Segregation of molecules in binary solvent mixtures without H bonds. A quantitative treatment based on the theory of mobile order and disorder

Huyskens, P.; Haulait-Pirson, Marie-Claire; Vandevyvere, P; Seghers, Katarine; Zeegers-Huyskens, The ́rèse

doi:10.1039/a806626d

Cited by 3 publications

(2 citation statements)

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“…MP2/6-31++G**//MP2/6-31G** calculations were carried out for uracil, 1, and the 18 derivatives (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) shown in Figure 1 employing the Gaussian98 program. 13 The QTAIM atomic properties were calculated by using the program AIMPAC 14 on the above indicated charge densities.…”

Section: Computational and Geometrical Detailsmentioning

confidence: 99%

“…On the other hand, recent studies pointed out the inadequacy of the resonance model to explain the atomic properties of the protonated forms of uracil and cytosine, , which had been extensively studied by Zeegers-Huyskens's research group. − This fact provides theoretical interest to calculate the modifications experienced by the atomic properties of uracil with diverse substitutions and compare them with those qualitatively predicted by the resonance model.…”

Section: Introductionmentioning

confidence: 99%

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On the Electron Donor and the Electrophilic Substitution Activating Abilities of Substituents in Uracil

Moa

Mosquera

2006

J. Phys. Chem. A

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QTAIM properties for uracil and 18 derivatives containing the substituents -NH(2), -OH, -OCH(3), -SH, -F, -Cl, -CH(3) -NO(2), and -Li in position 5 or 6 were computed on MP2/6-31++G//MP2/6-31G charge densities. The results indicate that -OH, -OCH(3), and -NH(2) groups are really retrieving charge from the ring. Also, the activating ability of the substituent groups, usually considered as the variation of electron population at the carbon where the electrophilic attack takes place, C, was studied. The study shows that the activating ability is reflected by the variation of pi charge or quadrupole moment at C, and also by the variation of the Laplacian of the charge density in the secondary charge concentration points around C (SCC-C). They indicate a similar, but not exactly equal, graduation of activating ability. The relative behavior of the substituents is basically the same as in benzene, though benzene has more tendency to concentrate charge in the SCC-C regions than uracil, where this tendency is larger for 6- than for 5-derivatives. sigma(+/-)(R) Taft parameters are found to display good correlations with the above indicated activating indexes. Finally, the resonance model predicts most of the main variations displayed by QTAIM atomic pi electron populations of derivatives with regard to uracil, but there are still some significant variations of the pi electron charge that it cannot predict.

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