SPECTROSCOPIC CHARACTERIZATION OF MESO-TETRAKIS(1-METHYLPYRIDINIUM-4-YL)PORPHYRINS, [(TMPYP)H2]4+ AND [(TMPYP)M]4+, IN AQUEOUS MICELLAR MEDIA, WHERE M = VO2+, CU(II), AND ZN(II)

Spectroscopic characterization of [(TMpyP)H-2]4+ and [TMpyP)M]4+, where M = Cu(II), Zn(II), or VO2+ and TMpyP = meso-tetrakis(1-methylpyridinium-4-yl)porphyrin, was carried out in water and in aqueous solutions containing the anionic surfactant sodium dodecyl sulfate (SDS), the cationic surfactant cetyltrimethylammonium bromide (CTAB), or the neutral surfactant Triton X-100 (TX-100). UV-visible H-1 NMR, and ESR spectral data indicate that these tetracationic porPHYRins interact with and exist as monomeric entities in the anionic SDS micelle. In contrast, neither the cationic nor the neutral micelle shows an interaction with the investigated porphyrins. Comparisons are made between the data for tetracationic and tetraanionic porphyrins in different micellar media and it is suggested that interaction of the positively charged porphyrins in SDS is due to Coulombic rather than hydrophobic interactions.