Electrocatalytic Reduction of Oxygen Using Water-Soluble Iron and Cobalt Phthalocyanines and Porphyrins

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

“…Cobalt porphyrins provide a rich electrochemistry consisting of both metal- (Co(I)/Co(II)/Co(III) and porphyrin-centred redox processes. By variation of the substituents on the phenyl core of the porphyrin ligands, these processes can cover a huge range of potentials [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. Moreover, there are one or two axial positions available for binding small molecules [ 10 , 11 , 12 , 26 , 27 , 28 , 29 ].…”

“…Moreover, there are one or two axial positions available for binding small molecules [ 10 , 11 , 12 , 26 , 27 , 28 , 29 ]. Both properties make Co porphyrins very suitable for redox catalysis [ 22 , 23 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ].…”

“…In view of the climate crisis, the photochemical or electrochemical conversion of CO 2 and H 2 O into energy-rich fuel products such as methanol [ 30 , 32 , 33 ] or dihydrogen (H 2 ) [ 45 , 46 , 47 ] are important goals, and cobalt porphyrin complexes have been studied as catalysts for the CO 2 reduction [ 30 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 44 ] and the H 2 evolution [ 18 , 41 , 42 , 48 ], besides other important redox processes such as O 2 reduction [ 19 , 23 , 49 , 50 , 51 , 52 , 53 , 54 ], O 2 evolution reaction (OER) [ 49 , 55 ], and interesting organic redox transformations [ 56 , 57 , 58 , 59 , 60 ].…”

“…However, fine-tuning of the reduction potentials of Co porphyrins is easily possible through substitution on the ligand core. The workhorses among the porphyrin ligands, the 5,10,15,20-tetraphenyl-porphyrins or meso -tetrakis(phenyl)porphyrins (TPP) have been varied in this respect to a large extent at the phenyl and pyrrole positions and these Co(TPP) complexes show reduction potentials in the range of −0.5 to −1.5 V vs. the SCE (saturated calomel electrode) [ 17 , 18 , 23 , 24 , 25 , 30 , 32 , 40 , 44 , 61 , 62 ]. The NHE potentials are converted into the current SCE scale by subtracting about 240 mV, while SCE differs from the ferrocene/ferrocenium couple by +160 mV [ 63 ].…”

Silicon Tetrapyrazinoporphyrazine Derivatives-Incorporated Carbohydrate-Based Block Copolymer Micelles for Photodynamic Therapy

“…Phthalocyanine (Pc) derivatives are strong candidates for efficient PSs because they possess suitable photophysicochemical properties including high molar coefficients, fluorescent emission in the near-infrared region, and high singlet oxygen generation quantum yield. − However, Pcs present the strong tendency to form aggregates owing to their planar geometry with large π-conjugation structure. Moreover, Pcs cannot exist as monomeric dispersions in aqueous media owing to their hydrophobic nature, which causes strong collisional quenching of their excited states. − However, silicon phthalocyanines (SiPcs), which are Pcs that feature Si as the central atom, prevent the formation of molecular aggregate because Si atoms could accommodate axial substituents. − Over the past decade, several SiPc-based PSs conjugated with carbohydrate moieties have been designed for improved tumor targeting ability and solubility in aqueous media. − Moreover, SiPc-loaded polymeric micelles (PMs) have been demonstrated to facilitate tumor localization via their enhanced permeation and retention effect. − …”