Results 281 to 290 of about 269,366 (337)

Steric Effects and Solvent Effects in Ionic Reactions

Science, 2002
Rates of S N 2 reactions of chloride ion with methyl- and tert -butyl–substituted chloroacetonitrile were measured by using Fourier transform–ion cyclotron resonance spectrometry to follow the isotopic exchange reaction.
Colleen K, Regan, Stephen L, Craig, John I, Brauman   +2 more
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Sterically crowded aryloxide compounds of aluminum: electronic and steric effects

Organometallics, 1991
The mononuclear, four-coordinate aluminum compounds AlR 2 (BHT)L and AlR(BHT) 2 L [R=Me, Et; BHT=2,6-di-tert-butyl-4-methylphenoxide; L=2-Mepy, 4-Mepy, 2,6-Me 2 py, CH 3 CN, N(C 2 H 4 ) 3 CH, HNEt 2 , HN i Bu 2 , H 2 N t Bu,H 2 N n Bu, NH 3 , py•O] are obtained when AlR 3 is treated with the correct molar equivalent of BHT-H and the appropriate Lewis ...
Matthew D. Healy, Joseph W. Ziller, Andrew R. Barron   +2 more
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Remote Control by Steric Effects

Science, 2014
A rhodium-catalyzed reaction places a silicon substituent on the site farthest away from the largest group present on an aromatic ring. [Also see Research Article by Cheng and Hartwig ]
Mamoru Tobisu, Naoto Chatani
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σ‐Correlations and steric effects

Organic Magnetic Resonance, 1982
AbstractCarbon‐1 shifts in 1‐dimethylimino‐3‐dimethylamino‐1‐(4‐substituted)phenylprop‐2‐ene perchlorates show high correlation and negative dependence v. a σ set having high f character, similar to α and carbonyl carbon shifts in 4‐substituted styrenes and N,N‐dimethylbezamides, respectively.
S. N. Balasubrahmanyam, I. M. Mallick
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Steric effects in carbene cycloadditions

Tetrahedron Letters, 1983
Abstract Steric effects in cycloadditions with alkenes prevent the occurrence of a general linear free energy relationship between the reactivities of carbenes. Nevertheless, the isoselective temperature remains constant.
Bernd Giese, Woo Bung Lee, Carola Stiehl
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Steric effects in the system

Tetrahedron, 1965
Increasing size of the group R leads to the formation of a higher proportion of ketone in the methylation of amines of the type, Ph·CH(NH2)·R, and of a higher proportion of secondary amine in the aluminohydride reduction of oximes of the type, Ph·C(:NOH)·R.
S.H. Graham, A.J.S. Williams
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Fisher information and steric effect

Chemical Physics Letters, 2007
Abstract A modified Fisher information, the sum of the one-electron Fisher information, is proposed. It is shown that the modified Fisher information is the original Fisher information plus a sum of differences of quantum and classical variances. A generalization of the Stam’s inequality is derived.
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Steric effects in [2.2]metaparacyclophanes. Steric isotope effect, remote substituent effect on a steric barrier, and other steric phenomena

Journal of the American Chemical Society, 1974
S. A. Sherrod, R. L. Da Costa, R. A. Barnes, V. Boekelheide   +3 more
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Steric effects—III

Tetrahedron, 1980
Jaques-Emile Dubois, John Anthony Macphee, Annick Panaye   +2 more
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Substituent effects on steric strain

Chemical Physics Letters, 2003
Accurate quantum chemical calculations were performed on a series of mono-substituted tetrahedranes and [3]-prismanes by the high-level ab initio G3/B3LYP method. The relative stabilities of substituted tetrahedranes vs. their [3]-prismane analogues and the influence of substitution on steric strain are discussed.
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