Detailed Analysis of Packing Efficiency Allows Rationalization of Solvate Formation Propensity for Selected Structurally Similar Organic Molecules

In structural study of seven bile acids it was identified that their propensity for solvate formation is directly related to the packing efficiency of the unsolvated phases: low packing index, voids, and unsatisfied hydrogen bonding lead to extensive solvate formation, whereas efficient packing leads to the opposite. This was determined to be caused by the presence of OH group attached to carbon C12. Solvate formation was determined to provide a noticeable improvement in the packing efficiency for compounds having ansolvates with inefficient packing.