Density functional theory acids

Richardson WEI, Peng C, Bashford D, Noodleman L, Case DA (1997) Incorporating Solvation Effects into Density Functional Theory Calculation of Absolute Acidities. Int J Quantum Chem 61 207-217. 

Bakalarski, G., P. Grochowski, J. S. Kwiatkowski, B. Lesyng, and J. Leszczynski. 1996. Molecular and electrostatic properties of the N-methylated nucleic acid bases by density functional theory. Chem. Phys. 204, 301. 

The aim of this chapter is to discuss chemical reactivity and its application in the real world. Chemical reactivity is an established methodology within the realm of density functional theory (DFT). It is an activity index to propose intra- and intermolecular reactivities in materials using DFT within the domain of hard soft acid base (HS AB) principle. This chapter will address the key features of reactivity index, the definition, a short background followed by the aspects, which were developed within the reactivity domain. Finally, some examples mainly to design new materials related to key industrial issues using chemical reactivity index will be described. I wish to show that a simple theory can be state of the art to design new futuristic materials of interest to satisfy industrial needs. 

A model system consisting of methyloxirane, formate, and formic acid has been used to study the nucleophile-catalysed and nucleophile- and acid-catalysed opening of an epoxide ring by applying ab initio quantum mechanical calculations [up to the MP4(SDQ)/6-31- -G //MP2/6-31- -G" level] and also density functional theory... 

Theoretical evidence [Hartree-Fock (RHF) calculations and density functional theory] has been obtained for a concerted mechanism of oxirane cleavage and A-ring formation in oxidosqualene cyclization. A common concerted mechanistic pathway has been demonstrated for the acid-catalysed cyclization of 5,6-unsaturated oxiranes in chemical and enzymic systems. For example, the conversion of (24) into (26) proceeds via (25) and not via a discrete carbocation (27). Kinetic studies and other evidence are presented for various systems. 

Density functional theory calculations (B3LYP/6-31G level) have provided an explanation for the stereodivergent outcome of the Staudinger reaction between acyl chlorides and imines to form 2-azetidinones (/3-lactams). When ketene is formed prior to cycloaddition, preferential or exclusive formation of ct5-j6-lactam (50) is predicted. If, however, the imine reacts directly with the acid chloride, the step that determines the stereochemical outcome is an intramolecular 5n2 displacement, and preferential or exclusive formation of trans isomer (51) is predicted. These predictions agree well with the experimental evidence regarding the stereochemical outcome for various reactants and reaction conditions. 

A new transition-state-searching algorithm was used to determine the mechanism for methanol condensation to form dimethyl ether within the microporous environment of the zeolite, chabazite, using periodic boundary conditions and density functional theory. An acid site in the zeolite produces MeOH2+ for nucleophilic attack by a second adsorbed MeOH molecule. 

With the aid of density functional theory, the ZnCl2 acceleration of the Simmons-Smith reaction of ethylene and allyl alcohol has been investigated. A pathway involving direct Lewis acid acceleration of the leaving halogen atom (327) was found to be a more facile process than the more popular pathway involving 1,2-chlorine migration (328). 

CW, continuous wave Cys, cysteine DFT, density functional theory ENDOR, electron nuclear double resonance ehba, 2-ethyl-2-hydroxybutanoate2 EPR, electron paramagnetic resonance Glc6P, D-glucose 6-phosphate GSH, reduced glutathione HEPES, 4-(2-hydroxyethyl)-l-piperazineethanesulfonic acid Hex, aldohexose ... 

Ac, acetyl AONs, antisense oligonucleotides B, boat Bn, benzyl Bz, benzoyl C, chair CD, circular dichroism CO, carbon monoxide ConA, concanavalin A DAST, diethylaminosulfur trifluoride DFT, density functional theory DMDO, dimethyldiox-irane DMT, dimethoxytriphenylmethyl DNA, deoxyribonucleic acid dsDNA, double-stranded DNA E, envelope Fmoc, fluorenylmethyloxycarbonyl GlcNAc, /V-acetylglucosamine ITC, isothermal titration calorimetry kcat, catalytic rate constant Aa, association constant K, inhibition constant KM, Michaelis constant LiSPh, lithium thiophenolate LPS, lipopolysaccharide pM, micromolar MMT,... 

In another quite recent study, the Lewis acidity of BiX3 (X = Cl, Br and I) towards alcohols has been investigated using density-functional theory (DFT) [110], and the results point to many of the conclusions experimentally found by Boyer et al. Interestingly, the DFT data suggested that the higher affinity of Bi for... 

Gridnev and Terada calculated the optimized structure of the complex derived from phosphoric acid and N-acyl imine [14], wherein the hydrogen-bond complex was observed by density functional theory (DFT) calculations. 

Phenol, from irradiated benzene, 3 181-182 Phenolic macrocycle, 39 140-141 Phenomenological modeling density-functional theory, 38 465 oxidized (-t3) and reduced (-H) clusters, four-iron clusters, 38 462 64 Phenylacetic acid, irradiation of, 5 201 Phenylalanine... 

Density functional theory has also been recently applied to several dissociative pathways of HO—ONO and its anion (ONO—0 ) in aqueous solution. For example, the Gibbs free energy for the homolysis of peroxynitrous acid (HO—ONO HO -h ONO) is calculated to be AG (aq.) = 11.1 kcalmol" , a value in good agreement with experiment (13.6 kcalmoD ). For peroxynitrite homolysis (ONO—O NO2 -b O ) the calculated AG (aq.) = 13.0 kcalmoD was obtained for ion-molecule complexes with watef ... 

Ludena EV, Ldpez-Boada (1996) Local-Scaling Transformation Version of Density Functional Theory Generation of Density Functionals. 180 169-224 Liining U (1995) Concave Acids and Bases. 175 57-100 Lundt I (1997) Aldonolactones as Chiral Synthons 187 117-156... 

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