EFFECT OF THE ELECTRODE MATERIAL ON THE REACTION ROUTE FOR THE ELECTROREDUCTION OF METAL-COMPLEXES CONTAINING LIGANDS WITH ACIDIC C-H BONDS- THE CATION OF NE]-(METHYLIMIDE)MOLYBDENUM,[CLMO(DPPE)(2)NCH3](+)
Vv. Strelets et Cj. Pickett, EFFECT OF THE ELECTRODE MATERIAL ON THE REACTION ROUTE FOR THE ELECTROREDUCTION OF METAL-COMPLEXES CONTAINING LIGANDS WITH ACIDIC C-H BONDS- THE CATION OF NE]-(METHYLIMIDE)MOLYBDENUM,[CLMO(DPPE)(2)NCH3](+), Russian journal of electrochemistry, 30(8), 1994, pp. 926-930
Low-temperature cyclic voltammetry with ultramicroelectrodes was used
to study the electroreduction of the methylimide complex of [ClMo(dppe
)(2)NCH3](+) [1(+); dppe stands for bis(diphenylphosphino)ethane] in a
bsolute tetrahydrofurane (THF). The 1(+) complex was shown to undergo
reversible one-electron reduction to [ClMo(dppe)(2)NCH3] (1), whose fa
te depends on the nature of the electrode material. At Hg and vitreous
carbon electrodes in a nitrogen atmosphere, the 1 intermediate underg
oes irreversible four-electron reduction to [Mo(N-2)(2)(dppe)(2)] and
methylamine. Being a strong base, the electrogenerated complex 1 depro
tonates the starting complex 1(+) in the course of a parallel reaction
to form the methylene amide complex [ClMo(dppe)(2)NCH2] (2). The Pt e
lectrode exhibits no further reduction of the intermediate 1; instead,
a wave of catalytic hydrogen evolution is observed. It is assumed tha
t the key step of the hydrogen evolution process is platinum-catalyzed
abstraction of a hydrogen atom from 1, which was turned to 2. Lowerin
g the temperature allows the reversible oxidation of 1(+) to the [ClMo
(dppe)(2)NCH3](2+) dication to be observed.