Gaughan R R, Shriver D F, Boucher L J
Proc Natl Acad Sci U S A. 1975 Feb;72(2):433-6. doi: 10.1073/pnas.72.2.433.
Unique resonance Raman spectra were obtained when manganese(III) tetraphenylporphin halides in noncoordinating solvents were illuminated by laser frequencies around 500 nm. Of particular interest is the observation of a feature that is sensitive to the nature of the axial ligand. This feature disappears when the coordinating solvent pyridine is employed, and it, therefore, appears to be diagnostic of the manganese coordination number.