141556-46-9Relevant academic research and scientific papers
Targeted and Systematic Approach to the Study of pKa Values of Imidazolium Salts in Dimethyl Sulfoxide
Dunn, Michelle H.,Konstandaras, Nicholas,Cole, Marcus L.,Harper, Jason B.
, p. 7324 - 7331 (2017)
A range of more than 25 imidazolium salts, chosen for their differing steric and electronic features, were prepared, and their pKa values were determined using the bracketing indicator method. Through the systematic change in the structure of the imidazolium cation, the effect of varying substituents at each position on the heterocyclic ring was determined; particularly, the transmission of electronic effects was quantified using Hammett parameters. These new data give an indication of the strength of base required for deprotonation and the potential to correlate these data with the nucleophilicity of the corresponding carbenes.
Estimated rate constants for hydrogen abstraction from n-heterocyclic carbene-borane complexes by an alkyl radical
Solovyev, Andrey,Ueng, Shau-Hua,Monot, Julien,Fensterbank, Louis,Malacria, Max,Lacote, Emmanuel,Curran, Dennis P.
supporting information; experimental part, p. 2998 - 3001 (2010/08/19)
Rate constants for hydrogen abstraction by a nonyl radical from 20 complexes of N-heterocyclic carbenes and boranes (NHC-boranes) have been determined by the pyridine-2-thioneoxycarbonyl (PTOC) competition kinetic method at a single concentration point. The rate constants range from 4 to 8 × 104 M-1 s-1. They show little dependence on the electronic properties of the carbene core, but there is a trend for increasing rate constants with decreasing size of the carbene N-substituents. Two promising new reagents with small N-substituents (R = Me) have been identified.
