R. Broussier

Synthèse de ferrocènes hétérodisubstitués à ancrage soufre ou sélénium via un précurseur original Fe(C5H4ELi)2,2THF (E S, Se). Nouvelle préparation des ferrocènes 1,1′-dithiol et -disélénol

Abstract The reaction of Fe(C 5 H 4 Li) 2 , TMEDA (1 mol) with E (S or Se) (2 mol) in a THF/toluene mixture leads directly to the new reagent, Fe(C 5 H 4 ELi) 2 , 2THF. This complex reacts cleanly with various electrophiles (alkyl halides, acyl chlorides and anhydrides) to give new families of open chains or cyclic heterodichalcogenated ferrocenes. The method describes here is more efficient and convenient than that previously employed.

Ferrocene-based phosphonite–phosphine ligands, Pd and Rh complexes

Abstract A variety of ferrocene-based 1-phosphonite-1′-phosphine ligands were prepared via 1-dichlorophosphino-1′-diphenylphosphinoferrocene from anionic ring opening of 1-phenyl-1-phospha-[1]ferrocenophane. The corresponding palladium and rhodium complexes have also been prepared and tested, respectively, in Heck and hydroformylation reactions.

FERROCENIC POLYPHOSPHINES AND POLYTHIOETHERS : SYNTHESIS, REACTIVITY AND STRUCTURE

Abstract The new ferrocenic polyphosphines [C 5 Me 3 -1,2-(PPh 2 ) 2 ](C 5 H 5 )Fe 2 , [C 5 Me 3 -1,2-(PPh 2 ) 2 ] 2 Fe 3 , [C 5 Me 3 -1,2-(PPh 2 ) 2 ][C 5 Me 4 (PPh 2 )]Fe 4 and polythioethers [C 5 Me 3 -1,2-(SCH 2 CH 2 CH 3 )2] 2 Fe 6 and [C 5 Me 3 -1,2-(SCH 2 CH 2 CH 3 ) 2 ](C 5 H 5 )Fe 7 have been prepared. The X-ray crystal structures of 3 and 6 have been determined. Some aspects of the reactivity of compounds 2 , 3 and 4 are reported (P(III)→P(V) transformation, chelating properties) as well as the X-ray structure of [C 5 Me 3 -1,2-(PPh 2 ) 2 W(CO) 4 ](C 5 H 5 )Fe 15 .

Synthese et etude de dichlorodialkylcyclopentadienylniobium(IV) et des derives dimethyles

The reactions of niobium pentachloride or tetrachloride with various cyclopentadienyl anions obtained from fulvenes are described. The products (η5-RCp)2NbCl2 are characterized by elementary analysis, mass and EPR spectroscopy. The EPR spectra of derivatives (η5-RCp)2Nb(CH3)2 are also discussed.

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.

Chlorodialkylcyclopentadienyloxoniobium(V), synthese et reactivite

Abstract The synthesis, starting from convenient dicyclopentadienylniobium dichloride, and the properties of several pseudo-tetrahedric complexes (η 5 -RCp) 2 NbOCl are described. For some of these species, the centrometallated prochirality has been detected by NMR. A number of derivatives have been isolated either by substitution of the chlorine atom or, probably via hydroxo species, by substitution of the oxygen atom.

Di(tertiobutylcyclopentadienyl)zircona[1]ferrocenophane precurseur de zirconocenes disubstitués dissymetriquement

Abstract There is an exceptional degree of steric hindrance to attack on the zirconium atom in (1,1′ferrocenediyl)bis(tert-butylcyclopentadienyl)zirconium, as shown by studies of the reactivity of the complex towards protic reagents. Some dissymmetrically disubstituted metallocenes, (tBuC5H4)2Zr(X)-(C5H5)Fe(C5H5) with X  OH, OAr′, OR, OCOPh have been synthesized. Some of them were used to make symmetrically disubstituted metallocenes (tBuC5H4)2ZrX2, X  OAr′, OR, OCOPh. By using radical species the chalcogenated complexes (tBuC5H4)2Zr(EPh)(C5H4FeC5H4EPh), E  S, Se, have been prepared.

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”.

NEUTRAL AND CATIONIC 1,4-DIPHOSPHA-2-RHODA-3-THIA-4-FERROCENOPHANE

Abstract A mixed bidentate ferrocenyl ligand Fe(η5-C5Me4P(S)Ph2)(η5-C5Me4PPh2) (abbreviated {P,PS}) was synthesised and used for complexation with [RhCl(CO)2]2. The neutral [4]-ferrocenophane {P,PS}Rh(CO)Cl 2 and the unusual dimeric cationic species [{P,PS}Rh(CO)(μ-Cl)(CO)Rh{P,PS}]+ 3 were obtained and characterized by crystal structure analysis. During investigations on the catalytic properties of 2 in carbonylation, some aspects of its behavior towards iodomethane were elucidated.

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).