Molecular conformational transition of chiral conjugated enantiomers dominated by Wallach's rule

Comparison of racemic and homochiral analogues reveals that the racemic compounds appear to crystallize easily upon external thermal annealing and show more stable morphology. These differences will induce the formation of a planar conformation in a racemic crystalline film but not in chiral enantiomers, which confirmed Wallach's rule in controlling condensed structures, associated with dense molecular packing.