Bis(trimethylsilyl)ethyne as a two-electron alkyne ligand in group 6 carbonylmetal(0) complexes: Photochemical syntheses and comprehensive 2 characterization of M(CO)(5)(eta(Me3SiC)-Me-2=CSiMe3) (M = W, Mo, Cr) and trans-Mo(CO)(4)(eta(2)-Me3SiC=CSiMe3)(2)

Grevels, FW
Jacke, J
Continued irradiation of W(CO)(6) in the presence of excess bis(trimethylsilyl)ethyne (btmse) in n-hexane solution yields W(CO)(5)(eta(2)-btmse) as the sole product, with quantum yields of 0.66 and 0.69 at lambda(exc) = 365 and 313 nm, respectively. Cr(CO)(6) behaves analogously, while with MO(CO)(6) the initially generated Mo(CO)(5)(eta(2)-btmse) undergoes further CO substitution to form trans-Mo(CO)(4)(eta(2)-btmse)(2) as the second product. All four compounds were isolated in crystalline form and fully characterized by elemental analysis, MS, IR, and NMR spectroscopies as well as by single-crystal X-ray crystallography. They assume a quasi-octahedral coordination geometry with the alkyne triple bond being eclipsed to one OC-M-CO axis and, in the case of trans-MO(CO)(4)(eta(2)-btmse)(2), in trans-orthogonal orientation to the second alkyne. Both Mo(CO)(5)(eta(2)-btmse) and Cr(CO)(5)(eta(2)-btmse) are labile toward alkyne displacement by CO, whereas W(CO)(5)(eta(2)-btmse) and trans-MO(CO)(4)(eta(2)-btmse)(2) undergo spontaneous (CO)-C-12/(CO)-C-13 exchange in the dark under mild conditions. Partially (CO)-C-13 labeled samples generated in this way provide complementary CO stretching vibrational data needed for thorough analyses at the level of the energy-factored CO force field approximation. From all the structural features and spectroscopic data it is evident that bis(trimethylsilyl)ethyne acts as a two-electron donor ligand in this series of d(6) carbonylmetal(0) complexes.


FISCHLER, I; GREVELS, FW; LEITICH, J; Özkar, Saim (Wiley, 1991-12-01)
Irradiation of Cr(CO)3(eta(6)-1,3,5-cycloheptatriene) (1) in the presence of bis(trimethylsilyl)ethyne results in [6 + 2] cycloaddition of the alkyne to the cycloheptatriene ligand, yielding Cr(CO)3{eta(4:2)-7,8-bis(trimethylsilyl)bicyclo[4.2.1]nona-2,4,7-triene} (2, 60% yield, PHI = 0.08), which upon oxidative decomposition with Ce(IV) releases the organic cycloadduct, 7,8-bis-(trimethylsilyl)bicyclo[4.2.1]-nona-2,4,7-triene (3). Photocatalytic hydrogenation of 1,3,5-cycloheptatriene in the presence of com...
A novel one-pot synthesis of ferrocenyl-substituted 1,2,4-oxadiazoles
Zora, Metin; Kelgokmen, YILMAZ (Elsevier BV, 2014-06-01)
One-pot synthesis of 5-ferrocenyl-1,2,4-oxadiazoles via the reaction between 3-ferrocenylpropynal and amidoximes is described. 3-Ferrocenylpropynal reacts with a variety of amidoximes in the presence of KOH in refluxing dioxane to afford a broad range of 5-ferrocenyl-1,2,4-oxadiazole derivatives. The reaction first produces the corresponding conjugate addition product which, upon cyclization and rearrangement, yields the targeted 1,2,4-oxadiazole. The reaction appears to be general for a diversity of amidox...
Application of ferrocenyl substituted aziridinylmethanols (FAM) as chiral ligands in enantioselective conjugate addition of diethylzinc to enones
İŞLEYEN, Alper; Doğan, Özdemir (Elsevier BV, 2007-03-30)
Easily available ferrocenyl substituted aziridinylmethanol FAM-4a complexes with nickel and catalyzes the enantioselective diethylzinc addition to various enones with enantiomeric excesses reaching 80%. The ligand can be recovered and used without losing its activity. The sense of induction was found to be dependent on the configuration of the aziridine ring.
Coupling of ferrocenyl chromium carbene complex with cyclobutenediones
Zora, Metin; Bekir Peynircioglu, N. (Elsevier BV, 2002-08-15)
The coupling of ferrocenyl chromium carbene complex with cyclobutenediones leads to ferrocenyl-substituted 5-alkylidenefuranones and 4-cyclopentene-1,3-diones, methyl ferrocenoate and acetylferrocene in varying amounts. The scope and limitations of these processes are investigated. In comparison with the phenyl analog, ferrocenyl chromium carbene complex has been found to be less reactive. This is also supported by PM3 calculations. The coupling of ferrocenyl chromium carbene complex with cyclobutenediones...
Carboligation reactions with benzaldehyde lyase immobilized on superparamagnetic solid support
Sopaci, S. Betuel; Turan, Ilke Simsek; Tural, Bilsen; Volkan, Mürvet; Demir, Ayhan Sıtkı (Royal Society of Chemistry (RSC), 2009-01-01)
Histidine-tagged recombinant benzaldehyde lyase (BAL, EC was efficiently immobilized to surface-modified magnetic particles with affinity ligand binding. In addition to conventional benzoin condensation reactions, two important representative BAL-catalyzed carboligation reactions, were also performed with this magnetically responsive biocatalyst. The results obtained from the carboligation reactions that were performed with this simple and convenient heterogenous biocatalyst were comparable to tha...
Citation Formats
F. Grevels and J. Jacke, “Bis(trimethylsilyl)ethyne as a two-electron alkyne ligand in group 6 carbonylmetal(0) complexes: Photochemical syntheses and comprehensive 2 characterization of M(CO)(5)(eta(Me3SiC)-Me-2=CSiMe3) (M = W, Mo, Cr) and trans-Mo(CO)(4)(eta(2)-Me3SiC=CSiMe3)(2),” ORGANOMETALLICS, pp. 4613–4623, 2005, Accessed: 00, 2020. [Online]. Available: