12184-22-4Relevant articles and documents
Aqueous chemistry of the metallocene [Cp2MoCl 2]BF4: Evidence of autocatalytic molybdenum(V) reduction in water
Kuo, Louis Y.,Shari'Ati, Yusef A.,Valente, Edward J.
, p. 2902 - 2907 (2013/06/27)
The aqueous chemistry of the air-stable Mo(V) metallocene [Cp 2MoCl2]BF4 (1) yields an unexpected autocatalytic reduction when water is added to an acetonitrile solution of 1. While 1 yields the expected stable Cp-Mo ligation and rapid chloride hydrolysis in water, a Mo(V) → Mo(IV) reduction to the metallocene Cp 2MoCl2 (2) was evident. Under acidic conditions (pH ～2) or trace amounts of water this reduction was slow enough to be monitored spectroscopically, and it is shown to be autocatalytic in aqueous 2. No reaction occurs when 1 and 2 are in the dichloride form in acetonitrile (i.e., no water). It is hypothesized that the added water serves two roles. First it initially reduces a small population of 1 to 2, and then as the aquated Mo(IV) metallocene, it catalyzes the reduction of the remaining Mo(V) in water. This is the first aqueous investigation of the Mo(V) metallocene, and it shows a novel and unprecedented autocatalytic reduction that is mediated by water.
New Molybdenocene Dihydrocarbyls
Dias, A. R.,Garcia, M. H.,Martins, A. M.,Pinheiro, C. I.,Romao, C. C.,Veiros, L. F.
, p. C59 - C62 (2007/10/02)
The preparation and characterization of 5-C5H5)2R2)> (R = C2H5, n-C4H9, C6H5) and 5-C5H5)2R2>PF6 (R = C2H5, n-C4H9) are described.Cyclic voltammograms in CH3CN and CH2Cl2 show that the reversible 1-electron oxidation of Mo
Energetics of transition-metal-sulfur and -oxygen bonds in M(η5-C5H5)2L2 complexes (M = Ti, Mo, W). Molecular structure of Mo(η5-C5H5)2(SO4)
Calhorda, Maria J.,Carrondo, Maria A. A. F. De C. T.,Dias, Alberto R.,Domingos, ?ngela M. T. S.,Martinho Sim?es, José A.,Teixeira, Clementina
, p. 660 - 667 (2008/10/08)
The energetics of transition-metal-sulfur bonds in bis(η5-cyclopentadienyl)bis(thiolato)metal complexes, M(η5-C5H5)2(SR)2 (M = Mo, W, Ti), has been reinvestigated and compared with reevaluated metal-oxygen data on the same type of molecules. Bond enthalpy terms, E(Mo-SR) (R = n-C3H7, i-C3H7, n-C4H9, t-C4H9, and n-C10H21), which were obtained by using calorimetric values for the standard enthalpies of formation of the complexes, confirm a strong steric effect in the case of t-C4H9S and indicate an increase in metal-sulfur bond strength with the length of the n-alkyl chain, E(Mo-SC10H21-n) ? E(Mo-SC4H9-n) ? E(Mo-SC3H7-n). The thermochemistry of the complex Mo(η5-C5H5)2(SO4) was also studied, leading to E(Mo-O) ≈ 338 ± 13 kJ mol-1. This value excludes noticeable strain on the metallacycle, since it compares with other molybdenum-oxygen bond enthalpy terms. The molecular structure of the sulfate complex, which was also determined in the present study, is compatible with the Mo-O bond enthalpy. The structural data were obtained by X-ray diffraction and show bidentate coordination of the sulfate ligand, with O-Mo-O = 66.1 (2)° and Mo-O = 211.3 (3) pm. The angle O-S-O = 98.3 (2)° (coordinated oxygen) shows a small distortion of this moiety, and extended Hu?ckel calculations show that the rigidity of the SO4 geometry is responsible for the small O-Mo-O angle. The sulfate complex crystallizes in the orthorhombic space group Cmcm with four molecules per unit cell; the lattice constants are a = 935.6 (5) pm, b = 854.7 (2) pm, and c = 1297.9 (4) pm.
