Probing the Reactive Center for Site Selective Protonation in a Molecule by the Local Density Functional Descriptors

2014 ◽  
pp. 653-666
Author(s):  
Sandip Kumar Rajak ◽  
Nazmul Islam ◽  
Dulal C. Ghosh
Keyword(s):  
Physical Process ◽  
Density Functional ◽  
Local Density ◽  
Local Descriptors ◽  
Fukui Functions ◽  
Reactive Center ◽  
Site Selectivity ◽  
Local Softness ◽  
Local Density Functional ◽  
Site Selective

In this study, the authors have explored the efficacy of the local density functional descriptors like the fukui functions (f), the local softness (s) and the local philicity as probe for the reactive centers and site selectivity of the chemico-physical process of protonation of some molecules having multiple site for protonation, viz CH3NCO (Methyl isocyanate), CH3NCS (methyl isothiocyanate), NH2OH (hydroxyl amine), NH2OCH3 (o-methylhydroxylamine), CH3NHOH (N-methylhydroxylamine), NH2CH2COOH (glycine), CH3CH(NH2)COOH (alanine) and OHCH2CH2NH2 (ethanol amine). The authors have seen in terms of the numerical values of the local descriptors measures the reactivity (nucleophilicity) of a particular atomic site of a donor center towards a proton. In all cases, it can be said that the dynamic chemico-physical process of site selectivity can nicely be correlated in terms of the computed values of the local descriptors. Thus, it is found that the theoretical descriptors of the DFT can be efficiently exploited to study the mechanism of site selectivity in a chemical reaction.

Probing the Reactive Center for Site Selective Protonation in a Molecule by the Local Density Functional Descriptors

2012 ◽  
pp. 235-249
Author(s):  
Sandip Kumar Rajak ◽  
Nazmul Islam ◽  
Dulal C. Ghosh
Keyword(s):  
Physical Process ◽  
Density Functional ◽  
Local Density ◽  
Local Descriptors ◽  
Fukui Functions ◽  
Reactive Center ◽  
Site Selectivity ◽  
Local Softness ◽  
Local Density Functional ◽  
Site Selective

In this study, the authors have explored the efficacy of the local density functional descriptors like the fukui functions (f), the local softness (s) and the local philicity as probe for the reactive centers and site selectivity of the chemico-physical process of protonation of some molecules having multiple site for protonation, viz CH3NCO (Methyl isocyanate), CH3NCS (methyl isothiocyanate), NH2OH (hydroxyl amine), NH2OCH3 (o-methylhydroxylamine), CH3NHOH (N-methylhydroxylamine), NH2CH2COOH (glycine), CH3CH(NH2)COOH (alanine) and OHCH2CH2NH2 (ethanol amine). The authors have seen in terms of the numerical values of the local descriptors measures the reactivity (nucleophilicity) of a particular atomic site of a donor center towards a proton. In all cases, it can be said that the dynamic chemico-physical process of site selectivity can nicely be correlated in terms of the computed values of the local descriptors. Thus, it is found that the theoretical descriptors of the DFT can be efficiently exploited to study the mechanism of site selectivity in a chemical reaction.

DFT Correlation of the Site Selectivity of Donor–Acceptor Chemical Interaction

2012 ◽  
pp. 144-161
Author(s):  
Dulal C. Ghosh ◽  
Soma Bhattacharyya
Keyword(s):  
Density Functional ◽  
Chemical Interaction ◽  
Local Density ◽  
Donor Ligands ◽  
Fukui Functions ◽  
Chemical Systems ◽  
Hsab Principle ◽  
Site Selectivity ◽  
Donor Acceptor ◽  
Local Softness

In this study, the time evolution of concept local HSAB principle as a necessary prelude to our jargon of the trade Correlation of the Site Selectivity of Donor–Acceptor Chemical Interaction in terms of the Local Density Functional Descriptors is discussed at length . The authors try to correlate the known facts relating to the formations of some donor acceptor supermolecules such as HCN–BF3,HNC–BF3, H3C–CN–BF3 and H3C–NC–BF3 by the chemical interaction of a well known Lewis acid, BF3 and various donor ligands/Lewis bases like HCN,HNC,H3C–CN, H3C–NC which are inherently structural isomers having multiple donating sites, in terms of the local DFT descriptors like the local softness (s) and fukui functions (f) of such chemical systems. It is also noted that the dynamic chemico-physical process of site selectivity is found to have a very nice correlation in terms of the computed values of the local descriptors namely the fukui functions and the local softnesses. Thus, the authors find that the theoretical descriptors of the local HSAB principle can be efficiently exploited to study the mechanism of site selectivity in a chemical reaction.

Magnetic Properties of Embedded Rh Clusters in Ni Matrix

1995 ◽  
Vol 384 ◽  
Author(s):  
Zhi-Qiang Li ◽  
Yuichi Hashi ◽  
Jing-Zhi Yu ◽  
Kaoru Ohno ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Magnetic Moments ◽  
Functional Formalism ◽  
Rhodium Clusters ◽  
Spin Polarized ◽  
Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

Reactivity Indices for ortho/para Monosubstituted Phenols

2007 ◽  
Vol 10 (1) ◽  
Author(s):  
Nevim San ◽  
Murat Kılıç ◽  
Zekiye Çınar
Keyword(s):  
Photocatalytic Degradation ◽  
Density Functional ◽  
Reaction Rates ◽  
Chemical Hardness ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Degradation Reactions ◽  
The Density Functional Theory ◽  
Local Softness ◽  
Soft Interactions

AbstractThe kinetics of the photocatalytic degradation reactions of twelve ortho/para mono-substituted phenols containing electron-donating or -withdrawing groups have been investigated experimentally. With the intention of determining the most suitable DFT reactivity descriptors, geometry optimizations of the compounds have been performed with the Density Functional Theory DFT at B3LYP/6-31G* level. In order to take the effect of solvent water into account, the calculations have been repeated for the optimized structures by using COSMO as the solvation model. Chemical hardness, softness, electronegativities, Fukui functions, local hardness and softness, local electrophilicities and softness differences for all phenol molecules have been calculated. Correlations between the apparent initial first-order rate constants determined in the experiments and the calculated DFT reactivity descriptors have been examined. Results show that the reactions investigated are electrophilic in nature. The local softness and softness differences correlate well with the reaction rates indicating that soft-soft interactions dominate in the photocatalytic degradation reactions of phenols.

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