Analysis of the solvent effects on the crystal growth of peripherally chlorinated boron subphthalocyanines

Abstract

We report the characterization of the crystal/nano-structures of hexachloro-boron subphthalocyanines (Cl₆BsubPc) grown via a variety of solvent diffusion methods and also having axial substitution variants: chloride, phenoxy, naphthoxy and m-iodophenoxy. Our goal was to determine if various solvents affect the respective crystal/nano-structure of the Cl₆BsubPcs as the effects may play a crucial role in the selection of solvent(s) used when depositing these materials into organic electronic devices with solution printing/casting as the method of device fabrication. In our study, looking at a variety of solvents for the diffusion crystal grown method led to only one case for Cl₆BsubPcs whereby the solvents were incorporated and influenced the crystal/nano-structural arrangements. The axial substituents are also variants to consider that can yield different types of crystal/nano-structural arrangements due to intermolecular forces. We found that the incorporated halogens (X) drive the intermolecular interactions through halogen bonding, X⋯X interactions, and C–X⋯C as well as C–X⋯π interactions. We also utilized CrystalExplorer to further show and support the presence of these interactions, using dynamic visualizations that align with the results shown through Mercury. Through extensive data acquisition and analysis, the ultimate outcome leads to future molecular design of Cl₆BsubPcs for further organic electronic applications based on solution casting methodologies and the lack of solvent incorporation into their crystal/nano-structure is a positive factor and will also be considered throughout the future.