AIM study on the transferability of the oxygen atom in linear ethers

Vila, Antonio; Carballo, E.; Mosquera, Ricardo A.

doi:10.1139/v00-148

Cited by 38 publications

(27 citation statements)

References 24 publications

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“…An excellent degree of correlation (r 2 ) 0.989) is found between the summation of the L(Ω) values and the error in the additivity of the electron populations N-ΣN(Ω), as was shown in previous works. 30,31 A. Geometries. Optimized C-O bond lengths and C-O-C bond angles for the neutral and protonated species are gathered in Table 2.…”

Section: Resultsmentioning

confidence: 99%

Topological Analysis of Fluorinated Dimethyl Ethers and Their Protonated Forms

Vila

Mosquera

2000

J. Phys. Chem. A

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Changes induced by stepwise substitution of hydrogen for fluorine in neutral and protonated dimethyl ethers are analyzed in the light of the Atoms in Molecules (AIM) theory. AIM atomic and bond properties were computed by using B3LYP/6-31++G(d,p)//B3LYP/6-31G(d,p) wave functions. The effects brought about by fluorine substitution on the atomic and bond properties of the C-O-C chain were analyzed. Fluorine substitution was found to strengthen the C-H bonds. The computed proton affinities were related to the charge and energy of the proton. Reorientation of the CF n H 3-n groups upon protonation was explained in terms of the balance between anomeric and steric interactions. This interpretation and lacking of F-H bond paths allow the rejection of the previously proposed hydrogen bonding O-H‚‚‚F linkages in these systems. The fluorine substitution destabilizes C atoms in neutral and protonated forms, whereas the O is stabilized in the neutral molecule and destabilized in the cation.

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Section: Resultsmentioning

confidence: 99%

Topological Analysis of Fluorinated Dimethyl Ethers and Their Protonated Forms

Vila

Mosquera

2000

J. Phys. Chem. A

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“…According to the above definition, the E corr ͑CH 3 -) values of CH 3 (CH 2 ) m CH 3 (mϭ1 -5) molecules are given in the bottom row in Table II and plotted in Fig. and E corr ͑C-H 2 ) values change a little in the above systems except in the CH 2 : system. The correlation energy of a methyl group is between Ϫ188.715 and Ϫ185.880 mh in CH 3 (CH 2 ) m CH 3 (m ϭ1 -5) molecules.…”

Section: A Ch 3 Fragments and Ch 3 Groupmentioning

confidence: 99%

“…1,2 In accordance with its practical importance in the predication of the properties of compounds, the concept of functional group has been the subject of several recent theoretical research papers. It is also employed as the basic concept sustaining many different theoretical or computational methodologies ranging from the straightforward calculation of thermochemical quantities by using the additivity of functional groups or bonds schemes.…”

Section: Introductionmentioning

confidence: 99%

Is there any group additive rules in the calculation of electron correlation energies of long straight chain alkane molecules?

Zhuo

Wei

et al. 2004

The Journal of Chemical Physics

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According to the definition in the text, the correlation energy of 1s2C of carbon atoms, the primary and secondary C-H bonding electron pairs in some CH3, CH2 fragments and CH3(CH2)mCH3 (m=1-5) linear alkane molecules are calculated and analyzed. The transferability of the correlation energies of these electron pairs in the linear alkanes is investigated. The results indicate that the correlation energy of 1s2C is perfectly transferable in the respective methyl and methylene groups, while the correlation energies of the primary and secondary C-H bonding electron pairs are approximately transferable in methyl and methylene groups. The analysis of the results of group correlation energy shows that both of the correlation energies of methyl and methylene groups are transferable in these linear alkanes. The correlation energies of methylene group in CH3(CH2)mCH3 (m=1-5) molecules are slightly decreasing showing a converging trend to a "standard" methylene group in linear alkanes. The excellent fitting relationship between the total correlation energy and the number of methylene groups of the linear alkanes shows that the total correlation energy is a linear function of the number of methylene groups, which means that the total correlation energies of large linear alkanes can be reproduced and predicted by counting the numbers of methylene groups. In this way, total correlation energy of large linear alkane molecule can be approximately calculated using this simple group additive scheme with substantial saving in computational time.

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“…The absolute value of the difference between the total electron population of the molecule and that obtained by the addition of the N (Ω) values was never larger than 0.01 a.u., and the corresponding quantity for the total energy was always smaller than 0.004 a.u. Atomic properties obtained with like values of these error estimators have been successfully used to define approximately transferable functional groups 25–27.…”

Section: Computational Detailsmentioning

confidence: 99%

AIM study of pyrimidyl carbocyclic analogues of nucleosides based on cyclopentene rings

Gonzalez-Moa

Terán

Mosquera

2001

Int J of Quantum Chemistry

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ABSTRACT:A topological charge electron density analysis using the atoms in molecules (AIM) theory with HF/6-31++G * * //HF/6-31G * wave functions was performed on cis-pyrimidyl and cis-5/6-halopyrimidyl derivatives of 1,2-disubstituted analogues of carbocyclic nucleosides. In these analogues, which belong to an important class of antiviral or antitumoral compounds, the usual ribose or deoxyribose is replaced by a carbocycle with a hydroxymethyl group and a heterocyclic base on adjacent carbons and a double bond between positions 2 and 3 of the carbocycle. The results obtained demonstrate that 5-halogenation does not alter the relative energy sequence of the conformers and gives rise to no meaningful distortion of the electron distribution in the cyclopentene ring. In fact, the difference in the total electron population of this cycle between the parent and any of the halogenated molecules is never larger than 7 × 10 −3 a.u. It has been found that the electron population of the αC atom in the chloro derivatives is enlarged with respect to the unhalogenated species. The 5-halogenation results in a destabilization of the C4, C5, and C6 atoms of the heterocyclic base. According to the AIM computed energy properties this destabilization originates from larger interelectronic repulsions in the C5 basin that are consistent with its reduced volume and its lower first moment of the electron density. On the other hand, 6-halogenation produces a significant modification of the conformational equilibrium, modifying the relative energy sequence of conformers. The electronic properties are also significantly modified by 6-halogenation. The charge transfer from the cyclopentene ring to the base reaches 0.71 a.u. in the 6-fluoro derivative and 0.69 a.u. in the 6-chloro derivative.

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AIM study on the transferability of the oxygen atom in linear ethers

Cited by 38 publications

References 24 publications

Topological Analysis of Fluorinated Dimethyl Ethers and Their Protonated Forms

Topological Analysis of Fluorinated Dimethyl Ethers and Their Protonated Forms

Is there any group additive rules in the calculation of electron correlation energies of long straight chain alkane molecules?

AIM study of pyrimidyl carbocyclic analogues of nucleosides based on cyclopentene rings

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