Kinetic Studies of the Homogeneous Coupling Reaction between Electrochemically Generated Aromatic Radical Anions and Alkyl Radicals.

Alkylation of [2,2′-([2,2′-bipyridine]-6,6′-diyl)bis[phenolato]-N,N′,O,O′]nickel(II) during catalytic reduction of 1-iodooctane

“…As shown in reaction (6), 1 could be produced in a reduced form, Ni(II)L ÅÀ , that exhibits ligand-radical character rather than nickel(I) character, whereupon Ni(II)L ÅÀ could interact with an alkyl radical to form a modified species (reaction (7)). This radical-coupling mechanism has been reported extensively in investigations of the homogeneous reduction of organic halides via electrogenerated aromatic radical anions [35][36][37][38][39][40][41]. Indeed the cyclic voltammetric behavior observed in Fig.…”

Evidence for Ionic Samarium(II) Species in THF/HMPA Solution and Investigation of Their Electron-Donating Properties

“…The reaction kinetics was monitored by UV/Vis spectroscopy using the dipprobe technique described elsewhere. [27] The decay of SmI 2 and [Sm(hmpa) 4 (thf) 2 ] 2 upon addition of the alkyl halide was detected at 620 and 540 nm, respectively. No build-up of intermediates during the reaction could be detected in the wavelength range 450 ± 800 nm.…”

“…The ET rate constants k ET were determined by cyclic voltammetry [26] or the dip-probe technique from measurement of the decay of the absorption of the aromatic radical anion upon addition of the alkyl halide in THF/0.2 m Bu 4 NPF 6 . [27] The radical anion was generated at the required initial concentration by electrochemical reduction of the parent aromatic compound. Addition of HMPA in the amounts used in the SmI 2 experiments to the solutions of the aromatic radical anions had no effect on the reaction rates.…”

A Century of Organic Electrochemistry

“…From the potential of the midpoint of the S-shaped curve, E 1/2 q , the standard potential, E R o , can be calculated when the total self-exchange reorganization energy R is known or estimated. k c is assumed constant 164,165 and about 10 9 M Ϫ1 s Ϫ1 . The weak point of the method is the estimation of , but the method gives a reasonable potential determination of short-lived radicals using easily available apparatus.…”