SKIE

The density functional theory calculations of primary 14C KIE and secondary deuterium kinetic isotope effects (SKIE)220 did not reproduce satisfactorily all the experimentally determined 14C KIE and deuterium (4,4-2H2)- and 6,6-2H2-SKIE, though the non-local DFT methods provide transition state energies on a par with correlated molecular orbital theory221. 

The above SKIE data were taken as evidence against an ionic transition state. Allylic cation-like species would result in much larger normal SKIE at C(4) in a polar medium than in non-polar media by approaching the maximum possible value for conversion of an sp3 C(4) of the ether to an sp2 carbon of an allyl cation. 

Final remarks. The 14C-KIE and 2H-SKIE data presented in this Section (VLB) clearly indicate the usefulness of isotope effect methodology in studies of mechanistic details of thermally induced Claisen rearrangement, which provides a synthetic route to y,5-unsaturatcd carbonyl compounds. The primary and secondary 14C KIE supplement strongly the deuterium SKIE. Especially easy for interpretation are 14C and 2H isotope... 

The intramolecular and intermolecular deuterium isotope effects in the cycloaddition of acrylonitrile to allene (equation 98) have been studied by Dolbier and Dai231,232. The intramolecular KIEs in the allene-acrylonitrile system were found to be 1.21 0.02 at 206°C and 1.14 0.02 at 225°C. A negligible intermolecular SKIE was found in the reaction of the mixture of tetradeuteriated and undeuteriated allene using a limited amount of acrylonitrile (ku/ku) = 1.04 0.05 at 190-210 °C for D0/D4 allene. An equilibrium deuterium IE of 0.92 0.01 was found at 280-287 5°C (15-45 h reaction time). 

FIGURE 18. (a) Anomerically destabilized protonated intermediate (b) transition state and (c) products from Am I reaction of A-acyloxy-A-alkoxybenzamides predicted SKIE values in... 

A solvent kinetic isotope effect (SKIE) of 0.44 from solvolysis in CD3CN-H2O versus CD3CN-D2O mixtures was in line with predicted values for the protonation-dissociation mechanism for which the SKIE should be between 0.48 and 0.33 (Figure 18a... 

Methane is slightly soluble in HF-SbF5 even at atmospheric pressure (0.005 M), which facilitates direct kinetic studies by NMR. Thus the transition states for methane activation in this medium have been studied experimentally by Ahlberg et al.49 The first-order rate constants [Eqs. (5.9) and (5.10)], determined experimentally on the basis of2H -decoupled 600-MHz 1H NMR time-dependent spectra (Figure 5.2), are on the order of 3.2 x 10 1 s 1 at —20°C and show a secondary kinetic isotope effect (SKIE) of 1 0 02. 

Since the theoretical SKIE calculated for the ring closure transition structure reproduces the experimental SKIE accurately, it can be deduced that the vinylcyelopropane-cyclopentene rearrangement proceeds via a diradicaloid stepwise mechanism. 

For early studies on SKIE of the Cope reaction see Humski K, Malojcic R, Borcic S, Sunko DE (1970) J Am Chem Soc 92 6534... 

Roginskil, S. Z, Teoretiche.skie osnovy geterogennogo kataliza (Theoretical Principles of Heterogeneous Contact Catalysis) 2, Moscow, 1935. 

Arterial puncture requires considerable skiE and is usuaEy performed only by physicians or speciaEy trained technicians or nurses. The preferred sites of arterial puncture are, in order, the (1) radial artery at the wrist, (2) brachial artery in the elbow, and (3) femoral artery in the groin. Because leakage of blood from the femoral artery tends to be greater, especially in the elderly, sites in the arm are most often used. The proper technique for arterial puncture is described in NCCLS Standard Hll-A3. ... 

Rappe, A. K., C. J. Casewit, K. S. Colwell, W. A. Goddard III, and W. M. SkiE. 1992. UFF, a rule-based full periodic table force field for molecular mechanics and molecnlar dynamics simulations. J. Am. Chem. Soc. 114 10024. 

Comparisons of body zinc in C. brunneus with the metal content in their habitats showed a close relationship between these variables, especially for the areas exposed to contaminants from non-ferrous metal plants from their vicinity (Szopienice). Grasshoppers collected from Kokotek showed also high zinc loads in gonads resulted from direct influence of the zinc plant in the vicinity (Miasteczko SI skie). 

The fire resistant concretes are discussed in the monographic book by Nadachowski F., Refractory materials technology . Editor Sl skie Wydawnictwo Techniczne, Katowice 1995. (in Polish). First International RILEM Workshop on Concrete Spalling Due to Fire Exposure (ed. F. Dehn, E.A.B. Koenders3-5 September 2009, Leipzig, Germany. 

The corrosion of reinforcement is discussed in details in a book by Gizegorz Wieczorek, Concrete corrosion initiated by ehlorides or carbonation of concrete cover , Editor Dolno skie Wydawnictwo Edukacyjne, Wroclaw 2002. (in Polish). 

Nadachowski, F. Zarys technologii materialow ogniotrwalych. Sl skie Wyd. Techniczne, Katowice (1995). (in Polish)... 

Particle sKie s = small, m = medium, 1 = large Equatitrn 13). 

Geometrical parameters and values of SKIE calculated at MP2/6-31 + G(d) level of... 

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