32799-25-0Relevant academic research and scientific papers
Gase-Phase Organometallic Catalysis: Kinetics and Mechanism of the Hydrogenation of Ethylene by Fe(CO)3(C2H4)2
Miller, Michael E.,Grant, Edward R.
, p. 7951 - 7960 (2007/10/02)
Inert homogeneous gas-phase mixtures of ethylene and hydrogen plus a catalytic amount of Fe(CO)5 are transformed into active ethylene hydrogenation systems upon irradiation by near-UV light from a pulsed nitrogen laser.Organometallic species present in the active catalytic mixture are identified and monitored by Fourier transform infrared spectroscopy.The catalyzed reaction is followed by gas chromatography, which provides a measure of ethylene and hydrogenated product concentrations.The catalytic process is efficient in its use of light, with typical room temperature quantum yields (product ethane molecules formed per photon absorbed) of 20 or more.The absorbed laser light generates a reservoir of Fe(CO)3(C2H4)2, which thermally dissociates by losing one highly labile ethylene to yield the active catalyst, Fe(CO)3(C2H4).When the photolysis light is removed, catalytic activity is observed to decline as the catalyst combines with free CO to form stable Fe(CO)4(C2H4).The rate of organic product formation is directly proportional to the catalyst reservoir concentration.Quantum efficiency of ethane production and the rate of Fe(CO)3(C2H4)2 decay are studied as functions of ethylene, hydrogen, CO, and Fe(CO)5 pressures.The results provide information on the mechanism of catalysis, as well as elementary rate parameters for many of the organometallic reactions.
Wavelegth-, Medium-, and Temperature-Dependent Competition between Photosubstitution and Photofragmentation in Ru3(CO)12 and Fe3(CO)12: Detection and Characterization of Coordinatively Unsaturated M3(CO)11 Complexes
Bentsen, James G.,Wrighton, Mark S.
, p. 4530 - 4544 (2007/10/02)
Irradiation of 0.1 mM Ru3(CO)12 (λ = 313 nm) or 0.02 mM Fe3(CO)12 (λ = 366 nm) in a methylcyclohexane or 2-methyltetrahydrofuran (2-MeTHF) glass at 90 K yields loss of one CO as the only IR detectable photoreaction to yield products formulated as M3(CO)11 or M3(CO)11(2-MeTHF), respectively.An initially observed axially vacant form of Ru3(CO)11 (II) having no bridging CO's rearranges at 90 K to an axially vacant form (III), having at least one bridging CO, also adopted by Fe3(CO)11 in an alkane glass.An initially observrd, equatorially substituted form of Ru3(CO)11(2-MeTHF) (I') rearranges at 90 K to III or a 2-MeTHF adduct of III.I' is extremely photosensitive with respect to further substitution by 2-MeTHF for up to three CO ligands.Ru3(CO)11 (III) reacts with N2 or 13CO to yield Ru3(CO)11(N2) or axial-13CO-Ru3(CO)11(13CO) complexes, respectively.Ru3(CO)11 and Fe3(CO)11 react with C2H4 to yield M3(CO)11(C2H4) complexes.M3(CO)11 (III) reacts with PPh3 to yield Ru3(CO)11(Ph3) at 298 K and Fe3(CO)11(PPh3) at 195 K.Long wavelegth excitation of Ru3(CO)12 (λ = 366 nm) or Fe3(CO)12 (λ = 436 nm) yields negligible photochemistry in alkane or 2-MeTHF glasses but yields associative photosubstitution of C2H4, C5H10, and 13CO but not N2 or 2-MeTHF for CO at 90 K.Long wavelegth (λ > 540 nm) excitation of Fe3(CO)12 yields no photochemistry at 90 K but gives assymetric fragmentation in C2H4-containing alkane solutions at 298 K to yield 1 equiv each of Fe(CO)5, Fe(CO)4(C2H4), and Fe(CO)3(C2H4)2; competitive photosubstitution occurs in the presence of PPh3 to yield Fe3(CO)11(PPh3).At 195 K, the Fe3(CO)11L/Fe(CO)5-n(L)n (L = C2H4, PPh3; n = 0-2) product ratios increase with decreasing irradiation wavelegth.Long wavelegth (λ > 420 nm) irradiation of o.2 mM Ru3(CO)12 in 195 K alkane solutions containing excess L = CO or C2H4 initially yields 1 equiv each of Ru(CO)4L and Ru2(CO)8L; Ru2(CO)8(C2H4) fragments at 195 K to yield 2 more equiv of Ru(CO)4(C2H4).Long wavelength irradiation of Ru3(CO)12 in PPh3-containing solutions at 195 K yields conversion to a CO-bridged product which reacts thermally at 195 K to form Ru(CO)11(PPh3), in competition with Ru3(CO)12 regeneration; Ru(CO)4(PPh3) and Ru(CO)3(PPh3)2 are only observed as secondary photoproducts at 195 K.The low temperature photochemistry of Ru3(CO)12 is discussed in terms of a wavelength-dependent competition between dissociative loss of equatorial CO from higher energy excitation and generation of a nonradical, reactive isomer of Ru(CO)12 from long wavelength excitation.Implications of the new results for the photocatalyzed isomerization of 1-pentene to cis- and trans-2-pentene by M3(CO)12 (M = Ru, Fe) precursors are discussed.
Photoelectron spectroscopic study of the bonding in tetracarbonyl(ethylene)iron
Beach, David B.,Jolly, William L.
, p. 2137 - 2139 (2008/10/08)
The iron 2p3/2, carbon 1s, and oxygen 1s binding energies of gaseous Fe(CO)4C2H4 have been measured. Atomic charge calculations based on binding energy shifts indicate that the ethylene group of Fe(CO)4/su
Chemistry of octacarbonyl(μ-methyliene) dliron and its derivatives
Sumner Jr., Chartes E.
, p. 1350 - 1360 (2008/10/08)
The reaction of the Fe2(CO)82- dianion with methylene iodide leads to the formation of the parent bridging methylene complex, octacarbonyl(μ-methylene)diiron, Fe2(CO)8CH2. The reaction appears to be general and several derivatives have been prepared by using other geminal diiodides. The bridging methylene complexes react with unsaturated reactants such as olefins and acetylenes to produce new organometallic complexes in which the unsaturated molecule has inserted between the methylene ligarid and an iron atom. With hydrogen, the complexes react to produce the dihydro form of the methylene ligand; nucieophilic reagents such as iodide ion, alcohols, and water appear to attack a Co ligand with subsequent rearrangement involving the bridging methylene group.
