Stability of Cu(II)− and Fe(III)−Porphyrins on Montmorillonite Clay: An X-ray Absorption Study

Autor: Kathleen A. Carrado, S. R. Wasserman
Rok vydání: 1996
Předmět:
Zdroj: Chemistry of Materials. 8:219-225
ISSN: 1520-5002
0897-4756
DOI: 10.1021/cm950330w
Popis: The Cu(II) and Fe(III) complexes of water-soluble tetrakis(N,N,N-trimethylanilinium)porphyrin (TTAP) and tetrakis(N-methylpyridyl)porphyrin (TMPyP) were placed within the interlayers of Ca(II)−montmorillonite through ion exchange. The free base forms of the porphyrins were also added to samples of Cu(II)− and Fe(III)−montmorillonites. X-ray absorption spectroscopy (XAS), both X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), were used to monitor the fate of the metal ions. The Cu(II)−metalloporphyrins do not demetalate upon contact with the acidic montmorillonite support. The XAS data also suggest that Fe(III)−porphyrin complexes are stable on smectite supports. XANES data demonstrate that the free base porphyrin TTAP metalates on the surface of a Cu(II)-exchanged clay to form a stable Cu(II)−porphyrin-clay complex.
Databáze: OpenAIRE