Raman microspectroscopy of phthalocyanine intercalates: tetrasulphonated cobalt and nickel phthalocyanines in layered double hydroxide

• Published in: Journal of Raman spectroscopy 1998-02, Vol.29 (2), p.103-108
• Main Authors: de Faria, D. L. A., Constantino, V. R. L., Baldwin, K. J., Batchelder, D. N., Pinnavaia, T. J., Chibwe, M.
• Format: Article
• Language: English
• ISSN: 0377-0486; 1097-4555
• DOI: 10.1002/(SICI)1097-4555(199802)29:2<103::AID-JRS199>3.0.CO;2-J

Tetrasulfonated cobalt and nickel phthalocyanines (CoPcTs and NiPcTs, respectively) intercalated in layered double hydroxide (LDH) were studied by Raman microscopy. In the case of the cobalt complex the investigation included the supported sample in which the phthalocyanine is not within the LDH galleries but on its outer surfaces. The interaction of CoPcTs with the surface (in both intercalated and supported samples) caused band shifting and changes in the relative intensities of some bands. The results for the intercalated compound are in agreement with x‐ray data, showing that the phthalocyanine assumes an edge‐on orientation in the LDH galleries electrostatically bound through the sulfonate groups, with negligible participation of the π‐electrons. This is not the case for supported CoPcTs, since the shift and changes in the relative intensity of the 1546 cm‐1 peak are consistent with variations in the pyrrole ring charge, as expected for a flat orientation with respect to the surface. The spectral behavior of NiPcTs does not follow that of CoPcTs. The Raman spectrum suggests that the nickel complex intercalates as an aggregate, which is confirmed by diffuse reflectance data and x‐ray diffraction. © 1998 John Wiley & Sons, Ltd.