Tetrabenz[a,c,h,j]anthracene-Bridged Carbaporphyrin Dimer

A new carbaporphyrin dimer (8) featuring a π-extended polycyclic aromatic hydrocarbon (PAH) bridge, namely, tetrabenz[a,c,h,j]anthracene (TBA), was synthesized and characterized. Single-crystal X-ray structure analysis revealed that 8 exhibits an overall nearly planar configuration. ¹H NMR spectroscopy and nucleus-independent chemical shift (NICS) calculations demonstrated reduced paratropicity in the two carbaporphyrin(1.1.1.0) subunits compared to the previously reported dibenzo[g,p]chrysene (DBC)-bridged analogue. The local aromaticity of the individual benzene rings of the TBA bridge is found to be disrupted by the fusion of the carbaporphyrin(1.1.1.0) units as well. Furthermore, 8 could coordinate with Cu(III) and Ag(III) ions to form bis-metal complexes. Metal coordination enhanced molecular planarity, and the bis-metallic complexes maintained antiaromatic characteristics. This research elucidates the regulatory role of the π extension of the PAH bridge on the (anti)aromatic character and coordination behavior of carbaporphyrin dimers, providing valuable insights for the design of novel PAH-porphyrin hybrid functional molecular systems.