ChemInform Abstract: PRIMARY AND SECONDARY β-DEUTERIUM KINETIC ISOTOPE EFFECTS IN THE 1,3-PROTOTROPIC REARRANGEMENT OF 1-METHYLINDENE USING TERTIARY AMINES AS CATALYSTS IN THE SOLVENTS TOLUENE AND DIMETHYL SULFOXIDE

1985 ◽  
Vol 16 (24) ◽  
Author(s):  
O. MATSSON
Keyword(s):  
Dimethyl Sulfoxide ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Tertiary Amines ◽  
Kinetic Isotope ◽  
Prototropic Rearrangement

scholarly journals Formation of Enamines via Catalytic Dehydrogenation by Pincer-Iridium Complexes

2019 ◽  
Author(s):  
Xiawei Zhang ◽  
Santanu Malakar ◽  
Karsten Krogh-Jespersen ◽  
Faraj Hasanayn ◽  
Alan Goldman
Keyword(s):  
Isotope Effects ◽  
Oxidative Addition ◽  
Kinetic Isotope Effects ◽  
Catalytic Dehydrogenation ◽  
Iridium Complexes ◽  
Tertiary Amines ◽  
Iridium Catalysts ◽  
Kinetic Isotope ◽  
Dehydrogenation Mechanism

Efficient pincer-ligated iridium catalysts are reported for the dehydrogenation of simple tertiary amines to give enamines, and for the dehydrogenation of β-functionalized amines to give the corresponding 1,2-difunctionalized olefins. Experimentally determined kinetic isotope effects in conjunction with DFT-based analysis support a dehydrogenation mechanism involving initial pre-equilibrium oxidative addition of the amine α C-H bond followed by rate-determining elimination of the β-C-H bond.<br>

The proton transfer reaction between bis(2,4-dinitrophenyl)methane and nitrogen bases in dimethyl sulfoxide and toluene solvents

1991 ◽  
Vol 69 (3) ◽  
pp. 468-473 ◽  
Author(s):  
Arnold Jarczewski ◽  
Grzegorz Schroeder ◽  
Kenneth T. Leffek
Keyword(s):  
Proton Transfer ◽  
Dimethyl Sulfoxide ◽  
Isotope Effects ◽  
Equilibrium Constants ◽  
Activation Parameters ◽  
Kinetic Isotope Effects ◽  
Proton Transfer Reaction ◽  
Kinetic Isotope ◽  
Deuteron Transfer ◽  
Classical Region

Rate constants have been measured for the proton and deuteron transfer reactions of bis(2,4-dinitrophenyl)methane (1) with 1,1,3,3-tetramethylguanidine (TMG) and 1,5-diazabicyclo[5.4.0]undec-7-ene (DBU) in dimethyl sulfoxide (DMSO) and toluene solvents. Equilibrium constants, primary deuterium kinetic isotope effects, and activation parameters are reported. The reaction of 1 with DBU is faster than that with TMG by factors of 5 and 50 in toluene and DMSO respectively. The primary deuterium kinetic isotope effects, kH/kD = 7–9, which are independent of the polarity of the solvent, indicate an uncoupled mechanism of proton transfer and are in the "classical" region with little or no indication of a tunnelling contribution to the enthalpy of activation for these reactions. Key words: proton transfer, bis(2,4-dinitrophenyl)methane, deuterium isotope effects.

scholarly journals Formation of Enamines via Catalytic Dehydrogenation by Pincer-Iridium Complexes

2019 ◽  
Author(s):  
Xiawei Zhang ◽  
Santanu Malakar ◽  
Karsten Krogh-Jespersen ◽  
Faraj Hasanayn ◽  
Alan Goldman
Keyword(s):  
Isotope Effects ◽  
Oxidative Addition ◽  
Kinetic Isotope Effects ◽  
Catalytic Dehydrogenation ◽  
Iridium Complexes ◽  
Tertiary Amines ◽  
Iridium Catalysts ◽  
Kinetic Isotope ◽  
Dehydrogenation Mechanism

Efficient pincer-ligated iridium catalysts are reported for the dehydrogenation of simple tertiary amines to give enamines, and for the dehydrogenation of β-functionalized amines to give the corresponding 1,2-difunctionalized olefins. Experimentally determined kinetic isotope effects in conjunction with DFT-based analysis support a dehydrogenation mechanism involving initial pre-equilibrium oxidative addition of the amine α C-H bond followed by rate-determining elimination of the β-C-H bond.<br>

SECONDARY KINETIC ISOTOPE EFFECTS IN BIMOLECULAR NUCLEOPHILIC SUBSTITUTIONS: II. α-DEUTERIUM EFFECTS IN MENSCHUTKIN REACTIONS OF METHYL IODIDE

1965 ◽  
Vol 43 (1) ◽  
pp. 40-46 ◽  
Author(s):  
K. T. Leffek ◽  
J. W. MacLean
Keyword(s):  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Systematic Change ◽  
Tertiary Amines ◽  
Nucleophilic Substitutions ◽  
Methyl Group ◽  
Kinetic Isotope ◽  
Deuterium Substitution ◽  
Different Temperatures ◽  
Rate Ratios

Secondary deuterium isotope effects have been measured for the reactions between methyl and methyl-d3 iodides and a series of tertiary amines in benzene solvent. Deuterium substitution increased the rate of each reaction but the rate ratios (kH/kD) show no systematic change with variation in the structure of the amine. The isotope effect for the reaction with 2-picoline was measured at different temperatures over a range of 40 deg and shows no change. These isotope effects may be rationalized as internal rotational effects of the methyl group or as solvation effects.

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