Probing Donor Acceptor Interactions of Chalcogenide Supported Fluorophosphonium Ions Using peri-substituted Acenaphthyl Scaffolds

Abstract

The fluorination of the peri-substituted acenaphthyl scaffolds 5-PhE-Ace-6-PPh2 (1E, E=O, S, Se, Te) using XeF2 afforded the difluorinated products 5-PhE-Ace-6-PF2Ph2 (2E, E=O, S, Se, Te) and tetrafluorinated products 5-PhEF2-Ace-6-PF2Ph2 (3E, E=Se, Te) depending on the stoichiometry applied. Fluoride abstraction of 2E using Me3SiOTf gave rise to the chalcogenide supported fluorophosphonium ions [5-PhE-Ace-6-P(F)Ph2](OTf) (4O and 5E, E=S, Se, Te). The molecular structure of 4O features a tetrahedral P atom, whereas those of the heavier analogues (5E, E=S, Se) contain trigonal bipyramidal P atoms that arise from intramolecular LP(E)→σ*(P−F) interactions.