An experimental and computational study into the crystallisation propensity of 2nd generation sulflower

Abstract

Persulfurated coronene cannot readily nucleate or crystallise due to its preference for face–face over edge–face interactions.

Combined Use of Structure Analysis, Studies of Molecular Association in Solution, and Molecular Modelling to Understand the Different Propensities of Dihydroxybenzoic Acids to Form Solid Phases

“…The difference in the ability of diOHBAs to form multiple crystal forms could be associated with the differences in propensity to form different intermolecular interactions. One of the tools that could be used for exploring this feature is ESP surfaces [ 66 , 67 ]. ESP surfaces generated for diOHBAs are given in Figure 7 and are arranged from left to right according to the grouping as in Table 1 (the observed tendencies in the propensity to form solid phases in the selected solvents).…”

Rationalising the difference in crystallisability of two sulflowers using efficient in silico methods

“…In plot 7, in the supplementary information, we expand the GAFF energy minimisation to the two entire CSP sets, showing on average a good agreement between the two energy models. The only exception arises in the Sulflower set, where structures with edge-face interactions 7 exhibit particularly low energies using GAFF when compared to the energies from DMACRYS.…”

“…Persulfurated coronene represents a "second generation Sulflower", with extended conjugation, and disulfide bridges, making it a possible cathode material for lithium-sulfur batteries, as well as opening possibilities to superconductors, field effect transistors, and organic photo-voltaics. However, as previously stated, the crystalline form of the material is key to its function, and only amorphous forms of the material have been derived to date 7 . This motivated a combined theoretical and experimental investigation into finding a crystal form of the molecule.…”

“…This consisted of electrostatic potential calculations, force-field-based interaction simulations between clusters of up to four molecules, and DFT calculations of the interaction potential landscape between dimers. All methods revealed a molecule that could only form interactions with other like molecules that were not conducive toward crystal growth 7 . This work did not however consider the behaviour of the molecule in a periodic crystal.…”

“…However, as previously stated, the crystalline form of the material is key to its function, and only amorphous forms of the material have been derived to date. 7 This motivated a combined theoretical and experimental investigation into finding a crystal form of the molecule. Initially, crystallisation was attempted via solvent and vapour phase growth methods.…”