The developments concerning new hybrids based on porphyrin derivatives and colloids destined for the detection of ascorbic acid (AA) in the relevant range for medical investigations are presented. Mn(III) tetratolylporphyrin chloride (MnTTPCl), spherical gold colloid (n-Au), and their hybrid (MnTTPCl/n-Au) were chosen to be comparatively investigated by ultravioletevisible spectroscopy in the presence of AA. The hybrid material (MnTTPCl/n-Au) has the best capacity to detect concentrations of AA in the range of 2.6 Â 10 À6 e4.38 Â 10 À5 M. Modified glassy carbon (GC) electrodes were obtained by thin film deposition of MnTTPCl, n-Au alone, and in successive mixed thin films, comparing their response during the electrochemical oxidation of AA. The electrocatalytic effect of the MnTTPCl on the AA oxidation is justified both by the increase in the peak current density and by the shift toward more negative potentials (0.024 V). The GC/MnTTPCl electrode has the best electrocatalytic effect for the AA oxidation and is promising for sensor applications.

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The successful preparation of a novel dimer complex formed between 5,10,15,20-tetrakis(3,4-dimethoxyphenyl)-porphyrin Fe(III) chloride and (5,10,15,20-tetraphenylporphinato) dichlorophosphorus(V) chloride using the well-known reactivity of the P–X bond is reported. The obtained complex was characterized by UV-vis, Fourier transform infrared spectroscopy (FT-IR), fluorescence, 1H-NMR, 13C-NMR, and 31P-NMR spectroscopic techniques and also by additional Heteronuclear Single Quantum Coherence (HSQC) and Heteronuclear Multiple Bond Correlation (HMBC) experiments in order to correctly assign the NMR signals. Scanning electron microscopy (SEM) and EDX quantifications completed the characterizations. This novel porphyrin dimer complex demonstrated fluorescence sensing of H2O2 in water for low oxygen concentrations in the range of 40–90 µM proving medical relevance for early diagnosis of diseases such as Alzheimer’s, Parkinson’s, Huntington’s, and even cancer because higher concentrations of H2O2 than 50 μM are consideredcytotoxic for life. Due to its optical properties, this novel metalloporphyrin–porphyrin based complex is expected to show PDT and bactericidal activity under visible-light irradiation.

Hybrid materials, with applications in fuchsine B color removal from wastewaters, were obtained by in situ incorporation of platinum nanoparticles and/or Pt-porphyrin derivatives into silica matrices. The inorganic silica matrices were synthesized by the sol-gel method, conducted in acid-base catalysis in two steps and further characterized by Nitrogen porosimetry, Small Angle Neutron Scattering (SANS), Scanning electron microscopy, Atomic force microscopy and UV-vis spectroscopy. All of the investigated silica hybrid materials were 100% efficient in removing fuchsine B if concentrations were lower than 1 × 10−5 M. For higher concentrations, the silica matrices containing platinum, either modified with Pt-metalloporphyrin or with platinum nanoparticles (PtNPs), are the most efficient materials for fuchsine B adsorption from wastewaters. It can be concluded that the presence of the platinum facilitates chemical interactions with the dye molecule through its amine functional groups. An excellent performance of 197.28 mg fuchsine B/g adsorbent material, in good agreement with the best values mentioned in literature, was achieved by PtNPs-silica material, capable of removing the dye from solutions of 5 × 10−4 M, even in still conditions.