Photosensitization of Base-Developable Poly(phenylhydrosilane) with 3,3‘,4,4‘-Tetra(tert-butylperoxycarbonyl)benzophenone. Mechanism of the Drastic Photosensitization in Terms of Photoinduced Electron Transfer

Abstract

A likely mechanism of especially large photosensitization for a base-developable poly-(phenylhydrosilane) resist (1) in the presence of 3,3′,4,4′-tetra(tert-butylperoxycarbonyl)benzophenone (EA1) is discussed in terms of photolysis rates and dissolution rates. The increase in the photolysis rate occurs through photoinduced electron transfers from polysilanes to electron acceptors. The fluorescence quenching rate of 1 in the presence of EA1 is almost the same as that in the presence of benzophenone (EA2). However, EA1 does increase both photolysis rates and resist sensitivities, but EA2 does not. The difference between EA1 and EA2 is discussed in terms of back-electron transfer in order to explain the importance of the presence of peroxide moieties. In the case of EA2, photoinduced electron transfers as well as back-electron transfers occur. In case of EA1, the cleavage of peroxide bonds on the benzophenone moiety would effectively inhibit the back-electron transfer to the 1 radical cation. The same phenomena are observed for C-60. EA1 photodecomposes to form compounds bearing carboxylic acids which also facilitate the dissolution of photolysis products of 1 into basic aqueous solutions.

The influence of a radical structure on the kinetics of photopolymerization

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Photodegradation of Poly[methyl(phenyl)silylene] in the Presence of Modifying Substances

“…However, the electron relaxation back to polymer (step (iii)) limits the efficiency of the photodegradation. (b) The second case requires the existence of a non-stable bond in the additive [7] . The bond is expected to be not stable in the form of anion radical; thus, radical and anion (nucleophilic) group is expected to be formed.…”

Aplicação e avanços da espectroscopia de luminescência em análises farmacêuticas

“…Assim, a quantificação luminescente de analitos, como filtros solares orgânicos, ácido p-metocinâmico, 2-etil-metil-p-metoxicinamato 182 e derivados da benzofenona; [183][184][185][186][187][188][189][190][191] substâncias estrogênicas, como os derivados do estradiol; e antiinflamatórios não-esteróides (AINEs) como a indometacina, acetamicina, ibuprofeno, e muitos outros fármacos, será plausível dependendo apenas da habilidade do pesquisador para investigar e/ou explorar novas rotas alternativas que permitam quantificar esses analitos através da espectroscopia de luminescência.…”