Studies on Tetrapyrrols Pigments—i. Absorption and Fluorescence of Biliverdin Dimethyl Esters of the Ix Series

Each of the four isomeric biliverdin dimethyl esters of the IX series give a fluorescent spectrum at ambient temperature, the intensity of which increases considerably when these biliverdins are complexed with zinc. A systematic study of the influence of protic and aprotic solvents failed to yield significant results. In methanol. variations in the pH greatly affect the emission absorption spectra of zinc complexes of biliverdins.