Exploring the structural landscape of molecular materials: multiple crystal forms, solid-state properties and patenting issues

The concept of crystal engineering is making crystals with a purpose and it is an indisputable fact that multicomponent molecular solids such as co-crystals, metal-organic frameworks (MOFs), and solid solutions are at the forefront of crystal engineering research. Multicomponent crystalline systems are important targets in the quest for novel solid forms that can show improvement of physical and chemical properties (solubility, intrinsic dissolution rate, morphology, thermal and hydration stability, etc.) compared to those of the parent components. As a result, multicomponent solids can find application in a variety of industrial fields. The research activity performed in my PhD was mainly dedicated to the investigations of multicomponent crystalline assemblies, namely molecular and ionic co-crystals and molecular solid solutions. The project can be subdivided into the following topics: 1. Investigation of solid solutions consisting of organic molecules. 2. Co-crystallization as a tool to modify physicochemical properties of interest. 3. The effect of co-crystallization on chirality and its possible application for chiral resolution. The first two parts of the project were focused on the search for novel multicomponent crystalline assemblies capable of modifying the physicochemical properties of interest: thermostability for the obtained molecular solid solutions and enhancement of the solubility and intrinsic dissolution rate characteristics for the ionic co-crystals. The final chapter of this project was dedicated to the investigation of the influence of co-crystallization of chiral molecules of pharmaceutical interest with inorganic salts.