Heteroaryl compounds
are valuable building blocks in medicinal
chemistry and chemical industry. A palladium-catalyzed direct α-C(sp3)
heteroarylation of ketones under microwave irradiation is developed
and reported in this study. Under optimized conditions, twenty-eight
(28) heteroarylated ketones were prepared in this study to demonstrate
the substrate scope of this reaction. The ground-state optimized structure
of Pd(0) active catalyst with 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl
(XPhos) in toluene, and the products of its reaction with 3-bromopyridine
and acetophenone were studied using all-atom density functional theory.
This study provided insightful information for palladium catalytic
system design to generate heteroaryl compounds.
The effect of different photoadditives in high and low activation energy resist resins on resist outgassing during lithographic exposure was studied by quartz microbalance and gas chromatography/ mass spectroscopy techniques. The resist outgassing was analyzed both qualitatively and quantitatively and structureproperty relationships were developed between resist outgassing and the molecular structure of photoacid generators (PAG) and other additives. The photoadditives examined included, aryl iodonium perfluoroalkylsulfonates, triarylsulfonium perfluoroakylsulfonates, photogenerators of sulfamic acids, 2-nitrobenzyl PAC's and doxyl derivatives. It was found that during exposure sulfonium salt formulated resists gave a lower outgassing of aromatic compounds than iodonium salt formulated resists while a formulation with a nitrobenzyl PAG did not show any aromatic materials outgassing. The use of a stable free radical additive, methyl 5doxyl stearate, in a resist formulated with an iodonium salt was found to also dramatically reduce outgassing of aromatic compounds probably through termination of triplet state radical photoproducts. Sweet PAG resist formulations were found to have greatly decreased outgassing during exposure originating from the cleavage of low activation energy acetal protecting groups.
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