Solvent Effects on Internal Rotational Barriers in Furfural. NMR Measurements and ab-Initio Molecular Orbital Methods Using Continuum Models

1997 ◽  
Vol 101 (38) ◽  
pp. 7182-7188 ◽  
Author(s):  
Alex D. Bain ◽  
Paul Hazendonk
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Solvent Effects ◽  
Continuum Models ◽  
Rotational Barriers ◽  
Internal Rotational Barriers

scholarly journals Structural Parameters and Internal Rotational Barriers of tert-Butylammonium Ion: AM1 and ab initio Calculations

1992 ◽  
Vol 47 (12) ◽  
pp. 1255-1256
Author(s):  
Hiroyuki Ishida ◽  
Yoshihiro Kubozono ◽  
Setsuo Kashino ◽  
Ryuichi Ikeda
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Internal Rotation ◽  
Barrier Height ◽  
Structural Parameters ◽  
Mo Calculations ◽  
Ab Initio Mo Calculations ◽  
Rotational Barriers ◽  
Ab Initio Mo ◽  
Internal Rotational Barriers

Semiempirical and ab initio MO calculations were performed to estimate the structural parameters of tert-butylammonium ion and its potential energies for the internal rotation of the CH3 and NH3+ groups. The barrier height for the rotation of NH3+ was found to be lower than for that of CH3 , corresponding to the C - N bond being longer than the C - C bond.

A theoretical approach to substituent effects. Stabilities and rotational barriers of β-substituted ethyl anions

1980 ◽  
Vol 33 (2) ◽  
pp. 241 ◽  
Author(s):  
A Pross ◽  
L Radom
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Theoretical Approach ◽  
Substituent Effects ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Rotational Barriers

Ab initio molecular orbital theory is used to study substituent effects in a series of substituted ethyl anions, XCH2CH2- (X = Li, BeH, BH2, CH3, NH2, OH and F). All substituents stabilize the anion relative to the corresponding neutral ethane. For electronegative substituents (NH2, OH and F) as well as CH3, this stabilization is achieved through enhanced hyperconjugative donation from the occupied 2p(C-) orbital to a vacant π*(CH2X) or π*(CH2) orbital; electropositive groups (Li, BeH and BH2) stabilize the anion primarily by 1,3-overlap between the occupied 2p(C-) orbital and the vacant 2p(X) orbital where such an interaction is possible. The importance of 1,3-interactions contrasts with the situation for cations XCH2CH2+ in which hyperconjugative interactions appear to be dominant.

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