A Raman spectroscopic study of molybdenum and tungsten dioxo complexes containing related cyclopentadienyl and trispyrazolylborato ligands

Synthesis and characterization of 3-[N,N′-bis-3-(salicylidenamino)ethyltriamine] Mo(vi)O2@SBA-15: a highly stable and reusable catalyst for epoxidation and sulfoxidation reactions

“…The characteristic peaks at 821 and 990 cm À1 , corresponds to asymmetric and symmetric stretching vibrations of the cis-coordinated MoO 2 moiety. 36 This indicates that the oxidation state of molybdenum is VI, which is though retained even aer immobilization over SBA-15. Further, results obtained from the Raman spectra are in good agreement with the results of the IR spectroscopic investigations.…”

Mononuclear Organomolybdenum(VI) Dioxo Complexes: Synthesis, Reactivity, and Catalytic Applications

“…In the case of complexes of the type L 3 MoO 2 X (Table ) the MoO frequencies are influenced in a similar fashion by the donor abilities of the ligands (X or L 3 ). Stronger electron-donating ligands, such as the Cp* ligand, are responsible for the shifting of MoO stretching frequencies to lower energies, when compared to less electron donating ligands, such as Cp or Tp* . The presence of electron-attracting groups in the X position, such as halogens, has the same effect on the MO stretching frequencies.…”

“…The Tp* ligand has even a more pronounced effect on increasing the stability of the complexes toward temperature, although it has been described as a weaker electron donor than the Cp* ligand in a spectroscopic study performed by Kiefer et al. for complexes Tp*MO 2 Me and Cp*MO 2 Me (M = Mo, W) …”

“…The derivatives MoO 2 (CH 2 CH 2 Ph) 2 (bpy) (30), MoO 2 (p-MeC 6 H 4 CH 2 ) 2 (bpy) (29), and MoO 2 (o-MeC 6 H 4 CH 2 ) 2 (bpy) (28) were synthesized as microcrystalline solids that require no special handling precautions. 8 The latter compound could be synthesized with higher yields using an organolithium instead of a Grignard reagent.…”

12 Chromium, molybdenum and tungsten

“…This proposal is supported by force ¢eld calculations. 188 A new metallo-ligand, considered as a modi¢ed tertiary phosphine, [MoCl{HB(3,5-Me 2 C 3 HN 2 ) 3 }(OC 6 H 4 PPh 2Àp )(NO)], has been prepared and characterised. It is proposed as a potentially good starting material for the design of novel bimetallic complexes exhibiting applicable nonlinear optical and/or optoelectronic properties.…”