(Pentamethylcyclopentadienyl)molybdenum Bromides and Iodides

Desai, Jahanvi U.; Gordon, John C.; Kraatz, Heinz‐Bernhard; Lee, Vincent T.; Owens-Waltermire, Beth E.; Poli, Rinaldo; Rheingold, Arnold L.; White, Corbet

doi:10.1021/ic00095a019

Cited by 31 publications

(25 citation statements)

References 2 publications

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“…Rather, these peaks could correspond to minor fragmentation pathways involving the elimination of SCH 2 CH 2 CO (m/z 88), thereby leaving an oxo bridge on the dinuclear complex. (3) Mo (2) [28] and Cp Ã 2 Mo 2 X 4 (l-X) 2 (X = Cl, Br) [29,30]. It probably involves alkylsulfido bridges rather than hydroxo bridges, since the former groups are generally better bridging ligands.…”

Section: Resultsmentioning

confidence: 99%

Reduction of [Mo2O5] by mercaptopropionic acid in an aqueous medium. Isolation and characterization of a dinuclear oxo- and 3-sulfido-proprionato(2-)-bridged molybdenum(IV) compound

Dinoi

Prikhodchenko

Demirhan

et al. 2007

Journal of Organometallic Chemistry

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Reaction of Cp Ã 2 Mo 2 O 5 with HSCH 2 CH 2 COOH in acidic (by CF 3 COOH) 50:50 MeOH-H 2 O solvent at room temperature yields compound Cp Ã 2 Mo 2 (l-O)(l-SCH 2 CH 2 CO 2 ) 2 , a dinuclear diamagnetic Mo IV compound with a two-leg-sharing bis(four-legged piano stool) structure and a Mo-Mo distance of 2.6833(6) Å . A reaction monitoring by ESI MS shows the formation of an intermediate 18 mass units heavier, interpreted as a dihydroxo analogue. Electrochemistry shows a reversible, pH independent oxidation process and an irreversible, pH-dependent reduction process. Contrary to a recently published analogous reaction with the closely related HSCH 2 COOH substrate, this process does not lead to C-S bond cleavage.

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Section: Resultsmentioning

confidence: 99%

Reduction of [Mo2O5] by mercaptopropionic acid in an aqueous medium. Isolation and characterization of a dinuclear oxo- and 3-sulfido-proprionato(2-)-bridged molybdenum(IV) compound

Dinoi

Prikhodchenko

Demirhan

et al. 2007

Journal of Organometallic Chemistry

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“…A key feature is that the two oxidation processes associated to free Ioccur at a less positive potential than the oxidation of It is relevant to mention here that MoI 4 is not a known compound [32] and, although additional ligands stabilize higher oxidation state MoI 4 moieties (e.g. in compounds [CpMoI 4 ]and [MoOI 4 ] -), [33,34] no MoI 4 L n or iodide-containing mixedhalide MoI n X 4-n L m coordination compounds where L = phosphine ligand are reported in the literature to the best of our knowledge. .…”

Section: Methodsmentioning

confidence: 99%

The Radical Trap in Atom Transfer Radical Polymerization Need Not Be Thermodynamically Stable. A Study of the MoX₃(PMe₃)₃ Catalysts

et al. 2005

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The molybdenum(III) coordination complexes MoX(3)(PMe(3))(3) (X = Cl, Br, and I) are capable of controlling styrene polymerization under typical atom transfer radical polymerization (ATRP) conditions, in conjunction with 2-bromoethylbenzene (BEB) as an initiator. The process is accelerated by the presence of Al(OPr(i))(3) as a cocatalyst. Electrochemical and synthetic studies aimed at identifying the nature of the spin trap have been carried out. The cyclic voltammogram of MoX(3)(PMe(3))(3) (X = Cl, Br, I) shows partial reversibility (increasing in the order Cl < Br < I) for the one-electron oxidation wave. Addition of X(-) changes the voltammogram, indicating the formation of MoX(4)(PMe(3))(3) for X = Cl and Br. On the other hand, I(-) is more easily oxidized than the MoI(3)(PMe(3))(3) complex; thus, the putative MoI(4)(PMe(3))(3) complex is redox unstable. Electrochemical studies of MoI(3)(PMe(3))(3) in the presence of X(-) (X = Cl or Br) reveal the occurrence of facile halide-exchange processes, leading to the conclusion that the MoI(3)X(PMe(3))(3) products are also redox unstable. The oxidation of MoX(3)(PMe(3))(3) with (1)/(2)Br(2) yields MoX(3)Br(PMe(3))(3) (X = Cl, Br), whose molecular nature is confirmed by single-crystal X-ray analyses. On the other hand, the oxidation of MoI(3)(PMe(3))(3) by I(2) slowly yields a tetraiodomolybdate(III) salt of iodotrimethylphosphonium, [Me(3)PI][MoI(4)(PMe(3))(3)], as confirmed by an X-ray study. This product has no controlling ability in radical polymerization. The redox instability of MoI(3)X(PMe(3))(3) can be reconciled with its involvement as a radical trapping species in the MoI(3)(PMe(3))(3)-catalyzed ATRP, given the second-order nature of its decomposition rate.

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“…The halogen nature determines the maximum allowed oxidation state of the [Cp * MoX n ] system (n = 4 for X = Cl and Br; 3 for X = I in the anionic complex [Cp * MoI 4 ] À ) [33]. The corresponding fluoride system has not been investigated for molybdenum, but Cp * WF 5 (prepared by aerial oxidation from Cp * WF 4 ) is a stable compound [35], whereas the highest oxidation state attainable for X = Cl appears to be the same as for the Mo 3 Cl] with tBuOOH [5], as well as that of [Cp * MoO 2 (CH 3 )] and other similar cyclopentadienyl derivatives by oxidation of the corresponding tricarbonyl methyl precursors with the same oxidizing reagent [6].…”

Section: Synthesesmentioning

confidence: 99%

Improved syntheses of [] and []: Structural characterization of Na[Cp∗MoO3]·5H2O and []

Dinoi¹,

Taban²,

Sözen³

et al. 2007

Journal of Organometallic Chemistry

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Use of aqueous conditions and the ROOH (R = tBu or H) compounds as oxidizing agents affords a simple two-step, one-pot synthetic procedure leading to [Cp Ã 2 M 2 O 5 ] (M = Mo, W) from [M(CO) 6 ] selectively and in high yields. The hexacarbonyl compounds are converted to Na[Cp * M(CO) 3 ] in refluxing THF, then the mixture is diluted with water (W) or aqueous NaOH (Mo) and directly treated with 6 equiv. of ROOH. Acidification of an aqueous solution of the Na[Cp * MO 3 ] product affords spectroscopically pure [Cp Ã 2 M 2 O 5 ] in high isolated yields (global yields from [M(CO) 6 ], for R = tBu: Mo, 91%; W, 87%). The X-ray structures of Na[Cp * MoO 3 ] AE 5H 2 O and [Cp Ã 2 W 2 O 5 ] are also reported.

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(Pentamethylcyclopentadienyl)molybdenum Bromides and Iodides

Cited by 31 publications

References 2 publications

Reduction of [Mo2O5] by mercaptopropionic acid in an aqueous medium. Isolation and characterization of a dinuclear oxo- and 3-sulfido-proprionato(2-)-bridged molybdenum(IV) compound

Reduction of [Mo2O5] by mercaptopropionic acid in an aqueous medium. Isolation and characterization of a dinuclear oxo- and 3-sulfido-proprionato(2-)-bridged molybdenum(IV) compound

The Radical Trap in Atom Transfer Radical Polymerization Need Not Be Thermodynamically Stable. A Study of the MoX₃(PMe₃)₃ Catalysts

Improved syntheses of [] and []: Structural characterization of Na[Cp∗MoO3]·5H2O and []

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(Pentamethylcyclopentadienyl)molybdenum Bromides and Iodides

Cited by 31 publications

References 2 publications

Reduction of [Mo2O5] by mercaptopropionic acid in an aqueous medium. Isolation and characterization of a dinuclear oxo- and 3-sulfido-proprionato(2-)-bridged molybdenum(IV) compound

Reduction of [Mo2O5] by mercaptopropionic acid in an aqueous medium. Isolation and characterization of a dinuclear oxo- and 3-sulfido-proprionato(2-)-bridged molybdenum(IV) compound

The Radical Trap in Atom Transfer Radical Polymerization Need Not Be Thermodynamically Stable. A Study of the MoX3(PMe3)3 Catalysts

Improved syntheses of [] and []: Structural characterization of Na[Cp∗MoO3]·5H2O and []

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The Radical Trap in Atom Transfer Radical Polymerization Need Not Be Thermodynamically Stable. A Study of the MoX₃(PMe₃)₃ Catalysts