10-Silacorroles Exhibiting Near-Infrared Absorption and Emission

10-Silacorroles were obtained from the Pd-catalyzed silylative cyclization of a bis(alpha,alpha'-dibromodipyrrin) Ni-II precursor with dihydrosilanes. These 10-silacorroles show substantially red-shifted absorption bands relative to those of normal porphyrins and isocorroles. Notably, the corresponding free base and Zn-II 10-silacorroles exhibit emissions in the NIR region. Theoretical calculations on these 10-silacorroles revealed the presence of sigma*-pi* conjugation between the silyl group and the tetrapyrrole pi system, which significantly lowers their LUMO energy levels.