Three sets of equations are described, for the Soret and visible regions of the electromagnetic spectrum, which allow the calculation of net absorption and fluorescence spectral shifts, directly induced by coordination of metalated tetrapyrroles to axial ligands. This was made possible by separating mathematically the axial ligand-induced spectral shifts from other spectral shifts induced by (a) non-coordination solvent effects; (b) peripheral group substitution; (c) temperature and (d) central metal substitution. In calculating the net spectral shifts, we made use of vapor spectral data published by others, and when such data were not available, solvated free-base spectral data were used. The importance of being able to calculate axial ligand-induced net spectral shifts lies in their quantitative relationship to the positive charge density on the central metal atom of metalated tetrapyrroles, which in turn plays an important role in orienting metallotetrapyrroles within biological membranes.
|Original language||English (US)|
|Number of pages||14|
|Journal||Spectrochimica Acta Part A: Molecular Spectroscopy|
|State||Published - Jan 1 1984|
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