Synthesis and structure of triarylphosphonium salts (APS). (A) Synthesis scheme: Reflux triphenylphosphine and the corresponding bromide (Benzyl bromide shown) in hot toluene until arylphosphonium salt precipitates. Wash with cold toluene, dry and characterize by IR, NMR and LC-MS. (B) Table of compounds, Y represents the starting bromide compound. Structures were geometrically optimized using molecular mechanics with Hyperchem software. Angstrom measurements from the phosphonium cation to the para carbon of the benzene ring are presented on the right. Abbreviations: TPP-Br, Tetraphenylphosphonium Bromide; Bz-TPP, Benzyl triphenylphosphonium Bromide; Et-TPP, 2-phenylethyl triphenylphosphonium Bromide; Pr-TPP, 3-phenylpropyl triphenylphosphonium Bromide; CTP-Cl, Cinnamyl triphenylphosphonium Chloride.