Sulfanyl vs sulfonyl, 4,5- vs 3,6- position. How structural variations in phthalonitrile substitution affect their infra-red, crystallographic and Hirshfeld surface analyses

Abstract Two structural factors (sulfonyl vs sulfanyl, 4,5- vs 3,6- position) of phthalonitriles - which are used in several material-related applications - have been comparatively investigated in terms of crystallographic properties and Hirshfeld surface analyses. The unexpected FT-IR spectra of the sulfonyl-substituted derivatives have been supported by DFT calculations.