Direct evidence for a rate–determining chelate ring closure mechanism during the reaction of 2,2′-bipyridine with the hexakis(dimethyl sulphoxide)-aluminium(III) ion in nitromethane solution

1977 ◽  
pp. 586-587 ◽  
Author(s):  
Alan J. Brown ◽  
Oliver W. Howarth ◽  
Peter Moore ◽  
William J. E. Parr
Keyword(s):  
Direct Evidence ◽  
Chelate Ring ◽  
Dimethyl Sulphoxide ◽  
Ring Closure ◽  
Closure Mechanism

Direct evidence for a rate determining chelate ring closure mechanism in the reaction of a platinum(II) complex with bidentate nitrogen ligands

1995 ◽  
Vol 235 (1-2) ◽  
pp. 281-290 ◽  
Author(s):  
Raffaello Romeo ◽  
Giuseppe Alibrandi ◽  
Giuseppe Arena ◽  
Luigi MonsùScolaro ◽  
Maria Rosaria Plutino
Keyword(s):  
Direct Evidence ◽  
Chelate Ring ◽  
Ring Closure ◽  
Nitrogen Ligands ◽  
Closure Mechanism

Barrierless Reactions of Three Benzonitrile Radical Cations with Ethylene

2020 ◽  
Vol 73 (8) ◽  
pp. 705
Author(s):  
Oisin J. Shiels ◽  
P. D. Kelly ◽  
Stephen J. Blanksby ◽  
Gabriel da Silva ◽  
Adam J. Trevitt
Keyword(s):  
Ion Trap ◽  
Radical Cations ◽  
Branching Ratios ◽  
Ring Closure ◽  
Van Der Waals Complexes ◽  
Rate Coefficients ◽  
Ion Trap Mass Spectrometry ◽  
Closure Mechanism ◽  
Product Ions ◽  
Product Branching

Reactions of three protonated benzonitrile radical cations with ethylene are investigated. Product branching ratios and reaction kinetics, measured using ion-trap mass spectrometry, are reported and mechanisms are developed with support from quantum chemical calculations. Reactions proceed via pre-reactive van der Waals complexes with no energy barrier (above the reactant energy) and form radical addition and addition–elimination product ions. Rate coefficients are 4-dehydrobenzonitrilium: 1.72±0.01×10−11 cm3 molecule−1 s−1, 3-dehydrobenzonitrilium: 1.85±0.01×10−11 cm3 molecule−1 s−1, and 2-dehydrobenzonitrilium: 5.96±0.06×10−11 cm3 molecule−1 s−1 (with±50% absolute uncertainty). A ring-closure mechanism involving the protonated nitrile substituent is proposed for the 2-dehydrobenzonitrilium case and suggests favourable formation of the protonated indenimine cation.

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