Chemical Reactivity and Excited-State Density Functional Theory

Chattaraj, Pratim Kumar; Poddar, A.

doi:10.1021/jp983821n

Cited by 84 publications

(74 citation statements)

References 40 publications

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“…However, DFT has recently witnessed a great progress in its conceptual branch [33]. It tackles the problem of chemical reactivity by employing a perturbative approach, similar to experimental thermodynamics [34]. A lot of properties known from experimental chemistry, such as chemical potential, electronegativity, polarizability or hardness and softness, can be given strict definitions on the ground of conceptual DFT.…”

Section: Introductionmentioning

confidence: 99%

Nucleophilic properties of purine bases: inherent reactivity versus reaction conditions

Stachowicz‐Kuśnierz

Korchowiec

2015

Struct Chem

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In the present study, nucleophilic properties of adenine and guanine are examined by means of density functional theory. H? is used as a model electrophile. Two modes of H ? attack on the bases are considered: on the neutral molecule and on the anion. Solvent effects are modeled by means of polarizable continuum model. Regioselectivity of attack is studied by analyzing two contributions. The first one is the energetic ordering of the tautomers. The second is the relative inherent reactivity of nucleophilic sites in the bases. Atomic softnesses calculated by means of charge sensitivity analysis are employed for this purpose. The most reactive sites in various tautomers are identified on the ground of Li-Evans model. For adenine, it is demonstrated that both in basic and in neutral pH N7 atom possesses the most nucleophilic character. In polar solvents, N7 substitution is also most favored energetically. In basic pH and nonpolar solvents as well as in the gas phase, N9 substitution is slightly more probable. For guanine, a mixture of N7-and N9-substituted products can be expected in basic pH. In neutral pH, inherent reactivity and energy trends are opposite to each other; therefore, the substitution does not occur. Experimentally observed products of reactions with various electrophiles and in various conditions confirm the results obtained in this study.

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Section: Introductionmentioning

confidence: 99%

Nucleophilic properties of purine bases: inherent reactivity versus reaction conditions

Stachowicz‐Kuśnierz

Korchowiec

2015

Struct Chem

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“…14 This principle states that the natural direction of evolution of any system is towards a state of minimum polarizability. Both principles have been applied successfully to the study of molecular vibrations, 9,15-18 internal rotations, 6͑b͒,19 excited states, 20,21 aromaticity, 22 and different types of chemical reactions. 12,[23][24][25][26][27][28][29][30][31][32][33] It has been found in most of these cases that the conditions of maximum hardness and minimum polarizability complement the minimum energy criterion for molecular stability.…”

Section: Introductionmentioning

confidence: 99%

“…However, relaxation of these constraints seems to be permissible, and in particular, it has been found that in most cases the MHP still holds even though the chemical and external potentials vary during the molecular vibration, internal rotation or along the reaction coordinate. 12,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Hereafter, we will refer to the generalized MHP ͑GMHP͒ or MPP ͑GMPP͒ as the maximum hardness or minimum polarizability principles that do not require the constancy of chemical and external potentials during molecular change. It is worth emphasizing that the generalized versions of these principles have not been proven.…”

Section: Introductionmentioning

confidence: 99%

Are the maximum hardness and minimum polarizability principles always obeyed in nontotally symmetric vibrations?

Torrent‐Sucarrat

Luis

Duran

et al. 2002

The Journal of Chemical Physics

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In a recent paper ͓J. Am. Chem. Soc. 123, 7951 ͑2001͔͒ we have shown for the first time the existence of molecules with nontotally symmetric vibrational modes that break the maximum hardness ͑MHP͒ and minimum polarizability ͑MPP͒ principles. We present here an extension of this previous work by devising a mathematical procedure that helps to determine the nontotally symmetric molecular distortions of a given molecule that do not follow the MPP or the MHP. This methodology is based on the diagonalization of the Hessian matrix of the polarizability or the hardness with respect to the vibrational normal coordinates. For a relatively large series of molecules, we have carried out diagonalizations of the Hessian matrix of the polarizability to determine the molecular distortions with a more marked MPP or anti-MPP character. From the results obtained, we have derived a set of simple rules that allow to predict a priori without calculations the existence of vibrational modes that break the MPP. With respect to the MHP, the results strongly depend on the method of calculation, but the same rules are useful to predict the existence of vibrational modes that disobey the MHP when the Koopmans' approximation is used to calculate the hardness.

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“…In addition, the benzene ring in the molecule achieves an aromatic π-sextet [16]. This modification in the structural geometry will give the required stability for the structure by allowing the atoms in the molecule to achieve a stable octet.…”

Section: Scheme (2) Exhibits the Transition State The Product Of Thementioning

confidence: 99%

Understanding the Thermal Cracking for Anthracene Molecule : A DFT Approach

Shanshal¹,

Yousif²

2012

JNUS

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Density Functional Theory (DFT) calculations were carried out to study the thermal cracking for anthracene molecule to estimate the bond energies for breaking the following bonds C1-C2, C1-C9a,C9-C9a, C2-C3, C1-H1,C2-H2,and C9-H9 as well as the activation energies. The activation energy values for C1-H1, C2-H2, and C9-H9 bond breakage is lower than required for C1-C2, C1-C9a, and C9-C9a. The carbon -hydrogen bond rupture depends only slightly on the position in the molecule so the values of reaction energy is close to 117 kCal/mol and unlike the carbon-carbon bonds. It seems that the characteristic planarity is important factor to acquire the molecule structure the required stability along the reaction paths. The trends in the bond energies and the configuration structures are discussed.

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Chemical Reactivity and Excited-State Density Functional Theory

Cited by 84 publications

References 40 publications

Nucleophilic properties of purine bases: inherent reactivity versus reaction conditions

Nucleophilic properties of purine bases: inherent reactivity versus reaction conditions

Are the maximum hardness and minimum polarizability principles always obeyed in nontotally symmetric vibrations?

Understanding the Thermal Cracking for Anthracene Molecule : A DFT Approach

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