Impact of Molecular Structure Change on the Hierarchy of Intermolecular Interactions Leading to Polar/Centrosymmetric Crystals

Abstract

Perfectly polar packing of molecules in molecular crystals is of fundamental interest in applications based on the electro-optic effect and piezo, pyro, and ferroelectric effects. The packing of molecules in the crystals of VO(acac) 2 (DMAP) complex is investigated and analyzed in the context of the perfect polar packing reported earlier in VO(acac) 2 (MP) and Zn(acac) 2 (DMAP) complexes. The subtle modification of the ligand is found to effect a drastic change in the molecular geometry between trans and cis in the vanadyl complexes. This in turn affects the hierarchy of intermolecular interactions with dramatic impact on the molecular packing, causing the perfectly polar packing motif in VO(acac) 2 (MP) to change to a centrosymmetric one in VO(acac) 2 (DMAP).