Executive Summary : | It is known that the electronic behaviour and structure of materials can exhibit surprising changes at high pressures. This project aims to develop a joint approach that combines high-pressure crystallography (HPC) and computational crystallographic tools to explore structure-stability relations in molecular crystals of pharmaceutical drugs and functional materials at high pressure. Exploring the changes in chemical bonds and intermolecular interactions at very high pressures (around 1-20 GPa) in such molecular crystals would offer valuable insights into their nature and strengths. A protocol combining computational crystal structure prediction (CSP), interaction energy topologies and HPC will be employed to a series of pharmaceutical drugs in order to discover possible high-pressure crystal forms (polymorphs). Structural variations in crystal structures upon applied isotropic pressure will be employed to derive bond compressibility values of exotic bonds and intermolecular interactions. Quantitative information on the relative strengths of bonds and interactions will be applied to rationalize mechanical flexibility in molecular materials. Further, changes in interactions and properties such as electronic band gaps with pressure will be estimated using quantum periodic calculations based on the high-pressure crystal structures. Aside from these scientific goals, a major technical goal of the project is to establish a high pressure-single crystal X-ray diffraction (HP-SCXRD) facility using a diamond anvil cell and a ruby-laser pressure gauge. Such a facility (HP-SCXRD) will be the first in the country and might lead to exciting avenues in the field of structure-property relations in materials research. |