Photo-base generator

Note 2 The term chemical amplification is commonly used in photoresist lithography employing a photo-acid generator or photo-base generator. 

Ito, K., Shigeru, Y., Kawata, Y., et al. Photo-initiated and thermal curing of epoxides by the use of photo-base generators bearing acyloxyimino groups. Can. J. Chem. 73, 1924-1932... 

Pyrene(Py)-modified duplexes containing uracil bases(U) Photo-induced generation of negative charges. ..-U-C-... -U" -C-... -. ..-U-C -... Py Py+ Py +... 

During the past two decades, five crad scales have been proposed to assess electronic effects in para- and meta-substituted benzyl radicals, four of which are of the kinetic type based on chemical reactivity. For example, the Fisher scale [Eq. (11)] [32] involves the A -bromosuccinimide(NBS)-initiated hydrogen abstraction from aryl-substituted m-cyanotoluenes. For the Jackson scale [Eq. (12)] [33], the thermolysis of dibenzylmercury compounds was employed. The most comprehensive scale is that by Creary [34] [Eq. (13)], which was derived from the relative rearrangement rates of 2-aryl-3,3-dimethylmethylenecyclopropanes. The most recent kinetic scale comes from Jiang et al. [35] [Eq. (14)], who applied the dimerization rates of substituted trifluorostyrenes for this purpose. Only Arnold s ax scale [36] is of the spectroscopic type, based on EPR a hyperfine coupling constants of photo-lytically generated aryl-substituted benzyl radicals [Eq. (15)]. 

By the mid-80s it was clear to most researchers that success on the conductivity side had taken its toll on polymer processability. Attention turned back to restoring the solubility and mechanical properties of the polymer. Polyaniline received the most attention initially. The nonconductive emeraldine base form is soluble in A-methylpyrrolidone [28] and films can be cast. Subsequent doping with a protonic acid from aqueous solution, or in situ with a photo-acid generator [45], is necessary to achieve conductivity. Polyaniline is also soluble in sulfuric acid, not the most convenient of solvents. Nevertheless it proved possible to spin fibers [46], cast films and extmde sheets of conductive polyaniline sulfate, but the laboratory experiments did not make the transition into large-scale manufacmring. 

D-A triads 2.134 (Chart 1.26) based on tetrathiafulvalene and oUgothiophenes as combined donor and fullerene as acceptor were synthesized by a Stille-type coupling reaction of bromooligothiophenes and stannylated tetrathiafulvalene. The attachment of the fullerene was achieved by successive reaction with the system fullerene-/V-methylglycine [234]. An increased photo-current generation was observed for triads 2.134 in comparison with oUgothiophene-fuUerene dyads 2.112. 

Zhang X, Cornelis R, De Kimpe J, and Mees L (1996) Arsenic speciation in serum of uraemic patients based on liquid chromatography with hydride generation atomic absorption spectrometry and on-line UV photo-oxidation digestion. Anal Chim Acta 319 177-185. 

D-HYSCORE was used to characterize radicals of zeaxanthin and violaxanthin photo-generated on silica-alumina and to deduce the anisotropic a-proton hyperfine coupling tensors. The couplings (MHz) were assigned based on DFT calculations. From such a comparison, the presence of the neutral radicals formed by proton loss from the radical cations was confirmed. 

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