BIS(ARENE)VANADIUM(0) COMPLEXES AS A SOURCE OF VANADIUM(II) DERIVATIVES BY BOTH DISPROPORTIONATION OF THE [V(ETA-6-ARENE)2]+ CATIONS AND OXIDATION OF [V(ETA-6-ARENE)2]

The [V(eta6-arene)2]+ Cation (arene = benzene, toluene or mesitylene) is disproportionate to [V(eta6-arene)2] and V(II) compounds in ether solvents such as THF or 1,2-dimethoxyethane (DME). The extent of disproportionation depends on the nature of both the counteranion and the arene ligand. Addition of the filtered crude reaction mixtures, presumably containing the [V(eta6-arene)2][Al2X7] derivatives, to THF gave [V2(mu-X)3(THF)6[AlX4] (arene = benzene or toluene; X = Cl or Br). For X = Cl and arene = toluene, addition to a THF solution of Lil yielded [V2(mu-Cl)3(THF)6]I. The atom connectivity was established for [V2(mu-Cl)3(THF)6][AlCl4], while [V2(mu-Cl)3(THF)6]I was fully characterized by X-ray diffraction methods. Crystal data: [V2(mu-Cl)3(THF)6]I: monoclinic, space group C2/c (no. 15), a 25.199(8), b 13.865(6), c 9.879(4) angstrom, beta 103.98(2)-degrees, V 3349.3 angstrom3, Z = 4, D(c) 1.523 g cm-3, mu 17.256 cm-1, F(000) = 1560. The vanadium(II) derivative VI2(THF)0.7 was obtained, together with [V(eta6-mesitylene)2] in the reaction of [V(eta6-mesitylene)2][AlI4] with THF. By reaction of [V(eta6-mesitylene)2] with CPh3X (X = Br or 1) in 1,2-dimethoxyethane (DME), the dihalides of vanadium(II), [VX2(DME)2] have been isolated in good yields. The crystal and molecular structure of the monomeric cis-[VI2(DME)2] of pseudo-octahedral geometry has been studied by X-ray diffraction methods. Crystal data: 2(DME)2]: monoclinic, space group P2(1)/n (non-standard No. 14), a 7.819(4), b 13.150(4), c 15.535(5) beta 90.23(3)-degrees, V 1597.3(1) angstrom3, Z = 4, D(c) 2.017 g cm-3, mu 44.231 cm-1, F(000) = 916.