DFT study

DFT STUDY OF 8-MERCAPTOQUINOLINE INTRAMOLECULAR HYDROGEN BOND, SINGLE PROTON TRANSFER AND WATER-ASSISTED TAUTOMERIZATION... 

In the same spirit DFT studies on peroxo-complexes in titanosilicalite-1 catalyst were performed [3]. This topic was selected since Ti-containing porous silicates exhibited excellent catalytic activities in the oxidation of various organic compounds in the presence of hydrogen peroxide under mild conditions. Catalytic reactions include epoxidation of alkenes, oxidation of alkanes, alcohols, amines, hydroxylation of aromatics, and ammoximation of ketones. The studies comprised detailed analysis of the activated adsorption of hydrogen peroxide with... 

While TD-DFT continuum calculations for molecules, such as camphor, are not yet quite practicable, efforts to create highly parallel computer codes capable of tackling this scale of problem are expected to be fruitful soon. In the meantime TD-DFT studies for computahonaUy less demanding small molecules [66-68] or highly symmetric molecules, such as SFg [79], have provided indicahons of the general value of the inclusion of electron response effects. 

Shi, F.-Q., Li, X., Xia, Y, Zhang, L. and Yu, Z.-X. (2007) DFT Study of the Mechanisms of In Water Au(I)-Catalyzed Tandem [3,3]-Rearrangement/Nazarov Reaction/[l,2]-Hydrogen Shift of Enynyl Acetates A Proton-Transport Catalysis Strategy in the Water-Catalyzed [l,2]-Hydrogen Shift. Journal of the American Chemical Society, 129, 15503-15512. 

Then, contrary to what was reported previously, the olefin dissociates from the zirconium metal complex. This conclusion was further supported by other experimental observations. However, it cannot be completely excluded that competition between dissociative and direct rearrangement pathways could occur with the different isomerization processes studied up to now. Note that with cationic zirconocene complexes [Cp2Zr-alkyl], DFT studies suggest that Zr-alkyl isomerizations occur by the classical reaction route, i.e. 3-H transfer, olefin rotation, and reinsertion into the Zr-H bond the olefin ligand appears to remain coordinated to the Zr metal center [89]. 

The apparent challenges presented by these recent readings of experimental ORR results, winning early support from a DFT study, have left some important questions to answer ... 

The intermediate-spin ground state of the ferric compounds published by Jager and coworkers is also stabilized by a N4-macrocyclic ligand, [N4] which exist in different varieties of substitutions. The apical ligands are weakly coordinating halides or pseudohalides, such as iodide in the case of [Fe [N4]l] (20) [68]. The electronic structure was elucidated by EPR, Mbssbauer and DFT studies. 

A DFT study found a corresponding TS to be the lowest energy.167 This study also points to the importance of the solvent, DMSO, in stabilizing the charge buildup that occurs. A further computational study analyzed the stereoselectivity of the proline-catalyzed aldol addition reactions of cyclohexanone with acetaldehyde, isobu-tyraldehyde, and benzaldehyde on the basis of a similar TS.168 Another study, which explored the role of proline in intramolecular aldol reactions, is discussed in the next section.169... 

Freccero, M. Di Valentin, C. Sarzi-Amade, M. Modeling H-bonding and solvent effects in the alkylation of pyrimidine bases by a prototype quinone methide a DFT study. J. Am. Chem. Soc. 2003, 125, 3544-3553. 

Wang, H. Wang, Y. Han, K.-L. Peng, X.-J. A DFT study of Diels-Alder reactions of o-quinone methides and various substituted ethenes selectivity and reaction mechanism. J. Org. Chem. 2005, 70, 4910-4917. 

Tuma, C., Boese, A. D., Handy, N. C., 1999, Predicting the Binding Energies of H-Bonded Complexes A Comparative DFT Study , Phys. Chem. Chem. Phys., 1, 3939. 

Sojka, Z., Pietrzyk, P., Martra, G. et al. (2006) EPR and DFT study of NO interaction with Ni/Si02 catalyst Insight into mechanistic steps of disproportionation process promoted by tripodal surface nickel complex, Catal. Today, 114, 154. 

Numerous quantum mechanic calculations have been carried out to better understand the bonding of nitrogen oxide on transition metal surfaces. For instance, the group of Sautet et al have reported a comparative density-functional theory (DFT) study of the chemisorption and dissociation of NO molecules on the close-packed (111), the more open (100), and the stepped (511) surfaces of palladium and rhodium to estimate both energetics and kinetics of the reaction pathways [75], The structure sensitivity of the adsorption was found to correlate well with catalytic activity, as estimated from the calculated dissociation rate constants at 300 K. The latter were found to agree with numerous experimental observations, with (111) facets rather inactive towards NO dissociation and stepped surfaces far more active, and to follow the sequence Rh(100) > terraces in Rh(511) > steps in Rh(511) > steps in Pd(511) > Rh(lll) > Pd(100) > terraces in Pd (511) > Pd (111). The effect of the steps on activity was found to be clearly favorable on the Pd(511) surface but unfavorable on the Rh(511) surface, perhaps explaining the difference in activity between the two metals. The influence of... 

A combination of matrix isolation IR and DFT studies have shown that condensation of monomeric NiX2 (X = C1, Br) in solid N2 matrices initially gives species NiX2- -(N2) with a physisorbed type of interaction. These can be converted by photolysis into pseudotetrahedral NiX2(r/l-N2)2 (115) moieties with end-on bound N2 in a chemisorbed type of interaction below 10 K. On warming to ca. 20 K the chemisorbed species revert to the physisorbed state.457... 

The first homoleptic, dinuclear platinum(I) carbonyl complex [Pt2(CO)6]2+ has been prepared by dissolving Pt02 in concentrated sulfuric acid under a CO atmosphere.92,93 The structure is rigid on the NMR time scale at room temperature. DFT studies suggested a staggered structure for the dimer.92,93... 

Parusel ABJ (2001) Excited state intramolecular charge transfer in N, N-heterocyclic-4-aminobenzonitriles a DFT study. Chem Phys Lett 340(5-6) 531-537... 

In this review, the DFT studies of biological systems are divided into two groups corresponding to different ways of addressing the second aforementioned issue. The first one... 

DFT Studies of Isolated Fragments of Large Biological Systems... 

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