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 [Co^III(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 [Co^II(TClPP)] (2) and [Co^III(TClPP)Cl] (3) starting materials, and the new Co(III) metalloporphyrin [Co^III(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 (J_s) and barrier height (ϕ_b), were measured.

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 (H₂T_NO2PP) 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.

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 E_1/2 = −0.91 V and E_1/2 = −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.

A joined experimental and theoretical study for unravelling the source of a strong hypsochromism.