N-Fusion Approach in Construction of Contracted Carbaporphyrinoids: Formation of N-Fused Telluraporphyrin

Insertion of PCl3 into 5,10,15,20-tetraaryl-21-telluraporphyrin leads to a phosphorus complex of N-fused dihydrotelluraporphyrin with an inverted tellurophene ring. Its CNN coordination core places the macrocycle in the family of contracted carbaporphyrinoids. A cycle of direct transformations affords an elegant triangle of three mutually convertible N-fused porphyrinoids, with distinct spectroscopic features: antiaromatic, nonaromatic and aromatic. The nonaromatic species has a dome shaped skeleton which forms in the solid state a ball and socket structure with C-60.