Conformational Analysis. X.1The Conformational Energy of Alkyl Groups

1965 ◽  
Vol 87 (22) ◽  
pp. 5039-5043 ◽  
Author(s):  
Ernest L. Eliel ◽  
Thomas J. Brett
Keyword(s):  
Conformational Analysis ◽  
Conformational Energy ◽  
Alkyl Groups

Conformational analysis by spin transmission into rotating alkyl groups

1975 ◽  
Vol 97 (3) ◽  
pp. 643-644 ◽  
Author(s):  
Rudolf Knorr ◽  
Heinz Polzer ◽  
Edith Bischler
Keyword(s):  
Conformational Analysis ◽  
Alkyl Groups

Conformational analysis of coordination compounds: R-N,N,N',N'-Tetrakis-(2'-aminoethyl)-1,2-diaminopropanecobalt(III)

1967 ◽  
Vol 20 (11) ◽  
pp. 2395 ◽  
Author(s):  
JR Gollogly ◽  
CJ Hawkins
Keyword(s):  
Conformational Analysis ◽  
Metal Complexes ◽  
Coordination Compounds ◽  
A Priori ◽  
Van Der Waals ◽  
Energy Difference ◽  
Conformational Energy ◽  
Van Der Waals Interactions ◽  
Large Energy

The stereospecificity of the ligand, R-N,N,N?,N?-tetrakis(2?- aminoethyl)-1,2-diaminopropane, when coordinated as a sexadentate chelate to cobalt(III), has been investigated by an a priori calculation of the conformational energy difference between the various possible absolute configurations of the complex. It has been shown that the L isomer is more stable than the D isomer by an extremely large energy difference which is due mainly to van der Waals interactions. Some of the terms which contribute to conformational energy differences between metal complexes have not been considered previously.

Conformational effect in the stannous chloride debromination of sym-tetrabromoethane

1967 ◽  
Vol 45 (10) ◽  
pp. 1161-1164 ◽  
Author(s):  
W. K. Kwok ◽  
Sidney I. Miller
Keyword(s):  
Transition State ◽  
Conformational Analysis ◽  
State Energy ◽  
Energy Analysis ◽  
Stannous Chloride ◽  
Conformational Energy ◽  
Present System ◽  
Transition State Energy ◽  
Conformational Effect ◽  
Conformational Energy Analysis

The initial ratios of cis- to trans-dibromoethene product in the stannous chloride reduction of sym-tetrabromoethane in dimethylformamide were 1.51 ± 0.04 at 25°, 1.36 ± 0.03 at 50°, and 1.20 ± 0.03 at 75°. Transition state energy differences in the trans–gauche tetrabromoethane rotamers are estimated as (Ht≠ – Hg≠) = 480 and (Ft≠ – Fg≠) = 244 cal/mole at 25°. A conformational energy analysis was performed. We have shown how a rate-equilibrium parallelism can be adapted to a conformational analysis for systems of this type, and how α, a constant between zero and unity, can be used to characterize the transition state relative to reactants and products (eq. [8]). In the present system, however, there is no rate-equilibrium parallelism and α cannot be defined.

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