School of Chemistry & Physics

Dr Thishana Singh

Senior Lecturer

Computational chemist in the inter-domain field of Physical-Organic Chemistry. Prior to joining academia, she worked in both the industrial and medical environments. She successfully completed a two-year postdoctoral visit at Stockholm University, Sweden, with Prof PG Andersson where she worked on transition-metal catalysed reactions. 

Dr Singh’s research is the quantum chemical modelling of homogenously catalysed organic reactions to reveal the reaction mechanism and to understand the selectivity process of the catalyst in a reaction.

Research interests

  • Computational chemistry
  • Chemical kinetics
  • Thermodynamics

Research profiles

Research overview

The focus of Dr Singh’s research area falls into two categories: Green Chemistry and Computational Nutraceutics. Computational chemistry is used as a tool in the field of Green Chemistry to develop efficient catalytic systems using abundant, inexpensive and environmentally friendly metals such as copper. This is an area where much focus and attention is dedicated to designing synthetic routes and products that require the use of non-toxic starting materials and generate the least amount of hazardous waste. “Computational Nutraceutics” is a term that was coined in 2013 as a new concept for predicting the molecular structure, spectroscopy, and chemical reactivity of bioactive compounds using computational chemistry. The aim is to understand enzyme-inhibitor interactions that will aid in the synthesis and strategic design of novel drugs for the treatment of diseases such as TB and cancer.

Current projects

There are a few projects currently being done which involve the quantum chemical modelling of homogenously catalysed organic reactions. The aim is to reveal the reaction mechanism and to understand the selectivity process of the catalyst in a reaction. One projects focuses on the kinetic resolution of racemic allylic alcohols via asymmetric hydrogenation and the other is enantio convergent hydrogenation of enamides. Dr Singh is  currently investigating the structural and electronic properties of a few bioactive triterpenoic acids: using density functional theory (DFT) to provide insight on the stability, reactivity and selectivity of these compounds as possible drug candidates. Calculated spectroscopic parameters such as UV-vis and IR are in agreement with experimental data. Charge distribution, frontier molecular orbitals, electrostatic potential plots, global and local reactivity descriptors were computed to predict the reactivity and the active sites on these molecules. Non-linear optical (NLO) properties, natural bond (NBO) and Fukui function analysis was also carried out. The study provides a theoretical understanding of the bioactivity.

Media

A DFT study of polyaniline/ZnO nanocomposite as a photocatalyst for the reduction of methylene blue dye published in the Journal of Molecular Liquids, 2019.

Collaborators

  • Dr J-Q Li, China Agricultural University, Beijing, China
  • Dr J Liu, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, China
  • Dr K K Govender, Centre for High Performance Computing, Pretoria
  • Dr K Anand, National Health Laboratory Service, University of the Free State, Bloemfontein.
  • Prof P G Andersson, Stockholm University, Sweden.
  • Dr S Kerdphon, Naresuan University, Thailand
  • Dr T Zhou, Southwest Petroleum University, Sichuan, China