Phosphirenium borate betaines from alkynylphosphanes and the halogeno-B(C6F5)2 reagents

Abstract

A series of phosphanyl substituted alkynes R¹₂P–CC–R² [R¹₂P: Mes₂P or ^tBu₂P; R²: SiMe₃, Ph, ^tBu] reacts with the X–B(C₆F₅)₂ reagents [X: Cl, Br] to give thermally rather stable neutral zwitterionic phosphirenium borate products. Five examples of this class of compounds were characterized by X-ray diffraction.