Protonation of some non-transition metal phthalocyanines: spectral and photophysicochemical consequences

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Akinbulu, "I. A."
Ogunsipe, "A. O. "
Idowu, "M. A."
Ogunbayo, "T. B."
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The photophysics and photochemistry of phthalocyanine complexes of magnesium (MgPc), aluminum chloride (ClAlPc) and zinc (ZnPc) are studied in N,N′-dimethylformamide (DMF). The values obtained for the photophysical and photochemical parameters are normal for simple metallophthalocyanine (MPc) complexes. Protonation of the azomethine bridges reduced the photoactivities of the complexes considerably; however the excited triplet states of the protonated species are more stable towards ground state oxygen. The interaction of the non-protonated MPcs with ground state oxygen is shown to be diffusion-assisted, with bimolecular rate constant values of the order of 1010 M-1.s-1. MgPc could not be protonated; it was easily demetalated by the protonating acid. The kinetics of the demetalation yielded the rate equation: Rate = 0.1[MgPc][H+] 2/3
Chemical Kinectics , Physical Chemistry , Photochemistry
Ogunsipe, A. O., Idowu, M. A., Ogunbayo, T. B., & Akinbulu, I. A. (2012). Protonation of some non-transition metal phthalocyanines—spectral and photophysicochemical consequences. Journal of Porphyrins and Phthalocyanines, 16(07n08), 885-894.