Esther C. E. Rosenthal

Organometallic compounds of the lanthanides XCVII. Synthesis and crystal structures of monomeric bis(ethyltetramethylcyclopentadienyl) amide and alkyl derivatives of the lanthanides

The trichlorides of yttrium, neodymium, samarium and lutetium react with 2 equiv. of Na[C5Me4Et] in THF to form [(C5Me4Et)2LnCl(THF)] (Ln = Y, 1; Nd, 2; Sm, 3; Lu, 4). Metathesis of (1–4) with NaN(SiMe3)2 and LiCH(SiMe3)2 in toluene gives [(C5Me4Et)2Ln{E(SiMe3)2}] (E = N, Ln = Y 5; Nd, 6; Sm, 7; Lu, 8; E = Ch, Ln = Y, 9; Nd, 10; S 10; Sm, 11). The new compounds were characterized by elemental analysis and mass and NMR spectrometry. Additionally, X-ray structural analysis of 5 and 11 was performed. The silylamide 5 crystallized in the monoclinic space group C2/c with a = 9.169(2), b = 21.166(8), c = 15.625(3) A, β = 94.15(2)°, V = 3025(2) A3 and Z = 4. The final refinement resulted in R1 = 2.86% (I>4σ(I)). Compound 11 crystallized in the orthorhombic space group Pbca with a = 18.499(6), b = 14.181(6), c = 23.290(5) A, V = 6110(3) A3, Z = 8, and R1 = 3.04% (I>4σ(I))

Organometallic compounds of the lanthanides. CIII Mixed sandwich complexes of the 4f elements: synthesis and crystal structure of (ν8-cyclooctatetraenyl)(ν5-2,5-di-tert.-butylpyrrolyl) samarium, -thulium, and -lutetium☆

[(ν8-C8H8)Ln(μ-Cl)(THF)]2 (Ln = Sm, Tm, Lu) reacts with Na[pyr∗] (pyr∗ = NC4H2tBu2-2,5) to form [(ν8-C8H8)Ln(ν5-pyr∗)(THF)x] (Ln = Sm 1, x = 1; Ln = Tm 2, Lu 3, x = 0). The novel sandwich compounds have been characterized by C,H,N analysis, mass spectrometry and NMR spectroscopy. Additionally, an X-ray structural analysis of 1 was performed. The crystals of 1 are monoclinic, space group P21/c with a = 11.131(2) A, b = 20.023(3) A, c = 20.118(5) A, β = 91.16(2)°, V = 4482.8(14) A3and Z = 4. The final refinement resulted in R1 = 3.09% (I>2σ(I)).

Metallorganische Verbindungen der Lanthanoide XCVIII Synthese und Strukturaufklärung von Dichloro(η5-2,5-di-tert.-butylpyrrolyl) bis(tetrahydrofuran) ytterbium(III)

Zusammenfassung The reaction between YbCl 3 (THF) 3 and Na[pyr ∗ ] (pyr ∗ = NC 4 H 2 t Bu 2 -2,5) yields the monopyrrolyl complex, [(pyr ∗ )YbCl 2 (THF) 2 ] ( 1 ). The X-ray structure of compound 1 confirms the π -coordination between the metal and the azacyclopentadienyl ligand.

Tetrahedral Coordination in the First Structurally Characterized Dichlorooxovanadium(V) Alkoxide

Reaction of VOCl3 with 2-phenoxyethanol in n-hexane in a 1:1 fashion gives dichlorooxo(2-phenoxyethanolato)vanadium(V). HCl elimination yields the orange vanadium(V) complex, which is the first structurally characterized dichlorooxovanadium(V) alkoxide. The structure analysis reveals an unexpected tetrahedral coordination around the vanadium atom in the monomeric compound. Alcoholysis and hydrolysis reactions of [VOCl2(OCH2CH2OPh)] are monitored by 51V NMR spectroscopy. Activated with Me3SiCH2MgCl or nBu2Mg the complex catalyses the polymerisation of styrene. Tetraedrische Koordination im ersten strukturell charakterisierten Dichlorooxovanadium(V)-alkoxid Die Reaktion von VOCl3 mit 2-Phenoxyethanol in n-Hexan im Verhaltnis 1:1 ergibt Dichlorooxo(2-phenoxyethanolato)vanadium(V). HCl-Eliminierung fuhrt zu dem orangefarbenen Vanadium(V)-Komplex, bei dem es sich um das erste strukturell charakterisierte Dichlorooxovanadium(V)-alkoxid handelt. Die Rontgenstrukturanalyse zeigt eine unerwartete tetraedrische Koordination am Vanadiumatom der monomeren Verbindung. Alkoholyse und Hydrolyse von [VOCl2(OCH2CH2OPh)] wurden mittels 51V-NMR-Spektroskopie untersucht. Nach Aktivierung mit Me3SiCH2MgCl oder nBu2Mg katalysiert der Komplex die Polymerisation von Styrol.

Chloride-bridged oxovanadium(V) complexes with alkoxyalkoxide ligands. Synthesis, structure, electrochemistry and reactivities

A series of mixed alkoxyalkoxo chloro complexes of vanadium(V), [VOCl2(OCH2CH2OR)]2 (R = Me, Et, iPr, Bz), [VOCl2(OCMe2CH2OMe)]2 and [VOCl2(OCH2(cyclo-C4H7O)]2, were synthesised and characterised. The title compounds can be obtained either from VOCl3 and the alkoxyalcohols by HCl elimination or from the corresponding lithium alkoxides and VOCl3 by salt metathesis reaction. X-Ray diffraction studies revealed the title compounds to be dimers with chloride bridging ligands and intramolecular ether coordination. Electrochemical results obtained by cyclic voltammetry indicate irreversible, reductive behaviour. The interactions of the title compounds with oxygen, nitrogen and phosphorus donor ligands were examined. Phosphorus and nitrogen donors lead to reduction products whereas tetrahydrofuran coordinates to the vanadium(V) centre by breaking the chloride bridge. All tetrahydrofuran complexes, [VOCl2(OCH2CH2OR)(thf)] (R = Me, Et, iPr) and [VOCl2(OCMe2CH2OMe)(thf)], have been characterised by single-crystal X-ray diffraction. The solid-state structures of these complexes show that they consist of six-coordinate monomers. Reaction of [VOCl2(OCH2CH(2)OMe)]2 with Me3SiCH2MgCl gave [VO(CH2SiMe3)3], which has been structurally characterised. The compounds were tested as catalysts for epoxidation and polymerisation reactions. They convert unfunctionalised olefins into the corresponding epoxides with moderate activity. They are good pre-catalysts for the polymerisation of ethene and oligomerise 1-hexene.