Synthesis and Molecular Structure of ⁹⁹ Tc Corroles

The first ⁹⁹ Tc corroles have been synthesized and fully characterized. A single-crystal X-ray structure of a ⁹⁹ TcO triarylcorrole revealed nearly identical geometry parameters as the corresponding ReO structure. A significant spectral shift between the Soret maxima of TcO (410-413 nm) and ReO (438-441 nm) corroles was observed and, based on two-component spin-orbit ZORA TDDFT calculations, ascribed to relativistic effects in the Re case. The syntheses reported herein potentially pave the way toward ^99m Tc-porphyrinoid-based radiopharmaceuticals.