ISOLATION OF A PHOSPHENIUM ION WITH A P-C SIGMA-BOND

The first example of an X-ray crystallographically characterized two-coordinate phosphorus cation. with a P-C single sigma bond is described. [P(mesityl)(N-i-Pr-2)][AlCl4] was prepared by treatment of PCl(mesityl)(N-i-Pr-2) with Al2Cl6 in dichloromethane. The phosphenium ion character of the cation is reflected in the large downfield P-31 chemical shift (500 ppm) and can be compared to 313 ppm in the corresponding bis(dialkylamido) cation [P(N-i-Pr-2)(2)](+).