Cationic Mn porphyrins are among the most potent catalytic antioxidants and/or cellular redox modulators. Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin chloride (MnTE-2-PyPCl5) is the Mn porphyrin most studied in vivo and has successfully rescued animal models of a variety of oxidative stress-related diseases. The stability of an authentic MnTE-2-PyPCl5 sample was investigated hereon by thermogravimetric, derivative thermogravimetric, and differential thermal analyses (TG/DTG/DTA), under dynamic air, followed by studies at selected temperatures to evaluate the decomposition path and appropriate conditions for storage and handling of these materials. All residues were analyzed by thin-layer chromatography (TLC) and UV-vis spectroscopy. Three thermal processes were observed by TG/DTG. The first event (endothermic) corresponded to dehydration, and did not alter the MnTE-2-PyPCl5 moiety. The second event (endothermic) corresponded to the loss of EtCl (dealkylation), which was characterized by gas chromatography-mass spectrometry. The residue at 279 °C had UV-vis and TLC data consistent with those of the authentic, completely dealkylated analogue, MnT-2-PyPCl. The final, multi-step event corresponded to the loss of the remaining organic matter to yield Mn3O4 which was characterized by IR spectroscopy. Isothermal treatment at 188 °C under static air for 3 h yielded a mixture of partially dealkylated MnPs and traces of the free-base, dealkylated ligand, H2T-2-PyP, which reveals that dealkylation is accompanied by thermal demetallation under static air conditions. Dealkylation was not observed if the sample was heated as a solid or in aqueous solution up to ∼100 °C. Whereas moderate heating changes sample composition by loss of H2O, the dehydrated sample is indistinguishable from the original sample upon dissolution in water, which indicates that catalytic activity (on Mn basis) remains unaltered. Evidently, dealkylation at high temperature compromises sample activity.

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The immobilization of cationic manganese porphyrins (MnP) over the surface of a magnetic hexagonal HMS silica (HMS‐Mag) produced a solid with high surface area and relatively homogeneous pores. Given the presence of the magnetite, the catalysts are easily recovered and reused without loss of mass. The MnP immobilization explored the strong interaction between the positive charges of the cationic MnP and the deprotonated Si‐OH groups on the surface of HMS‐Mag. Soret bands on the UV‐Vis spectra of the MnP‐loaded HMS‐Mag confirmed the presence of MnP on the prepared solids. The catalytic efficiency, robustness, and reusability of the prepared solids were investigated on cis‐cyclooctene and cyclohexane oxidations. The solids showed similar or higher catalytic efficiency than the corresponding MnP under homogeneous catalysis, with selectivity for cyclohexanol in cyclohexane oxidation. Additionally, the solid catalysts showed high resistance against deactivation, confirming the reusability capacity in at least five cycles of cyclooctene oxidation.

The quantification of zinc in over-the-counter drugs as commercial propolis extracts by molecular fluorescence technique using meso-tetrakis(4-carboxyphenyl)porphyrin (H TCPP ) was developed for the first time. The calibration curve is linear from 6.60 to 100 nmol L of Zn . The detection and quantification limits were 6.22 nmol L and 19.0 nmol L , respectively. The reproducibility and repeatability calculated as the percentage variation of slopes of seven calibration curves were 6.75% and 4.61%, respectively. Commercial propolis extract samples from four Brazilian states were analyzed and the results (0.329-0.797 mg/100 mL) obtained with this method are in good agreement with that obtained with the Atomic Absorption Spectroscopy (AAS) technique. The method is simple, fast, of low cost and allows the analysis of the samples without pretreatment. Moreover the major advantage is that Zn-porphyrin complex presents fluorescent characteristic promoting the selectivity and sensitivity of the method.

Simple neutral and cationic Mn porphyrins were immobilized on ordinary chromatographic silica or chloropropyl-functionalized silica supports to yield efficient and reusable biomimetic catalysts for C–H activation and oxyfunctionalization of alkanes.

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