Pure Appl. Chem., 2009, Vol. 81, No. 8, pp. 1385-1396
http://dx.doi.org/10.1351/PAC-CON-08-08-35
Published online 2009-06-29
Layered silicate films with photochemically active porphyrin cations
Abstract:
The objective of this study was to prepare and characterize hybrid films based on layered silicates with a tetracationic porphyrin dye 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) intercalated in the inorganic matrix. The properties of the TMPyP cations in the materials were compared with those of other systems (solutions, colloids) characterized mainly by absorption and fluorescence spectroscopies. Linearly polarized absorption spectroscopy, X-ray diffraction (XRD), and fluorescence microscopy were used as well. Using appropriate layered silicate templates, applying the premodification of the inorganic component with hydrophobic alkylammonium surfactants and selecting an appropriate method, one can prepare the materials of broadly variable spectral properties of the dye. The spectral variation takes place while preserving the photochemical activity of TMPyP. The interpretations of spectral changes are based on the structural changes of the TMPyP molecules adsorbed on layered silicate surface related to the flattening of cationic pyridinium substituents.
Keywords
clay minerals; fluorescence spectroscopy; intercalation; layer charge; porphyrin; smectites; visible spectroscopy.