Portal de Periódicos da CAPES

Monomere und dimere Oxovanadium(IV)-phenolate: Synthese, Struktur und Reaktionen mit reduzierenden und arylierenden Reagenzien

1999; Wiley; Volume: 625; Issue: 11 Linguagem: Inglês

10.1002/(sici)1521-3749(199911)625

1521-3749

K. Thiele, Helmar Görls, Wolfgang Imhof, Wolfram W. Seidel,

Coordination Chemistry and Organometallics

Die Reaktion von [OVCl2(THF)2] mit LiOMes ergibt dimeres [Li(Et2O)2OVCl2(μ-OMes)]2 (1), das mit weiterem LiOMes zum Substitutionsprodukt [Li(THF)2OV(OMes)3(THF)] (2) umgesetzt werden kann. Die Umsetzung von 1 mit LiMes liefert [Li(THF)3OVMes3] (3) und [Li(THF)3OVMes2(OMes)] (4). Als Nebenprodukt einer ungeklärten Reaktion zwischen [OV(OMes)3] und Lithium wurde die Verbindung [{Li(THF)2OV(OMes)2 · (μ-OH)}2 · 2 THF] (6) isoliert. Die Strukturen von 1, 2, 3 und 6 wurden durch Kristallstrukturanalyse bestimmt. In 1 (monoklin, P21/c, a = 9.522(1) Å, b = 19.777(2) Å, c = 12.311(1) Å, β = 104.45(1)°, Z = 2) liegen die Vanadiumatome quadratisch-pyramidal koordiniert vor und werden durch Phenolat-Liganden verbrückt. Das Zentralatom in 2 (monoklin, P21/c, a = 17,755(2) Å, b = 11,629(1) Å, c = 20,956(3) Å, β = 113,98(1)°, Z = 4) hat trigonal-bipyramidale Koordination, die durch Anlagerung eines THF-Donors erreicht wird. Die (THF)2Li-Einheit ist über Phenolat-Brücken gebunden. In der Struktur von 3 (orthorhombisch, P212121, a = 15,465(2) Å, b = 15,456(2) Å, c = 15,469(2) Å, Z = 4) liegen zwei über das Oxo-Sauerstoffatom verbundene Tetraeder vor. Dimeres 6 (triklin, P1, a = 10,780(4) Å, b = 11,428(2) Å, c = 13,734(3) Å, α = 77,24(2)°, β = 84,79(2)°, γ = 74,35(2)°, Z = 1) ähnelt in seinem Aufbau 1, wobei die beiden Vanadiumatome über zwei OH-Gruppen und die Li-Kationen über Phenolat-Liganden mit den V-Atomen verbrückt sind. Monomeric and Dimeric Oxovanadium(IV)-phenolate Complexes: Synthesis, Structure, and Reaction with a Reducing and Arylation Agent Reaction of [OVCl2(THF)2] with LiOMes yields dimeric [Li(Et2O)2OVCl2(μ-OMes)]2 (1) which can be converted with excess LiOMes to the substitution product [Li(THF)2OV(OMes)3(THF)] (2). Treatment of (1) with LiMes results in the formation of complexes [Li(THF)3OVMes3] (3) and [Li(THF)3OVMes2(OMes)] (4). Complex [{Li(THF)2OV(OMes)2(μ-OH)}2 · 2 THF] (6) has been isolated as a by-product of an unknown reaction of [OV(OMes)3] and Li. The structures of 1, 2, 3, and 6 have been determined by X-ray analysis. In 1 (monoclinic, P21/c, a = 9.522(1) Å, b = 19.777(2) Å, c = 12.311(1) Å, β = 104.45(1)°, Z = 2) the vanadium atoms which are bridged by the phenolate ligands show a square-pyramidal coordination sphere. The central atom in 2 (monoclinic, P21/c, a = 17.755(2) Å, b = 11.629(1) Å, c = 20.956(3) Å, β = 113.98(1)°, Z = 4) has a bipyramidal environment which is realized by coordination of a THF donor molecule. The (THF)2Li fragment is bound via bridging phenolate ligands. The structure of 3 (orthorhombic, P212121, a = 15.465(2) Å, b = 15.456(2) Å, c = 15.469(2) Å, Z = 4) is built up by two tetrahedrons linked by the oxo atom. Dimeric 6 (triclinic, P1, a = 10.780(4) Å, b = 11.428(2) Å, c = 13.734(3) Å, α = 77.24(2)°, β = 84.79(2)°, γ = 74.35(2)°, Z = 1) has a structure similar to 1. The vanadium atoms are bridged by two OH groups while phenolate ligands link the lithium cations with the vanadium atoms.