Can crystal structure prediction be used as part of an integrated strategy for ensuring maximum diversity of isolated crystal forms? The case of 2-amino-4-nitrophenol

Crystal structure prediction was used to explore possible modes of assembly of 2-amino-4-nitrophenol (ANP) molecules in the solid state. The results from this simulation were employed for the rational selection of solvents for the isolation of solid phases by solution crystallisation. Implementation of this crystal engineering based approach is seen as a first step in utilising predicted structural data and in this example resulted in the isolation of three crystal forms, one non-solvated structure and two solvated forms. Though too complex to be predicted, each contained elements of the packing modes identified from the crystal modelling simulations. This work demonstrates the potential application and limitations of available crystal structure modelling techniques as part of a strategy for the discovery of new crystal forms of molecular materials.