A. Fakhr

Electrochemical studies on organometallic compounds: IX. Electrogeneration of an unusual specias of niobium(III)

Abstract The one-electron reduction in THF/(Bu 4 N + PF 6 − ) of the complex Cp 2 NbCl 2 (Cp = η 5 -C 5 H 5 ) at a low temperature (−30°C) yields the anionic dimer (Cp 2 NbClCl 2 NbCp 2 ) − which remains stable for several hours.

Synthese et etude electrochimique de complexes dithiolenes du dicyclopentadienyl niobium

Abstract Dithiolene complexes (Cp2NbvS2C2R2)+ are synthesized and characterized by spectroscopic data. They show two reversible monoelectronic reduction steps. A controlled potential reduction on the plateau of the first wave leads to stable niobium(IV) complexes Cp2NbS2C2R2.

Electrochemical studies on organometallic compounds XXXII. Pseudo-reversibility of the first reduction stage of Nb[η5-1,3-C5H3(SiMe3)2]2Cl2

Abstract The one-electron reduction of Nb[η5-1,3C5H3(SiMe3)2]2Cl2 yields the derivative Nb[η5-1,3C5H3(SiMe3)2]2Cl. Pseudo-reversible behaviour is observed due to a return of Cl− to the molecule. The effect of the disubstitution of the cyclopentadienyl ring is discussed.

Etude électrochimique de complexes organométalliques. XV: Réduction électrochimique du dichlorure de niobiocène

Abstract The one electron reduction of Cp 2 NbCl 2 at low temperature (−30°C) yields the anionic dimer (Cp 2 NbClCl 2 NbCp 2 ) − . At room temperature the electro-reduction gives Cp 2 NbClL (L = trimethylphosphite or triphenylphosphine) or (Cp 2 NbCl) 2 . Only the latter compound can be reduced to niobocene “Cp 2 Nb”.

Electrochemical studies on organometallic compounds. VI: Electrogeneration of stable complexes of cyclopentadienyl derivatives of niobium(III)

Abstract The one electron reduction in THF (Bu 4 N + PF 6 − )of the complex (η 5 -MeCp) 2 -NbCl 2 in the presence of trimethylphosphite (TMP) yields the complex (η 5 -MeCp) 2 -NbCl(TMP), which reacts with CO to give the species (η 5 -MeCp) 2 NbCl(CO).

Etude électrochimique de complexes organométalliques: XXVII. Électrogénération du complexe anionique Nb(η5-C5H4SiMe3)2Cl2−☆

Abstract The one-electron reduction of Nb(η5-C5H4SiMe3)2Cl2 at −30°C yields the corresponding stable anion wich slowly decomposes at room temperature to give [Nb(η5C5H4SiMe3)Cl]2.

Electrochemical studies on organometallic compounds: XI. Electrogeneration of the zirconium(III) and hafnium(III) anions of zirconocene and hafnocene dichlorides

Abstract The one-electron reduction of zirconocene and hafnocene dichlorides Cp 2 MCl 2 (M = Zr or Hf) yields the corresponding anion Cp 2 MCl 2 − . There is no cleavage of an MCl bond, in contrast to the result in the case of the analogous titanocene and vanadocene dichlorides.

Etudeélectrochimique de complexes organométalliques: XXX. Caractéristiquesélectrochimiques de Nb2(η5-Cp)4Cl2S (S =N,N-diméthylformamide) générépar réduction monoélectronique de Nb(η5-Cp)2Cl2

Abstract The one-electron reduction of Nb(η5-Cp)2Cl2 inN,N-dimethylformamide (S) yields the dimeric species Nb2(η5Cp)4Cl2S, which is relatively stable at −30°C.

Electrochemical studies on organometallic compounds: XIV. Electrogeneration of the bis(phenylethynyl)dicyclopentadienyltitanium(III) anion☆

Abstract The one-electron reduction of (C 5 H 5 ) 2 Ti IV (CCC 6 H 5 ) 2 is reversible and gives the anion which is very stable at −30°C. At 25°C, the anion undergoes a slow transformation with loss of a cyclopentadienyl anion.

Electrochemical studies on organometallic compounds: XXVIII. Catalysis of the electrochemical reduction of benzyl chloride by niobium(III) anionic complexes and formation of carboncarbon bonds☆

Abstract The dicyclopentadienylniobium(III) dichloride anion has been shown to be an effective catalyst for the electrochemical reduction of benzyl chloride. Indirect cathodic reduction yields diphenylethane.