G. Tainturier

Chlorures de mono- et dialkyl-zirconocene et-hafnocene

Condensation of cyclopentadienyl anions obtained from fulvenes and tetra- chloride metal to prepare (η5-RC5H4)2MCl2, R = alkyl; M = Zr or Hf is described. The prochiral complexes (η5-RC5H4) (η5-C5H5)MCl2 are prepared in a similar way from MCl4 (M = Zr), but the best method uses (η5-C5H5)ZrCl3 or (η5-C5H5)HfCl3, 2THF. Preparation of this adduct is described.

Synthese et reactivite de nouveaux dihydrurozirconocenes et -hafnocenes substitues achiraux et chiraux

Abstract Hydrogenolysis of (M(CH3)2) (M = Zr, Hf) bonds gives new racemic and optically active substituted zirconocene and hafnocene dihydrides A: (RCp)2MH2 (M = Zr, Hf; R = Me, Me2CH, Me3C, PhCH2) and B: (R*Cp)2MH2 (M = Zr, Hf; R* = MeCHEtCH2, PhCHEtCH2), R*CpCpHfH2 R* = PhCHCH3). Substitution of hydridic hydrogens by halogens, mobile hydrogen compounds, addition with unsaturated derivatives are studied. The A and B type complexes are good catalysts in hydrogenation of alkenes; the B type complexes give only poor asymmetric induction in catalytic reduction of prochiral alkenes.

Structure cristalline et proprietes du dichlorure de bis(pentahapto-benzylcyclopentadienyl)zirconium triboluminescent

Abstract The product ( n 5 -C 5 H 4 CH 2 C 6 H 5 ) 2 ZrCl 2 is orthorhombic: a 12.05(1), b 24.12(2), c 6.99(1) A; space group Aba 2, Z 4. Final R 0.077. The Zr atom is tetrahedrally coordinated by two ZrCl σ bonds and two ZrCp π bonds. The crystal is tri-boluminescent and highly piezoelectric.

Composes chiraux du zirconium et du hafnium

Abstract The first chiral dicyclopentadienyl compounds of zirconium (IV) and hafnium(IV) of the form (η 5 -C 5 H 5 ) (η 5 -RC 5 H 4 )MClX (X = alkoxy, aryloxy or benzyl group) have been prepared and studied. The presence of an asymmetric metal atom is shown by NMR of these complexes containing suitable ligands.

Formation of a zirconium—molybdenum bond via methane elimination

Reaction of (n5-C5H5)2Zr(CH3)2 and (n5-C5H5)Mo(CO)3H gives (C5H5)2CH3Zr--Mo(C5H5)(CO)3. Some properties of this compound are described.

Derives organoselenies du zirconium et du hafnium. Insertion de se dans la liaison M = CH3 (M = Zr, Hf)

Abstract New selenium complexes (η 5 -RC 5 H 4 ) 2 M(SeR′) 2 (M = Zr, Hf; R′ = CH 3 , C 6 H 5 ) have been synthesized and their NMR, mass and IR spectra are discussed. The possibility of insertion of elemental selenium into the MCH 3 bond is reported (M = Zr, Hf).

Cyclopentadienylhafnium trichloride, its synthesis and use to prepare a chiral hafnium compound

The preparation and characterisation of the new hafnium compound (η5-C5H5)HfCl3,2THF is reported; it has been used to prepare the first chiral complex of hafnium.

Metallocen-chalcogen-verbindungen: Eine einfache synthese von [(η-C5H4R)2ZrTe]2 komplexen mit einem planaren metallacyclischen vierringgerüst

Abstract Reaction of the (η4-butadiene)Zr(C5H4R)2 complexes, 1a (R = t-butyl) or 1b (R = 1,1-dimethylpentyl), with elemental tellurium at 70°C in toluene for 30 h leads to liberation of the butadiene ligand and formation of the compounds [(η-C5H4R)2ZrTe]2 (2,ab). 2a crystallizes in the space group P21/c with cell parameters a 9.517(4), b 12.273(5), c 15.664(7) A, β 96.72(3)°. In the crystal state 2a exhibits a square planar Zr2Te2 framework (d(ZrTe) 2.855(1) A; TeZrTe* 89.14(1), ZrTeZr* 90.86(1)°).

Reactivity of zirconocene and hafnocene dihydrides towards elemental selenium and sulfur. Strong evidence for insertion of a chalcogen unit into the metal—hydrogen bond

Abstract Dimeric metallocene dihydrides [(η 5 -t-BuC 5 H 4 ) 2 MH(μ-H)] 2 (1; M = Zr, Hf) react with elemental chalcogens to give the four-membered metallacycles [(η 5 -t-BuC 5 H 4 ) 2 M(μ-E)] 2 (2, E = Se; 3, E = S). In the case of sulfur, the reaction also gives (η 5 -t-BuC 5 H 4 ) 2 MS 5 (4). Both 3 and 4 are shown to come from subsequent reactions of the primary insertion product (η 5 -t-BuC 5 H 4 ) 2 M(SH) 2 .

Preparation of bis(μ-chalcogeno) complexes [(η5-RC5H4)2M(μ-E)]2 M = Zr, Hf; R = H, t-Bu; E = S or Se from metallocene dichlorides, and isolation of the mixed μ-complexes [(t-BuC5H4)2Zr2](μ-O)(μ-E)

Abstract Metallocene dichlorides (RCp) 2 MCl 2 (M = Zr, Hf; R = H, t-Bu) react with E/2HLiBEt 3 (E = S, Se) to give the symmetrical dinuclear compounds [(RCp) 2 M(μ-E)] 2 . UV irradiation in toluene of [(t-BuCp) 2 Zr(CH 3 )] 2 (μ-O) in the presence of powdered sulfur or gray selenium gives the new compounds [(t-BuCp) 2 Zr 2 ](μ-O)(μ-E).