Edge-shared [M2Cl10]2? complexes of reaction between oxophilic group 4 metal and phosphorus ylides

The reactions between oxophilic group 4 metal chlorides, ??-keto ylides in THF, led to the formation of titanium, zirconium and hafnium edge-shared [M₂Cl₁₀]^2? complexes (1a?C3f). We describe that the reaction between MCl₄ (M = Ti, Zr and Hf) with phosphorus ylides produce edge-shared [M₂X₁₀]^2? complexes instead of O-coordination previously reported complexes. Adding dimethyl sulfoxide (DMSO) to these complexes in room temperature crystalline solid [M(DMSO)₈] · 4Cl · mH₂O · DMSO] (M = Ti (1g), Zr (2g) and Hf (3g); m = 0?C3) together with phosphonium salts in mother liquid were formed. The compounds were characterized by elemental analysis, IR and ¹H, ¹³C and ³¹P NMR spectroscopy.     

Homoleptic alkenyls of the early transition metals and related compounds

The first stable homoleptic alkenyls of the early transition metals, MR_n, (R = C(Ph)=CMe₂; M = Ti, Zr, Hf, n = 4; and M = Cr, n = 3) and the related species (C₅H₅)₂MR₂ (M = Ti, Zr) and (C₅H₅)₂Zr(Cl)R have been prepared using appropriate organolithium reagents. Cleavage and insertion reactions are reported for the new compounds.     

Zur Wechselwirkung einiger Übergangsmetallhalogenide mit o-Mercaptophenol

The interaction of some transition metal halides with o-mercaptophenol o-Mercaptophenol reacts with WCl₆, TiCl₄, ZrCl₄, NbCl₅ and TaCl₅ giving the corresponding tris-chelat-komplexe W(C₆H₄OS)₃, H₂[M(C₆H₄OS)₃] (M = Ti, Zr), H[M(C₆H₄OS)₃] (M = Nb, Ta). (C₅H₅)₂TiCl₂ and (C₅H₅)₂ZrBr₂give in presence of triethylamine the compounds (C₅H₅)₂M(C₆H₄OS) (M = Ti, Zr). By reaction of nickel(II) acetyl-acetonate with o-mercaptophenol the polymeric octahedral complex nickel-bis-(o-hydroxy-thiophenolate) results.     

Ti Group Metallocene-Catalyzed Synthesis of 1-Hexene Dimers and Tetramers

1-Hexene transformations in the catalytic systems L₂MCl₂–XAlBuⁱ₂ (L = Cp, M = Ti, Zr, Hf; L = Ind, rac-H₄C₂[THInd]₂, M = Zr; X = H, Bu ⁱ) and [Cp₂ZrH₂]₂-ClAlR₂ activated by MMAO-12, B(C₆F₅)₃, or (Ph₃C)[B(C₆F₅)₄] in chlorinated solvents (CH₂Cl₂, CHCl₃, o-Cl₂C₆H₄, ClCH₂CH₂Cl) were studied. The systems [Cp₂ZrH₂]₂-MMAO-12, [Cp₂ZrH₂]₂-ClAlBuⁱ₂-MMAO-12, or Cp₂ZrCl₂-HAlBuⁱ₂-MMAO-12 (B(C₆F₅)₃) in CH₂Cl₂ showed the highest activity and selectivity towards the formation of vinylidene head-to-tail alkene dimers. The use of chloroform as a solvent provides further in situ dimer dimerization to give a tetramer yield of up to 89%. A study of the reaction of [Cp₂ZrH₂]₂ or Cp₂ZrCl₂ with organoaluminum compounds and MMAO-12 by NMR spectroscopy confirmed the formation of Zr,Zr-hydride clusters as key intermediates of the alkene dimerization. The probable structure of the Zr,Zr-hydride clusters and ways of their generation in the catalytic systems were analyzed using a quantum chemical approach (DFT).     

Syntheses and Molecular Structures of [(thf)4Li] [{(thf)Li}M(C4H8)3] (M = Zr,Hf) and Their Solution Behavior

The reaction of MCl₄(thf)₂ (M = Zr, Hf) with 1,4-dilitiobutane in diethyl ether at –25 °C or at 0 °C with a molar ratio of 1 : 3 yields the homoleptic “ate” complexes [(thf)₄Li] [{(thf)Li}M(C₄H₈)₃] 1 - Zr (M = Zr) and 1 - Hf (M = Hf). The crystalline compounds form ion lattices with solvent-separated [(thf)₄Li]⁺ cations and [{(thf)Li}M(C₄H₈)₃]^– anions. The NMR spectra at –20 °C show magnetic equivalence of the M–CH₂ and of the β-CH₂ groups of the butane-1,4-diide ligands on the NMR time scale. Analogous reactions of MCl₄(thf)₂ with 1,4-dilithiobutane with a molar ratio of 1 : 2 proceed unclear. However, single crystals of [Li(thf)₄] [HfCl₅(thf)] ( 2 ) can be isolated with the hafnium atom in a distorted octahedral coordination sphere of five chloro and one thf ligand. NMR spectra allow to elucidate the time-dependent degradation of 1-Hf and 1-Zr in THF and toluene at 25 °C via THF cleavage. Addition of tmeda to a solution of 1-Zr allows the isolation of intermediately formed [{(tmeda)Li}₂Zr(nBu)₂(C₄H₈)₂] ( 3 ).     

Access a divers dichalcogenophenylenes metallocenes (M = Ti, Zr, Hf). Premier exemple d'un ditellurophenylene-zirconocene

Elementary sulfur and selenium combine (in boiling heptane) with [(tBuCp)₂-Zr(C₆H₄R)₂] (Cp = η⁵-C₅H₄; R = OCH₃) to give the corresponding dichalcogenophenylenezirconocene. With tellurium, the reaction proceeds only at lower temperature (in boiling hexane), affording the first ditellurophenylenezirconocene. As no metallacycle was obtained with the Cp ligand or when the metal is Hf, complexes of the general type [(RCp)₂MSe₂C₆H₄-o] (M = Ti, Zr, Hf; R = H, t-Bu, (CH₃)₅) have been synthesized by allowing metallocene dichlorides to react with potassium benzenediselenolate, prepared by cleaving [(t-BuCp)₂ZrSe₂C₆H₄-o] with t-BuOK.     

Group 4 metallocene complexes with non-bridged and tetramethyldisiloxane-bridged methyl-phenyl-cyclopentadienyl ligands: synthesis, characterization and olefin polymerization studies

The non-vicinal methyl-phenyl-substituted zirconocene dichlorides meso-and rac-[Zr{η⁵-(1-Ph-3-Me-C₅H₃)}₂Cl₂] and [Zr(η⁵-C₅H₅){η⁵-(1-Ph-3-Me-C₅H₃)}Cl₂] have been isolated by transmetallation of the lithium salt Li(1-Ph-3-Me-C₅H₃) to ZrCl₄(THF)₂ and [Zr(η⁵-C₅H₅)Cl₃ · DME] (DME = dimethoxyethane), respectively. Similar transmetallation of the lithium salt Li₂[(Me-Ph-C₅H₂SiMe₂)₂O] to MCl₄ gave the ansa-metallocenes [M{η⁵-(Me-Ph-C₅H₂SiMe₂)₂O}Cl₂] (M = Zr, Hf) for which the meso- and rac-diastereomers were separated. The dimethyl and dibenzyl derivatives of these metallocenes were also prepared and the structure of all of these compounds determined by NMR spectroscopy. The molecular structure of rac-[Zr{η⁵-(2-Me-4-Ph-C₅H₂SiMe₂)₂O}Cl₂] was determined by single crystal X-ray diffraction methods. The activity of the dichlorometallocenes/MAO catalysts for ethene and propene polymerization was evaluated.     

Vibrational spectra of cyclopentadienyl chlorides of titanium,zirconium and hafnium. internal rotation and thermodynamic functions

The infrared and Raman spectra of some cyclopentadienyl compounds of the transition metals, namely Ti(C₅H₅)Cl₃ and M(C₅H₅)₂Cl₂ (M = Ti, Zr and Hf), are reported and discussed. The infrared spectra of the gaseous species isolated in argon matrices at 10 K provide structural information about the single molecules. Particular attention has been paid to the low-frequency region in order to achieve more reliable assignments for the internal-rotation modes. The structural data and the fundamental frequencies derived from the spectra are employed in a calculation of the thermodynamic functions for these compounds in the ideal gas state.     

A cyclopentadienyl ring exchange method for the attachment of early transition metal metallocene dichlorides to a polymer support

PMR and mass spectral analysis have been used to study the interchange of π-bonded cyclopentadienyl rings with σ-bonded cyclopentadienyl rings in the compounds (C₅H₅)₄M (M = Ti, Zr, Hf, Nb, Ta, Mo and W) and (C₅H₅)₃V or a-bonded benzylcyclopentadienyl rings in the compounds (C₆H₅CH₂C₅H₄) (C₅H₅)₂MC1 (M = Ti, Zr, Hf, Nb, Ta, Mo and W). As soon as the Cp₄M species are generated (indicated by a color change), the interchange occurs and the equilibrium is established. As reported, no such interchange was observed in (C₅H₅) ₄Mo in the PMR time scale; however, it does occur after a longer time. By using this interchange behavior of the cyclopentadienyl ring, metallocene dichlorides of Ti, Zr, Hf, V, Nb, Ta, Mo and W have been attached to polystyrene-divinylbenzene beads.     

Transition metal derivatives of 1,1′-dichloroferrocene

Complexes of the general formula [Cl₂Fc] _nML, (Cl₂Fc = C1C₅H₄FeC₅H₃Cl; ML = Fe(CO)₂C₅H₅, AuP(C₆H₅)₃, Mn(CO)₅ or Ir(CO)[P(C₆H₅)₃]₂ when n = 1; ML = Ti(C₅H₅)₂ when n = 2) have been prepared from a salt elimination reaction between 1,1′-dichloro-2-lithioferrocene and transition metal halide complexes. Spectroscopic properties of the compounds are reported. The titanium complex exists in meso and dl forms.     

Hydridoorganostannylene Coordination: Group 4 Metallocene Dichloride Reduction in Reaction with Organodihydridostannate Anions

Organodihydridoelement anions of germanium and tin were reacted with metallocene dichlorides of Group 4 metals Ti, Zr and Hf. The germate anion [Ar*GeH₂]⁻ reacts with hafnocene dichloride under formation of the substitution product [Cp₂Hf(GeH₂Ar*)₂]. Reaction of the organodihydridostannate with metallocene dichlorides affords the reduction products [Cp₂M(SnHAr*)₂] (M=Ti, Zr, Hf). Abstraction of a hydride substituent from the titanium bis(hydridoorganostannylene) complex results in formation of cation [Cp₂M(SnAr*)(SnHAr*)]⁺ exhibiting a short Ti–Sn interaction. (Ar*=2,6-Trip₂C₆H₃, Trip=2,4,6-triisopropylphenyl).     

Ruthenium(II) complexes with triphenylphosphine or triphenylarsine and other monodentate ligands

Synthesis and studies on some five-coordinate ruthenium(II) complexes, viz. [Ru(MPh₃)(C₆H₅CHO)₂Cl₂] and [Ru(MPh₃)₂(CO)Cl₂] (where M = P or As) have been described. Reactions of [Ru(MPh3)(C₆H₅CHO)₂Cl₂] with N,N-dimethylformamide, dimethylsulphoxide and pyridine and of [Ru(MPh₃)₂(CO)Cl₂] with pyridine are described.     

Complexes du titane et du zirconium contenant les ligands cyclopentadienyldiphenylphosphine et cyclopentadienylethyldiphenylphosphine: acces a des structures heterobimetalliques

Reactions of Ph₂P(CH₂)_n(C₅H₄)Li, (n = 0, 2), with MCl₄ or CpTiCl₃ (M = Ti, Zr; Cp = η⁵-C₅H₅) form Cl₂M[(η⁵-C₅H₄)(CH₂)_nPPh₂]₂ or Cl₂CpTi[(η⁵-C₅H₄)-(CH₂)₂PPh₂] in good yields. Chemical reduction with Al, or electrochemical reduction of these complexes, under CO, are described. The titanium(IV) and zirconium(IV) derivatives react with metal carbonyls (Mo(CO)₆, Cr(CO)₆, Fe(CO)₅, Mo(CO)₄(C₈H₁₂)) under formation of new heterobimetallic complexes. Reduction with Al of Cl₂CpTi[(η⁵-C₅H₄)(CH₂)₂PPh₂]Mo(CO)₅ under CO results in a new heterobimetallic species containing low valent titanium. Both complexes Cl₂M[(η⁵-C₅H₄)(CH₂)₂PPh₂]₂ (M = Ti, Zr) react with [Rh(μ-Cl)(CO)(C₂H₄)]₂ to yield {RhCl(CO)(Cl₂M[(η⁵-C₅H₄)(CH₂)₂PPh₂]₂)}x, which is assumed to be a dimer, in which the titanium or the zirconium compounds act as bridging diphosphine ligands between the rhodium atoms.     

Synthesis and reactions of substituted zirconocene and hafnocene dimethyls and the corresponding dihydrides

Hydrogenolysis of M(CH₃)₂(M = Zr, Hf) bonds gives novel substituted zirconocene and hafnocene dihydrides. The use of the optically active complex [η⁵-C₆H₅C★H(CH₃)C₅H₄] (η⁵-C₅H₅)Zr(CH₃)₂ as a catalyst in homogeneous hydrogenation of prochiral alkenes is reported.     

Zirconium and hafnium amide, alkoxide, and pyrrolyl complexes manifesting with pyrrolyl-linked N-donor ligands: Syntheses, characterization, and ring opening polymerization of ε-caprolactone

A series of zirconium and hafnium alkoxide and amide complexes containing symmetrical tridentate pyrrolyl ligand, [C₄H₂NH(2,5-CH₂NMe₂)₂] have been synthesized conveniently by treatment of 2,6-di-tert-butylphenol, tert-butanol or pyrrole in pentane and their reactivity over ring opening polymerization of ε-caprolactone have been carried out. Reactions of [C₄H₂NH(2,5-CH₂NMe₂)₂] with M(NEt₂)₄ (M = Zr or Hf) originate [C₄H₂N(2,5-CH₂NMe₂)₂]M(NEt₂)₃ (1, M = Zr; 2, M = Hf). Furthermore, reactions of [C₄H₂N(2,5-CH₂NMe₂)₂]M(NEt₂)₃ with 2,6-di-tert-butylphenol, tert-butanol or pyrrole afford [C₄H₂N(2,5-CH₂NMe₂)₂]M(OC₆H₃-2,6-^tBu₂)(NEt₂)₂ (3, M = Zr; 4, M = Hf), [C₄H₂N(2,5-CH₂NMe₂)₂]M(O^tBu)₃ (5, M = Zr; 6, M = Hf) and [C₄H₂N(2,5-CH₂NMe₂)₂]M(C₄H₄N)₃ (7, M = Zr; 8, M = Hf), respectively, in satisfactory yield. All the complexes have been characterized by NMR spectra as well 3, 4 and 6 subjected to the X-ray diffraction analysis. Complexes 3-8 have been used as initiators for the ring-opening polymerization of ε-caprolactone and observed broad PDI values (1.84-2.75) representing multiple reactivity centers of these complexes.     

Preparation of dicyclopentadienylmetal-bis(trimethyl phosphite) complexes of titanium(II) and zirconium(II) by sodium atom reduction

The complexes (C₅H₅)₂M[P(OCH₃)₃]₂ (M = Ti and Zr) can be prepared by condensing sodium atoms at ?100°C into tetrahydrofuran solutions containing (C₅H₅)₂MCl₂ and excess trimethyl phosphite.     

Synthesis and Reactivity of Boron‐, Silicon‐, and Tin‐Bridged ansa‐Cyclopentadienyl–Cycloheptatrienyl Titanium Complexes (Troticenophanes)

A novel one‐pot method was developed for the preparation of [Ti(η⁵‐C₅H₅)(η⁷‐C₇H₇)] (troticene, 1 ) by reaction of sodium cyclopentadienide (NaCp) with [TiCl₄(thf)₂], followed by reduction of the intermediate [(η⁵‐C₅H₅)₂TiCl₂] with magnesium in the presence of cycloheptatriene (C₇H₈). The [n]troticenophanes 3 (n=1), 4 , 8 , 10 (n=2), and 11 (n=3) were synthesized by salt elimination reactions between dilithiated troticene, [Ti(η⁵‐C₅H₄Li)(η⁷‐C₇H₆Li)] ? pmdta ( 2 ) (pmdta=N,N′,N′,N′′,N′′‐pentamethyldiethylenetriamine), and the appropriate organoelement dichlorides Cl₂Sn(Mes)₂ (Mes=2,4,6‐trimethylphenyl), Cl₂Sn₂(tBu)₄, Cl₂B₂(NMe₂)₂, Cl₂Si₂Me₄, and (ClSiMe₂)₂CH₂, respectively. Their structural characterization was carried out by single‐crystal X‐ray diffraction and multinuclear NMR spectroscopy. The stanna[1]‐ and stanna[2]troticenophanes 3 and 4 represent the first heteroleptic sandwich complexes bearing Sn atoms in the ansa bridge. The reaction of 3 with [Pt(PEt₃)₃] resulted in regioselective insertion of the [Pt(PEt₃)₂] fragment into the Sn? C_ipso bond between the tin atom and the seven‐membered ring, which afforded the platinastanna[2]troticenophane 5 . Oxidative addition was also observed upon treatment of 4 with elemental sulfur or selenium, to produce the [3]troticenophanes [Ti(η⁵‐C₅H₄SntBu₂)(η⁷‐C₇H₆SntBu₂)E] ( 6 : E=S; 7 : E=Se). The B? B bond of the bora[2]troticenophane 8 was readily cleaved by reaction with [Pt(PEt₃)₃] to form the corresponding oxidative addition product [Ti(η⁵‐C₅H₄BNMe₂)(η⁷‐C₇H₆BNMe₂)Pt(PEt₃)₂] ( 9 ). The solid‐state structures of compounds 5 , 6 , and 9 were also determined by single‐crystal X‐ray diffraction.     

Synthesis,characterization and toxicity of new heterobimetallic complexes of platinum(II) and palladium(II)

Heterobimetallic complexes of the type [M(C₆H₆N₂)₂(M′)₂(R)₄]Cl₂ have been synthesized by the direct reaction of [M(C₆H₈N₂)₂]Cl₂ with Group 4 or 14 organometallic dichlorides Ph₂M′Cl₂,Me₂M′Cl₂ or Cp₂M″Cl₂ in 1:2 molar ratio in MeOH (M = Pd or Pt, M′ = Si or Sn and M″ = Ti or Zr). The compounds were characterized by elemental analysis, molecular weight determination, electronic, ¹H NMR and IR spectra, magnetic susceptibilities and conductivity measurements. These studies showed that the compounds are monomers and dimagnetic in nature, with a square‐planar geometry around palladium and platinum metals. Both the free ligands and their metal complexes were screened for antimicrobial activity on different species of pathogenic fungi and bacteria and were found active in this respect.Copyright © 2001 John Wiley & Sons, Ltd.     

C2-Bridged sandwich and half-sandwich entities with Ti(IV) and Cr(0) centers

The intense purple colored bi- and trimetallic complexes {Ti}(CH₂SiMe₃)[CC(η⁶-C₆H₅)Cr(CO)₃] (3) ({Ti}=(η⁵-C₅H₅)₂Ti) and [Ti][CC(η⁶-C₆H₅)Cr(CO)₃]₂ (5) {[Ti]=(η⁵-C₅H₄SiMe₃)₂Ti}, in which next to a Ti(IV) center a Cr(0) atom is present, are accessible by the reaction of Li[CC(η⁶-C₆H₅)Cr(CO)₃] (2) with {Ti}(CH₂SiMe₃)Cl (1) or [Ti]Cl₂ (4) in a 1:1 or 2:1 molar ratio. The chemical and electrochemical properties of 3, 5, {Ti}(CH₂SiMe₃)(CCFc) [Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄)] and [Ti][(CC)_nMc][(CC)_mM′c] [n, m=1, 2; n=m; n≠m; Mc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄); M′c=(η⁵-C₅H₅)Ru(η⁵-C₅H₄); Mc=M′c; Mc≠M′c] will be comparatively discussed.