Dibenzoheterole-Fused -Indacenes.

Heterole (pyrrole, thiophene, furan, thiophene-,-dioxide)-fused -indacenes are known for their enhanced paratropic ring-current strength. However, the outcome of the antiaromatic properties for dibenzoheterole-fused -indacene antiaromatics remained underexplored. Carbazole-, dibenzothiophene-, dibenzofuran-, and dibenzo[,]thiophene-5,5-dioxide-fused -indacenes -, respectively, were synthesized and characterized by experimental (NMR, single-crystal, UV-vis, CV) and computational (DFT) approaches to study the ground-state antiaromatic properties.

Unveiling two antiaromatic -indacenodicarbazole isomers with tunable paratropicity.

Linear and curved antiaromatic -indacenodicarbazole isomers were synthesized and characterized to show the tunable paratropicity of -indacene, as analyzed by NICS(1) and ACID (ring-current) calculations. The curved isomer showed a greater degree of antiaromaticity than the linear isomer, as predicted by the Glidewell-Lloyd rule. This degree of antiaromaticity was further validated by the red-shifted UV-vis absorption and smaller HOMO-LUMO energy gap.