Interplay between the crystal stability and the energy of the molecular conformation

Abstract

The specially designed new compound of 5,5’-bis(4-hydroxyphenyl)-2,2’-dihydroxy-1,1’-biphenyl, can crystallize in different crystallographic systems. The molecule adopts the C–conformation for the torsion angle around 60o and the T–conformation for the angle...

Solvent induced conformational polymorphism

“…However, less thermodynamically stable crystals can also form during the crystal growth, which could be related to the kinetics. 4–7 Oswald stated that the polymorphs represent metastable forms in the free energy landscape. The metastable form of a given chemical system does not search for the most stable form but for the closest metastable one that can be adopted with the least loss of free energy.…”

“…5 Typically, the formation of different polymorphs by crystallization from different solvents, by milling and recrystallization, can be observed. 4,8–10 The arrangement of molecules in the different polymorphs is stabilized by different inter- and intramolecular interactions between the molecules. In turn, this leads to the achievement of a stable or metastable crystalline phase.…”