Chlorophosphaethenyl phosphonium ions by chloride abstraction from dichlorophosphanyl ylides

Dichlorophosphanyl ylides readily lose a chloride ion to Lewis acidic metal chlorides. In the cations so generated, a considerable part of the phosphenium charge is transferred to the phosphonium center leading to a chlorophosphaalkene structure. This is demonstrated by NMR data as well as by an X-ray structure analysis. The residual phosphenium charge becomes visible in weak but definite contacts with the GaCl⁻₄ anions that expand the coordination sphere of the P(III) atom from ψ-trigonal two-coordination to ψ-trigonal bipyramidal (ψ-TBP) tetra-coordination. © 1996 John Wiley & Sons, Inc.