A Spectroscopic and Theoretical Investigation of a Free‐Base meso‐Trithienylcorrole

The unique optical properties of free‐base meso‐tris(5‐methylthien‐2‐yl)corrole were compared to those of the widely investigated meso‐triphenyl‐substituted analogue. A combination of spectroscopic and computational experiments was undertaken to elucidate the relationship between structural features of the neutral, mono‐anionic and mono‐cationic forms of the corroles and their corresponding optical properties. A general bathochromic shift was measured for the thienyl‐substituted corrole. The experimental spectra are supported by excited state calculations. A systematic series of ground state minimizations were performed to determine energy minima for the flexible and solvent‐sensitive molecules. Trithienylcorrole was found to have a more nonplanar macrocycle in conjunction with a high degree of π‐overlap with the meso‐substituents. Both structural features contribute to their bathochromically shifted optical spectra. The configurational character of the thienyl‐substituted corrole is shown to have a larger degree of molecular orbital mixing and doubly excited character, which suggest a more complex electronic structure that does not fully adhere to the Gouterman four‐orbital model. The reactivity of the thienyl groups, particularly with respect to their ability to be (electro)‐polymerized, combined with the tight coupling of the meso‐thienyl groups with the corrole chromophore elucidated in this work, recommends the meso‐thienylcorroles as building blocks in, for instance, organic semiconductor devices.