Reactivity descriptors global

TABLE 2 Calculated global reactivity descriptors global hardness (ii), global softness (S), electrophilicity index (oo), electronegativity (x) of the mesoionic heterocychc compounds. 

Conceptual density functional theory (DFT) [1-7] has been quite successful in explaining chemical bonding and reactivity through various global and local reactivity descriptors as described in the previous chapters. The Fukui function (FF) [4,5] is an important local reactivity descriptor that is used to describe the relative reactivity of the atomic sites in a molecule. The FF [4,5] is defined as... 

The global reactivity descriptors, such as chemical potential and chemical hardness, are the derivative of energy with respect to the number of electrons. The formal expressions for chemical potential (p.) and chemical hardness (rj) are [1,11]... 

Describes various global reactivity descriptors, such as electronegativity, hardness, and electrophilicity... 

The book comprises chapters on bonding, interactions, reactivity, dynamics, toxicity, and aromaticity as well as fundamental aspects of DFT. Several chapters are minireviews of the key global and local reactivity descriptors and their variations under different perturbations. 

The utility of global and local reactivity descriptors to predict chemical reactivity and C- versus O-alkylation has been investigated for the case of lithium enolates.298... 

As opposed to the global reactivity descriptors described above, the analysis of site selectivity in a molecule demands the local descriptors like the Fukui function defined as [35,36],... 

In this chapter, we present different global and local reactivity descriptors vis-a-vis the associated electronic structure principles for analyzing structures, properties, reactivity, bonding, interactions, and dynamics in the contexts of various physicochemical processes such as molecular vibrations, internal rotations, chemical reactions, aromaticity, stability of isomers, ion-atom collisions, atom-filled interactions, solvent effect, etc. Global reactivity descriptors are presented in Section 2, whereas Section 3 provides their theoretical basis. Section 4 delineates the local reactivity descriptors. Electronic structure principles associated with electronegativity and hardness are given in Sections 5 and 6, respectively. Section 7 presents the reactivity... 

R. Balawender, B. Safi, P. Geerlings, Solvent Effects on the Global and Atomic DET-Based Reactivity Descriptors Using the Effective fragment Potential Model. Solvation of Ammonia,/. Phys. Chem. A, 2001, 105, 6703-6710. 

Abstract Quantitative structure-activity relationship (QSAR) models are generated for biological activity and toxicity in terms of global and local reactivity descriptors within a conceptual density functional theory framework. Possible anticancer activity of two new metal-borane clusters is analyzed. 

In addition to the various conceptual DFT-based global reactivity descriptors, the local reactivity descriptors also provide valuable insights in determining chemical reactivity patterns. The various local reactivity indices like electron density (p(r)), Fukui function (/(r)), local softness (s(r)), local hardness ( (r)), and philicity (ft)(r)) help to assess the response of a particular atomic site in a molecule during a chemical attack. 

In this work, we have developed a model for the evaluation of proton affinity in terms of some akin conceptual reactivity descriptors which can be concepmally linked and associated with the physico-chemical process of protonation. The akin descriptors are the ionization energy (I), the global softness(S), the electronegativity (x), and the global electrophilicity index (co). 

Mathematical Formulae of the Global Reactivity Descriptors Invoked in the Study... 

Conceptual density functional theory has been quite successful in providing quantitative definitions for popular qualitative chemical concepts like electronegativity , hardness and electrophilicity . It has also been found to be useful in providing firm theoretical bases for the associated electronic structure principles. Various global and local reactivity descriptors " have played an important role in analyzing bonding, reactivity, stability, interactions and aromaticity in a variety of many-electron systems as well as a host of their physico-chemical properties. 

The reactivity descriptors described above have been defined for an atom or a molecule as a whole and accordingly they are termed as global reactivity descriptors. In order to analyze the site selectivity in a molecule several local reactivity descriptors or their condensed-to-atom variants have been thought of. 

Brief Outline of Global and Local Reactivity Descriptors.392... 

BRIEF OUTLINE OF GLOBAL AND LOCAL REACTIVITY DESCRIPTORS... 

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