86050-32-0Relevant articles and documents
Stereorigid titanocene and zirconocene derivatives. Synthesis and crystal structure of the dialkyl complex 5-η5-(C5H4)2Si(CH3)2>Ti2
Gomez, Rafael,Cuenca, Tomas,Royo, Pascual,Herrmann, W. A.,Herdtweck, E.
, p. 103 - 108 (1990)
Reaction of M'25-C5H4)2Si(CH3)2> (M'=Li, Na, K) with MCl4 produced the known complexes 5-C5H4)2Si(CH3)2>MCl2 (M=Ti (1) and Zr (2)).Along with the predominant product in each case a new titanium and zirconium compound is isolated.Treatment of the complexes 1 and 2 with LiCH2Si(CH3)3 gives the novel derivatives 5-C5H4)2Si(CH3)2>M2 (M=Ti (4) and Zr (5)) which have been characterized by NMR and mass spectrometry and in the case of 4 by an X-ray structural determination.
Dinuclear ansa zirconocene complexes containing a sandwich and a half-sandwich moiety as catalysts for the polymerization of ethylene
Alt, Helmut G,Ernst, Rainer,B?hmer, Ingrid K
, p. 259 - 265 (2002)
Dinuclear ansa zirconocene complexes containing a half-sandwich and a sandwich moiety and their ligand precursors have been synthesized and characterized. After activation with methylalumoxane (MAO), these catalysts produce polyethylenes with bimodal mole
Ancillary ligand and ketone substituent effects on the rate of ketone insertion into Zr-C bonds of zirconocene-l-Aza-l,3-diene complexes
Zhang, Jie,Krause, Jeanette A.,Huang, Kuo-Wei,Guan, Hairong
, p. 2938 - 2946 (2009/10/24)
Zirconocene-l-aza-l,3-diene complexes, [Me2Si(C 5H4)2]Zr[N(Ar)CH=CHCH(Ph)] (Ar = Ph, 2a; Ar = /J-MeOC5H4, 2b) and Cp2Zr[N(Ar)CH=CHCH(Ph)] (Ar = Ph, 3a; Ar = p-MeOC6Hs
Mono, di and tetranuclear ansa zirconocene complexes as catalysts for the homogeneous and heterogeneous polymerization of ethylene
Alt, Helmut G.,Ernst, Rainer,B?hmer, Ingrid
, p. 177 - 185 (2008/10/08)
Mono, di and tetranuclear ansa zirconocene complexes have been synthesized and characterized. After activation with methylalumoxane (MAO) these catalysts were used for the homogeneous and heterogeneous polymerization of ethylene. The properties of the catalysts and the produced polymers were compared. The multinuclear catalysts show a different performance than the corresponding mononuclear derivatives. The tetranuclear catalysts have the lowest activities because of steric crowding.
Dicyclopentadienyl zirconium and hafnium complexes with the bridged (dimethylsilanodiyl)dicyclopentadienyl [(SiMe2)(η5-C5H4) 2]2- ligand. X-ray molecular structure of [Zr{(SiMe2)(η5-C5H4) 2}(CH2Ph)]2(μ-O)
Cuenca, Tomas,Gomez-Sal, Pilar,Martin, Carlos,Royo, Beatriz,Royo, Pascual
, p. 134 - 140 (2007/10/03)
Reaction of the bridged (dimethylsilanediyl)dicyclopentadienyl dilithium salt [(SiMe2)(C5H4)2Li2] with MCl4, in toluene, gave the zirconium and hafnium complexes [M{(SiMe2)(η5-C5H4) 2}Cl2] [M=Zr (1), Hf (2)]. Addition of two equivalents of M′R (M′=MgCl, R=CH3; M′=Li, R=CH2CMe2Ph; M′=MgBz, R=CH2Ph) to toluene or diethyl ether solutions of [M{(SiMe2)(η5-C5H4) 2}Cl2] afforded the dialkyl derivatives [M{(SiMe2)(η5-C5H4) 2}R2] [R=CH3, M=Zr (3), Hf (4); R=CH2CMe2Ph, M=Zr (5), Hf (6); R=CH2Ph, M=Zr (7)]. Compound 1 reacted with LiMe and Mg(CH2Ph)2(THF)2 in the presence of a stoichiometric amount of water to give the μ-oxo derivatives [Zr{(SiMe2)(η5-C5H4) 2}R]2(μ-O) [R=CH3 (8), CH2Ph (9)]. The X-ray molecular structure of [Zr{(SiMe2)(η5-C5H4) 2}(CH2Ph)]2(μ-O) (9) has been determined by diffraction methods. Its most remarkable feature is the planarity of the Bz-Zr-O-Zr-Bz and the linearity of the Zr-O-Zr systems.
Group 4 ansa-metallocenes in oxidation state III: Synthesis, characterization, and chemical behavior. Crystal structure of {[η5:η5-(C5H4) 2Si(CH3)2]TiCl(PMe2Ph)}
Gómez, Rafael,Cuenca, Tomás,Royo, Pascual,Pellinghelli, Maria Angela,Tiripicchio, Antonio
, p. 1505 - 1510 (2008/10/08)
Two new dimeric titanium(III) and zirconium(III) ansa-metallocenes {[(Me2SiCp2)MCl]2} (M = Ti (2a), Zr (2b)) were synthesized by reducing the dichlorometallocenes with Na/Hg. The same reduction of the titanium derivative in the presence of PMe2Ph led to the monomeric titanium(III) complex [(Me2SiCp2)TiCl(PMe2Ph)] (3), which was also obtained by addition of PMe2Ph to 2a. Alkylation of 3 led to the titanium(III) alkyls [(Me2SiCp2)TiR(PMe2Ph)] (R = Me (4), CH2SiMe3 (5)). 4 was also obtained by reduction of [(Me2SiCp2)TiClMe] (6) with Na/Hg in the presence of PMe2Ph. All the titanium(III) complexes were paramagnetic, and their EPR behavior was studied, whereas the diamagnetic zirconium(III) derivative was characterized by NMR spectroscopy. All of them are easily oxidized by oxygen, and the intermediate dimeric {(μ-O)[(Me2SiCp2)ZrCl]2} (7) was spectroscopically identified in solution. The structure of 3 has been determined by X-ray diffraction methods. Crystals are triclinic, space group P1 with Z = 4 in a unit cell of dimensions a = 7.130 (3) A?, b = 15.201 (6) A?, c = 20.261 (6) A?, α = 105.42 (2)°, β = 96.20 (2)°, and γ = 92.46 (2)°. The structure has been solved from diffractometer data by Patterson and Fourier methods and refined by full-matrix least squares on the basis of 4449 observed reflections to R and Rw values of 0.0517 and 0.0696, respectively. The structure of 3 is very similar to that of comparable Ti(IV) compound [(Me2SiCp2)TiCl2], except for the much longer Ti-Cl bond (2.463 (2) against 2.356 (1) and 2.379 (2) A?), whereas no significant modifications are induced into the dimethylsilyl bridge.
Synthesis, structural characterization, and electrochemistry of [1]metallocenophane complexes, [Si(alkyl)2(C5H4)2]MCl2, M = Ti, Zr
Bajgur, Chandrasekhar S.,Tikkanen, Wayne R.,Petersen, Jeffrey L.
, p. 2539 - 2546 (2008/10/08)
A series of modified metallocene dichloride compounds, [SiR2(C5H4)2]MCl2 (M = Ti, R = CH3; M = Zr, R = CH3, C2H5, n-C3H7), have been prepared to evaluate the presence of a dialkylsilyl bridge on their electrochemical behavior. The compounds have been characterized by elemental analysis and 1H and 13C NMR, and the molecular structures of [Si(CH3)2(C5H4)2]MCl 2, M = Ti, Zr, have been determined by X-ray diffraction methods. The 13C NMR resonance of the bridgehead carbons is consistently located substantially upfield from the corresponding resonances for the proximal and distal carbons of the rings in these compounds. Cyclic voltammetric measurements have shown that these [1]metallocenophane dichlorides exhibit only one one-electron reversible reduction in THF within a scan range of +1.0 to -3.0 V vs. SCE. Complementary EPR studies were conducted to identify and monitor the stability of the paramagnetic species generated during the electrochemical reduction of [Si(CH3)2(C5H4) 2]TiCl2 and the sodium naphthalide reduction of [Si(CH3)2(C5H4)2]MCl 2, M = Ti, Zr. These reduction processes proceed similarly with the formation of only one paramagnetic product, [Si(CH3)2(C5H4)2]MCl 2-. The inherent stability observed for these d1 M(III) monoanions apparently follows directly from the ability of the dimethylsilyl bridge to restrict the mobility of the cyclopentadienyl rings and thereby limit their potential participation in these reduction reactions. The compounds [Si(CH3)2(C5H4)2]MCl 2, M = Ti, Zr, similarly crystallize in a monoclinic unit cell of C2/c symmetry with the following refined lattice parameters: for M = Ti, a = 13.309 (5) ?, b = 9.871 (2) ?, c = 13.337 (4) ?, β = 132.79 (1)°, V = 1285.8 (7) ?3, and ρcalcd = 1.576 g/cm3; for M = Zr, a = 13.391 (3) ?, b = 9.965 (2) ?, c = 10.922 (3) ?, β= 113.37 (2) ?, V = 1337.8 (5) ?3, and ρcalcd = 1.730 g/cm3. Full-matrix least-squares refinement (based on Fo2) converged with respective final discrepancy indices of R(Fo) = 0.024, 0.032 and σ1 = 1.69, 1.93 for diffractometry data with Fo2 > σ(Fo2).
Zirconocene-η4-1,3-pentadiene complex and its higher homologues. A new synthetic method involving σ-π rearrangement of the hydrido-2,4-pentadienylzirconium species
Yasuda,Nagasuna,Akita,Lee,Nakamura
, p. 1470 - 1478 (2008/10/08)
The (1,3-pentadiene)zirconocene complex and its higher homologues of the type (η5-C5H5)2Zr(CR 1-(CH3)=CR2CR3=CR4H) were prepared by reaction of (η-C5H5)2ZrHCl with alkyl-substituted or non-substituted pentadienyl anions through novel σ-π rearrangement of hydrido-2,4-pentadienylzirconium species. The 1H NMR studies on these complexes revealed that the 1,3-pentadiene and 2,4-hexadiene complexes are composed of ca. 1:1 mixture of s-cis and s-trans isomers while each of the complexes containing 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, 1-(trimethylsilyl)-1,3-pentadiene, and 1,5-bis(trimethylsilyl)-1,3-pentadiene ligands consists of a single isomer of s-cis structure. The process of hydrogen transfer was elucidated on the basis of the analysis of the stoichiometric reaction between (η5-C5H5)2ZrDCl and (2-methylpentadienyl)potassium. The reaction of (η5-C5H5)2Zr(2,4-hexadiene) with 1-alkenes or 2-butyne showed that the coordinated diene is easily expelled to give zirconacyclopentanes or a zirconacyclopentadiene derivative, respectively. The addition of butanal or 3-pentanone resulted in double insertion into the 2,4-hexadiene moiety to selectively afford 3-hexene-1,6-diols through hydrolysis.
Metallocenophanes: 1H NMR Investigations
Koepf, Hartmut,Klouras, Nikolaos
, p. 321 - 325 (2007/10/02)
The synthesis of a series of metallocenophanes has been achieved.The structure and conformation of these compounds are discussed in the light of their 1H NMR spectra. - Key words: Bridged Metallocenes, Hafnocenophanes, Titanocenophanes, Zirconocenophanes
