The current investigation began by repeating the earlier triphosphorylation work of Taylor where the TBA (tetrabutylammonium) salt of TriMP is activated with mesitylenesulfonyl chloride and nucleophilic N-donor bases, such as DABCO (1,4-diazabicyclo[2.2.2]octane), pyridine, and N -methylimidazole. The putative mesitylenesulfonyl TriMP species was unisolated in Taylor's reports. However, in an analogous reaction of the PPN (bis(triphenylphosphine)iminium) salt of TriMP and tosyl chloride we were able to isolate and crystallographically characterize tosyl TriMP (1, Figure ). Performing this reaction in dried acetone under anhydrous conditions results in precipitation of anhydrous crystals of a mixed PPN and triethylammonium salt of 1.