60938-59-2Relevant articles and documents
METALLOCENE DERIVATIVES OF EARLY TRANSITION ELEMENTS. PART 4. SYNTHESIS AND CRYSTAL STRUCTURES OF A SERIES OF ZIRCONOCENE(IV) HALIDES (X = Cl OR Br) AND 2X2> ( X =F, Br, OR I)
Antinolo, Antonio,Lappert, Michael F.,Singh, Anirudh,Winterborn, Duncan J. W.,Engelhardt, Lutz M.,et al.
, p. 1463 - 1472 (1987)
A series of zirconocene(IV) halides, and 2X2> , has been prepared, either by (i) substitutive procedures from ZrCl4 , or (ii), for complexes (3), (5), or (6), by oxidative addition to 2(CO)2>.The only vasym(ZrX2) vibration to be assigned with confidence is for X = F at 563 cm-1, (1)H and (13)C n.m.r.data are unexceptional.X-Ray structure determinations of complexes (1)-(5) have been carried out.Their molecular symmetry is close to 2, or crystallographically imposed 2 in (3), with the stereochemistry about the metal centre best described as distorted tetrahedral.The angle X-Zr-X is 93.70(7), 94.2(1), 100.5(3), 100.25(5), and 100.37(4)deg for the halides (1)-(5), respectively; and the corresponding centroid-Zr-centroid angles are 129.1, 128.2, 131.4, 131.4, and 131.8 deg.Metalhalogen distances in (1) and (3) are significantly longer than in the parent zirconocene(IV) halides (cf. 2.44 Angstroem for X = Cl and 1.98 Angstroem for X = F) as are the metal-centroid distances in (3)-(5).
Synthesis, structural characterization and reactivity of new tin bridged ansa-bis(cyclopentadiene) compounds: X-ray crystal structures of Me2Sn(C5Me4R-1)2 (R = H, SiMe3)
Gómez-Ruiz, Santiago,Prashar, Sanjiv,Fajardo, Mariano,Anti?olo, Antonio,Otero, Antonio
, p. 3057 - 3064 (2008/02/02)
The organo-tin compounds, Me2Sn(C5H4R-1)2 (R = Me (1), Pri (2), But (3), SiMe3 (4)) and Me2Sn(C5Me4R-1)2 (R = H (5), SiMe3
CH-Aktivierungsreaktionen an substituierten Zirconocenkomplexen und deren Verwendung in der katalytischen Ethylenpolymerisation
Licht, Andrea I.,Alt, Helmut G.
, p. 91 - 104 (2007/10/03)
Zirconocene dichloride complexes with substituents containing aliphatic end groups at the aromatic ligands react with two equivalents of n-butyllithium to give metallacyclic zirconocene complexes via aliphatic CH-activation reactions. As well as ω-alkenyl substituted zirconocene dichloride complexes with terminal aliphatic groups as zirconocene dichloride complexes with purely aliphatic substituents are suitable for the synthesis of such metallacycles. In combination with methylalumoxane (MAO), these metallacycles are excellent catalysts for ethylene polymerization. Their activities can be three and a half times higher than the activities of the corresponding zirconocene dichloride educts. The catalyst 25/MAO is able to produce 2640 kg PE g-1 Zr h (60 deg C, pentane solution, 10 bar ethylene pressure).
Cyclopentadienylmetal trichloride formation versus metallocene dichloride formation in the reactions of silylated cyclopentadienes with zirconium and hafnium chlorides. Crystal structure of (1,3-bis- (trimethylsilyl)cyclopentadienyl)titanium trichloride
Winter,Zhou,Dobbs,Heeg
, p. 210 - 214 (2008/10/08)
The reaction of zirconium and hafnium tetrachlorides with tris(trimethylsilyl)cyclopentadiene affords the monocyclopentadienyl complexes (1,3-bis(trimethylsily)cyclopentadienyl)zirconium trichloride (1, 73%) and (1,3-bis(trimethylsilyl)cyclopentadienyl)hafnium trichloride (2, 76%) in good isolated yields. The reaction of 1 with (1,3-bis(trimethylsilyl)cyclopentadienyl)lithium affords 1,1′,3,3′-tetrakis(trimethylsilyl)zirconocene dichloride (74%). In contrast to the preparations of 1 and 2, reaction of bis(trimethylsilyl)cyclopentadiene with zirconium and hafnium tetrachlorides affords 1,1′-bis- (trimethylsilyl)zirconocene dichloride (5, 73%) and 1,1′-bis(trimethylsilyl)hafnocene dichloride (6, 76%). The reaction of (trimethylsilyl)cyclopentadiene with zirconium and hafnium tetrachlorides affords zirconocene dichloride (7, 91%) and hafnocene dichloride (8, 90%). The intermediacy of monocyclopentadienyl species in the preparation of the metallocene dichlorides is supported by the reaction of cyclopentadienylzirconium trichloride with (trimethylsilyl)cyclopentadiene to afford 7 (85%). Reaction of zirconium tetrachloride with 1 equiv of (trimethylsilyl)cyclopentadiene at 0 °C for 0.5 h affords 7 and cyclopentadienylzirconium trichloride in a (69 ± 2):(31 ± 2) ratio. The silyl group regiochemistry in 1 and 2 was established through an X-ray crystal structure determination of the titanium analogue (1,3-bis(trimethylsilyl)cyclopentadienyl)titanium trichloride (3). Complex 3 crystallizes in the orthorhombic space group Pbnm with a = 7.459 (3) angstrom, b = 11.799 (3) angstrom, c = 20.535 (3) angstrom, V = 1807.1 (9) angstrom3, and Z = 4.