Fourier-transform Raman and infrared spectroscopic analysis of dipyrrinones and mesobilirubins

The Fourier-transform Raman (FT-Raman), infrared (FT-IR), and UV-visible ab sorption spectra of four dipyrrinones and two mesobilirubins have been inve stigated in the solid state and in CH,Cl, solutions. A detailed spectral an alysis, assignment and discussion of these spectra are presented. The bands at 1735-1738, 1691-1707 and 1359-1377 cm(-1) which were assigned to the st retching vibrations of the C-O-C and C-O-H and symmetric deformation of C-H bonds, respectively, can act as a marker to distinguish the compounds of t his class. The striking differences between the spectra of the compounds su ggest that mesobilirubin XIII alpha is tending to adopt as ridge-tile confo rmation, rather than linear conformation. (C) 2001 Elsevier Science B.V. Al l rights reserved.