| Autor: |
Ong Chin Choon, G.A. Rodley |
| Rok vydání: |
1983 |
| Předmět: |
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| Zdroj: |
Inorganica Chimica Acta. 78:171-176 |
| ISSN: |
0020-1693 |
| DOI: |
10.1016/s0020-1693(00)86509-3 |
| Popis: |
Complexes of magnesium protoporphyrin and magnesium mesoporphyrin with L-histidine have been prepared in solution and studied by circular dichroism and optical rotatory dispersion spectroscopy. Large induced Cotton effects are observed, in particular for the Soret transitions. These are interpreted in terms of the formation of six-coordinate magnesium porphyrin-(L-histidine) 2 species where the asymmetry of the L-histidine groups is coupled to the magnesium porphyrin electronic transitions. The major, five-coordinate components of these solutions do not produce Cotton effects. These results, when compared with data for corresponding protein complexes, lend support for the coupled oscillator description of the origin of optical activity in hemoproteins. The observation of Cotton effects for porphyrin complexes of the type reported here may enable the existence of six-coordinate species to be more clearly established in instances where the major equilibrium product is a five-coordinate species. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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