On the mass spectra of thallium(III) porphyrin chelates

Thallium(III) porphyrins show anomalous features in their mass spectra compared with other metalloporphyrins. The base peak in all of the spectra arises by loss of the thallium atom and its axial ligands with transfer of two hydrogens to the macrocycle; the liberated thallium undergoes ion-molecule interaction with the thallium porphyrin, resulting in the observation of ions containing two thallium atoms per porphyrin ligand.