H-porphine Manganese Research Articles

Molecular Differentiation of Cathepsins B and D, and of p53 Protein, and their Quantitative Assay in Biological Samples

Cathepsins B, D and protein p53 are three of the biomarkers with a large spectrum of implications in the field of physiopathology as many diseases proved to be associated with their variation in concentration. Therefore, there is a need for reliable tools able to perform molecular recognition/differentiation, and also reliable quantification of cathepsins B, cathepsin D, and protein p53. Two stochastic microsensors based on diamond/graphene nanopowders modified with 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine manganese (III) chloride were proposed for the simultaneous differentiation and quantification of cathepsins B, D and protein p53 in whole blood, urine, saliva, and tumoral tissues. The lowest limits of determination and the highest sensitivities were recorded when the stochastic microsensor based on nanopowder of graphene was used. Wide linear concentration ranges were recorded for both microsensors. The recovery values obtained for the microsensors, were higher than 97.00%, and the relative standard deviations values were lower than 1.00%, when used for screening of whole blood, urine, saliva, and tumoral tissues.

Tuning structural, optical, and dispersion functions of polystyrene via addition of meso-tetraphenylporphine manganese (III) chloride towards optoelectronic applications

Using a standard casting procedure, a polymeric composite of polystyrene (PS) and 5,10,15,20-tetraphenyl-21H,23H-porphine manganese (III) chloride (MnTPPCl) has been created. The structural alteration in the PS matrix brought on by MnTPPCl filling is confirmed by X-ray diffraction (XRD). According to vibrational groups that defined the prepared samples, the main distinctive peaks were found using Fourier transform infrared (FTIR). After filling, the majority of these absorption intensities have randomly varied from their values in the virgin polymer. Furthermore, new peaks at 1230 and 3642 cm−1 appeared and steadily increased with the increase in MnTPPCl content. Changes in the main vibrational bands in the FTIR spectra indicated the interaction of the composite components. The optical properties of the PS/MnTPPCl composite were investigated utilizing measurements of transmittance and reflectance. The absorption coefficient spectra demonstrate the emergence of new peaks (372–618 nm) after filling, which can be related to π→π* orbital transition of MnTPPCl. The optical energy gaps for the indirect and direct allowed transition were found to decrease with increasing MnTPPCl contents. A normal dispersion was found in the wavelength range of 830–2500 nm and an anomalous dispersion in the wavelength range of 190–830 nm, according to an analysis of the refractive index n. Calculations were made for the oscillator parameters, including oscillator and dispersion energies. The possibility of their employment in optoelectronic devices is implied by the reduction of the optical energy gap and the rise in refractive index caused by the addition of MnTPPCl.

N,S-Decorated graphenes modified with 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine manganese(III) chloride-based 3D needle stochastic sensors for enantioanalysis of arginine: a key factor in the metabolomics and early detection of gastric cancer.

Arginine has an important role in the metabolomics of gastric cancer. Two 3D enantioselective needle stochastic sensors based on the physical immobilization of 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine manganese(III) chloride (solution, 10-3 mol L-1) in graphene paste matrices decorated with N and S atoms were designed, characterized and validated for the enantioanalysis of arginine in whole blood and tissue samples. The signature values obtained for the enantiomers of arginine confirmed that the stochastic sensors are enantioselective. The lowest limit of quantification obtained for both enantiomers of arginine was 1 fmol L-1, while sensitivity of up to 1011 s-1 mol-1 L was recorded for the stochastic sensors. High recoveries were obtained for the determination of one enantiomer in the presence of the other one; moreover, very good correlation was found between the results obtained with the two 3D enantioselective needle stochastic sensors.

3D stochastic microsensors for molecular recognition and determination of heregulin-α in biological samples.

Two 3D stochastic microsensors based on single and multi-walled carbon nanotubes modified with 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine manganese (III) chloride were proposed for the molecular recognition and determination of heregulin-α, in whole blood samples and tumour brain tissues. The proposed 3D stochastic sensors had limits of determinations of 102fgmL-1 and high sensitivities. The linear concentration ranges of the two 3D stochastic microsensors covered the healthy people as well as the patients confirmed with brain cancer. Determination of heregulin-α was done in whole blood and tissue samples using the screening method based on the proposed 3D stochastic microsensors as well as using the ELISA method; very good correlations were obtained between the two methods proving that the proposed method can be used in screening tests of whole blood and tumoural tissue samples for molecular recognition and determination of heregulin-α.

A new decomposition mechanism for metal complexes under water-oxidation conditions

Herein, water-oxidation reaction by cobalt(II) phthalocyanine, N,N′-bis (salicylidene) ethylenediamino cobalt(II), nickel(II) Schiff base (N,N′-bis (salicylidene)ethylenediamino nickel(II), nickel(II)) phthalocyanine-tetrasulfonate tetrasodium, manganese(II) phthalocyanine, 5,10,15,20-Tetraphenyl-21H,23H-porphine manganese(III) chloride, manganese(III) 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine chloride tetrakis(methochloride) was investigated using electrochemistry, UV-vis spectroscopy and spectroelectrochemistry. According to our results, a new decomposition pathway for these metal complexes under water-oxidation conditions was proposed. The produced metal oxide obtained by decomposition of metal complex under water -oxidation conditions not only catalyzes water-oxidation reaction but this metal oxide also accelerates decomposition of the corresponding complex to form higher amounts of the metal oxide. We hypothesize that such a mechanism could be investigated for many metal complexes under different oxidation or reduction reactions.

Colorimetric Gas Sensing Washable Threads for Smart Textiles

A fabrication method for a stable entrapment of optically responsive dyes on a thread substrate is proposed to move towards a detection system that can be integrated into clothing. We use the dyes 5,10,15,20-Tetraphenyl-21H,23H-porphine manganese(III) chloride (MnTPP), methyl red (MR), and bromothymol blue (BTB), for a proof-of-concept. Our optical approach utilizes a smartphone to extract and track changes in the red (R), green (G) and blue (B) channel of the acquired images of the thread to detect the presence of an analyte. We demonstrate sensing of 50–1000 ppm of vapors of ammonia and hydrogen chloride, components commonly found in cleaning supplies, fertilizer, and the production of materials, as well as dissolved gas sensing of ammonia. The devices are shown to be stable over time and with agitation in a centrifuge. This is attributed to the unique dual step fabrication process that entraps the dye in a stable manner. The facile fabrication of colorimetric gas sensing washable threads is ideal for the next generation of smart textile and intelligent clothing.

Extraction of hydrophobic analytes from organic solution into a titanate 2D-nanosheet host: Electroanalytical perspectives

Titanate nanosheets (single layer, typically 200 nm lateral size) deposited from aqueous colloidal solution onto electrode surfaces form lamellar hosts that bind redox active molecular redox probes. Here, hydrophobic redox systems such as anthraquinone, 1-amino-anthraquinone, deca-methylferrocene, 5,10,15,20-tetraphenyl-21H,23H-porphine manganese (III) chloride (TPPMnCl), and α-tocopherol are shown to bind directly from cyclopentanone solution (and from other types of organic solvents) into the titanate nanosheet film. For anthraquinone derivatives, stable voltammetric responses are observed in aqueous media consistent with 2-electron 2-proton reduction, however, independent of the pH of the outside solution phase environments. For decamethylferrocene a gradual decay of the voltammetric response is observed, but for TPPMnCl a more stable voltammetric signal is seen when immersed in chloride containing (NaCl) electrolyte. α-Tocopherol exhibits chemically irreversible oxidation and is detected with 1 mM–20 mM linear range and approximately 10−3 M concentration limit of detection. All redox processes exhibit an increase in current with increasing titanate film thickness and with increasing external electrolyte concentration. This and other observations suggest that important factors are analyte concentration and mobility within the titanate host, as well as ion exchange between titanate nanosheets and the outside electrolyte phase to maintain electroneutrality during voltammetric experiments. The lamellar titanate (with embedded tetrabutyl-ammonium cations) behaves like a hydrophobic host (for hydrophobic redox systems) similar to hydrophobic organic microphase systems. Potential for analytical applications is discussed.

Novel radiochromic porphyrin-based film dosimeters for γ ray dosimetry: investigation on metal and ligand effects

Abstract As the utilizing of porphyrins and metalloporphyrins in high dose dosimetry becomes more prevalent, research on structural effects of these molecules on dosimetric characteristics and physicochemical properties of their film dosimeters becomes more and more essential. The present study emphasizes dosimetry (measuring radiolytic bleaching of two novel film dosimeters with spectrophotometric methods against 60Co γ-rays exposure in dose range of 0–100 kGy) and evaluating substituent effects on the radiation response of the film dosimeters (role of organic groups and changing the metal core of porphyrins). With casting of solutions of polycarbonate (PC) containing 0.5 wt.% 5,10,15,20-Tetrakis(2,4,6-trimethoxyphenyl) porphyrin (TTMPP) and 5,10,15,20-Tetraphenyl-21H,23H-porphine manganese (III) chloride (Mn-TPP), two novel radiochromic films with the thickness of 20 μm were fabricated. The presence of porphyrin fragments has been observed in the UV–Vis spectra after γ radiation. Due to the changes of the metal core and substituents of the dye ring, meaningful shifts of maximum absorbance of Soret bands of porphyrins and different radiation response of film-dosimeters were observed. The results were compared with the other polycarbonate/porphyrin film dosimeters. The results indicate that the radiation-induced decoloration of PC/Porphyrin films can be reliably tuned and used in high dose dosimetry.

Structural and optical characterization of thermally evaporated nanocrystalline 5,10,15,20-tetraphenyl-21H,23H-porphine manganese (III) chloride thin films

Thin films of 5,10,15,20-Tetraphenyl-21H,23H-porphine manganese (III) chloride, MnTPPCl, were successfully deposited by thermal evaporation technique. The structure of thin films was characterized using Thermal Gravimetric Analysis, TGA, Fourier Transform Infrared, FTIR, X-ray Diffraction, XRD, and Atomic Force Microscope, AFM, techniques. TGA showed that MnTPPCl films are thermally stable up to 623 K. FTIR analysis revealed that thermal deposition technique is a convenient one to obtain chemically stable MnTPPCl thin films. XRD patterns showed nanocrystallites dispersed in the amorphous matrix for the pristine and annealed thin films. Annealing temperature increased the crystallite size and improved crystallinity of films. The observed results obtained by XRD technique are in agreement with those observed by AFM technique. Optical constants (n and k indices) of MnTPPCl films were calculated from absolute values of transmittance and reflectance measured by spectrophotometric technique in the wavelength range 200–2500 nm. The dispersion curve showed anomalous dispersion in the wavelength range <650 nm and normal dispersion in the wavelength range 650–2500 nm. The dispersion parameters of MnTPPCl films were calculated by applying single oscillator model in the transparent region of the spectrum. The molar extinction coefficient indicated the possibility of incorporating MnTPPCl films in devices fabrication. The absorption parameters of MnTPPCl films were calculated by applying band to band electron transition theory. The type of electron transition is direct allowed and the optical energy gap is 2.48 eV. Annealing temperatures have no influence on optical energy gap but it increased the onset energy gap.

Manganese(III) Porphyrin as Electrocatalyst for Hydrogen Evolution Reaction

5,10,15,20-tetraphenyl-21H,23H-porphine manganese(III) chloride (Mn(TPP)Cl) has been evaluated as electrocatalyst for Hydrogen Evolution Reaction (HER) in the presence of triethylamine hydrochloride (Et3NHCl) as source of proton. The direct reduction of Et3NHCl on vitreous carbon electrode occurs at Ep -1.6 V vs Ag/AgCl in [Bu4N][BF4]-CH3CN. Interestingly, in the presence of Mn(TPP)Cl as electrocatalyst the reduction potential shifts to -1.20 V. Based on gas chromatography analysis, the formation of H2 gas, with a current efficiency of ca. 58% after 2 h, is observed with a yield of 8 μmoles and a turnover of 2.5. However, the chemical yield at carbon electrode was about 35%. These results reflect the exquisite electrocatalytic efficiency of Mn(TPP)Cl in Hydrogen Evolution Reaction (HER).

Interfacial Molecular Assemblies of Metalloporphyrins with Two Trans or One Axial Ligands

Molecular assemblies of metalloporphyrins trans-dichloro(5,10,15,20-tetra-p-tolylporphyrinato)tin(IV) (SnCl2TPPMe) and trans-dihydroxo(5,10,15,20-tetra-p-tolylporphyrinato)tin(IV) (Sn(OH)2TPPMe), which have two trans axial ligands, as well 5,10,15,20-tetrakis(4-methoxyphenyl)-21H,23H-porphine iron(III) chloride (FeClTPPOMe) and 5,10,15,20-tetraphenyl-21H,23H-porphine manganese(III) chloride (MnClTPP), which have one axial ligand, are interfacially organized by Langmuir and Langmuir-Blodgett (LB) techniques. SnCl2TPPMe and Sn(OH)2TPPMe form nanofibrous structures which can display distinct supramolecular chirality, although the molecular units themselves are achiral, while FeClTPPOMe and MnClTPP form irregular nanoparticles that display negligible supramolecular chirality. An interpretation in terms of the effects of the axial ligands is proposed for this interesting phenomenon. Moreover, compared with assemblies of the diprotonated free-base porphyrins, which are fabricated by interfacial (air/2.4 M HCl) organization of free-base porphyrin, those of SnCl2TPPMe and Sn(OH)2TPPMe display higher stability in terms of supramolecular chirality. These results indicate that the assembly properties of metalloporphyrins can essentially be affected by the axial ligands that are attached to their chromophores, and that stable chiral porphyrin supramolecular associations can be easily produced by using achiral metalloporphyrins bearing two trans axial ligands.

A manganese porphyrin-based sensor for flow-injection potentiometric determination of thiocyanate

Metalloporphyrin-based ion-selective electrodes for flow-injection potentiometric determination of thiocyanate are described. The detection system is based on a coated glassy carbon electrode membrane sensor incorporating 5,10,15,20-tetraphenyl-21H,23H-porphine manganese(III) chloride as the active ingredient. The influences of the membrane composition, pH, and the effects of flow-injection parameters on the response of the system were investigated. At the optimized flow-injection potentiometric conditions, the sensor exhibited a Nernstian slope of -58.0 mV per decade of thiocyanate activity over the range 4.2 × 10-7–7.6 × 10-2M , where 50 μL of each sample solution was injected into the carrier solution. The detection limit of thiocyanate in the FIP mode was 4.2 × 10-7M . The selectivity of the flow-injection potentiometric system with respect to several common inorganic and organic anions was superior to that of the batch mode using the same sensor and similar operating conditions. The sensor was applied to the determination of thiocyanate in urine samples.

Excited-State Dynamics of 5,10,15,20-Tetraphenyl- 21H,23H-porphine Manganese(III) Chloride Encapsulated in TiMCM-41 and MCM-41; Proved by fs-Diffuse Reflectance Laser Photolysis

5,10,15,20-Tetraphenyl-21H,23H-porphine manganese(III) chloride (MnIIITPP(Cl)) was encapsulated into MCM-41 and TiMCM-41, and its photoinduced electron transfer had been studied by using femtosecond diffuse reflectance photolysis. Two different transient species (c.a. 10 ps and c.a. 80 ps) were observed. The shorter-lived species should be originated from relaxation of a “tripmultiplet” state and the longer-lived species should be attributed to the spin-forbidden relaxation (slower than the spin-allowed decay of triptquintet) via a quintet CT state. After irradiation, MnTPPCl+• radicals are detected in MCM-41 or TiMCM-41, indicating that the mesoporous silicate framework plays a good electron acceptor. Furthermore, it has been found that the formation MnTPPCl+• is easier in TiMCM-41 than in MCM-41, indicating that framework modification by incorporating the Ti4+ into the MCM-41 enhances the electron-accepting ability of the MCM-41 framework.

Metalloporphyrin chloride ionophores: induction of increased anion permeability in lung epithelial cells

5,10,15,20-Tetraphenyl-21H,23H-porphine manganese (III) chloride [TPPMn(III)] is a positively charged lipophilic anion carrier that is widely used as a Cl- sensor. TPPMn(III) increased anion permeability of cultured mouse lung epithelial (MLE) cells as measured by short-circuit current (ISC) to a level similar to that induced by forskolin analogues. Anion permeability was also studied in cultured human lung epithelial (A549) cells by measurement of the rates of change of fluorescence of the anion sensitive fluorescent dye, 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ). In these studies, cells were incubated with SPQ in SO2-4- medium, washed free of extracellular SPQ, and then perfused with medium containing anions that are known to quench SPQ fluorescence. The effect of TPPMn(III) on anion transport was then determined either microscopically in single cell studies or using cell monolayers mounted in a front face fluorimeter. TPPMn(III) in the range from 1 to 100 micrograms/ml induced a dose-dependent increase in Br- transport. The half-maximal quenching effect was estimated to be approximate 5 micrograms/ml. TPPMn(III) increased the rates of fluorescence quench of anions by up to fourfold. TPPMn(III) was without effect on -Ca2+-i level in A549 cells as measured with fura 2-AM. This indicates that TPPMn(III) effects were not mediated through effects on Ca+2 -activated Cl- channels, or by compromise of energy metabolism or membrane integrity of the cells. This study suggests that TPPMn(III) and, by extension, other lipophilic Mn(III) or Co(III) derivatives wherein the selectivity of lipophilicity is altered, could increase the anion permeability of biological membranes, and suggests a new approach for treatment of diseases such as cystic fibrosis, where transport of Cl- is defective.