Complementary polytopic interactions (CPI) as revealed by molecular modelling using the XED force field

Abstract

To explain 1 ∶ 1 compound formation between HAT (2,3,6,7,10,11-hexaalkoxytriphenylene) discogens and PTP (2,3,6,7,10,11-hexakis(4-alkylphenyl)triphenylene or PDQ (2,3,6,7,10,11-hexakis(4-alkylphenyl)dipyrazino[2,3,-f:2′,3′-h]quinoxaline) derivatives we have exploited the XED (extended electron distribution) force field method. This is the only method that we have found which is able to explain why compound formation occurs in some cases but not in others. Not only is the force field successful in the case of these discogens and in a number of systems investigated by Hunter and Rebek, but we also show that it can explain the observed stability of other π-stacked systems including HAT–TNF (trinitrofluorenone), benzene–hexafluorobenzene, triphenylene–perfluorotriphenylene, benzene multiyne–TNF systems and complementary mixtures of selectively fluorinated 1,4-bis(phenylethynyl)benzene derivatives. In each case the interaction is expressed as a sum of atom-based van der Waals and multipole interactions: a complementary polytopic interaction.