Photochemical base generator

In general, the chemical transformations associated with the chemical amplification mechanism in resists is effected through heating the exposed resist film, in a process called postexposure bake (PEB). Although, in principle, the active catalytic species (ions or radicals) could be generated from either photochemical (or radiochemical) acid or base generators, the acid generators are now used almost exclusively in advanced resist systems. ... 

Nakatani, K. Higashida, N. Saito, I. Highly efhcient photochemical generation of o-quinone methide from Mannich bases of phenol derivatives. Tetrahedron Lett. 1997, 38, 5005-5008. 

When silylenes are generated photochemically in hydrocarbon matrices in the presence of electron-pair donors, they may form Lewis acid-base complexes that act as intermediates in the silylene dimerization to disilenes.3233 In a typical example, Mes2Si(SiMe3)2 was photolyzed in 3-meth-ylpentane (3-MP) matrix containing 5% of 2-methyltetrahydrofuran. At 77 K, dimesitylsilylene (Amax 577 nm) was formed. When the matrix was... 

Tazuke and Kitamura162 reported the first example of an artificial photosynthetic system based on electron transport sensitization, although the product was not a hydrocarbon, but rather formic acid. Their system is shown schematically in Fig. 17. In this system, the photochemically generated singlet excited state of an aromatic hydrocarbon, such as pyren (Py) or perylene (Pe), was... 

Beside the use of MIPs in conventional HPLC, Mi-polymers may also be established in supercritical fluid chromatography, which is characterized by faster equilibration times combined with the use of the environmental friendly C02 as mobile phase. Although preliminary results show relatively broad peaks, chiral separation could be performed based on polymers imprinted with an enantiomer. However, the long-term stability of the photochemically generated polymers seems to be a problem [89]. 

Direct coupling of carbon nucleophiles with 1,3-dinitrobenzene is promoted by ultraviolet irradiation in the presence of quaternary ammonium fluorides, which can act not only as the base to generate the carbon nucleophile, but also as a proton transfer agent in the rearomatization step [83], The dinitrobenzene acts as the electron acceptor in the photochemical step. No reaction occurs in the absence of the fluoride and, surprisingly, although simple ketones, nitriles, esters and fl-kcto esters react, pentan-2,4-dione does not. 

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