Dipyrrin-Strapped NiII Porphyrins

A dipyrrin-strapped NiII porphyrin and its anthracene-bridged dimer were synthesized as the first examples of free base carbasubporphyrins-fused porphyrins by Suzuki–Miyaura coupling reaction of 2,18-bis(5-borylpyrr-2-yl)-substituted NiII porphyrin with 9,10-bis(2,2′-dibromoethenyl)anthracene. Upon treatment with BPhCl2 and triethylamine (TEA), these porphyrins were converted into the corresponding BIII carbasubporphyrin complexes. A similar coupling reaction of the diborylated NiII porphyrin with 9-(2,2′-dibromoethenyl)fluorene gave a meso-fluorenyl adduct, which was also converted into a similar BIII complex. These BIII complexes have a dual electronic system consisting of aromatic 18π-porphyrin and a global antiaromatic 24π circuit.