First principles investigation on the polymorphs of symmetrically substituted thiourea derivatives / Nur Najwa Alyani Mohd Nabil

Polymorphism is a well-known phenomenon where a compound is able to form more than one crystalline form in the solid state. Compounds having this ability would display different stabilities for different forms, hence affecting its applicability. In this study, polymorphism on 26 symmetrically substituted thiourea derivatives, which possess rotational flexibility in the C-N bond, were carried out using theoretical investigations. To find the yet to be found possible stable configurations, exhaustive computations at the adequate level of theory B3 L YP / def2-TZVP were performed on the monomers and dimers of the compounds. Rotating the substituents along the C-N bond, starts from the existing stable configuration shows that energetically CT and TT configurations are equally preferable.