Interrelation of crystal morphology and intermolecular contacts in a newthiophosphoramide structure: an energy framework analysis

The morphology of the crystal structures is an influencing factor on some physical properties.Particularly, morphology affects the dissolution rate, tabletibility, and stability of pharmaceuticals[۱,۲]. In a crystal lattice, the morphological feature originates from the intermolecular interactions[۳,۴]. Understanding the interplay of “intermolecular interactions” and “morphological features”can help to provide insight into changing the properties. Herein, the synthesis, characterization,and crystal structure of a new thiophosphorylated thiourea with the formula(C۲H۵O)۲P(S)(NHC(S)NHCH۲(C۴H۷O)) is reported. The N—H···S═C and C—H···S═Chydrogen bonds are the strongest intermolecular interactions, which appear as red spots on theHirshfeld surface map and propagate the molecular assembly along the b-axis. The energyframeworks, calculated using CE-B۳LYP/۶-۳۱G(d,p) method, show that these interactions takepart in the most potent molecular pairs (with the energy values of –۵۷.۲ and –۴۸.۸ kJ/mol) in thestructure. Interaction energies in two other directions are remarkably weaker. The combinations ofthe interactions in the b-direction with some weaker interactions lead to the formation of platesparallel to the ab-plane. The plates (with a thickness of about ۱ nm) are stacked together with theweakest interactions. This feature reduces the ability of the crystal to grow in the c-directioncompared to the a- and b- directions.

Keywords:

Thiophosphoramide , Morphology , Interactions , Energy framework , DFT