David K. Lavallee

Rapid synthesis of radiolabeled porphyrin complexes for medical application

This invention relates to a novel method for the rapid synthesis of radiolabeled porphyrin complexes which are highly useful for biomedical application, i.e. conjugation to protein antibodies for use in tumor imaging and internal radiation therapy.

Visible absorption and luminescence spectra of N-methyldeuteroporphyrin complexes and the question of “sitting-atop” complexes

Abstract Visible spectra of manganese(II), cobalt(II), and zinc(II) complexes of N-methyldeuteroporphyrin IX dimethyl ester are similar to each other in both energies and intensities of absorption bands. These spectra are also quite similar to the spectrum of the monoprotonated ligand, as found earlier for complexes of N-methyltetraphenylporphyrin. Luminescence intensities of N-methyldeuteroporphyrin complexes, however, are dependent on identity of the metal ion and axial ligand, varying in the order: free ligand /gt Cl-Zn(II) complex /gt Br-Zn(II) complex ⪢ Mn(II) complex, Co(II) complex. Complexation of metal ions to N-methyltetraphenylporphyrin results in reduction in emission, with intensities of the complexes varying in the order: Zn(II) /gt Cd(II) ⪢ Fe(II), Mn(II), Co(II). Formation of ion pairs consisting of a porphyrin cation and a metal-containing anion results in a fluorescence spectrum similar to that of the porphyrin ion pair formed by addition of HCl, without substantial quenching. Luminescence spectra provide conclusive evidence for the formation of ion pairs rather than “sitting-atop” complexes under conditions where the nature of such species has been controversial.

Visible absorption spectra of N-methyltetraphenylporphyrin complexes

Abstract The Mn(II), Co(II), Cu(II) and Zn(II) complexes of N-methyl-α,β,γ,δ-tetraphenylporphine exhibit very similar visible absorption spectra. These species are true complexes, yet the spectral similarities resemble results for porphyrin ion-pairs in which the porphyrin moiety is protonated. Such spectral comparisons have been made in discussions of the existence of porphyrin “sitting-atop” complexes as intermediates in the formation of natural metalloporphyrins. The changes in the spectrum of the free base N-methylporphyrin when a metal complex is formed involve bathochromic shifts that have been observed on protonation of the corresponding nonmethylated porphyrin, TPP.