Effect of Amino Acid Residue Model on the Photoinduced Long-Distance Electron Transfer from the Excited Ru(bpy)32+ to Methylviologen in a Polymer Film

Nagai, Keiji; Tsukamoto, Jiro; Takamiya, Nobuo; Kaneko, Masao

doi:10.1021/j100017a055

Cited by 54 publications

(29 citation statements)

References 5 publications

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“…In the present study, average intermolecular distance between the acid and NBAb is estimated to be in the range of 10 -15 nm according to Poisson statistics. [20] 4.Conclusion We observed diffusion of the acids from PAG in PMMA and PEMA by using diffusioncontrolled acid-base reaction with NBAb. The method consists of measuring the decrease in absorption spectra of NBAb.…”

Section: Absorptionmentioning

confidence: 86%

Measurement of Acid Diffasion from a Photoacid Generator in Polymer Solids by using Nile Blue A Base.

Yamakawa

Horie

1999

J. Photopol. Sci. Technol.

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In chemically amplified resists, acid diffusion from a photo-acid generator (PAG) is one of the important factors which control their efficiency. This paper reports observation and estimation of the acid diffusion from PAG (p-nitrobenzyl 9,10-dimethoxyanthracene-2-sulfonate, NAS, or 2,4-dinitrobenzyl tosylate, DNBT) in polymer solids (PMMA or PEMA) by using a diffusion-controlled acid-base reaction. Nile Blue A base used as a basic indicator changes its absorption peak by protonation. The rate constants and hence the diffusion coefficients of acids from the PAG in polymer solids were estimated from second-order reaction kinetics.

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Section: Absorptionmentioning

confidence: 86%

Measurement of Acid Diffasion from a Photoacid Generator in Polymer Solids by using Nile Blue A Base.

Yamakawa

Horie

1999

J. Photopol. Sci. Technol.

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“…[8 -11] For a long-range electron transfer in a syn-thetic system, the mediation effects of 3-methylindole as a tryptophan model compound on the photoinduced electron transfer from the tris(2,29-bipyridine)ruthenium(II) complex [Ru(bpy) 3 2+ ] to methylviologen (MV 2+ ) have been investigated in a polymer membrane. [12] This result indicated that the electron-transfer distance doubled in the presence of 3-methylindole. Furthermore, it is reported that for electrochemical water oxidation in a polymer membrane, the charge-transfer distance between reactive centers increases in the presence of p-cresol from 1.28 nm to 2.25 nm, indicating that the p-cresol functions as a mediator for the charge transport.…”

Section: Introductionmentioning

confidence: 93%

“…For the C 6 Tyr systems, the charge separation is less effective at C 12 RuVQPIm despite having the best quenching efficiency; the initial rate of the viologen radical formation decreases with increasing rate of the forward reaction (quenching reaction) in the mediated process. This may be because the rate of the back reaction in the mediated process is the largest for C 12 RuVQPIm. The initial rate for the C 12 Tyr system shows the opposite length-dependence on the luminescence intensity, indicating that the initial rate directly reflects the forward reaction rate increases in the mediated process.…”

Section: Photosensitized Charge Separationmentioning

confidence: 99%

L-Tyrosine Ester-Mediated Photosensitized Charge Separation - Length Effects of Alkyl Side Chains in Polymers and Alkyl Groups inL-Tyrosine Esters

Suzuki¹,

Kimura

Hanabusa

et al. 2001

Macromol. Chem. Phys.

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The ruthenium(II) complex‐ and viologen‐containing partially quaternized poly(1‐vinylimidazole)s with a butyl (C4RuVQPIm), an octyl (C8RuVQPIm), a dodecyl (C12RuVQPIm), and hexadecyl (C16RuVQPIm) as alkyl side chains have been prepared. The length‐effects of the alkyl side chain in the polymers and the alkyl groups in the L‐tyrosine esters on the L‐tyrosine‐ester‐mediated intra‐polymer photosensitized charge‐separation reactions have been investigated in methanol. The L‐tyrosine esters with a hexyl (C6Tyr), an octyl (C8Tyr), and a dodecyl (C12Tyr) group were used. The luminescence intensities decreased with the addition of the L‐tyrosine esters, and they significantly depended on the length of the alkyl side chains on the polymers, C12RuVQPIm showed the smallest luminescence intensity. In contrast, the luminescence intensity of C4RuVQPIm depended on the length of the alkyl groups in the L‐tyrosine esters, but not for CnRuVQPIms (n ≥ 8). These results were explained by a difference in the microdomain structure formed by the polymer structure between C4RuVQPIm and other polymers. During the photosensitized charge separation, the reaction proceeded through a mediated process, using L‐tyrosine esters, and a direct process (without L‐tyrosine esters). The initial rate of the viologen radical formation was influenced by both the alkyl side chains on the polymers and alkyl groups in the L‐tyrosine esters, particularly; particularly influenced was the back reaction in the mediated process.

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“…[14][15][16][17] It is well-known that the phosphorescence of Ru(bpy) 3 2+ is quenched by electron transfer to an acceptor such as methyl viologen (MV 2+ ). 7,8,[18][19][20][21][22][23] In the present paper we propose the polysaccharide quasisolids as a new medium for photochemical reactions. We have investigated the photoinduced electron transfer from Ru(bpy) 3 2+ to MV 2+ or propyl viologen sulfonate (PVS 0 ) ( Figure 2) in polysaccharide (agarose, κ-carrageenan) quasi-solids containing a large amount of water, by which fundamental properties of the polysaccharide quasi-solids as a medium for photochemical reactions will be discussed.…”

Section: Introductionmentioning

confidence: 99%

New Quasi-solid Materials as a Medium for Photochemical Reactions

et al. 2003

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Polysaccharide quasi-solids containing a large excess of water were proposed as a new medium for photochemical reactions. Photochemical reaction was studied by the electron-transfer quenching of photoexcited tris(2,2′-bipyridine)ruthenium(II) (Ru(bpy) 3 2+ ) by methyl viologen (MV 2+ ) or propyl viologen sulfonate (PVS 0 ). The maximum wavelengths of the visible absorption and emission spectra of Ru(bpy) 3 2+ were 452 and 627 nm, respectively, in both agarose and κ-carrageenan quasi-solids, similar to those in an aqueous solution. Photoinduced electron transfer from the photoexcited Ru(bpy) 3 2+ to MV 2+ took place by a dynamic mechanism in a 2 wt % agarose/water quasi-solid, the same as in pure water, but occurred by both the dynamic and static mechanisms in a 2 wt % κ-carrageenan/water quasi-solid in high MV 2+ concentration regions ([MV 2+ ] > 1 mM). Since κ-carrageenan contains anionic sulfonate groups, the cationic Ru 2+ complex and MV 2+ were supposed to be bound electrostatically near the main chain, so that the static electron transfer would take place. On the contrary, photoinduced electron transfer from the Ru(bpy) 3 2+ to PVS 0 took place by a dynamic mechanism even in the κ-carrageenan quasi-solid because of the neutral acceptor. The electron transfer in the κ-carrageenan was analyzed with a mechanism involving both the dynamic and static electron transfer by assuming a multistep incorporation of the MV 2+ into the static quenching sphere around the Ru complex. The electron-transfer rate constants from the photoexcited Ru(bpy) 3 2+ to MV 2+ were 4.7 × 10 8 M -1 s -1 in the agarose quasi-solid and 2.1 × 10 9 M -1 s -1 for the dynamic part in the κ-carrageenan quasi-solid. The latter value is approximately 1 order of magnitude as large as that in a homogeneous aqueous solution. Thus, the tight and elastic quasi-solid can in principle work as a medium like liquid water. However, the nanoscale heterostructured main chain can provide a kind of molecular surface where interaction of the reactants controls the mechanism and kinetics, as shown in the κ-carrageenan case.

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Effect of Amino Acid Residue Model on the Photoinduced Long-Distance Electron Transfer from the Excited Ru(bpy)32+ to Methylviologen in a Polymer Film

Cited by 54 publications

References 5 publications

Measurement of Acid Diffasion from a Photoacid Generator in Polymer Solids by using Nile Blue A Base.

Measurement of Acid Diffasion from a Photoacid Generator in Polymer Solids by using Nile Blue A Base.

L-Tyrosine Ester-Mediated Photosensitized Charge Separation - Length Effects of Alkyl Side Chains in Polymers and Alkyl Groups inL-Tyrosine Esters

New Quasi-solid Materials as a Medium for Photochemical Reactions

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