B3LYP calculations reaction

As the formation of betaines from amide-stabilized ylides is known to be reversible (in contrast with aryl- or semistabilized ylides, which can exhibit irreversible anti betaine formation see Section 1.2.1.3), the enantiodifferentiating step cannot be the C-C bond-forming step. B3LYP calculations of the individual steps along the reaction pathway have shown that in this instance ring-closure has the highest barrier and is most likely to be the enantiodifferentiating step of the reaction (Scheme 1.16) [25]. 

The calculated reaction parameters with BP86//B3LYP methods at two higher temperatures (150 and 250 °C) are shown in Tables VI and VII, respectively. Further corrections for low H2 and olefin pressure/concen-tration and high alkane pressure/concentration (36,37) on BP86// B3LYP values are shown in Tables VIII and IX. 

Experimentally, two equivalents of the alkyne for one equivalent of the metal species are necessary to achieve reaction. One equivalent serves to abstract H2 from the starting materials, RuH(H2)XL2 or OsH3XL2, hence generating in situ the very reactive 14-electron compound MHXL2 (M = Ru, Os). It is assumed that the reaction starts from the 14-electron complex modeled as MHC1(PH3)2 (M = Ru, Os) and the acetylene is used as a model for phenyl acetylene. DFT (B3LYP) calculations were carried out to... 

Figure 8.5 Observed and calculated reaction pathways from aliphatic CgClg-species to hexachlorobenzene. Numbers are values (KJ/mol) calculated by B3LYP/6-31G(2d). (From H. Detert et al., to be published.)...

The calculated reaction profile for H abstraction for the TauD Fe(IV)=0 model is shown in Fig. 2 (23). The calculations were carried out with the ORCA package (24), using the B3LYP density functional (25,26) and Karlsruhe basis sets for all atoms (27—29) in combination with the RIJONX (30) or RIJCOSX approximations (31) and appropriate auxiliary basis sets (32—34). The protein environment was modeled by the COSMO solvation model with a dielectric constant of... 

A new transition state (7) of the addition step in the Baeyer-Villiger reaction was found by B3LYP calculations. The role of proton acceptor is played by the carbonyl-oxygen atom, and the free energy barrier is lower than that previously estimated. This finding changes the mechanism for the acid catalysis.231... 

The Sn2 reaction in solution. We saw above the application of microsolvation to Sn2 reactions ([14, 15]). Let us now look at the chloride ion-chloromethane Sn2 reaction in water, as studied by a continuum method. Figure 8.2 shows a calculated reaction profile (potential energy surface) from a continuum solvent study of the Sn2 attack of chloride ion on chloromethane (methyl chloride) in water. Calculations were by the author using B3LYP/6-31+G (plus or diffuse functions in the basis set are considered to be very important where anions are involved Section 5.3.3) with the continuum solvent method SM8 [22] as implemented in Spartan [31] some of the data for Fig. 8.2 are given in Table 8.1. Using as the reaction coordinate r the deviation from the transition state C-Cl... 

Experimental results of an unprecedented haloform-type reaction in which 4-alkyl-4-hydroxy-3,3-difluoromethyl trifluoromethyl ketones undergo base-promoted selective cleavage of the CO-CF3 bond, yielding 3-hydroxy-2,2-difluoro acids and fluoro-form, have been rationalized using DFT (B3LYP) calculations.159 The solvent-induced effects on the two pathways, introduced within the SCRF formalism through PCM calculations, do not reverse the predicted preference of the CO-CF3 over the CO-CF2 bond cleavage in the gas phase. 

Comparison of theoretical data with experimental spectra led also to the identification of compounds which have germanium-nitrogen double and triple bonds. Foucat et al. report about the results of flash vacuum thermolysis of substituted germacyclopentenes and DFT (B3LYP) calculations of model compounds of possible reaction products114. The authors took the experimental photoelectron (PE) spectra and compared them with... 

Formation of GeF2 in reactions between GeF4 and Si2H6 was studied by CCSD(T)// B3LYP calculations using the basis set of the DZP quality390. These reactions are related... 

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