CO2 to CO Electroreduction, Electrocatalytic H2 Evolution, and Catalytic Degradation of Organic Dyes Using a Co(II) meso-Tetraarylporphyrin

The meso-tetrakis(4-(trifluoromethyl)phenyl)porphyrinato cobalt(II) complex [Co(TMFPP)] was synthesised in 93% yield. The compound was studied by 1H NMR, UV-visible absorption, and photoluminescence spectroscopy. The optical band gap Eg was calculated to 2.15 eV using the Tauc plot method and a semiconducting character is suggested. Cyclic voltammetry showed two fully reversible reduction waves at E1/2 = −0.91 V and E1/2 = −2.05 V vs. SCE and reversible oxidations at 0.30 V and 0.98 V representing both metal-centred (Co(0)/Co(I)/Co(II)/Co(III)) and porphyrin-centred (Por2−/Por−) processes. [Co(TMFPP)] is a very active catalyst for the electrochemical formation of H2 from DMF/acetic acid, with a Faradaic Efficiency (FE) of 85%, and also catalysed the reduction of CO2 to CO with a FE of 90%. Moreover, the two triarylmethane dyes crystal violet and malachite green were decomposed using H2O2 and [Co(TMFPP)] as catalyst with an efficiency of more than 85% in one batch

Synthesis of a Novel Zinc(II) Porphyrin Complex, Halide Ion Reception, Catalytic Degradation of Dyes, and Optoelectronic Application

This work describes the synthesis of a novel zinc(II) porphyrin complex, namely [Meso-4α-tetra-(1,2,3-triazolyl)phenylporphyrinato]zinc(II) symbolized by 4α-[Zn(TAzPP)] (4), using the click chemistry approach in the presence of copper iodide. All of the synthetic porphyrin species reported herein were fully characterized by elemental analysis, infrared spectroscopy, proton nuclear magnetic resonance, UV-visible spectroscopy, and fluorescence. To synthesize the 4α-[Zn(TAzPP)] complex (4), we produced 4α-Meso-tetra-o-nitrophenylporphyrin (H2TNO2PP) and 4α-meso-tetra-o-aminophenylporphyrin (4α-H2TNH2PP) (1) using known classic literature methods. This 4α atropisomer was converted to 4α-meso-tetra-o-azidophenylporphyrin (4α-H2TN3PP) (3) by reaction with sodium nitrite and sodium azide, and then it was metalated by Zn(II), leading to [4α-meso-tetra(2-azidophenyl)porphyrinate]zinc(II) (4α-[Zn(TN3PP)]) (3). The click chemistry synthetic method was finally used to prepare 4α-[Zn(TAzPP)] (4). This new tetracoordinated zinc(II) porphyrin complex was prepared and characterized in order to: (i) produce a receptor for anion recognition and sensing application for Cl− and Br−; (ii) study the catalytic decomposition of rhodamine B (RhB) and methyl orange (MO) dyes; and (iii) determine the electronic characteristics as a photovoltaic device. Complex (4) formed 1:1 complex stoichiometric species with chloride and bromide halides and the average association constants of the 1:1 addicts were ~ 103. The photodecomposition of RhB and MO dyes in the presence of complex (4) as a catalyst and molecular oxygen showed that complex (4) presented a photodegradation yield of approximately 70% and could be reused for five successive cycles without any obvious change in its catalytic activity. The current-voltage characteristics and impedance spectroscopy measurements of complex (4) confirmed that our zinc(II) metalloporphyrin could be used as a photovoltaic device

Hydrogen Evolution Reaction, Electrochemical CO₂ Reduction, and Oxidative Photodegradation of Organic Dyes Catalyzed by Co(II) Trimethoxy-<i>Meso</i>-Arylporphyrin

In search of robust catalysts for redox transformations such as the hydrogen evolution reaction (HER) or CO2 to CO reduction, we stepped on the previously reported meso-tetrakis(3,4,5-trimethoxyphenyl)porphyrinato cobalt(II) complex [Co(TTMPP)]. We prepared [Co(TTMPP)] in good yields and characterized it by IR, UV-vis absorption, photoluminescence spectroscopy, and cyclic voltammetry (CV). The [Co(TTMPP)] was used as a homogeneous catalyst for the electrochemical formation of H2 (HER) in DMF (N,N’-dimethylformamide)/TFA (trifluoroacetic acid) and DMF/EtN3BF4 solutions, with high faradic efficiencies (FE). Additionally, the reduction of CO2 to CO in DMF under a CO2 atmosphere was catalyzed in DMF/TFE (TFE = 2,2,2-trifluoroethanol) and DMF/PhOH with high FE and only traces of H2 as a by-product. Turnover frequencies of 15.80 or 9.33 s−1, respectively were determined from CV experiments or controlled potential electrolysis in the presence of 1eq. TFE. They were lower with PhOH as proton source with 13.85 or 8.31 s−1, respectively. Further, [Co(TTMPP)] as a solid catalyst (suspension) allowed the photodecomposition of the organic dyes methylene blue (MB) and rhodamine B (RhB) using H2O2 under visible light irradiation. The photocatalyst was photostable over five cycles. A photocatalytic mechanism was proposed based on trapping experiments of reactive oxygen species

Copper-based MOF, Cu 3 (SDBA) 2 (HSDBA), as a catalyst for efficient reduction of 4-nitrophenol in the presence of sodium borohydride

International audienceHerein, we report the synthesis of the copper-based MOF, Cu3(SDBA)2(HSDBA), using a solvothermal method. The physicochemical properties of the as-prepared sample were examined by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared and UV-vis spectroscopy techniques, and thermal analysis. Cu3(SDBA)2(HSDBA) was then investigated as a catalyst for the reduction of 4-nitrophenol (4-NP) in the presence of sodium borohydride (NaBH4) at 25 °C, and related kinetics and thermodynamics analyses were carried out. In a nutshell, it can be emphasized that, under our conditions, the Cu3(SDBA)2(HSDBA) catalyst is able to completely reduce 4-NP to 4-aminophenol (4-AP) in a very short time such as 20 s. Additionally, Cu3(SDBA)2(HSDBA) can be re-used for seven successive cycles without obvious change in its catalytic activity

Synthesis of New Cobalt(III) <i>Meso</i>-Porphyrin Complex, Photochemical, X-ray Diffraction, and Electrical Properties for Photovoltaic Cells

The present work describes the preparation and characterization of a new cobalt(III) porphyrin coordination compound named (chlorido)(nicotinoylchloride)[meso-tetra(para-chlorophenyl)porphyrinato]cobalt(III) dichloromethane monosolvate with the formula [CoIII(TClPP)Cl(NTC)]·CH2Cl2 (4). The single-crystal X-ray molecular structure of 4 shows very important ruffling and waving distortions of the porphyrin macrocycle. The Soret and Q absorption bands of 4 are very red-shifted as a consequence of the very distorted porphyrin core. This coordination compound was also studied by fluorescence and cyclic voltammetry. The efficiency of our four porphyrinic compounds—the H2TClPP (1) free-base porphyrin, the [CoII(TClPP)] (2) and [CoIII(TClPP)Cl] (3) starting materials, and the new Co(III) metalloporphyrin [CoIII(TClPP)Cl(NTC)]·CH2Cl2 (4)—as catalysts in the photochemical degradation was tested on malachite green (MG) dye. The current voltage of complexes 3 and 4 was also studied. Electrical parameters, including the saturation current density (Js) and barrier height (ϕb), were measured

Synthesis, Characterization and Catalytic Studies of Chromium(III) Porphyrin Complex with axial cyanate ligands

International audienceWe report the synthesis and the spectroscopic, structural and electrochemical characterization of a new chromium(III) coordination compound namely the bis(cyanato-N)[meso-tetratolylporphyrinato]chromate(III) (cryptand-222)potassium dihydrate [K(crypt-222)][CrIII(TTP)(NCO)2]•2H2O (complex I). This compound crystallizes in the orthorhombic crystal system with the non-centrosymmetric space group C2221. The chromium and the potassium atoms are located at special positions in a two-fold axis. The crystal lattice of complex I is stabilized by O-H…O, C-H…O, C-H…N and C-H…pi intermolecular contacts involving the negatively charged [CrIII(TTP)(NCO)2]- species, the [K(crypt-222)]+ counterions and the two non-coordinated water molecules. Further insights on these weak intermolecular contacts are provided by the Hirshfeld surface analysis. Molecular electrostatic potential (MEP) theoretical calculation on [K(crypt-222)][CrIII(TTP)(NCO)2]•2H2O are reported. The new Cr(III) complex was efficient as a catalyst in the decomposition of Rhodamine B (RbH) dye by hydrogen peroxide. This coordination compound was also tested as photocatalyst of the photodecomposition of RbH dye by molecular oxygen

Effect of the coordination of pi-acceptor 4-cyanopyridine ligand on the structural and electronic properties of meso-tetra(para-methoxy) and meso-tetra(para-chlorophenyl) porphyrin cobalt(ii) coordination compounds. Application in the catalytic degradation of methylene blue dye

International audienceTo examine the influence of both the important pi-acceptor character of the 4-cyanopyridine ligand and the nature of the para-substituted phenyls of meso-porphyrins on the electronic, electrochemical and structural properties of cobaltous metalloporphyrins, we prepared and fully characterized two coordination compounds the (4-cyanopyridine)[meso-tetra(para-methoxyphenyl)porphyrinato]cobalt(ii) and the (4-cyanopyridine)[meso-tetra(para-chlorophenyl)porphyrinato]cobalt(ii) with the [Co-II(TMPP)(4-CNpy)] and [Co-II(TClPP)(4-CNpy)] formulas (complexes 1-2). The solution structures of compounds 1-2 were confirmed by H-1 NMR spectroscopy and mass spectrometry methods. They were further characterized by cyclic voltammetry and photoluminescence studies. The X-ray molecular structure data show that the Co-TClPP-4-NCpy derivative (2) exhibits high ruffling deformation compared to that of the Co-TMPP-4-CNpy species (1). Notably, the crystal packing of complex 1 shows the formation of CoMIDLINE HORIZONTAL ELLIPSISCo supramolecular dimers with a distance of 5.663 angstrom. As an application of our two cobaltous compounds, an investigation involving complexes 1-2 in the degradation of the methylene blue dye in the presence and absence of H2O2 in aqueous solutions was carried out. These promising results show that 1-2 can be used as catalysts in the degradation processes of dyes

Spectroscopic, Electrochemical, Magnetic and Structural Characterization of an Hexamethylenetetramine Co(II) Porphyrin Complex - Application in the Catalytic Degradation of Vat Yellow 1 Dye

International audienceIn this study, a new cobaltous-(hexamethylenetetramine) [meso-tetra(para-methoxyphenyl)porphyrin complex with the formula [CoII(TMPP)(HMTA)] (I) was synthesized. The molecular structure was confirmed in solution by 1H NMR spectroscopy and mass spectrometry methods, and the single crystal X-ray diffraction structure of (I) was determined at both room temperature and low temperature. This species was further characterized by infrared, UV-visible and fluorescence spectroscopies, magnetic susceptibility measurements and cyclic voltammetry. The chemical reactivity behavior was also assessed theoretically through Density Functional Theory (DFT) approach. Magnetic investigation indicates that the Co(II)-HMTA porphyrin (I) species at low temperature is a cobaltous low-spin (S~=~1/2) species while at high temperature complex (I) exhibits a spin-crossover low-spin (S~=~1/2) ↔ high-spin (S~=~3/2). The adsorption kinetic of the ``vat yellow 1 dye'' was carried out in aqueous solution at pH~=~6. The experimental results are better fitted using the pseudo second order model. Furthermore, complex (I) was tested as catalyst in the degradation of the vat yellow 1 dye using an aqueous H2O2 solution and by photodegradation under solar light

Spectroscopic characterization, X-ray molecular structures and cyclic voltammetry study of two (piperazine) cobalt(II) meso-arylporphyin complexes. Application as a catalyst for the degradation of 4-nitrophenol

International audienceTwo new cobaltous-porphyrin complexes, namely (mu-piperazine)-bis[(meso-tetra(para-methoxyphenyl)porphyrinato)]cobalt(II) and (piperazine)[meso-tetra(para-chlorophenyl)porphyrin]cobalt(II) dichloromethane disolvate, with the formulas [{CoII(TMPP)}2(mu 2-pipz)] (complex 1) and [CoII(TClPP)(pipz)].2CH2Cl2 (complex 2), were used efficiently as catalysts in the degradation of 4-nitrophenol (4-NP) in an aqueous hydrogen peroxide solution. These cobalt(II)-pipz porphyrin complexes were characterized by a variety of spectroscopic methods including infrared, UV-visible, fluorescence, proton nuclear magnetic resonance, electron paramagnetic resonance (EPR) as well as mass spectrometry. A cyclic voltammetry investigation was also carried out on these two Co(II) metalloporphyrins. The EPR results indicate that both complexes 1 and 2 are paramagnetic low-spin (S = 1/2) cobalt(II) porphyrin complexes. Furthermore, the X-ray diffraction crystal structures of 1 and 2 were determined, and the intermolecular interactions were investigated by Hirshfeld surface analysis