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Mesityl-phenolato-vanadium(III)-Komplexe: Synthese, Struktur und Verhalten

2002; Wiley; Volume: 628; Issue: 1 Linguagem: Inglês

10.1002/1521-3749(200201)628

1521-3749

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

Vanadium and Halogenation Chemistry

Protolysereaktionen an [VMes3(THF)] mit 2-iso-Propyl-(H–IPP), 2-tert.-Butyl-(H–TBP), 2,4,6-Trimethyl-phenol (MesOH) und 2,2′-Biphenol (H2–Biphen) liefern partiell und vollständig substituierte Vanadium(III)-phenolate: [VMes(OAr)2(THF)2] (OAr = IPP (1), TBP (2)), [VMes2(OMes)(THF)] (4), [V(OAr)3(THF)2] (OAr = TBP (3), OMes (5)) und [V2(Biphen)3(THF)4] (6). Die Umsetzung von 6 mit Li2Biphen(Et2O)4 ergibt [{Li(OEt2)}3V(Biphen)3] (7), mit LiMes [{Li(THF)2}2VMes(Biphen)2] (8) und [Li(DME)VMes2(Biphen)] (9). Durch Metathesereaktionen an [VCl3(THF)3] mit LiOMes (1 : 1 bis 1 : 4) werden die Verbindungen [VCl3–n(OMes)n(THF)2] (n = 1 (5 b), 2 (5 a), 3 (5)) und [Li(DME)2][V(OMes)4] (5 c) erhalten. 1, 2, 5 a und 5 bilden mit LiMes die Gemischtligandkomplexe [{Li(DME)n}{VMes2(OAr)2}] (ArO = IPP (10), TBP (11), OMes (12) (n = 2 oder 3) sowie [{Li(DME)2}{VMes(OMes)3}] (15). Durch Ligandenaustausch an 10 entsteht [Li(DME)2(THF)][VMes3(IPP)] (13). Addition von LiOMes an [VMes3(THF)] unter Bildung von [Li(THF)4][VMes3(OMes)] (14) komplettiert die Reihe [Li(solv)x][VMes4–n(OMes)n] (n = 1 bis 4). Diese Vanadatkomplexe können zu ihren neutralen Homologen [VMes4–n(OMes)n] oxidiert werden. Die Strukturen von 1, 3, 5, 5 a, 5 a–Br, 7, 10 und 13 wurden bestimmt: In den Verbindungen 1 (monoklin, C2/c, a = 29,566(3) Å, b = 14,562(2) Å, c = 15,313(1) Å, β = 100,21(1)°, Z = 8), 3 (orthorhombisch, Pbcn, a = 28,119(5) Å, b = 14,549(3) Å, c = 17,784(4) Å, Z = 8), 5 (triklin, P1, a = 8,868(1) Å, b = 14,520(3) Å, c = 14,664(3) Å, α = 111,44(1)°, β = 96,33(1)°, γ = 102,86(1)°, Z = 2), 5 a (monoklin, P21/c, a = 20,451(2) Å, b = 8,198(1) Å, c = 15,790(2) Å, β = 103,38(1)°, Z = 4) und 5 a–Br (monoklin, P21/c, a = 21,264(3) Å, b = 8,242(4) Å, c = 15,950(2) Å, β = 109,14(1)°, Z = 4) hat das Vanadium-Zentralatom eine trigonal-bipyramidale Umgebung mit den THF-Liganden in axialen Positionen. Das Zentralatom in 7 (trigonal, P3c1, a = 20,500(3) Å, b = 20,500(3) Å, c = 18,658(4) Å, Z = 6) ist oktaedrisch koordiniert. Die drei {Li(OEt2)}-Einheiten sind mit den Biphenolat-Liganden verbrückt. Die Verbindungen 10 (monoklin, P21/c, a = 16,894(3) Å, b = 12,181(2) Å, c = 25,180(3) Å, β = 91,52(1)°, Z = 4) und 13 (orthorhombisch, Pna21, a = 16,152(4) Å, b = 17,293(6) Å, c = 16,530(7) Å, Z = 4) bilden getrennte Ionen mit tetraedrisch aufgebauten Vanadat(III)-Anionen und oktaedrisch bzw. trigonal-bipyramidal koordinierten Lithium-Kationen. Mesityl-vanadium(III)-phenolate Complexes: Synthesis, Structure, and Reactivity Protolysis reactions of [VMes3(THF)] with ortho-substituted phenols (2-iso-propyl-(H–IPP), 2-tert-butyl(H–TBP), 2,4,6-trimethylphenol (HOMes) and 2,2′biphenol (H2–Biphen) yield the partially and fully phenolate substituted complexes [VMes(OAr)2(THF)2] (OAr = IPP (1), TBP (2)), [VMes2(OMes)(THF)] (4), [V(OAr)3(THF)2] (OAr = TBP (3), OMes (5)), and [V2(Biphen)3(THF)4] (6). Treatment of 6 with Li2Biphen(Et2O)4 results in formation of [{Li(OEt2)}3V(Biphen)3] (7) and with MesLi complexes [{Li(THF)2}2VMes(Biphen)2] · THF (8) and [{Li(DME)}VMes2(Biphen)] (9) are formed. Reacting [VCl3(THF)3] with LiOMes in 1 : 1 to 1 : 4 ratios yields the componds [VCl3–n(OMes)n(THF)2] (n = 1 (5 b), 2 (5 a), 3 (5)) and [{Li(DME)2}V(OMes)4] (5 c), the latter showing thermochromism due to a complexation/decomplexation equilibrium of the solvated cation. The mixed ligand mesityl phenolate complexes [{Li(DME)n}{VMes2(OAr)2}] (OAr = IPP (10), TBP (11), OMes (12) (n = 2 or 3) and [{Li(DME)2}{VMes(OMes)3}] (15) are obtained by reaction of 1, 2, 5 a and 5 with MesLi. With [{Li(DME)2(THF)}{VMes3(IPP)}] (13) a ligand exchange product of 10 was isolated. Addition of LiOMes to [VMes3(THF)] forming [Li(THF)4][VMes3(OMes)] (14) completes the series of [Li(solv.)x][VMes4–n(OMes)n] (n = 1 to 4) complexes which have been oxidised to their corresponding neutral [VMes4–n(OMes)n] derivatives 16 to 19 by reaction with p-chloranile. They were investigated by epr spectroscopy. The molecular structures of 1, 3, 5, 5 a, 5 a–Br, 7, 10 and 13 have been determined by X-ray analysis. In 1 (monoclinic, C2/c, a = 29.566(3) Å, b = 14.562(2) Å, c = 15.313(1) Å, β = 100.21(1)°, Z = 8), 3 (orthorhombic, Pbcn, a = 28.119(5) Å, b = 14.549(3) Å, c = 17.784(4) Å, β = 90.00°, Z = 8), (5) (triclinic, P1, a = 8.868(1) Å, b = 14.520(3) Å, c = 14.664(3) Å, α = 111.44(1)°, β = 96.33(1)°, γ = 102.86(1)°, Z = 2), 5 a (monoclinic, P21/c, a = 20.451(2) Å, b = 8.198(1) Å, c = 15.790(2) Å, β = 103.38(1)°, Z = 4) and 5 a–Br (monoclinic, P21/c, a = 21.264(3) Å, b = 8.242(4) Å, c = 15.950(2) Å, β = 109.14(1)°, Z = 4) the vanadium atoms are coordinated trigonal bipyramidal with the THF molecules in the axial positions. The central atom in 7 (trigonal, P3c1, a = 20.500(3) Å, b = 20.500(3) Å, c = 18.658(4) Å, Z = 6) has an octahedral environment. The three Li(OEt2)+ fragments are bound bridging the biphenolate ligands. The structures of 10 (monoclinic, P21/c, a = 16.894(3) Å, b = 12.181(2) Å, c = 25.180(3) Å, β = 91.52(1)°, Z = 4) and 13 (orthorhombic, Pna21, a = 16.152(4) Å, b = 17.293(6) Å, c = 16.530(7) Å, Z = 4) are characterised by separated ions with tetrahedrally coordinated vanadate(III) anions and the lithium cations being the centres of octahedral and trigonal bipyramidal solvent environments, respectively.