- Low-spin 1,1′-diphosphametallocenates of chromium and iron
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We report two anionic diphosphametallocenates, [K(2.2.2-crypt)][M(PC4Me4)2] (M = Cr, 2-Cr; Fe, 2-Fe). Both are low-spin (S = ?) by EPR spectroscopy and SQUID magnetometry. This contrasts the high-spin (S = ) ferrocenate, [K(2.2.2-crypt)][Fe(C5H2-1,2,4-tBu)2] (4-Fe). Quantum chemical calculations suggest this is due to significant differences in ligand field splitting of the d-orbitals which also explain structural features in the 2-M complexes. This journal is
- Greer, Samuel M.,üngor, ?kten,Beattie, Ross J.,Kiplinger, Jaqueline L.,Scott, Brian L.,Stein, Benjamin W.,Goodwin, Conrad A. P.
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supporting information
p. 595 - 598
(2021/01/29)
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- Di- and trinuclear iron/titanium and iron/zirconium complexes with heterocyclic ligands as catalysts for ethylene polymerization
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The properties of polyolefin resins depend very much on their molecular weights, the amount of side chain branchings and molecular weight distributions. One way to obtain such tailored products in only one reaction step consists in the application of dissymmetric multi nuclear catalysts with different active sites. Since every active site is producing its own polymer, a “molecular blending” is the result. In order to reach this goal, a variety of mono, di- and trinuclear complexes of iron, titanium and zirconium, containing 2,6-bis(aryliminoethyl)pyridine and phenoxyimine building blocks have been synthesized and characterized. The reaction of iodo functionalized 2,6-bis(arylimino-ethyl)pyridine derivatives with alkyne functionalized phenoxyimine compounds via Sonogashira cross-coupling reactions results in ligand precursors that can provide coordination sites for two different metals. Trinuclear complexes with the combinations Ti/Fe and Zr/Fe, each molecule containing two iron atoms in two 2,6-bis(aryliminoethyl)pyridine units, gave the best ethylene polymerization results. Due to fast ligand exchange reactions, dinuclear iron/titanium complexes could not be isolated from reactions of mono(phenoxyimine) titanium complexes and the coupled bis(chelate) ligand precursor. Since the metal centers show their best performances at different polymerization temperatures, the compositions (and, therefore, the molecular weight distributions) of the desired polyethylenes may be adjusted by a simple change of the reaction temperature.
- G?rl, Christian,Betthausen, Eva,Alt, Helmut G.
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- MESO-SELECTIVE SYNTHESIS OF ANSA-METALLOCENES
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The present invention relates to a process for the meso-selective preparation of ansa-metallocene complexes of the formula (I), which comprises reacting a ligand starting compound of the formula (II) with a transition metal compound of the formula III, where R1, R1 are identical or different and are each hydrogen or an organic radical having from 1to 40 carbon atoms, R2, R2 are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms, R3 is a bulky organic radical which has at least 3 carbon atoms, is bound to the oxygen atom via a nonaromatic carbon or silicon atom and may be substituted by halogen atoms or further organic radicals having from 1 to 20 carbon atoms and may also contain heteroatoms selected from the group consisting of Si, N, P, O and S, T, T’ are identical or different and are each a divalent organic group which has from 1 to 40 carbon atoms and together with the cyclopentadienyl ring forms at least one further saturated or unsaturated, substituted or unsubstituted ring system having a ring size of from 5 to 12 atoms, where T and T’ may contain the heteroatoms Si, Ge, N, P, As, Sb, O, S, Se or Te within the ring system fused to the cyclopentadienyl ring, A is a bridge consisting of a divalent atom or a divalent group, M1 is an element of group 3, 4, 5 or 6 of the Periodic Table of the Elements or the lanthanides, the radicals X are identical or different and are each an organic or inorganic radical which is able to be replaced by a cyclopentadienyl anion, x is a natural number from 1 to 4, M2 is an alkali metal, an alkaline earth metal or a magnesium monohalide fragment, p is 1 in the case of doubly positively charged metal ions or 2 in the case of singly positively charged metal ions or metal ion fragments, LB is an uncharged Lewis base ligand, and y is a natural number from 0 to 6, and also the subsequent reaction of these complexes to form ansa-metallocenes of the formula (IV), the use of transition metal compounds of the formula (III) for preparing metallocenes and also transition metal compounds of the formula (III), ansa-metallocene complexes of the formula (I) and the use of these as constituents of catalyst systems for the polymerization of olefines.
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Page/Page column 15
(2008/06/13)
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- PROCESS FOR THE RACEMOSELECTIVE PREPARATION OF ANSA-METALLOCENES
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The present invention relates to a process for the racemoselective preparation of ansametallocene complexes of the formula (I) which comprises reacting a ligand starting compound of the formula (II) with a transition metal compound of the formula (III) where R1, R1’ are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms, R2, R2’ are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms, R3 is an organic having from 1 to 40carbon atoms.
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Page/Page column 14
(2008/06/13)
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- RACEMOSELECTIVE PREPARATION OF ISOLABLE ANSA-METALLOCENE BIPHENOXIDE COMPLEXES
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The invention relates to a process for preparing racemic metallocene biphenoxide complexes by reacting bridged transition metal complexes with cyclopentadienyl derivatives of alkali metals or alkaline earth metals and heating the reaction mixture obtained
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Page/Page column 27
(2008/06/13)
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- RACEMOSELECTIVE PREPARATION OF BRIDGED METALLOCENE COMPLEXES HAVING UNSUBSTITUTED OR 2-SUBSTITUTED INDENYL LIGANDS
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The invention relates to a process for preparing racemic metallocene complexes by reacting transition metal complexes with cyclopentadienyl derivatives of alkali metals or alkaline earth metals and heating the reaction mixture obtained in this way to a temperature in the range from -78 to 250 DEG C, to the corresponding metallocene complexes themselves and to their use as catalysts or as constituents of catalysts for the polymerization of olefinically unsaturated compounds or as reagents or catalysts in stereoselective synthesis.
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Page/Page column 27
(2008/06/13)
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- PREPARATION OF PARTIALLY HYDROGENATED RAC-ANSA-METALLOCENE COMPLEXES
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The invention relates to a process for preparing hydrogenated or partially hydrogenated, racemic ansa-metallocene complexes by reacting bridged or unbridged transition metal complexes with alkali metal compounds or alkaline earth metal compounds, heating the resulting reaction mixture to a temperature in the range from -78 to 250°C and at least partially hydrogenating the reaction products in the presence of a suitable catalyst, to the corresponding hydrogenated or partially hydrogenated metallocenes and to their use as catalysts or as a constituent of catalysts for the polymerization of olefinically unsaturated compounds or as reagents or catalysts in stereoselective synthesis.
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Page/Page column 23; 32; 34
(2008/06/13)
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- Method for the selective production of racemic metallocene complexes
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The invention relates to a method for producing racemic metallocene complexes by reacting bridged or non-bridged transition metal complexes with cyclopentadienyl derivatives of alkaline or alkaline earth metals and optionally, subsequently substituting th
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Page/Page column 13; 14
(2008/06/13)
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- RACEMOSELECTIVE SYNTHESIS OF RAC-DIORGANOSILYLBIS(2-METHYLBENZO[E]INDEYL) ZIRCONIUM COMPONDS
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The present invention relates to a specific process for the diastereoselective synthesis of racy diorganosilylbis(2-methylbenzo[e]indenyl)zirconium compounds of the formula I, by reacting the silyl-bridged bisindenyl ligand with a dihalozirconiumbis(3,5-di-tert-butylphenoxide)- base adduct to form the diorganosilylbis(2-methylbenzo[e]indenyl)zirconium bis(3,5-di-tert-butylphenoxide) and subsequently replacing the phenoxide groups by X using suitable replacement reagents to give the compound of the formula (I); where the substituents X can be identical or different and are each F, CI, Br, I or linear, cyclic or branched C1-10-alkyl; and the substituents R can be identical or different and are each linear, cyclic or branched C1-10-alkyl or C6-10-aryl; and also to the use of these compounds as catalysts.
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Page/Page column 13; 16; 19; 21
(2010/02/06)
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- Titanium and zirconium complexes with sterically hindered arylsubstituted iminophosphoranato ligands
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The benzyliminophosphorane 4-ButC6H4CH2P(Ph)2=NC 6H2Me3-2,4,6 reacted with TiCl4 or ZrCl4 to give the N-donor adducts, MCl4{4-ButC6H4CH2P(Ph) 2=NC6H2Me3-2,4,6}. Whereas the zirconium compound proved unreactive, solutions of the titanium analogue at 10-20 °C slowly underwent C-H activation to give the phosphoranato complex TiCl3{4-ButC6H4CHP(Ph)2=N C6H2Me3-2,4,6}. The trichloro complexes MCl3{4-ButC6H4-CHP(Ph)2=N C6H2Me3-2,4,6} were also accessible from Li[4-ButC6H4CHP(Ph)2=NC6H 2Me3-2,4,6] and MCl4 (M = Ti or Zr). The reaction of 4-ButC6H4CH2P(Ph)2=NC 6H2Me3-2,4,6 with Zr(NMe2)4 in refluxing toluene led to Zr(NMe2)3-{4-ButC6H4CHP(P h)2=NC6H2Me3-2,4,6}. The compound is fluxional in solution. Treatment with an excess of Me3-SiCl led to silylation of the ligand to give ZrCl4{4-ButC6H4CH(SiMe3)P (Ph)2=NC6H2Me3-2,4,6}. The structures of 4-ButC6H4CH2P(Ph)2=NC 6H2Me3-2,4,6 and Zr(NMe2)3{4-ButC6H4CHP(Ph )2=NC6H2Me3-2,4,6} were determined by X-ray diffraction.
- Said, Musa,Thornton-Pett, Mark,Bochmann, Manfred
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p. 2844 - 2849
(2007/10/03)
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- Multidentate Lewis acids. Synthesis, structure, and reactions of complexes of bidentate zirconium trichloride alkoxides
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The 1:2 tetrahydrofuran adduct 5 of zirconium trichloride isopropoxide adopts a mer octahedral geometry in solution. Partial redistribution occurs to give the 1:2 tetrahydrofuran adduct 3 of ZrCl4. A bidentate zirconium trichloride alkoxide 8 could be prepared by treating the bis(trimethylsilyl) ether 7 of racemic trans-1,2-cyclohexanediol with 2 equiv of the 1:2 tetrahydrofuran adduct 3 of ZrCl4. An X-ray crystallographic study of the tetrahydrofuran adduct of bidentate Lewis acid 8 showed that the electrophilic sites are trans-diaxially oriented and independently bind two molecules of tetrahydrofuran to give mer octahedral complexes. In solution, the adduct decomposes by a redistribution that produces the 1:2 tetrahydrofuran adduct 3 of ZrCl4. The adduct crystallizes in the monoclinic space group P21/c with a = 16.111 (9) ?, b = 10.868 (6) ?, c = 25.178 (13) ?, β = 121.32 (4)°, V = 3766.1 ?3, and Z = 4. Refinement of 3699 reflections yielded R = 0.042 and Rw = 0.042.
- Galeffi, Bruno,Simard, Michel,Wuest, James D.
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p. 955 - 958
(2008/10/08)
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