Formation of new larger ring cyclic triphosphenium ions in solution - A 31P NMR study

► Synthesis of new 7- or 8-membered ring cyclic triphosphenium ions (CTIs). ► Synthesis of CTIs with different anions to those in the literature. ► Synthesis of new CTIs from ferrocene derivatives. ► CTIs identified in solution by 31P NMR spectroscopy. ► Three of these CTIs protonated successfully.