Structural studies of water-soluble beta-brominated manganese porphyrins: Stabilities of MnTDCSPPBr8 and MnTSPPBr8 as homogeneous and supported reagents toward hydrogen peroxide and sodium hypochlorite

Abstract

This article describes the structural stabilities of [2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(2,6-dichloro-3-sulfonatophenyl)porphinato]manganese(III) X (where X = $H_2O$ and/or OH- , depending on pH) (MnTDCSPPBr8 ) and [2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetra(4-sulfonatophenyl)porphinato] manganese(III) X (where X = $H_2O$ and/or OH- , depending on pH) ($MnTSPPBr_8$ ) toward $H_2O_2$ and NaOCl at various pH's, I = 0.2 M and 30oC. In addition, the structural stabilities of these manganese porphyrins were investigated when they were bound to quaternary ammonium containing supports, namely, hexadecyltrimethylammonium bromide (CTAB), 2,6-ionene, 2,10-ionene and a poly[(vinylbenzyl)trimethylammonium chloride] latex. In alkaline media, both manganese porphyrins degraded and precipitated even in the absence of both of the oxidants. In neutral and acidic solutions, they showed increasing stabilities toward $H_2O_2$ as pH decreased and almost no stabilities toward NaOCl. When bound to CTAB and the latex, they gained very high stabilities toward $H_2O_2$ at pH > 2 and almost no degradation was observed. On the other hand, the stabilities of the ionene-bound manganese porphyrins were close to the free complexes. The pseudo-first order degradation rate constants of $MnTDCSPPBr_8$ , $MnTSPPBr_8$ and their supported analogues were determined.

This article describes the structural stabilities of [2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(2,6-dichloro-3-sulfonatophenyl)porphinato]manganese(III) X (where X = $H_2O$ and/or OH- , depending on pH) (MnTDCSPPBr8 ) and [2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetra(4-sulfonatophenyl)porphinato] manganese(III) X (where X = $H_2O$ and/or OH- , depending on pH) ($MnTSPPBr_8$ ) toward $H_2O_2$ and NaOCl at various pH's, I = 0.2 M and 30oC. In addition, the structural stabilities of these manganese porphyrins were investigated when they were bound to quaternary ammonium containing supports, namely, hexadecyltrimethylammonium bromide (CTAB), 2,6-ionene, 2,10-ionene and a poly[(vinylbenzyl)trimethylammonium chloride] latex. In alkaline media, both manganese porphyrins degraded and precipitated even in the absence of both of the oxidants. In neutral and acidic solutions, they showed increasing stabilities toward $H_2O_2$ as pH decreased and almost no stabilities toward NaOCl. When bound to CTAB and the latex, they gained very high stabilities toward $H_2O_2$ at pH > 2 and almost no degradation was observed. On the other hand, the stabilities of the ionene-bound manganese porphyrins were close to the free complexes. The pseudo-first order degradation rate constants of $MnTDCSPPBr_8$ , $MnTSPPBr_8$ and their supported analogues were determined.