0000000000704950
AUTHOR
Dolores Morales
Preparation and structure of the 17-electron (η5-C5R5)Mo(OH)2(dppe) (R=Me, Et) organometallic compounds containing two gem-terminal hydroxide ligands
International audience; Oxidation of (η5-C5R5)MoH3(dppe) (R=Me, Et) by Cp2Fe+ in wet THF leads to the formation of the corresponding (η5-C5R5)Mo(OH)2(dppe). These compounds show a low-potential reversible oxidation wave. The structure of the C5Et5 complex has been confirmed by X-ray diffraction methods: triclinic; space group ; a=11.030(1); b=12.533(1); c=16.241 (1) Å; α=68.585(7); β=75.197(5); γ=83.991(7)°; V=2020.6(3) Å3; Z=2; Dcalc=1.324 g cm−3, μ(Mo–Kα)=0.441 mm−1; R1=0.0325; wR2=0.0875 for 415 parameters and 6823 independent reflections [Rint=0.0177] with I=2σ(I). The molecule shows a four-legged piano-stool geometry with two terminal OH ligands in a relative trans configuration. The c…
Synthesis of new half sandwich tetrachloro derivatives of molybdenum(V) and tungsten(V). X-ray structures of (C5HPri4)W(CO)3(CH3) and (C5Et5)WCl4
International audience; The new synthetic intermediates (Ring)MCl4 [Ring=C5HPri4 or 4Cp, M=Mo, 2; Ring=C5Et5 or VCp, M=W, 4, Ring=4Cp, M=W, 6] containing sterically protecting cyclopentadienyl ligands have been synthesized. Along the synthetic pathway to 2, it was found that the treatment of [4CpMo(CO)3]− with an aqueous ferric solution according to the well established Manning procedure affords the hydride compound 4CpMo(CO)3H (1) by hydrolysis rather than the expected neutral dimer by oxidation. Compound 1 could be converted, however, to 2 upon oxidation with PhICl2 in good yields. Compound 4 is shown by a single crystal X-ray analysis to adopt a monomeric four-legged piano stool structur…
Protonation and oxidation chemistry of a pentaethylcyclopentadienyl-containing molybdenum(IV) trihydride complex
International audience; Compound CpEtMoCl4 (CpEt=η5-C5Et5) (1) can be transformed into CpEtMoH3(dppe) (2) and CpEtMoD3(dppe) (2-d3) [dppe=1,2-(diphenylphosphino)ethane] by reaction with LiAlX4 (X=H and D, respectively). The protonation and oxidation studies of these two compounds, in comparison with previously reported studies on (C5Me5) analogs, show important differences that may be attributed to a kinetic stabilization of the products, which is steric in nature. Protonation of 2 with HBF4 in acetonitrile affords [CpEtMoH4(dppe)]+ (3), which only slowly decomposes to [CpEtMoH2(MeCN)(dppe)]+ (4). Further protonation of the latter affords the monohydride species [Cp*MoH(dppe)(MeCN)2]2+ in t…
Half-sandwich complexes of molybdenum-(III), -(IV) and -(V) with P–O and P–N bifunctional ligands Ph2PCH2X (X = 2-oxazolinyl, or C(O)NPh2)
International audience; The reaction of the ligands Ph2PCH2X (X = 2-oxazolinyl, I; or C(O)NPh2, II) with the half-sandwich molybdenum(III) precursors [Mo(η-C5R5)(μ-Cl)2]2 (R = H or Me) has been investigated. Ligand I reacts with both complexes to form the corresponding adducts [Mo(η-C5R5)Cl2(Ph2PCH2C3H4NO)] (R = H, 1; or Me, 2). The reaction between I and [MoCp*Cl4] (Cp* = η-C5Me5) affords [MoCp*Cl4(Ph2PCH2C3H4NO-κ1P)] as a kinetic isomer, which then transforms quantitatively to [MoCp*Cl3(Ph2PCH2C3H4NO-κ2P,N)]+Cl−, 3. Ligand II reacts with [MoCp(μ-Cl)2]2 (Cp = η-C5H5) to afford the adduct [CpMoCl2{Ph2PCH2C(O)NPh2-κ2P,O}], 4, as an equilibrium mixture of two isomers. Longer reaction times in…