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Steric effect on fluorescence quenching
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2005In this communication we have reported the steric effect on the fluorescence quenching rate constants of the electron transfer (ET) process. We have done a comparative study using donor (D)-acceptor (A) systems with different exergonicity (-deltaG(f)). Different carbazole derivatives (CZ): 1,4-dicyanobenzene (DCB) systems (-deltaG(f) = 0.7-0.8 eV) were
Nandita Ghosh +3 more
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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.
A.J.S. Williams, S.H. Graham
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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.
A.J.S. Williams, S.H. Graham
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σ‐Correlations and steric effects [PDF]
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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Conformational, Steric, and Stereoelectronic Effects [PDF]
, 1984 The total energy of a molecule is directly related to its geometry. Several aspects of molecular geometry can be recognized, and, to some extent, the energetic consequences can be dissected and attributed to specific structural features. Among the factors which contribute to total energy and have a recognizable connection with molecular geometry are ...
Francis A. Carey, Richard J. Sundberg
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Conformational and Other Steric Effects [PDF]
, 1977 The total energy of a molecule is directly related to its geometry. Several aspects of molecular geometry can be recognized, and, to some extent, the energetic consequences can be dissected and attributed to specific structural features. The features that are of greatest significance in organic chemistry are nonbonded interactions, both repulsive and ...
Francis A. Carey, Richard J. Sundberg
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Steric Effects and Solvent Effects in Ionic Reactions
Science, 2002Rates 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.
Stephen L. Craig +2 more
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Steric effects in dispersion forces interactions
Physical Review E, 2008Classically, there have been two different ways to obtain mean-field theories for liquid crystals. One is based on short-range repulsive steric forces and the other on long-range attractive dispersion forces. In the former approach, it is the anisotropic shape of the molecules that leads to the anisotropic interaction, and in the latter it is the ...
SONNET A. M +1 more
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Remote Control by Steric Effects
Science, 2014A 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 ]
Naoto Chatani, Mamoru Tobisu
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Fisher information and steric effect
Chemical Physics Letters, 2007Abstract 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 carbene cycloadditions
Tetrahedron Letters, 1983Abstract 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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