Positional Isotope Exchange Studies of Enzyme Mechanisms

2006 ◽  
pp. 361-395 ◽  
Author(s):  
Irwin A. Rose
Keyword(s):  
Isotope Exchange ◽  
Enzyme Mechanisms

Isotope exchange and mechanisms of heterolytic substitution

1948 ◽  
Vol 45 ◽  
pp. 232-242
Author(s):  
S. K. Hsü ◽  
C. K. Ingold ◽  
C. K. Ingold ◽  
C. G. Raisin ◽  
E de Salas ◽  
...  
Keyword(s):  
Isotope Exchange

Isotope Exchange Capacity on Li4SiO4 and Comparison of Tritium Inventory in Various Solid Breeder Blankets.

2001 ◽  
Vol 38 (11) ◽  
pp. 944-951 ◽  
Author(s):  
Masabumi NISHIKAWA ◽  
Noriaki NAKASHIMA ◽  
Kazuhisa HASHIMOTO ◽  
Serguei BELOGLAZOV
Keyword(s):  
Isotope Exchange ◽  
Exchange Capacity

The effect of decationation of hydroxylated HNaY zeolites on their interaction with ethylene and propylene. hydrogen complexes, oligomeration and isotope exchange

1980 ◽  
Vol 45 (11) ◽  
pp. 3101-3115 ◽  
Author(s):  
Ludmila Kubelková ◽  
Jana Nováková ◽  
Zdeněk Dolejšek ◽  
Pavel Jírů
Keyword(s):  
Isotope Exchange ◽  
Decisive Role ◽  
Single Step ◽  
Hydroxyl Groups ◽  
Isotope Exchange Reaction ◽  
Factors Affecting ◽  
Step Mechanism ◽  
Formed Hydrogen ◽  
Lower Basicity ◽  
Multiple Step

The effect of decationation on the interaction of propylene and ethylene with the hydroxylated forms of HNaY zeolites has been studied. The compounds formed in the zeolite cavities were studied using their infrared spectra, the composition of the gaseous phase was followed by mass spectrometry. The results showed that among factors affecting the interaction with propylene properties of hydroxyl groups play the decisive role. With the increasing decationation of the zeolite the strength of the OH bond in the hydrogen complex of the large-cavity hydroxyls with propylene decreased and the rate of propylene oligomeration at 310 K as well as the isotope exchange rate of propylene-d6 with the zeolite hydroxyls at 570 K increased. The propylene isotope exchange reaction proceeded by the multiple-step mechanism. In the case of ethylene only the physical sorption with a non-specific character was observed at 310 K. The adsorbed amount increased with the increasing content of Na+ ions in the zeolite (with the decreasing decationation). A part of the adsorbed molecules formed hydrogen complexes with hydroxyls of large cavities. The observed lower weakening of the OH bond was in agreement with the lower basicity of ethylene if compared with propylene. The isotope exchange of ethylene-d4 with the zeolite hydroxyls proceeded by a single-step mechanism, it had an autocatalytic character and its rate was 70 times lower than that of the isotope exchange of propylene-d6 with OH.

Determination of trace amounts of cobalt by homogeneous isotope exchange in an organic phase

1980 ◽  
Vol 45 (12) ◽  
pp. 3332-3337
Author(s):  
Václav Jiránek
Keyword(s):  
Organic Phase ◽  
Isotope Exchange ◽  
Radiochemical Method

A new radiochemical method for determining trace amounts of cobalt has been worked out. It is based on a homogeneous isotope exchange between cobalt(III) diethyldithiocarbamate and cobalt(III) caprate in an organic phase. The method, tested in the range 0.005-8 μg Co, has proved to be selective.

Late-Stage Carbon Isotope Exchange of Aryl Nitriles through Ni-Catalyzed C–CN Bond Activation

2021 ◽  
Vol 143 (12) ◽  
pp. 4817-4823
Author(s):  
Sean W. Reilly ◽  
Yu-hong Lam ◽  
Sumei Ren ◽  
Neil A. Strotman
Keyword(s):  
Carbon Isotope ◽  
Late Stage ◽  
Isotope Exchange ◽  
Bond Activation ◽  
Aryl Nitriles
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