ensemble of conformation have to be sampled using molecular mechanics (Macromodel) in the Schrödinger suite which will lead to many calculations of transition states of the rate-limiting step of the reaction that will be the bottle-neck for this reaction. The Tetralith cluster is well suited to perform these optimisations using both the Schrödinger suite including Jaguar. The third project concerns the understanding of the supramolecular structure of low-molecular gels. In my lab, we discovered a low-molecular sulfonimidamide gelates unipolar solvents. The computational part of this structure will be to calculate the possibles helical structures using DFT and to correlate these structures with the obtained ECD-spectra and the calculated spectra. Due to the supramolecular structures of the gels, the systems are quite large and needs high-performing computational resources to be carried out in an reasonable time. The project will start with conformational analysis of the supramolecular structures using molecular mechanics in the Schrödinger suite and continue with the TDFT-based calculations of the ECD-spectra in order to correlate them with experimental spectra.