A study of photoelectron spectra in the framework of the semiempirical AM1 method

1993 ◽  
Vol 42 (5) ◽  
pp. 822-826
Author(s):  
V. K. Turchaninov ◽  
A. I. Vokin ◽  
D. -S. D. Toryashinova ◽  
S. E. Korostova
Keyword(s):  
Photoelectron Spectra ◽  
Am1 Method ◽  
Semiempirical Am1 Method

Gas Phase Basicity of Substituted Benzaldehydes and Methylbenzoates.A Semiempirical Molecular Orbital Study

1988 ◽  
Vol 43 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Walter Fabian
Keyword(s):  
Gas Phase ◽  
Population Analysis ◽  
Resonance Effect ◽  
Am1 Method ◽  
Proton Affinities ◽  
Isodesmic Reactions ◽  
Mulliken Population ◽  
Semiempirical Am1 Method ◽  
Substituted Benzaldehydes ◽  
The Difference

AbstractThe semiempirical AM1 method is used to calculate relative proton affinities of a series of meta-and para-substituted benzaldehydes and methylbenzoates. Close agreement between the results of these calculations and experimental relative gas phase basicities could be obtained. The influence of a substituent on the stability of both neutral as well as protonated forms is estimated via isodesmic reactions. In any case the influence of a substituent is most pronounced in the protonated carbonyl compound. The contribution of the inductive/field effect of a substituent is approximated by the results of isolated molecule calculations. The resonance contribution is estimated by the charge transfer to or from the substituent as revealed by a Mulliken population analysis. Alternatively, the difference between isodesmic stabilization energies and isolated molecule results for the protonated compounds is taken as a measure for the resonance effect. Linear regression analyses with these substituent parameters show good correlation with both experimental as well as calculated relative basicities of the compounds studied.

Vibrational Stark effect: Theoretical determination through the semiempirical AM1 method

1992 ◽  
Vol 13 (7) ◽  
pp. 821-829 ◽  
Author(s):  
Josep Martí ◽  
Agustí Lledós ◽  
Juan Bertrán ◽  
Miquel Duran
Keyword(s):  
Stark Effect ◽  
Am1 Method ◽  
Theoretical Determination ◽  
Semiempirical Am1 Method

Reaction sites of N,N′-substituted p-phenylenediamine antioxidants

2007 ◽  
Vol 61 (1) ◽  
Author(s):  
I. Kortišová ◽  
M. Breza ◽  
Z. Cibulková
Keyword(s):  
Second Step ◽  
Am1 Method ◽  
Antioxidant Effectiveness ◽  
Semiempirical Am1 Method

AbstractThe geometries of N,N′-diphenylbenzene-1,4-diamine (DPPD), N-phenyl-N′-(1-phenylethyl)benzene-1,4-diamine (SPPD), N-(4-methylpentan-2-yl)-N′-phenylbenzene-1,4-diamine (6PPD), N-propan-2-yl-N′-phenylbenzene-1,4-diamine (IPPD), N-(2-methoxybenzyl)-N′-phenylbenzene-1,4-diamine (MBPPD), and N-phenyl-N′-(2-phenylpropan-2-yl)benzene-1,4-diamine (CPPD) as well as of their dehydrogenation products were optimized by the semiempirical AM1 method. The results support the idea of stable NB=CX structures formation during the consecutive dehydrogenation of SPPD, 6PPD, IPPD, and MBPPD antioxidants. The biradicals formed during the second step of dehydrogenation of substituted phenylenediamines might be important for their antioxidant effectiveness.

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