Hydrogen evolution sensitized by tin-porphyrin in microheterogeneous systems

Wang, Sheng; Tabata, Isao; Hisada, Kenji; Hori, Teruo

doi:10.1016/s0143-7208(02)00069-4

Cited by 21 publications

(12 citation statements)

References 18 publications

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“…The dissociated sulfonate groups of SnTPPS are considered to hinder the free encounter between protons and/or electrons. We reported previously that the decisive step is obviously focused on the final process, in which the proton was reduced to evolve hydrogen, and the amount of hydrogen evolution was affected appreciably by the ionic properties of porphyrin [4]. Therefore, they are prevented electron transfers, hydrogen evolution decreased with using SnTPPS.…”

Section: Highly Efficient Photoinduced Hydrogen Evolution Systemmentioning

confidence: 99%

“…Wang et al reported that tin meso-tetraphenylporphyrin (SnTPP) for photoinduced hydrogen evolution. SnTPP was effective not only as a photosensitizer (S) but also as an electron carrier (C) [4]. The reduction potential of tin porphyrin was more negative than that of zinc or manganese porphyrin, the reduction ability of tin porphyrin seems to be more efficient than those of others.…”

Section: Introductionmentioning

confidence: 99%

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A Photoinduced Hydrogen Evolution System Using Polymer-Supported Tin Porphyrin

et al. 2007

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: We examined the photoinduced evolution of hydrogen using a tin meso-tetraphenylporphyrin tetrasulfonate (SnTPPS) and tin meso-tetraphenylporphyrin (SnTPP) supported in various polymer films and fabrics. The hydrophilic polymers are more effective than the hydrophobic polymer as a supporter, because water penetration is easier and also the mobilities of the porphyrin molecules as well as protons and electrons in the film. A larger amount of hydrogen evolved using the SnTPPS-adsorbed keratin film (derivation of wool) than other film systems. The results indicated that keratin is a good electron transfer material. The evolved hydrogen was 25 -160 times that in other SnTPP-supported polymer films. Moreover, the fabric systems were more effective than the polymer film systems, because of the much higher specific surface area. In the SnTPP/PET fabric system, the turnover number exceeded 400 under the highpressure mercury lamp, which was about 1600 times larger than that under the tungsten lamp.

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Section: Highly Efficient Photoinduced Hydrogen Evolution Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Photoinduced Hydrogen Evolution System Using Polymer-Supported Tin Porphyrin

et al. 2007

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“…In Nature, the reaction center in photosystem II (PSII) contains a photosensitizer and redox-active entities, which are arranged with noncovalent interactions. − A series of stepwise electron-transfer (ET) reactions are triggered by excitation of the special pair (P680), which is a chlorophyll dimer, to afford a long-lived charge-separated state. − Inspired by the photoinduced ET reactions in PSII, synthetic photoinduced ET systems based on porphyrins ( H 2 P ) have been prepared and investigated to develop photodevices and photocatalytic systems − because H 2 P or its metal complexes ( MP ) act as not only photosensitizers but also electron mediators to achieve stepwise ET. − So far, artificial photoinduced charge-separation systems have been constructed using porphyrinoids as photosensitizers, which are connected with redox-active molecules through covalent bonds to accomplish ET cascades. − However, multistep synthetic processes were required to link components for the construction of charge-separation systems that contain more than three redox-active components in one molecules such as triads and tetrads . On the other hand, noncovalent interactions, such as hydrogen bonding, have synthetic advantages over covalent bonds because of the ease and diversity .…”

Section: Introductionmentioning

confidence: 99%

A Diprotonated Porphyrin as an Electron Mediator in Photoinduced Electron Transfer in Hydrogen-Bonded Supramolecular Assemblies

et al. 2019

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We have successfully constructed hydrogen-bonded supramolecular assemblies based on a diprotonated saddle-distorted porphyrin (H 4 DPP 2+ ) and redox-active molecules bearing a carboxylate group, such as a RuII polypyridyl complex (Ru II COO – ) that can act as an electron donor and a benzyl viologen derivative (BV 2+ COO – ) that can act as an electron acceptor. Formation of supramolecular assemblies of H 4 DPP 2+ with Ru II COO – (H 4 DPP 2+ (Ru II COO – ) 2 and H 4 DPP 2+ (Ru II COO – )(Cl – )) and BV 2+ COO – (H 4 DPP 2+ (BV 2+ COO – ) 2 ) was confirmed in acetone by 1H NMR measurements, CSI-TOF-MS, and X-ray crystallographic analysis. The photodynamics of H 4 DPP 2+ (Ru II COO – ) 2 and H 4 DPP 2+ (BV 2+ COO – ) 2 was elucidated by femto-, pico-, and nanosecond time-resolved transient absorption spectroscopy. In H 4 DPP 2+ (Ru II COO – ) 2 , intrasupramolecular photoinduced electron transfer (ET) occurred from the RuII center to the singlet excited state of H 4 DPP 2+ to afford an ET state involving one-electron-reduced H 4 DPP •+ and the corresponding one-electron-oxidized RuIII complex with the lifetime of 150 ps. On the other hand, in the presence of an external electron donor, intermolecular photoinduced ET occurred from an electron donor to the triplet excited state of H 4 DPP 2+ (BV 2+ COO – ) 2 to afford H 4 DPP •+ , following intrasupramolecular thermal ET proceeded from H 4 DPP •+ to BV 2+ COO – to form H 4 DPP 2+ (BV •+ COO – )(BV 2+ COO – ) with the lifetime of 1.1 ms. Thus, H 4 DPP 2+ can act as an electron mediator in hydrogen-bonded supramolecular assemblies. This is the first example of porphyrins as a photosensitizer and an electron mediator in hydrogen-bonded ET systems.

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“…33 In its 1 H-NMR spectrum, a broad singlet signal of two inner protons at δ –1.17 ppm confirmed the formation of TPBP . To obtain the desired metallated benzoporphyrins, TPBP was reacted with Zn(OAc) 2 ·2H 2 O,34 Co(OAc) 2 ·4H 2 O35 and SnCl 2 ·2H 2 O36 as described in the previous studies, leading to Zn-TPBP , Co-TPBP and Sn-TPBP , respectively, in 80–97% yield. Complete metallation of TPBP in these reactions was monitored by the absence of the broad singlet signal of the benzoporphyrinic inner protons at δ –1.17 ppm in the 1 H-NMR spectra and disappearance of the characteristic emission peak of TPBP at 787 nm.…”

Section: Resultsmentioning

confidence: 99%

“…Following a previously published procedure,36 a solution of TPBP (0.102 g, 0.125 mmol) and SnCl 2 ·2H 2 O (0.141 g, 0.625 mmol) in dimethylformamide (DMF, 5 mL) was treated with pyridine (0.05 mL) and refluxed for 4 h. A blue green precipitate was formed and collected by filtration. After that, the resulting crude product was purified by column chromatography (silica gel, CH 2 Cl 2 /MeOH (99 : 1)) to afford Sn-TPBP as a deep green solid (0.047 g, 90%).…”

Section: Methodsmentioning

confidence: 99%