Simple and effective synthesis of pentamethylcyclopentadienyl oxo-peroxo and dioxo tungsten acetylide complexes

Synthesis of New Selenium- and Oxygen-Containing Tungsten Acetylide Complexes [(η5-C5Me5)W(O)(Se2)(CCPh)] and [(η5-C5Me5)W(Se5CCPh)]

“…Whereas formation of the previously reported 3 can be understood as involving a formal addition of two tungsten acetylide units to an opened Fe 3 Se 2 cluster, the formation of 1 and 2 is more complicated. Preparation of 1 by our reaction contrasts with that of another metal oxo−acetylide complex recently reported in the literature; reaction of [(C 5 H 5 )W(CO) 3 (CCR)] (R = Ph, CH 2 OMe or Pr n ) with an acidic solution of hydrogen peroxide forms the oxo−peroxo acetylide complexes (C 5 H 5 )W(O)(O 2 )(CCR), which on treatment with PPh 3 affords the dioxo complexes, (C 5 H 5 )W(O) 2 (CCR) . Investigations are in progress to explore the potential of 1 and 2 as precursors for obtaining heterometallic clusters which are stabilized by Se ligands and contain oxo and acetylide groups.…”

“…Serendipitously therefore we shifted our interest in the hope of obtaining a complex containing both an oxo and an acetylide ligand. Such complexes, which contain oxo and hydrocarbon ligands, are of particular interest as models for metal-mediated oxidations and other reactions in which high-valent metal species are employed as catalysts. , Furthermore, the presence of the oxo ligand may give rise to novel types of reactivity which would otherwise be inhibited in its absence. Here we report on the synthesis and characterization of two novel mononuclear complexes, one that contains the oxo, acetylide, and selenium ligands and the other which bears an unusual array of five selenium atoms and an acetylide group.…”

η2-Alkynyl and Vinylidene Transition Metal Complexes. 8.1 Synthesis of Bimetallic Tungsten Gold Complexes by Addition of ClAuPPh3 to the Acetylide Li[(η5-C5H5)(CO)(NO)W(C⋮C−R)]

“…The signal for the cyclopentadienyl ring splits at −80 °C into three well-resolved signals at 94.7 for the main isomer and two very minor isomers at 97.2 and 95.6 ppm. At this temperature the signal for μ-CO and μ-C⋮ appears at 246.3 and 162.3 ppm. , Two weak signals at 230.6 and 87.2 ppm are assigned to the CO group and C α of the η 2 -alkyne complex 9 . Supporting this structure, the signal at 87.2 ppm shows a small phosphorus carbon coupling 2 J C - P of 20 Hz .…”

High oxidation state organomolybdenum and organotungsten chemistry in protic environments

“…Using this strategy, the acetylide complexes [Cp * WO(O 2 )(C CR)] (R = Ph, CH 2 OMe, nPr and C(Me) = CH 2 ) were obtained in good yields from the corresponding [Cp * W(CO) 3 (C CR)] and acidic solutions of H 2 O 2 at room temperature and then converted to [Cp * WO 2 (C CR)] [108]. The same strategy gives 3 Cp * ] via the corresponding peroxide complexes [109].…”

“…Thus, formation of the peroxido ligand occurs by ligand exchange rather than by oxygen atom transfer.As detailed in Section 4.1, the peroxidation reaction is particularly easy for alkyl derivatives. Thus, peroxide derivatives are obtained in good yields by addition of H 2 O 2 or TBHP to tricarbonyl adducts[98,108,109].4.4.8. Cleavage of the Cp-M bondA rare example of a reaction where the Cp * Mo is cleaved heterolytically (albeit very slowly) was revealed during an attempt to crystallize a salt of the[Cp * MoO 2 (H 2 O)] + cation, which was generated by dissolving [Cp * 2 Mo 2 O 5 ] in water at low pH.…”