Synthesis and properties of 4,5,6-triphospha[3]radialene.

[3]Radialenes: 4,5,6-tris(2,4,6-tri-tert-butylphenyl)phospha[3]radialene has been synthesized. The compound can be easily handled in air under ambient conditions, despite the [3]radialene moiety containing P=C bonds, and exhibits red-shifted absorption as well as high electron-accepting ability. The unique electronic properties are brought about by the synergistic effect of the [3]radialene framework and the phosphorus substitution.