The meso-reactivity of porphyrins and related compounds. Part III. Deuteriation

Abstract

The deuteriation of the meso-positions of octaethylporphyrin has been observed in dideuteriosulphuric acid. The n.m.r. spectra of this porphyrin and the related chlorin and a-tetrahydroporphyrin are discussed and are employed to evaluate rates of meso-deuteriation in trifluoroacetic [²H]acid. The rates increase in the sequence: porphyrin chlorin αβ chlorin γδ < a-tetrahydroporphyrin βδ < a-tetrahydroporphyrin γ. The interpretation of these results is discussed.