REGIOSELECTIVE DEUTERATION AND RESONANCE RAMAN-SPECTROSCOPIC CHARACTERIZATION OF BILIVERDIN AND PHYCOCYANOBILIN

5-Deuteriophycocyanobilin (4), 5,15,18(2),18(2)-tetradeuteriobiliverdi n IX alpha dimethyl ester (6), and 5,15-dideuteriomesobiliverdin IX al pha dimethyl ester (8) have been prepared and analyzed by resonance Ra man spectroscopy in the C-H out-of-plane region, based on a previous n ormal-mode analysis of biliverdin XI alpha dimethyl ester (5). In this way most of the modes containing out-of-plane vibrations of the methi ne bridges could be assigned unambiguously. These results are of speci al relevance with regard to the interpretation of the resonance Raman spectra of the chromoprotein phytochrome.