نتایج جستجو برای: alternative substituents
تعداد نتایج: 311992 فیلتر نتایج به سال:
The title compound, C50H44, 1, was synthesized as a derivative of hepta-zethrene bearing two methyl and two tert-butyl-phenyl substituents, respectively, at the 1,9- and 7,15-positions. The asymmetric unit consists of one half of the mol-ecule, which lies about an inversion centre. Albeit remotely located, the substituents contort the hepta-zethrene plane. The tert-butyl-phenyl substituents sta...
A series of 5-spirocyclohexyl-3-(2,6-dimethylphenyl)-1,5-dihydro-2H-pyrrol-2-one derivatives (3) with various substituents on the spirocyclohexyl ring was synthesized and evaluated for its insecticidal activity against the aphid, Myzus persicae. Substituents at the 1- and 4-positions of the dihydropyrrole ring were also varied to optimize the activity. An investigation of the structure-activity...
The angles within the benzene ring in the title compound, C(30)H(49)N(3)O, ranging from 116.34 (16) to 124.18 (16)°, reflect the presence of electron-donating and electron-withdrawing substituents. The angles at the two electron-donating tert-butyl substituents are smaller than 120°, at the electron-withdrawing eth-oxy substituent larger than 120°, and at the imine substituent equal to 119.59 (...
The 1 : 2 reactions of isolable dialkylsilylene with nitriles having electron-donating aromatic substituents gave 1,4-diaza-2-siloles with a hitherto-unknown type of ring system, in contrast to the previous studies showing exclusive formation of the corresponding 1,3-diaza-2-siloles; the reactions of with aromatic nitriles bearing electron-withdrawing substituents afforded the latter ring syste...
Photodynamic inactivation of bacteria (PIB) by efficient singlet oxygen photosensitizers might be a beneficial alternative to antibiotics in the struggle against multiresistant bacteria. Phenothiazinium dyes belong to the most prominent classes of such sensitizers due to their intense absorption in the red-light region (λ(abs, max) ca. 600-680 nm, ε > 50,000 L mol(-1) cm(-1)), their low toxicit...
Electrochemistry, spectroscopy, and electrogenerated chemiluminescence of silole-based chromophores.
We studied the electrochemical and spectroscopic properties of a series of extended silole-based chromophores to understand the effect of structure on behavior. By changing the substituents attached to the chromophore, we observed large variations in luminescence quantum efficiency (ca. 0-0.6), lambdamax for absorbance and photoluminescence (PL), and radical ion stability. The differences are r...
Catalytic hydroboration of alkynes and alkenes was well demonstrated in the presence neosilyllithium as catalyst pinacolborane, under ambient conditions, to form corresponding alkyl boronic ester products excellent yield. Electron-withdrawing, electron-donating substituents, were tolerated on phenyl rings styrenes. Further, aliphatic substituents yielded desired boronate good quantities. The me...
stability of the ;-; stacking interactions in the substituted-coronene||cyclooctatetraene complexes wasstudied using the computational quantum chemistry methods (where || denotes ;–; stackinginteraction, and substituted-coronene is coronene which substituted with four similar x groups; x =oh, sh, h, f, cn, and no). there are meaningful correlations between changes of geometricalparameters and t...
[reaction: see text] A new method for the synthesis of 5-arylethynyl-8-hydroxyquinoline ligands using Sonogashira-Hagihara coupling was developed. The electronic nature of arylethynyl substituents affects the emission color and quantum yield of the resulting Al(III) complex. Photophysical properties of the metallocomplexes correspond to the electron-withdrawing/-donating character of the arylet...
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