Hydride ion transfer reactions in the gas phase. Pressure dependence of reaction efficiency as a criterion for the recognition of anchimeric assistance

1995 ◽  
pp. 121 ◽  
Author(s):  
Maria Elisa Crestoni ◽  
Simonetta Fornarini ◽  
Massimo Lentini ◽  
Maurizio Speranza
Keyword(s):  
Gas Phase ◽  
Pressure Dependence ◽  
Transfer Reactions ◽  
Ion Transfer ◽  
Reaction Efficiency ◽  
Hydride Ion ◽  
Anchimeric Assistance ◽  
Hydride Ion Transfer ◽  
Phase Pressure

A gas phase study of the regioselective BH4− reduction of some 2-substituted maleic anhydrides

1988 ◽  
Vol 66 (10) ◽  
pp. 2587-2594 ◽  
Author(s):  
Hans van der Wel ◽  
Nico M. M. Nibbering ◽  
Margaret M. Kayser
Keyword(s):  
Carbon Atom ◽  
Gas Phase ◽  
Ion Cyclotron Resonance ◽  
Ion Transfer ◽  
Hydride Ion ◽  
Ion Molecule Reactions ◽  
Phase Study ◽  
Olefinic Double Bond ◽  
Gas Phase Ion ◽  
Hydride Ion Transfer

Gas phase ion/molecule reactions in a Fourier transform ion cyclotron resonance mass spectrometer have been carried out for reductions of isotopically labelled citraconic (methylmaleic), phenylmaleic, and ethoxymaleic anhydrides by BH4−. In citraconic anhydride the carbonyl group neighbouring the methyl substituent is reduced preferentially in agreement with the ab initio calculations, which show the higher LUMO coefficients at this site. Hydride ion transfer to the olefinic double bond occurs as well; however, in that case no preference for either of the carbon atoms is observed. In phenylmaleic anhydride strong indications are found for a theoretically unexpected hydride ion transfer to the phenyl ring. For ethoxymaleic anhydride experimental evidence is presented showing hydride ion transfer to the carbon atom carrying the ethoxy group, which is in agreement with the "best overlap" consideration predicting that this carbon atom bears the highest LUMO coefficient.Most of the hydride transfers from BH4− to the molecules studied seem, therefore, to take place under orbital control rather than under control of long-range ion-induced dipole interactions between reactants.

scholarly journals Kinetics and Mechanism of the Oxidation of Substituted Benzaldehydes by Oxo(salen)manganese(v) Complexes

1999 ◽  
Vol 23 (8) ◽  
pp. 480-481
Author(s):  
Varsha Bansal ◽  
Pradeep K. Sharma ◽  
Kalyan K. Banerji
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Atom Transfer ◽  
Kinetics And Mechanism ◽  
Atom Transfer ◽  
Ion Transfer ◽  
Hydride Ion ◽  
Substituted Benzaldehydes ◽  
Hydride Ion Transfer

The oxidation of benzaldehyde by oxo(salen)manganese(v) complexes proceeds via either a hydride-ion transfer or a hydrogen-atom transfer from the aldehyde to the manganese(v) complex.

The dehydrogenation of 1,4-dihydronaphthalene by tetrachloro-p-benzoquinone

1976 ◽  
Vol 54 (14) ◽  
pp. 2261-2265 ◽  
Author(s):  
Z. M. Hashish ◽  
I. M. Hoodless
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Reaction Rate ◽  
Second Order ◽  
Charge Transfer Complexes ◽  
Ion Transfer ◽  
Hydride Ion ◽  
Rate Determining Step ◽  
Hydride Ion Transfer

The dehydrogenation of 1,4-dihydronaphthalene by tetrachloro-p-benzoquinone in phenetole solution has been investigated. The present work does not fully confirm earlier studies which report that the reaction follows second-order kinetics and that the hydride ion transfer is rate determining. In the investigations described in this paper second-order kinetics are only observed in the later stages of the reaction and a 1:1 stoichiometry of the reactants in the process is not obtained. Substitution of tritium in the 1,4-positions of the hydrocarbon appears to not significantly affect the reaction rate. The present results indicate that charge-transfer complexes are formed in the reaction and it is suggested that electron transfer within these complexes could be the rate-determining step in the dehydrogenation.

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