Behavior of the Local Reactivity Descriptors during Complexation:  A Case Study of BXX‘X‘ ‘NH3(X, X‘, X‘‘= H, F)

2004 ◽  
Vol 108 (52) ◽  
pp. 11838-11845 ◽  
Author(s):  
Akhilesh Tanwar ◽  
Sourav Pal
Keyword(s):  
Reactivity Descriptors ◽  
Local Reactivity ◽  
Local Reactivity Descriptors

scholarly journals Functionalization of single-walled (n,0) carbon and boron nitride nanotubes by carbonyl derivatives (n = 5, 6): a DFT study

2016 ◽  
Vol 94 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Parisa Nematollahi ◽  
Mehdi D. Esrafili ◽  
Amin Bagheri
Keyword(s):  
Boron Nitride ◽  
External Surface ◽  
Surface Reactivity ◽  
Boron Nitride Nanotubes ◽  
Chemical Functionalization ◽  
Reactivity Descriptors ◽  
Carbonyl Derivatives ◽  
Local Reactivity ◽  
Average Local Ionization Energy ◽  
Local Reactivity Descriptors

By using density functional theory calculations, the chemical functionalization of finite-sized (5,0) and (6,0) carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs) by different carbonyl derivatives –COX (X = H, CH3, OCH3, OH, and NH2) is studied in terms of geometrical and electronic structure properties. Also, the benefits of local reactivity descriptors is studied to characterize the reactive sites of the external surface of the tubes. These local reactivity descriptors include the electrostatic potential VS(r) and average local ionization energy ĪS(r) on the surfaces of these nanotubes. The estimated ĪS(r) values show that the functionalized CNTs tend to activate the surface toward electrophilic/radical attack. Results show that the chemical functionalization of CNTs leads to the reduction of VS(r) values and therefore enhances the surface reactivity. On the other hand, BNNTs resist chemical functionalization due to the negligible decrease in the VS,min and ĪS,min values. Generally, in contrast to BNNTs, the chemical functionalization of CNTs can considerably improve their surface reactivity. To verify the surface reactivity pattern based on the chosen reactivity descriptors, the reaction energies for the interaction of an H + ion or hydrogen radical with external surface of the functionalized CNTs and BNNTs are calculated. A general feature of all studied systems is that stronger potentials are associated with regions of higher curvature.

The DFT local reactivity descriptors of α-tocopherol

2015 ◽  
Vol 21 (4) ◽  
Author(s):  
Ivana Fabijanić ◽  
Cvijeta Jakobušić Brala ◽  
Viktor Pilepić
Keyword(s):  
Reactivity Descriptors ◽  
Local Reactivity ◽  
Local Reactivity Descriptors

Calculation of global and local reactivity descriptors of carbodiimides, a DFT study

2017 ◽  
Vol 16 (03) ◽  
pp. 1750019 ◽  
Author(s):  
Kathy Ramirez-Balderrama ◽  
Erasmo Orrantia-Borunda ◽  
Norma Flores-Holguin
Keyword(s):  
Electron Affinity ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Basis Set ◽  
Chemical Hardness ◽  
Geometrical Parameters ◽  
Reactivity Descriptors ◽  
Local Reactivity ◽  
Global And Local ◽  
Local Reactivity Descriptors

Carbodiimides have been widely used for different purposes, such as an intermediary to form peptides bonds and esters, which have generated industrial, organic and biological applications. Diisoproylcarbodiimide (DIC), (3-(dimethylamino) propyl)ethylcarbodiimide (EDC) and N,N′-dicyclohexylcarbodiimide (DCC) are the most common carbodiimides, however, there exist other carbodiimides that are not normally used. Twelve carbodiimides including the above mentioned were chosen to study their chemical reactivity as well as their nucleophilic and electrophilic attack sites. Geometry optimization in gas and solution phases was obtained using Density Functional Theory (DFT) through B3LYP with 6-31G(d) and 6-311[Formula: see text]G(d,p) level. Global and local reactivity descriptors were calculated and analyzed such as chemical hardness, ionization potential, electron affinity, Fukui functions, dual descriptor and hypersoftness. The results obtained for geometrical parameters do not have significant differences for gas and solution phase. The introduction of diffuse functions has great impact in electron affinity, modifying notably the values of reactivity descriptors, but didn’t show qualitative differences, since the results found for both basis set calculations show that Cyanamide or CD1 is the most stable and CD11 present greater reactivity of all studied molecules. Also, the hypersoftness results obtained with 6-31G(d) are in agreement with the general affirmation that carbodiimides are easily attacked by nucleophiles and electrophiles in the central carbon–nitrogen double bond.

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