Substituent effects on poly(p-phenylenevinylene) backbone, interrupted with silicon atoms: molecular orbital theory

2004 ◽  
Vol 141 (3) ◽  
pp. 251-257 ◽  
Author(s):  
Seeyearl Seong ◽  
Maeng Eun Lee ◽  
Tae Bum Lee ◽  
Kyoung Tai No ◽  
Hwan Kyu Kim
Keyword(s):  
Molecular Orbital ◽  
Substituent Effects ◽  
Molecular Orbital Theory ◽  
Orbital Theory

Photoelectron (HeI) Spectra of Aromatic Thiocarbonyls and Corresponding S-Oxides

1978 ◽  
Vol 33 (4) ◽  
pp. 468-471
Author(s):  
Fernando Bernardi ◽  
Francesco Paolo Colonna ◽  
Giuseppe Distefano ◽  
Gaetano Maccagnani ◽  
Giuseppe Spunta
Keyword(s):  
Molecular Orbital ◽  
Ionization Energy ◽  
Substituent Effects ◽  
Molecular Orbital Theory ◽  
Orbital Theory

The low ionization energy regions of the photoelectron (He I) spectra of several p-p′-substituted thiobenzophenones (X-C6H4)2CS and of the corresponding S-oxides (sulphines) (XC6H4)2CSO (where X = H , OCH3, CH3, I, Br, Cl and NO2) have been assigned on the basis of perturbational molecular orbital theory arguments coupled with CNDO/2 computations and substituent effects. For the thioketones, the ordering of the outermost MO's results to be n(S), π7, π6, π5/π4, π3, n(S) being the HOMO; while for the sulphines the two outermost MO’s have π character and correspond to π7 and π6 in the thioketones.In the light of the above results the different behaviour toward oxidation of these two classes of compounds can be rationalized.

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.

The relationship between substituent effects on energy and on charge from ab initio molecular orbital theory

1977 ◽  
Vol 99 (17) ◽  
pp. 5821-5822 ◽  
Author(s):  
W. F. Reynolds ◽  
P. G. Mezey ◽  
W. J. Hehre ◽  
R. D. Topsom ◽  
R. W. Taft
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Substituent Effects ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
The Relationship

Bonding in Transition Metal Silyl Dimers. Molecular Orbital Theory

1989 ◽  
Author(s):  
Alfred B. Anderson ◽  
Paul Shiller ◽  
Eugene A. Zarate ◽  
Claire A. Tessier-Youngs ◽  
Wiley J. Youngs
Keyword(s):  
Transition Metal ◽  
Molecular Orbital ◽  
Molecular Orbital Theory ◽  
Orbital Theory
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