alpha- or beta-Substituted functional phthalocyanines bearing thiophen-3-ylmethanol substituents: synthesis, characterization, aggregation behavior and antioxidant activity

Abstract

The tetra - or -thiophene substituted metal and metal-free phthalocyanines (Pcs) M[Pc(-OCH(2)Thiopen)(4)] and M[Pc(-OCH(2)Thiopen)(4)] {(-ThMet-MPc), (-ThMet-MPc) [ThMet: Thiophene methoxy], M=Zn(II), Co(II) and, 2H} were synthesized from the corresponding 3'-(thiophen-3-ylmethoxy)phthalonitrile or 4'-(thiophen-3-ylmethoxy)phthalonitrile (ThMePN). The structural characterization, spectral, and antioxidant properties of a series of new Pcs were also presented. Both - and -substituted Pc complexes increased solubility in polar solvents, such as THF, DMF, and DMSO. FT-IR, H-1-NMR, C-13-NMR, UV-vis, MALDI-TOF/MS spectral, and elemental analysis data were used to characterize the compounds. The aggregation behaviors of 3-8 were also investigated at different concentrations in THF. Antioxidant test methods, ,-diphenyl--picrylhydrazyl radical scavenging activity, metal chelating activity, and reducing power, were used to determine the antioxidant activities. 6 showed very good ferrous ion chelating activity of 81 +/- 1%. 6, 5, 4, and 3 showed better reducing power than trolox, ascorbic, acid and butylated hydroxytoluene, commercially used antioxidants.