Redox interplay of oxo-thio-tungsten centers with sulfur-donor co-ligands.
The oxo-thio-W(VI) complexes TpWOS(S(2)PR(2)-S) and TpWOS(pyS-S) (Tp = hydrotris(3,5-dimethylpyrazol-1-yl)borate, R = OEt, Ph; pyS = pyridine-2-thiolate) have been prepared and characterized by microanalytical, spectroscopic, and structural techniques. Crystals of the 1,2-dichloroethane hemisolvate of TpWOS(S(2)PPh(2)-S) belong to the triclinic space group Ponemacr; with a = 10.732(6) A, b = 16.91(1) A, c = 10.021(4) A, alpha = 104.40(4) degrees, beta = 107.52(3) degrees, gamma = 96.09(5) degrees, V = 1647(1) A(3) for Z = 2. The complex exhibits a distorted octahedral structure featuring a facial tridentate Tp ligand and mutually cis terminal oxo (W-O(1) = 1.712(7) A), terminal thio (W-S(1) = 2.162(3) A), and monodentate dithiophosphinate ligands. X-ray absorption and extended X-ray absorption fine structure results support a related oxo-thio formulation for TpWOS(pyS-S). The complexes are reduced to the corresponding oxo-thio-W(V) anions, [TpWOS(S(2)PR(2)-S)](-) and [TpWOS(pyS-S)](-), which exhibit highly anisotropic EPR spectra. They are oxidized to form the EPR-active (dithio)oxo-W(V) cations, [TpWO(S(3)PR(2)-S,S')](+) and [TpWO(pyS(2)-N,S)](+) (pyS(2) = pyridine-2-dithio). Green [TpWO(pyS(2)-N,S)]BF(4), formed in the reaction of TpWOS(pyS) and NOBF(4), has been isolated and spectroscopically and structurally characterized. Crystals of [TpWO(pyS(2)-N,S)]BF(4) belong to the monoclinic space group Cc with a = 16.007(5) A, b = 14.091(4) A, c = 13.608(4) A, beta = 124.525(4) degrees, V = 2528.8(13) A(3) for Z = 4. The cation exhibits a distorted octahedral structure featuring facial tridentate Tp, terminal oxo (W-O(1) = 1.632(12) A), and bidentate pyridine-2-dithio-N,S (W-S(1) = 2.317(7) A, S(1)-S(2) = 2.037(9) A) ligands. The structures and redox behavior of the complexes are compared and contrasted with those of the related molybdenum complexes, TpMo(VI)OS(S(2)PR(2)-S) and TpMo(IV)O(pyS(2)-N,S) (Hill, J. P.; Laughlin, L. J.; Gable, R. W.; Young, C. G. Inorg. Chem. 1996, 35, 3447).
Thomas
Simon
S
School of Chemistry, University of Melbourne, Victoria 3010, Australia.
Eagle
Aston A
AA
Sproules
Stephen A
SA
Hill
Jason P
JP
White
Jonathan M
JM
Tiekink
Edward R T
ER
George
Graham N
GN
Young
Charles G
CG
D018360:Crystallography, X-Ray; D007202:Indicators and Reagents; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D013455:Sulfur / Q000737:chemistry*; D014414:Tungsten / Q000737:chemistry*
D007202:Indicators and Reagents; D008024:Ligands; D013455:Sulfur; D014414:Tungsten