Photochemistry of Iron-porphyrin complexes. Biomimetics and catalysis

Maldotti, Andrea; Амаделли, Р.; Bartocci, C.; Carassiti, V.; Polo, Eleonora; Varani, G.

doi:10.1016/0010-8545(93)85014-u

Cited by 59 publications

(48 citation statements)

References 27 publications

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“…The first reduction step, from PFe(III)Cl to PFe(II), occurs via homolytic FeÀCl bond breaking after irradiation of the ligand-tometal charge transfer (LMCT) band with a peak at approxi-mately 335 nm. [27][28][29][30][31][32][33][34] This reduction step occurs without the need of a sacrificial electron donor, but we did observe, as reported previously, a significant increase in the reduction efficiency (yield and rate constant) with the addition of a sacrificial electron donor, such as triethylamine (Et 3 N), to the solution.…”

Section: Successive Reductions Of Pfesupporting

confidence: 53%

Homogeneous Photocatalytic Reduction of CO₂ to CO Using Iron(0) Porphyrin Catalysts: Mechanism and Intrinsic Limitations

et al. 2014

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A photochemical catalytic reduction of CO2 was performed in an organic solvent with iron(0) porphyrins as homogeneous molecular catalysts under visible light irradiation. With modified tetraphenylporphyrins consisting of internal phenolic groups, the photochemical process led to the production of CO, with H2 as a minor product. High catalytic selectivity for CO formation and turnover numbers up to 30 were obtained. Degradation of the catalyst occurred at longer irradiation times, along with decreased selectivity. Furthermore, addition of a weak acid, which increased the reduction efficiency under electrochemical conditions, led to rapid deactivation of the catalyst. With the unmodified tetraphenylporphyrin as catalyst, we observed lower performance and higher proportion of H2, which highlighted differences in the reduction pathways followed. A combination of a spectroscopic study and product analysis performed under various conditions led to detailed reduction mechanisms and helped pave the way for designing durable photocatalytic systems.

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Section: Successive Reductions Of Pfesupporting

confidence: 53%

Homogeneous Photocatalytic Reduction of CO₂ to CO Using Iron(0) Porphyrin Catalysts: Mechanism and Intrinsic Limitations

et al. 2014

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“…Although speculative for water and seawater, it has been shown that iron porphyrins show catalytic behavior, efficiently catalyzing thermal redox reactions on organic substrates by reversible modification of the oxidation state of the metal center (Suslick and Watson, 1992;Maldotti et al, 1993;Frausto da Silva and Williams, 1994). The irradiation of iron porphyrin complexes could via an axial ligand to metal charge transfer (LMCT) realize a photo-assisted redox cycle in which molecular oxygen is activated by coordination to Fe(II) in the ferrous porphyrin complex leading to the production of superoxide and radical ligand species (Maldotti et al, 1989).…”

Section: Protoporphyrin IXmentioning

confidence: 99%

Enhancement and inhibition of iron photoreduction by individual ligands in open ocean seawater

Rijkenberg

Gerringa

Carolus

et al. 2006

Geochimica et Cosmochimica Acta

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“…This type of metalloporphyrins can be formed with the ions of the iron group, such as Fe(III), Co(III), and Ni(II). However, while the photoredox chemistry of iron(III) and cobalt(III) porphyrins was thoroughly studied in the past 2-3 decades [6,7,8,9,10], the corresponding nickel(II) complexes were hardly examined in this respect [11,12]. Since the complexes of iron(III), cobalt(III) as well as manganese(III) with the cationic 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (H2TMPyP 4+ ) proved to be promising in various photocatalytic systems [3,7,8,13,14,15,16,17], in this work some photophysical and photochemical properties of Ni(II)TMPyP 4+ were studied in order to examin the potential applicability of this metalloporphyrin in utilization of solar radiation in the visible range.…”

mentioning

confidence: 99%

Photophysical and photocatalytic behavior of nickel(II) 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin

Major

Horváth

Fodor

et al. 2016

Inorganic Chemistry Communications

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Kinetically inert cationic Ni(II)TMPyP 4+ (H2TMPyP 4+ = 5,10,15,20-tetrakis(methylpyridinium-4-yl)porphyrin) displayed a characteristic fluorescence (τ = 1.2-1.4 ns, Φ = 2.0×10 -3 ), which was quenched with triethanolamine (TEOA) in a static way. This complex proved to be an efficient photocatalyst in the system containing TEOA and methylviologen (MV 2+ ) as electron donor and acceptor, respectively. Interestingly, however, deviating from the behavior of the analogous Co(III) and Mn(III) complexes in such a system, TEOA did not dinamically quench the triplet excited state of Ni(II)TMPyP 4+ (τ = 6.31 μs), hence no reduction of the metal center occured upon irradition. Instead, in the presence of this electron donor (at 1×10 -3 M) the excited-state lifetime dramatically increased (to τ = 36.6 μs), indicating the formation of a Ni(II)TMPyP 4+ -TEOA associate. This longer-lived triplet was efficiently quenched by MV 2+ (kq = 9.9×10 6 M -1 s -1 ), leading to the formation of MV •+ . The overall quantum yield of this one-step photoassisted electron transfer is considerably high (Φ = 0.011-0.013 at Soret-band irradiation). Hence, this system, combined with a suitable cocatalyst, may be applicable for visible light-driven hydrogen generation from water.

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Photochemistry of Iron-porphyrin complexes. Biomimetics and catalysis

Cited by 59 publications

References 27 publications

Homogeneous Photocatalytic Reduction of CO₂ to CO Using Iron(0) Porphyrin Catalysts: Mechanism and Intrinsic Limitations

Homogeneous Photocatalytic Reduction of CO₂ to CO Using Iron(0) Porphyrin Catalysts: Mechanism and Intrinsic Limitations

Enhancement and inhibition of iron photoreduction by individual ligands in open ocean seawater

Photophysical and photocatalytic behavior of nickel(II) 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin

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Photochemistry of Iron-porphyrin complexes. Biomimetics and catalysis

Cited by 59 publications

References 27 publications

Homogeneous Photocatalytic Reduction of CO2 to CO Using Iron(0) Porphyrin Catalysts: Mechanism and Intrinsic Limitations

Homogeneous Photocatalytic Reduction of CO2 to CO Using Iron(0) Porphyrin Catalysts: Mechanism and Intrinsic Limitations

Enhancement and inhibition of iron photoreduction by individual ligands in open ocean seawater

Photophysical and photocatalytic behavior of nickel(II) 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin

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Homogeneous Photocatalytic Reduction of CO₂ to CO Using Iron(0) Porphyrin Catalysts: Mechanism and Intrinsic Limitations

Homogeneous Photocatalytic Reduction of CO₂ to CO Using Iron(0) Porphyrin Catalysts: Mechanism and Intrinsic Limitations