A new and general synthesis of tetraphenylporphyrin analogs is described. The tetraphenyl-21,23-dithiaporphyrin was prepared in a pure form. Its electronic spectrum, as well as preliminary X-ray measurements, suggests that the central sulfur and nitrogen atoms are somewhat out of the plane of the molecule, facilitating attainment of a smaller angle between the phenyl groups and the porphin plane than is found in tetraphenylporphyrin. The chemical shift of the β-pyrrole hydrogens as found in the 1H NMR spectrum at room temperature is almost identical with that found for tetraphenylporphyrin at −80°. Protonation is seen to occur at the nitrogen atoms and the optical spectrum of the conjugate acid is qualitatively similar to that of the conjugate acid of tetraphenylporphyrin.
ASJC Scopus subject areas
- Colloid and Surface Chemistry