Estimated rate constants for hydrogen abstraction from N-heterocyclic carbene-borane complexes by an alkyl radical.
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 <1 x 10(4) to 8 x 10(4) 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.
Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
Andrey
A
Solovyev
Shau-Hua
SH
Ueng
Julien
J
Monot
Louis
L
Fensterbank
Max
M
Malacria
Emmanuel
E
Lacôte
Dennis P
DP
Curran
D001880:Boranes / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D007700:Kinetics; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
D001880:Boranes; D005609:Free Radicals; D006571:Heterocyclic Compounds; C030011:carbene; D006859:Hydrogen; D008697:Methane