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91.
Shigeyoshí Nishino Yasuhiro Nagato Yoshihiro Hasegawa Hisanao Yamamoto Kazuo Kamaike Yoshiharu Ishido 《Heteroatom Chemistry》1991,2(1):187-196
Reagent systems of sodium– and tetrabutylammonium nitrite–acetic anhydride were proved to be extremely efficient for the deanilidation of nucleoside 3′-phosphoranilidates, whose reactions were rapid with the former and instant with the latter. It was further found that the reagent system is applicable to oligonucleotide synthesis provided that the exocyclic amino groups of 2′-deoxyadenosine, 2′-deoxyguanosine, and 2′-deoxycytidine were protected by succinylation. 相似文献
92.
Yoshihiro Itoh Masamitsu Inoue Akira Hachimori 《Journal of polymer science. Part A, Polymer chemistry》1996,34(1):89-93
Alternating and random copolymers of 2-(9-carbazolyl)ethyl methacrylate with aromatic vinyl monomers were synthesized and their fluorescence properties were compared in good and poor solvents. Contraction of the polymer coils induced the hypochromic effect, i.e., the mutual interaction of the ground-state chromophores, but caused little quenching of their excited state. This is sharp in contrast with the vinyl-type of polymers, exhibiting large interactions in both the ground and excited states. Introduction of bulky groups on the comonomers in the alternating copolymers further suppressed these interactions. © 1996 John Wiley & Sons, Inc. 相似文献
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The electron spin resonance spectra of Mn2+ ions have been studied in GexTe100?x with x = 15, 17.5 and 20, and Ge20?xTe80Six with 0 ?x? 20. All samples are found to exhibit six hyperfine lines centered at g = 4.3 with hyperfine interaction constant A = 56 × 10?4cm?1. The g = 4.3 line is interpreted as being caused by Mn2+ ions incorporated in the amorphous network and surrounded by four Te atoms in an arrangement of orthorhombic symmetry. Some of the samples of GeTe show a g = 2.0 line. This line also appears after heat treatment in air at temperatures above the glass transition temperature. It is concluded that the g = 2.0 line is caused by Mn2+ ions in phase separated microcrystalline or concentrated regions of MnO in the glass. 相似文献
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