Boron(III) Carbazosubphthalocyanines: Core-Expanded Antiaromatic Boron(III) Subphthalocyanine Analogues.

Condensation of 1,8-diamino-3,6-dichlorocarbazole with a series of disubstituted 1,3-diiminoisoindolines, followed by treatment with BF3OEt2 led to the formation of the corresponding core-expanded boron(III) subphthalocyanine analogues. These air-stable pi-conjugated boron(III) carbazosubphthalocyanines possess two boron-containing seven-membered-ring units and a 16 pi-electron skeleton, and represent the first examples of antiaromatic boron(III) subphthalocyanine analogues as supported by spectroscopic and theoretical studies. The molecular structure of one of these compounds was unambiguously determined by single-crystal X-ray diffraction analysis. In contrast to typical boron(III) subphthalocyanines, which adopt a cone-shaped structure, the pi skeleton of this compound is almost planar.