Vanadium(IV) Complexes with Mixed O,S Donor Ligands. Syntheses, Structures, and Properties of the Anions Tris(2-mercapto-4-methylphenolato)vanadate(IV) and Bis(2-mercaptophenolato)oxovanadate(IV)Inorganic Chemistry (1996)
AbstractReaction of VO(acac)2 with 2-mercaptophenol (mpH2) in the presence of triethylamine gives the mononuclear tris complex (Et3NH)2[V(mp)3] (1), in which the vanadyl oxygen has been displaced. An analogous reaction using 2-mercapto-4-methylphenol (mmpH2) afforded (Et3NH)(PNP)[V(mmp)3] (2), which was structurally characterized. 2 crystallizes in the orthorhombic space group Pna21 with unit cell parameters (at −163 °C) a = 23.974(7) Å, b = 9.569(4) Å, c = 25.101(6) Å, and Z = 4. The coordination geometry around the vanadium is between octahedral and trigonal prismatic. Reaction of VO(acac)2 with the sodium salt of 2-mercaptophenol produces the vanadyl(IV) complex Na(Ph4P)[VO(mp)2]·Et2O (3), which crystallizes in the triclinic space group P1̄ with unit cell parameters (at −135 °C) a = 12.185(4) Å, b = 12.658(4) Å, c = 14.244(4) Å, α = 103.19(2)°, β = 100.84(2)°, and γ = 114.17(2)°. The unit cell of 3 contains a pair of symmetry-related [VO(mp)2]2- units bridged through vanadyl and ligand oxygen atoms by a pair of sodium ions, in addition to two PPh4+ ions. The coordination geometry around the vanadium is square pyramidal, with a VO bond length of 1.611(5) Å. 1, 2, and 3 are characterized by IR and UV−vis spectroscopies, magnetic susceptibility, EPR spectroscopy, and cyclic voltammetry. 1 and 2 can be oxidized by I2, Cp2Fe+, or O2 to [V(mp)3]- and [V(mmp)3]-, respectively, which in turn can be reduced back to the dianions by oxalate ion. These reversible redox processes can be followed by UV−vis spectroscopy.
Publication DateJanuary 17, 1996
Citation InformationPaul R. Klich, Andrew T. Daniher, Paul R. Challen, David B. McConville, et al.. "Vanadium(IV) Complexes with Mixed O,S Donor Ligands. Syntheses, Structures, and Properties of the Anions Tris(2-mercapto-4-methylphenolato)vanadate(IV) and Bis(2-mercaptophenolato)oxovanadate(IV)" Inorganic Chemistry Vol. 35 Iss. 2 (1996)
Available at: http://works.bepress.com/paul_challen/2/