Results 191 to 200 of about 142,813 (213)
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The Unusual Fluorescence Strengthened by Steric Hindrance
Chemistry Letters, 1998Abstract In four dyads of fluorescein and carbazole, photoinduced intramolecular electron transfer occurred in polar solvents and was negligible in nonpolar solvents. However, unprecedented fluorescence strengthening in the dyad linked with a semi-rigid bridge (-CH2-Ph-CH2-) at the carboxyl of fluorescein (as 3.2 and 10 times as the ...
Manhua Zhang +3 more
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Steric hindrance of diffusion controlled reactions
Journal of Molecular Liquids, 1984Abstract For diffusion controlled reactions in solution a theory is proposed which includes the diffusion process, the lifetime of an encounter complex, and the rotation of the reacting species in the encounter complex. For some types of reaction the analytical equations of this scheme are solved and discussed.
W. Knoche +2 more
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STERIC HINDRANCE IN PROPOSED PHOTOISOMERS OF BILIRUBIN
Photochemistry and Photobiology, 1980Abstract— Semi‐empirical potential energy calculations have been used to examine the stabilities of the proposed geometric isomers of bilirubin. The calculations show that for either of the dipyrrole moieties, the ‘anti‐E’ and ‘syn‐E’ planar conformations are sterically unacceptable. The most stable form of the E isomer has the two pyrrole rings almost
A. J. Geddes +2 more
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The influence of steric hindrance on the lithiation of ferrocenylalkylamines
Journal of Organometallic Chemistry, 19901-{N,N-Dimethylamino[(1R,2S,5R)-2-isopropyl-5-methylcyclohexyl]-(R)-methyl}-ferrocene and 1-{N,N-dimethylamino[(1R,2S,5R)-2-isopropyl-5-methylcyclohexyl]-(S)-methyl}ferrocene have been prepared from (-)-menthone and ferrocene, and their conformation in solution elucidated by NMR spectroscopy.
Rudolf Herrmann +2 more
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Steric Hindrance Enzyme Immunoassay (Sheia)
1985We have developed a new enzyme immunoassay for the quantitation of small antigens. The assay is called SHEIA (Steric Hindrance Enzyme Immunoassay) since, this assay involves the interference of complex formation between the antigen (or hapten) coupled enzyme and the enzyme inhibitor attached to agarose by antibody to the antigen (or hapten), probably ...
A. Castro, Nobuo Monji
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Steric hindrance and percolation in orientational glasses
Journal of Non-Crystalline Solids, 1994Abstract Using a very simple renormalized site percolation model, the rich phase diagram exhibited by ACNxMn1−x mixtures, where A stands for K, Na or Rb while Mn represents Br, Cl or I, is obtained as function of cyanide concentration, x. From a steric hindrance argument, some cyanides are found to be randomly frozen at low temperatures being thus ...
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Arylglyoxals and Steric Hindrance
Journal of the American Chemical Society, 1939Hugh W. Gray +2 more
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Steric hindrance in the benzylation of anilines
The Journal of Organic Chemistry, 1979Antonino Mamo +2 more
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Steric Hindrance in the Stobbe Condensation
Journal of the American Chemical Society, 1949Jack Linsk, Melvin S. Newman
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Steric Hindrance to Planarity in Dye Molecules.
Chemical Reviews, 1947S. G. Dent +4 more
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