- Phase Transfer Generation of Acyltetracarbonyliron Anions: their Role in the Phase Transfer Carbonylation of Reactive Halides to give Carboxylic Acids and Symmetrical and Unsymmetrical Ketones
-
Acyltetracarbonyliron anions RCOFe(CO)4(1-) (3) are readily synthesised under mild phase transfer (PT) conditions from pentacarbonyliron and reactive organic halides; the in situ generated anions (3) (R = ArCH2) are the true catalysts in the PT carbonylation of benzyl halides to give ketones or carboxylic acids.
- Laurent, Pascale,Tanguy, Guy,Abbayes, Herve des
-
-
Read Online
- Synthesis of Bis(trityl)iron(II) and Formation of the Iron(0)-Stabilized o, o-Isomer of Gomberg's Dimer
-
Treatment of Fe(OAc)2 in THF with 2 equiv of Li(CPh3) at -25 °C results in the formation of [Fe(ν5-CPh3)2] (1) in 22% yield. Complex 1 was characterized by X-ray crystallography, NMR spectroscopy, and 57Fe M?ssbauer spectroscopy and features an ν5 binding
- Hayton, Trevor W.,Touchton, Alexander J.,Wu, Guang
-
supporting information
p. 4045 - 4049
(2021/12/13)
-
- Phosphorus-carbon bond forming reactions of iron tetracarbonyl-coordinated phosphenium ions
-
Abstraction of chloride from [Fe(CO)4(PPh2Cl)] (1) in the presence of PPh3 leads to [Fe(CO)4(PPh2(PPh3))][AlCl4] (2), an iron complex of a phosphine-coordinated phosphenium ion. The PPh3 is readily displaced by ferrocene, leading to an electrophilic aromatic substitution reaction, and formation of [Fe(CO)4{PPh2Fc}] (3) (Fc = ferrocenyl). Alternately, chloride abstraction from 1 in the presence of ferrocene leads directly to 3, via a transient phosphenium ion complex. The transient phosphenium ion complex also reacts with N,N-diethylaniline, indole, and pyrrole to form the respective p-anilinyl, 3-indolyl, and 2-pyrryl phosphine complexes via electrophilic aromatic substitution. Chloride abstraction from [Fe(CO)4(PPhCl2)] in the presence of ferrocene leads to a double substitution reaction, forming [Fe(CO)4{PPhFc2}] (13).
- King, Ryan C.,Nilewar, Shrikant,Sterenberg, Brian T.
-
-
- Iron Catalyzed Hydroformylation of Alkenes under Mild Conditions: Evidence of an Fe(II) Catalyzed Process
-
Earth abundant, first row transition metals offer a cheap and sustainable alternative to the rare and precious metals. However, utilization of first row metals in catalysis requires harsh reaction conditions, suffers from limited activity, and fails to tolerate functional groups. Reported here is a highly efficient iron catalyzed hydroformylation of alkenes under mild conditions. This protocol operates at 10-30 bar syngas pressure below 100 °C, utilizes readily available ligands, and applies to an array of olefins. Thus, the iron precursor [HFe(CO)4]-[Ph3PNPPh3]+ (1) in the presence of triphenyl phosphine catalyzes the hydroformylation of 1-hexene (S2), 1-octene (S1), 1-decene (S3), 1-dodecene (S4), 1-octadecene (S5), trimethoxy(vinyl)silane (S6), trimethyl(vinyl)silane (S7), cardanol (S8), 2,3-dihydrofuran (S9), allyl malonic acid (S10), styrene (S11), 4-methylstyrene (S12), 4-iBu-styrene (S13), 4-tBu-styrene (S14), 4-methoxy styrene (S15), 4-acetoxy styrene (S16), 4-bromo styrene (S17), 4-chloro styrene (S18), 4-vinylbenzonitrile (S19), 4-vinylbenzoic acid (S20), and allyl benzene (S21) to corresponding aldehydes in good to excellent yields. Both electron donating and electron withdrawing substituents could be tolerated and excellent conversions were obtained for S11-S20. Remarkably, the addition of 1 mol % acetic acid promotes the reaction to completion within 16-24 h. Detailed mechanistic investigations revealed in situ formation of an iron-dihydride complex [H2Fe(CO)2(PPh3)2] (A) as an active catalytic species. This finding was further supported by cyclic voltammetry investigations and intermediacy of an Fe(0)-Fe(II) species was established. Combined experimental and computational investigations support the existence of an iron-dihydride as the catalyst resting state, which then follows a Fe(II) based catalytic cycle to produce aldehyde.
- Pandey, Swechchha,Raj, K. Vipin,Shinde, Dinesh R.,Vanka, Kumar,Kashyap, Varchaswal,Kurungot, Sreekumar,Vinod,Chikkali, Samir H.
-
supporting information
p. 4430 - 4439
(2018/04/05)
-
- Coordination chemistry and oxidative addition of trifluorovinylferrocene derivatives
-
Complexes using trifluorovinylferrocene and 1,1′-bis(trifluorovinyl)ferrocene as ligands can be obtained by the reaction with a series of fragments of transition metal complexes. Formation of [Pt(η2-trifluorovinylferrocene)(PPh3)2] (1), [{Pt(PPh3)2}2(η2-1,1′-bis(trifluorovinyl)ferrocene)] (2) and [Pt(η2-1,1′-bis(trifluorovinyl)ferrocene)(PPh3)2] (3) were achieved by ligand substitution in [Pt(η2-CH2?=?CH2)(PPh3)2]. Treatment of eneacarbonyldiiron with trifluorovinylferrocene provided [Fe(CO)4(η2-trifluorovinylferrocene)] (4). Photolytically activated reactions of [MnCp(CO)3] and [MnCp′(CO)3] (Cp′?=?C5H4CH3) afforded [MnCp(CO)2(η2-trifluorovinylferrocene)] (5a) and [MnCp′(CO)2(η2-trifluorovinylferrocene)] (5b) respectively. [Ni(η2-trifluorovinylferrocene)(Cy2P(CH2)2PCy2)] (6) could be obtained by reaction with [Ni(COD)2] and Cy2P(CH2)2PCy2. Furthermore the C[sbnd]F bond activation by oxidative addition in the presence of lithium iodide yielding two isomers of [PtI{η1-difluorovinylferrocene}(PPh3)2] (7a/7b) is presented. Molecular structures of 1, 4 and 7a were elucidated using X-ray single crystal diffraction. The spectroscopic and structural data of these complexes prove the powerful π acceptor abilities of these ligands.
- Heinrich, Darina,Schmolke, Willi,Lentz, Dieter
-
p. 105 - 112
(2016/11/11)
-
- Complexes of four-membered group 13 metal(I) N-heterocyclic carbene analogues with metal carbonyl fragments
-
The four-membered gallium(I) and. indium(I) heterocycles, [:M(Giso)] (M = Ga or In; Giso = [[N(Ar)I2CN(C6Hu)2)-, Ar = C6H3iPr2-2,6), were treated with a series of transition metal carbonyl
- Jones, Cameron,Stasch, Andreas,Moxey, Graeme J.,Junk, Peter C.,Deacon, Glen B.
-
p. 3593 - 3599
(2009/12/02)
-
- Biomimetic model featuring the NH proton and bridging hydride related to a proposed intermediate in enzymatic H2 production by fe-only hydrogenase
-
Iron azadithiolate phosphine-substituted complex and its protonated species featuring the NH proton and/or bridging Fe hydride, [Fe2(μ- S(CH2)2NnPr(H)m(CH2) 2S)(M-H)n(
- Chiang, Ming-Hsi,Liu, Yu-Chiao,Yang, Shu-Ting,Lee, Gene-Hsiang
-
p. 7604 - 7612
(2011/03/16)
-
- Extraction and recovery characteristics of Fe element from Nd-Fe-B sintered magnet powder scrap by carbonylation
-
Iron element was extracted from the powder scrap of Nd-Fe-B sintered magnets via the carbonylation reaction with sulfur as a catalyst. The resultant carbonyl complex was Fe(CO)5 and the yield was evaluated to be ~56% by energy dispersion X-ray analysis. After applying the hydrogenation disproportionation treatment on the powder scrap, the extraction rate for Fe element was considerably accelerated on the resultant α-Fe/Fe2B/NdH2 (or neodymium oxides) nanocomposite powders to produce Fe(CO)5 in a maximum yield of ~92%.
- Miura, Koji,Itoh, Masahiro,Machida, Ken-Ichi
-
p. 228 - 232
(2009/05/06)
-
- Ring closure of alkoxycarbonyl(tetracarbonyl)pyruvoyliron complexes into metallalactones induced by nucleophilic attack of carbanions
-
The reaction of carbanions with the pyruvoyl-substituted iron complex [(CO)4Fe(CO2CH3){C(O)C(O)CH3}] (1) affords the anionic trifunctionalized metallalactones [(CO)3Fe{C(O) C(CH3)(CRR′R″)OC4(O)(Fe-C4)} (CO2CH3)]- (3), whose formation results from the addition of the nucleophile to the β carbonyl of the pyruvoyl moiety, followed by attack of the oxygen of this β carbonyl on a terminal carbonyl ligand. These anionic lactones react, at low temperature, with HCl to give rise to the neutral lactones [(CO)4Fe{C(O)C(CH3) (CRR′R″)OC4(O)(Fe-C4)}] (2), which were previously obtained by addition of NuH nucleophiles to 1. Complex 3(3), whose lactonic ring formation has been performed using the diethyl malonate anion (R = R′ = CO2C2H5; R″ = H), and the dimethyl-substituted neutral lactone 2(1) (R = R′ = R″ = H) have been characterized by X-ray diffraction studies. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Cabon, Patrice,Rumin, Rene,Salauen, Jean-Yves,Des Abbayes, Herve,Triki, Smail
-
p. 1515 - 1524
(2007/10/03)
-
- Lewis base character of hydroxygermylenes for the preparation of heterobimetallic LGe(OH)M systems (M = Fe, Mn, L = HC[(CMe)(NAr)]2, Ar = 2,6-iPr2C6H3)
-
LGeOH (1; L = HC[(CMe)(NAr)]2, Ar = 2,6-iPr2C 6H3) reacted with iron and manganese complexes to give LGe(OH)Fe(CO)4 (2) and LGe(OH)Mn(Cp)(CO)2 (3; Cp = cyclopentadienyl). Compounds 2 and 3
- Pineda, Leslie W.,Jancik, Vojtech,Colunga-Valladares, Juan F.,Roesky, Herbert W.,Hofmeister, Anja,Magull, Joerg
-
p. 2381 - 2383
(2008/10/09)
-
- Low-valent α-diimine iron complexes for catalytic olefin hydrogenation
-
A family of low-valent α-diimine iron complexes has been synthesized and their utility in catalytic olefin hydrogenation reactions evaluated. Reduction of the ferrous dichloride complex [ArN=C(Me)C(Me)=NAr]FeCl2 (Ar = 2,6-(CHMe2)2-C6H3) with sodium amalgam in benzene or toluene furnished the iron arene complexes, [ArN=C(Me)C(Me)=NAr]Fe(η6-C6H5R) (R = H, Me). The solid-state structure of the toluene adduct revealed a contracted carbon-carbon backbone, short iron-imine bonds, and elongated imine nitrogen-carbon distances, suggesting significant reduction of the α-diimine ligand. The analogous reduction in alkane solvents afforded the bis(α-diimine) complex [ArN=C(Me)C(Me)=NAr]2Fe, which has also been crystallographically characterized. The arene complexes and the bis(a-diimine) complexes are inactive for catalytic olefin hydrogenation. Performing the reduction in the presence of internal alkynes such as diphenylacetylene and bis(trimethylsilyl)acetylene furnished the alkyne adducts [ArN=C(Me)C(Me)=NAr]Fe(η2-RC=CR) (R = Ph, SiMe3 ). Analogous olefin complexes with 1,5-cyclooctadiene and cycloctene have also been isolated using similar reduction procedures. The olefin adducts provide more active precatalysts than the alkyne compounds for the hydrogenation of 1-hexene. In each case, formation of rfarene adducts serves as a major catalyst deactivation pathway.
- Bart, Suzanne C.,Hawrelak, Eric J.,Lobkovsky, Emil,Chirik, Paul J.
-
p. 5518 - 5527
(2008/10/09)
-
- The transition metal carbonyl complexes of 1,3-bis(di-R-stibino)propanes (R = Me or Ph)
-
The synthesis and characterisation of complexes of two distibinopropanes R2Sb(CH2)3SbR2 (R = Me or Ph) with a variety of metal carbonyls is described. These include cis-[M(CO) 4{R2Sb(CH2)3SbR2}] (M = Cr, Mo or W), [{Fe(CO)4}2{μ-R2Sb(CH 2)3SbR2}], [{Ni(CO)3} 2{μ-R2Sb(CH2)3SbR2}], [Co2(CO)6{Ph2Sb(CH2) 3SbPh2}], [Co2(CO)4{Me 2Sb(CH2)3SbMe2}3][Co(CO) 4]2 and [Mn2(CO)8{Ph 2Sb(CH2)3SbPh2}]. The complexes have been characterised by analysis, mass spectrometry, IR and multinuclear NMR spectroscopy as appropriate. Comparison of the spectroscopic data on these complexes with those of other stibine complexes and with complexes of Group 16 ligands has been used to establish the relative electronic properties of the distibines.
- Brown, Michael D.,Levason, William,Manning, Joanna M.,Reid, Gillian
-
p. 1540 - 1548
(2007/10/03)
-
- Formation of anionic trifunctionalized metallalactones by nucleophilic addition at the β-carbonyl of a pyruvoyl ligand
-
Anionic nucleophilic reagents Nu- = CH3O-, C2H5O-, t-BuO-, CH 3S-, and P(C6H5)2 - were found to react with (CO)
- Cabon,Rumin,Salauen,Triki,Des Abbayes
-
p. 1709 - 1717
(2008/10/09)
-
- Unraveling the photochemistry of Fe(CO)5 in solution: Observation of Fe(CO)3 and the conversion between 3Fe(CO)4 and 1Fe(CO)4(solvent)
-
The photochemistry of Fe(CO)5 (5) has been studied in heptane, supercritical (sc) Ar, scXe, and scCH4 using time-resolved infrared spectroscopy (TRIR). 3Fe(CO)4 (34) and Fe(CO)3(solvent) (3) are formed as primary photoproducts within the first few picoseconds. Complex 3 is formed via a single-photon process. In heptane, scCH4, and scXe, 34 decays to form 14·L (L = heptane, CH4, or Xe) as well as reacting with 5 to form Fe2(CO)9. In heptane, 3 reacts with CO to form 14·L. The conversion of 34 to 14·L has been monitored directly for the first time (L = heptane, kobs = 7.8(±0.3) x 107 s-1; scCH4, 5(±1) x 106 s-1; scXe, 2.1(±O.1) x 107 s-1). In scAr, 34 and 3 react with CO to form 5 and 34, respectively. We have determined the rate constant (kCO = 1.2 x 107 dm3 mol -1 s-1) for the reaction of 34 with CO in scAr, and this is very similar to the value obtained previously in the gas phase. Doping the scAr with either Xe or CH4 resulted in 34 reacting with Xe or CH4 to form 14·Xe or 14·CH4. The relative yield, [34]:[3] decreases in the order heptane > scXe > scCH4 ? scAr, and pressure-dependent measurements in scAr and scCH4 indicate an influence of the solvent density on this ratio.
- Portius, Peter,Yang, Jixin,Sun, Xue-Zhong,Grills, David C.,Matousek, Pavel,Parker, Anthony W.,Towrie, Michael,George, Michael W.
-
p. 10713 - 10720
(2007/10/03)
-
- Contributions to the reactivity of phosphaalkynes with transition metal complexes - (see abstract) net Beitraege zum reaktionsverhalten von phosphaalkinen gegenueber uebergangsmetallkomplexen - (See abstract)
-
The reaction of MesC≡P (Mes = 2,4,6-Me3C6H 2) with [(Ph3P)2Pt(η2-C 2H4)] leads to [(Ph3P)2Pt(η 2-PCMes)] (1) whereas with Fe2/su
- Himme, Daniel,Seitz, Markus,Scheer, Manfred
-
p. 1220 - 1228
(2008/10/09)
-
- Oriented long single walled carbon nanotubes on substrates from floating catalysts
-
A new and feasible method to prepare long and well-oriented SWNTs on substrates in large scale is developed by applying a floating catalyst chemical vapor deposition (CVD) process. The catalysts for SWNT growth come from the decomposition of iron pentacarbonyl (Fe(CO)5) formed in situ from the reaction of iron powder and carbon monoxide gas. The growth of SWNTs is found to happen both on the substrate and in the gas flow. Both long and short nanotubes are formed on the substrates but only the long SWNTs are aligned by gas flow. The growth direction and the density of the long SWNTs can be easily controlled. In addition, long SWNTs can be cut and patterned using photolithography and water plasma etching techniques, offering a way to prepare patterned SWNTs with controllable orientation, density and lengths for various applications.
- Huang, Shaoming,Cai, Xianyu,Du, Chunsheng,Liu, Jie
-
p. 13251 - 13254
(2007/10/03)
-
- Specific formation of isocyanide iron complexes by reaction of primary carbamoyl ferrates with oxalylchloride
-
Reaction of primary carbamoyl ferrates {(CO)4Fe[C(O)NHR]} - (R=Me, Et, allyl, decyl, cyclohexyl, t-butyl, benzyl, phenyl) with 1/2 equiv. of oxalylchloride affords cis-bis-carbamoyl intermediates: (CO) 4Fe[C(O)NHR]2 which thermally give rise, in good yields, to the mono-isocyanide complexes (CO)4Fe(CNR). The mechanism of the reaction is discussed. Via a similar process, an alkoxycarbamoyl intermediate (CO)4Fe[C(O)NHR](CO2Me) affords Fe(CO)5 and 1,3-dialkylurea.
- Luart, Denis,Salaün, Jean-Yves,Patinec, Véronique,Rumin, René,Des Abbayes, Hervé
-
p. 656 - 660
(2008/10/08)
-
- Protonation studies of the new iron carbonyl cyanide trans-[Fe(CO) 3(CN)2]2-: Implications with respect to hydrogenases
-
The new iron carbonyl cyanide trans-[Fe(CN)2(CO) 3]2-, [2]2-, forms in high yield via photosubstitution of Fe(CO)5 with 2 equiv of Et4NCN. Protonation of [2]2- generated [HFe(CN)
- Kayal, Ajay,Rauchfuss, Thomas B.
-
p. 5046 - 5048
(2008/10/08)
-
- Synthesis and characterization of high-spin [(CO)3FeII(CO2R)3]2Fe II complexes formed by thermolysis of cis-(CO)4Fe(CO2R)2 (R = Me, t-Bu, allyl, 1,1′-dimethylallyl). X-ray crystal structure of the allyl derivative
-
Instead of the expected carbon-carbon coupling into oxalates, thermolysis at 30 °C of the cis-bis(alkoxycarbonyl) monomers (CO)4Fe(CO2R)2 (1) affords the novel trimetallic compounds [(CO)3Fe(μ,η2-CO2R)3]2 Fe (R = Me (2a), t-Bu (2b), allyl (2c), 1,1′-dimethylallyl (2d)). As shown by 1H and 13C NMR, these complexes 2, which can be described as a central Fe(II) surrounded by two [(CO)3Fe(CO2R)3]- ligands, are paramagnetic. A Mo?ssbauer study of 2a and 2d revealed that these complexes display a high-spin configuration of their central iron atom and a low-spin configuration of the two lateral iron atoms. The easy formation of these complexes 2 by reacting fac-[(CO)3Fe(CO2R)3]- anions with FeCl2 suggests that formation of 2 by thermal evolution of 1 could occur via an associative mechanism, giving rise to the [(CO)3Fe(CO2R)3] pattern. Further thermolysis of 2 at 50 °C affords alcohols, Fe(CO)5, carbon monoxide, and bis(alkyl carbonates).
- Le Gall, Nathalie,Luart, Denis,Salaün, Jean-Yves,Talarmin, Jean,Des Abbayes, Hervé,Toupet, Lo?c,Menendez, Nieves,Varret, Fran?ois
-
p. 1775 - 1781
(2008/10/08)
-
- A new approach to studying the mechanism of catalytic reactions: An investigation into the photocatalytic hydrogenation of norbornadiene and dimethylfumarate using polyethylene matrices at low temperature and high pressure
-
This paper presents a new method for investigating the mechanisms of homogeneously catalyzed reactions involving gases, particularly H2. We show how the combination of polyethylene (PE) matrices and high pressure - low temperature (HPLT) experiments can be used to provide new mechanistic information on hydrogenation processes. In particular, we show how we are able to generate reaction intermediates at low temperature, and then to extract the contents of the PE film at room temperature to characterize the organic products using GC-MS. We have used our new technique to probe both the hydrogenation of dimethyl fumarate (DF), using Fe(CO)4(η2-DF) as the catalytic species, and the hydrogenation of norbornadiene (NBD), using (NBD)M(CO)4 (M = Cr or Mo) as the catalytic species. Irradiation of Fe(CO)4(η2-DF) in a PE matrix at 150 K resulted in the formation of an intermediate complex tentatively assigned Fe(CO)3(η4-DF). Warming this complex to 260 K under H2 leads to the formation of Fe(CO)3(η2-DF)(η2-H2). Further warming of the reaction system results in the hydrogenation of the coordinated DF, to generate dimethyl succinate (DS). Characterization of the intermediate species was obtained using FTIR spectroscopy. Formation of DS was confirmed using both FTIR spectroscopy and GC-MS analysis. UV photolysis of (NBD)M(CO)4 in PE under H2 in the presence of excess NBD results in the formation of the hydrogenated products norbornene (NBN) and nortricyclene (NTC), with trace amounts of norbornane (NBA) being observed. These products were in similar ratios to those observed in fluid solution. However, for (NBD)Mo(CO)4, the relative amounts of the organic products change considerably when the reaction is repeated in PE under H2 in the absence of free NBD, with NBA being the major product. The use of our HPLT cell allows us to vent and exchange high pressures of gases with ease, and as such we have performed gas exchange reactions with H2 and D2. Analysis of the reaction products from these exchange reactions with GC-MS provides evidence for the mechanism of formation of NBA, in both the presence and absence of excess NBD, a reaction which has been largely ignored in previous studies.
- Childs,Cooper,Nolan,Carrott,George,Poliakoff
-
p. 6857 - 6866
(2007/10/03)
-
- Chain-ring isomerism vs. carbon-carbon coupling on two (tetracarbonyliron)-γ-ketoesters: Cis-[Fe(COR)(COCOR′)(CO)4] (R = Me, R′ = OMe; R = OMe, R′ = Me)
-
Ferra-γ-ketoesters 1 and 2 induce thermally either a carbon-carbon coupling process or a chain-ring isomerization; the orientation of the reaction likely depends on the proximity of the ester group to the metal centre.
- Sellin, Murielle,Luart, Denis,Salauen, Jean-Yves,Laurent, Pascale,Toupet, Loic,Des Abbayes, Herve
-
p. 857 - 858
(2007/10/03)
-
- Charge-transfer crystals of octacarbonyldiferrate. Solid-state structure and oxidation-reduction of an iron-iron-bonded electron donor
-
The dinuclear carbonylmetalate [Fe2(CO)8]2- forms deeply colored crystals A2[Fe2(CO)8] with various phosphonium and pyridinium cations (A+) by metathesis in aqueous solution. Diffuse reflectance absorption spectroscopy and X-ray crystallography establish the colors to derive from anion-to-cation charge-transfer (CT) within the triple ion [A+, Fe2(CO)82-, A+] extant in the solid state. Partial electron transfer in the charge-transfer salts is established by the significant shortening of the iron-iron bond in the [Fe2(CO)8]2- moiety when it is ion paired with the N-methyllutidinium acceptor. In solution, the charge-transfer salts can undergo interionic electron transfer, and they lead to the dimeric A2 and a series of iron carbonyl products that are uniquely dependent on the solvent (water, ether, and acetonitrile).
- Bookman,Cho,Kochi
-
p. 5221 - 5231
(2008/10/09)
-
- Radical processes in the reduction of nitrobenzene promoted by iron carbonyl clusters. X-ray crystal structures of [Fe3(CO)9(μ3-NPh)]2-, [HFe3(CO)9(μ3-NPh)]-, and the
-
The halides Cl-, Br-, and I- and the pseudo-halide NCO- react with Fe3(CO)12 (1) in aprotic solvents to induce a disproportionation reaction yielding the radical anion [Fe3(CO)s
- Ragaini, Fabio,Song, Jeong-Sup,Ramage, David L.,Geoffroy, Gregory L.,Yap, Glenn A. P.,Rheingold, Arnold L.
-
p. 387 - 400
(2008/10/08)
-
- Chemical Behaviour of the Mixed-metal Carbonyl Clustrs (1-) and (2-). Crystal Structures of (1-) and >(1-)
-
Addition of triphenylphosphine to the cluster (1-) yielded the derivative (1-), which is stable enough to allow a single-crystal X-ray analysis on the (1+) salt.The cluster contains a triangular metallic framework, the vertices of which are occupied by two Fe(CO)4 groups and one Rh(CO)(PPh3) moiety; the unsaturation of the cluster (46 valence electrons) is brought about by this 16-electron square-planar fragment.The cluster (2-) was obtained by treating with (1-) (molar ratio 1 : 2) in refluxing acetone, and was characterized by infrared spectroscopy and elemental analyses.The adduct >(1-) was prepared by stoichiometric addition of in acetone and the crystal structure of the (1+) salt was elucidated by X-ray analysis.The cluster contains a trigonal-bipyramidal arrangement of metal atoms, with one Au(PPh3) and one Fe(CO)3 group occupying the apical positions.The vertices of the FeRh2 equatorial plane are bound to two terminal carbonyl ligands, and the edges are spanned by three bridging carbonyls.The 31P NMR spectral data for (1-) and >(1-) are consistent with the solid-state structures, but do not exclude the presence of fluxional processes in solution.
- Pergola, Roberto Della,Fracchia, Lucia,Garlaschelli, Luigi,Manassero, Mario,Sansoni, Mirella
-
p. 2763 - 2768
(2007/10/03)
-
- Synthesis and reactivity of bis(alkyloxalyl) and alkoxycarbonyl alkyloxalyl iron complexes and (R, R'=Me or Et): evidence for reductive elimination of oxalate
-
The new complexes cis- (R=Me or Et) and cis- (R,R'=Me, Et or i-Pr) have been synthesized.The bis-(alkyloxalyl) complexes decarbonylate at +12 deg C to their alkoxycarbonyl alkyloxalyl homologues.The latter decompo
- Laurent, Pascale,Salauen, Jean-Yves,Gall, Gwenaeelle Le,Sellin, Murielle,Abbayes, Herve des
-
p. 175 - 184
(2007/10/02)
-
- C-H bond-making and -breaking processes in heteronuclear monoazadienyl complexes: Reactivity of HFeRu(CO)5{RC=C(H)C(H)=N-iPr} toward CO
-
In the photochemically induced reaction of Ru2(CO)6{RC=C(H)CH2N-iPr} (1a, R = Ph; 1b, R = Me) with Fe2(CO)9 the heteronuclear complex HFeRu(CO)5{RC=C(H)C(H)=N-iPr} (5) is formed in 35 % yield. HRu2(CO)6{RC=C(H)C(H)=N-iPr} (4), which is prepared quantitatively by photolysis of H2Ru4(CO)8{RC=C(H)C(H)=N-iPr}2 under a CO atmosphere, can act as an intermediate in this reaction and is proposed to be formed from 1 by a β-H-elimination reaction. Complex 5 is most likely formed via oxidative addition of the Ru-H bond in 4 to a Fe(CO)4 fragment. Complex 5 reacts with CO at 293 K to give reductive elimination of the monoazadiene ligand and formation of Fe(CO)5/Ru3(CO)12, probably via a mechanism involving opening of the hydride bridge. In the reaction of 5 with CO at 373 K the hydride is shifted to the monoazadienyl (MAD-yl) ligand, which is reduced from formally monoanionic to dianionic. In the case of R = Ph selective hydride transfer to Cβ is observed, resulting in the formation of FeRu(CO)6-{PhC(H)C(H)C(H)N-iPr} (6a), which features an unprecedented coordination mode of the MAD-yl ligand. For R = Me, both transfer to Cβ (affording 6b) and to Cim is observed, the latter affording FeRu(CO)6{MeC=C(H)CH2N-iPr} (7). This R-group dependence and also the difference in the reactivity of 5 and its homonuclear Ru2 analogue 2 is rationalized by the strength of the π-C=C coordination in the intermediate HFeRu(CO)6{RC=C(H)C(H)=N-iPr} (9). Complex 9a could not be prepared by the reaction of [FeRu(CO)6(PhC=C(H)C(H)=N-iPr}][BF4] (8a) with NaBH4, which afforded one diastereomer of FeRu(CO)6{PhCC(H)C(H)N-(H)-iPr} (10a), but 9a was formed by the conversion of 8a on silica. The X-ray crystal structures of 6a and 9a have been determined. Crystals of 6a are monoclinic, space group P21/c, with unit-cell dimensions a = 12.106(14) A?, b = 9.490(10) A?, c = 16.780(7) A?, β = 97.61(7)°, V = 1911(3) A?3, Z = 4, final R = 0.055, and Rw = 0.040 for 2215 reflections with I > 3.0σ(7) and 245 parameters. Crystals of 9a are orthorhombic, space group P212121, with a = 9.819(1) A?, b = 11.928(1) A?, c = 17.338(1) A?, V = 2030.7(3) A?3, Z = 4, and final R = 0.044 for 1434 reflections with I > 2.5σ(7) and 254 parameters. The most important conclusion of this work is that isostructural FeRu- and Ru2-MAD-yl complexes show a large difference in reactivity, which can be rationalized by stronger π-coordination of the MAD-yl ligand to Fe as compared to Ru.
- Beers, Olaf C. P.,Elsevier, Cornelis J.,Kooijman, Huub,Smeets, Wilberth J. J.,Spek, Anthony L.
-
p. 3187 - 3198
(2008/10/08)
-
- Energetics and mechanism of the thermal decarboxylation of (CO)4FeCOOH- in the gas phase
-
The energetics and mechanism of decarboxylation of (CO)4FeCOOH- to form CO2 and (CO)4FeH-, a key step in the Fe(CO)5-catalyzed water-gas shift reaction, is investigated using the flowing afterglow-triple quadrupole technique. Previous studies of collisional activation of (CO)vFeCOOH- in the gas phase showed only loss of CO ligands, suggesting that base catalysis is necessary for decarboxylation. We have now observed gas-phase decarboxylation of this hydroxycarbonyl km using energy-resolved collision-induced dissociation. Decarboxylation competes with decarbonylation at translational energies near the reaction threshold, indicating that unimolecular β-elimination of CO2 can occur. Loss of two carbonyl ligands to form (CO)3FeOH- is the dominant process at somewhat higher energies. The thresholds for loss of CO, 2CO, and CO2 are 21.4 ± 3.9, 30.2 ± 2.8, and 18.9 ± 3.2 kcal/mol, respectively. The latter number corresponds to a barrier for an exothermic reaction. DH[Fe(CO)5-OH-] = 60.8 ± 3.4 kcal/mol is determined by measurement of the equilibrium constant for hydroxide exchange between Fe(CO)5 and SO2. (CO)4FeSOOH- + CO2 is formed as a side product of this reaction, and the structure of this species is investigated. These data are combined with other thermochemistry to derive a model reaction-energy profile for the Fe(CO)5-catalyzed water-gas shift reaction.
- Sunderlin,Squires, Robert R.
-
p. 337 - 343
(2007/10/02)
-
- Synthesis of the square-bipyramidal cluster 4-SiMe)2(CO)11> by two routes and its reaction with GeMe2H2. The crystal structures of 4-SiMe)2(CO)11> and 4-SiMe)2(CO)10>
-
4-SiMe)2(CO)11> (1a) is the major product from the reaction of with (synthesised from SiMeH2Cl and Na2).An alternative, quantitative synthesis of 1a is from SiMeH3 and , 1a reacts with an
- Anema, Skelte G.,Lee, Siew Kim,Mackay, Kenneth M.,Nicholson, Brian K.
-
p. 211 - 218
(2007/10/02)
-
- Synthesis, reactivity of the dialkoxycarbonyl carbonyl iron complexes (L = CO or PPh3; R = CH3, C2H5), and an easy access to +
-
The cis-dialkylcarboxytetracarbonyliron complexes were readily obtained from reaction of oxalyl chloride with the corresponding tetracarbonylcarboxyiron anion - (R = Me, 1a; R = Et, 1b). 1a underwent a clean ligand exchange with triphenylphosphine to give (2).Neither 1a nor 2 yielded dimethyl oxalate after thermolysis; rather, a mixture of methanol and methyl carbonate was obtained.The mobility of the alkoxy groups on 1 was shown by several exchange experiments.A clean reaction of the tetrafluoroboric acid ether with 1a gave + which was isolated and characterized by IR, 1H, and 13C NMR spectroscopy.
- Salauen, Jean-Yves,Gall, Gwenaeelle le,Laurent, Pascale,Abbayes, Herve des
-
-
- Reaction of potassium tetracarbonylhydridoferrate with aryl halides: mechanistic study and extension to the catalytic carbonylation of iodobenzene by a bimetallic Fe(CO)5-Co2(CO)8 system
-
Potassium tetracarbonylhydriodoferrate, KHFe(CO)4, reacts with aryl iodides in wet methanol to yield the corresponding arenes. This reaction is catalytic under carbon monoxide (1 atm) in the presence of an excess of base. Mechanistic investigations, both by IR analysis and by electrochemical experiments, show that the reaction involves an electron transfer from HFe(CO)4- to the aryl halide to generate the corresponding radical anion. The resulting aryl radical either abstracts an hydrogen atom from potassium methoxide of combines with the [HFe(CO)4] radical species to form ArFe(H)(CO)4, which yields ArH by reductive elimination. The catalytic carbonylation of iodobenzene to benzoic acid can be performed under very mild conditions by a bimetallic system, viz. HFe(CO)4--Co(CO)4-. The observed synergetic effect is believed to involve first an electron transfer from HFe(CO)4- to iodobenzene and generation of a phenyl radical, followed by reaction with Co(CO)4-, which acts as the actual carbonylation catalyst. In agreement with these hypotheses, the carbonylation of bromobenzene, which on its own is unreaction under these conditions, can be promoted by the presence of iodobenzene.
- Brunet,de Montauzon,Taillefer
-
p. 341 - 346
(2008/10/08)
-
- Group- and electron-transfer reactions of tetracarbonylferrate(2-)
-
Reactions of Fe(CO)42- with metal carbonyl complexes lead to distinct mechanisms. Reaction with metal carbonyl cations gives a two-electron process that we interpret as a CO2+ transfer. Reaction with Mn2(CO)10 occurs by a single-electron transfer producing Fe2(CO)82- and Mn(CO)5-. Reaction with Mn(CO)5Br also occurs by a single-electron transfer. Reaction with Re(CO)5Br could be either SET or direct nucleophilic displacement. Kinetic studies are reported for several reactions.
- Zhen, Yueqian,Atwood, Jim D.
-
p. 2778 - 2780
(2008/10/08)
-
- Studies on the synthesis and C-C bond-forming reactions of binuclear iron complexes: Evidence for intramolecular interactions between organic fragments bonded to the metal
-
In an attempt to investigate the various reaction pathways available for C-C bond-forming reactions, the synthesis and study of the chemical behavior of the binuclear complex bis(μ,η2-decanoyl)hexacarbonyldiiron was undertaken. Thermal decomposition of the complex in cyclohexane yields three organic products, n-octadecane, 10-nonadecanone, and 10,11-eicosadione. The principal organometallic product is Fe(CO)5. The decomposition when monitored by FT-IR spectroscopy displays a clean first-order kinetics and is characterized by an unusually large negative entropy of activation, ΔS? = -29.7 eu (log A = 6.07). Absence of crossover products in the combined decomposition of mixtures of bis(acyl)diiron complexes indicates that the principal products are formed in processes that do not involve alkyl group scrambling and presumably occur by intramolecular pathways. Additional evidence for this postulate is derived from the observed kinetics of the reaction of the diiron complex with triphenylphosphine, implying a unimolecular rate-determining equilibrium step prior to a fast product-forming sequence. The reactivity of the bis(decanoyl)hexacarbonyldiiron complex with methyl iodide, methyl alcohol, and acetic acid is also briefly examined.
- Sundararajan
-
p. 1377 - 1382
(2008/10/08)
-
- Redox Reaction of Aromatic Aldehydes with Fe3(CO)12
-
Aromatic aldehydes react with Fe3(CO)12 in refluxing benzene ultimately to give arylmethyl alcohols and 1,2-diaryl-1,2-ethanedione in a 1:1 ratio.In some cases, small amounts of 2,4,5-triaryl-1,3-dioxolanes are formed as minor products.Dinuclear iron complex (1,2-diphenyl-1,2-ethanedioxido)Fe2(CO)7 has been isolated as an intermediate in the reaction of benzaldehyde with Fe3(CO)12.The mechanism of this redox reaction of aromatic aldehydes are discussed on the basis of the kinetic study of the reaction and also of the reactivity of the isolated dinuclear iron complex.
- Itoh, Keiji,Nakanishi, Saburo,Otsuji, Yoshio
-
p. 118 - 122
(2007/10/02)
-
- Reaction Kinetics of Coordinatively Unsaturated Iron Carbonyls Formed on Gas-Phase Excimer Laser Photolysis of Fe(CO)5
-
The reactions of species produced on gas-phase excimer laser photolysis of Fe(CO)5 have been followed by transient infrared spectroscopy employing a diode laser probe.The initial photoproducts formed on 193-nm photolysis are identified as Fe(CO)2 and a product that is most likely Fe(CO).Both Fe(CO)2 and Fe(CO)3 are produced on 248-nm photolysis.Photolysis at 351 nm leads to the production of both Fe(CO)3 and Fe(CO)4.Species best assigned as excited states of Fe(CO)3 and Fe(CO)4 are observed to form as initial photoproducts following 248- and 351-nm photolysis, respectively.The magnitudes of the rate constants for reaction of the various coordinatively unsaturated metal carbonyls formed in this study with parent Fe(CO)5 or CO (summarized in Table I) are consistent with the hypothesis that spin-allowed reactions will be rapid while spin-disallowed reactions will be considerably slower.To provide further data in testing this hypothesis, the reaction of Fe(CO)4 with both O2 and H2 has been measured.
- Ryther, Robert J.,Weitz, Eric
-
p. 9841 - 9852
(2007/10/02)
-
- Electron transfer between mononuclear metal carbonyl anions (M(CO)5-, M = Mn, Re; CpFe(CO)2-; CpM(CO)3-, M = Cr, Mo) and trinuclear clusters (M3(CO)12, M = Fe, Ru, Os) and between trinuclear dianions (M3(CO)112-, M = Fe, Ru, Os) and metal carbonyl dimers (Mn ...
-
Full title: Electron transfer between mononuclear metal carbonyl anions (M(CO)5-, M = Mn, Re; CpFe(CO)2-; CpM(CO)3-, M = Cr, Mo) and trinuclear clusters (M3(CO)12, M = Fe, Ru, Os) and between trinuclear dianions (M3(CO)112-, M = Fe, Ru, Os) and metal carbonyl dimers (Mn2(CO)10 and Cp2M2(CO)6, M = Cr, Mo, W). Reaction of mononuclear metal carbonyl anions with trinuclear clusters of group 8 (M3(CO)12, M = Fe, Ru, Os) at ambient conditions leads to four separate outcomes: (1) formation of the metal carbonyl dimer and the trinuclear dianion which occurs whenever the two-electron reduction potential for the dimer is more negative than for the trinuclear cluster, (2) formation of MFe2(CO)7- by elimination of Fe(CO)5 which occurs for M = Re(CO)5, Mn(CO)5, and CpMo(CO)3, (3) formation of the adduct, MRu3(CO)11-, which occurs for Re(CO)5, and (4) no reaction when the two-electron reduction potential for the trinuclear complex is more negative than for the dimer. For complexes where the two-electron potential for the cluster is more negative than for the dimer, reaction of M3′(CO)112- with M2 to give M3′(CO)12 and 2M- is observed. The observed reactions allow an estimate of the two-electron reduction potentials for the trinuclear clusters. The kinetics of all of these reactions indicate a first-order dependence on the oxidant and on the reductant and are most consistent with outer-sphere electron transfer.
- Shauna Corraine,Atwood, Jim D.
-
p. 2647 - 2651
(2008/10/08)
-
- Synthesis of metal-rich metallaborane clusters. Evidence for a mechanism involving fragment condensation
-
A mechanistic hypothesis of metallaborane cluster build-up the condensation of metal and boron containing fragments, which is supported by circumstantial evidence from previous work, suggests improved routes to the synthesis of ferraboranes.This work desc
- Meng, Xiangsheng,Bandyopadhyay, Ananda K.,Fehlner, Thomas P.,Grevels, Friedrich-Wilhelm
-
-
- Addition of electrophiles to metalladiborane anions 2-B2H5)>- (Fe, Ru, Os)
-
Addition of the electrophiles (CH3)+, H+, + to the metalladiborane anions 2-B2H5)>- (M = Fe, Ru, Os) has been investigated.Addition occurs at the metal center.The complexes CH3Os(CO)4(η2-B2H5), HM(CO)4(η2-B2H5) (M = Ru, Os) and (PPh3)AuM(CO)4(η2-B2H5) (M = Fe, Ru, Os) have been formed.NMR spectra of HM(CO)4(η2-B2H5) indicate that the H atom on the metal is cis to the B2H5 ligand.Relative stabilities of the complexes LM(CO)4(η2-B2H5) are in the order M = Os > Ru > Fe for a given electrophile and the order L = (Ph3P)Au > H for a given metal.
- Coffy, Tim J.,Shore, Sheldon G.
-
p. C27 - C30
(2007/10/02)
-
- Synthesis and reactivity of the metal-substituted borane (CO)4CoBH2·THF. Preparation of the ambiphilic clusters (CO)9Co3C(CH2)nOH (n = 4, 5)
-
The reaction Co2(CO)8 + 2BH3·THF → 2(CO)4CoBH2·THF (I) + H2 has been demonstrated to occur cleanly at -15°C in THF. I has been characterized by low-temperature 11B NMR and infrared spectroscopies as well as classical chemical analysis. The formation of I bears a remarkable similarity to that of (CO)4CoSiR3. Displacement of the bound THF of I occurs with Lewis bases, and the Lewis acidity of I relative to that of BH3·THF for SMe2 has been estimated. Displacement of [Co(CO)4]- from I occurs easily; e.g., reaction with PhMgBr yields PhBH2. I readily accepts hydride from [HFe2(CO)8]-, losing [Co(CO)4]- but reduces the CO ligands of hydride-free metal carbonylate anions. I is a very active reducing agent and above 10°C cleaves THF and condenses with hydrocarbyl and metal fragments to yield a mixture of clusters including an unusual tailed cluster (CO)9Co3C(CH2)nOH (n = 4,5) (II). A deuterium labeling experiment showed that four of the n carbons in the hydrocarbyl chain of II arise from THF. The results of an X-ray diffraction study suggest association of II in the solid state. [Crystals of II (the ratio of II with n = 5/n = 4 is 4) form in the space group R3 with unit cell parameters a = 34.409 (15) A?, b = 34.398 (21) A?, c = 8.575 (5) A?; β = γ = 90°, γ = 120°, V = 8789.8 A?3, and Z = 18. Solution was by direct methods, and all atoms were refined to R1 = 0.077 and R2 = 0.096 for 1443 independent reflections (Fo > 3σ(Fo)). Because of the disorder caused by the cocrystallization of species with different chain lengths, the last two atoms at the OH end of the chain could not be fully defined.] Association of II in solution is shown by a 1H NMR study, thereby demonstrating that II behaves as an ambiphilic cluster.
- Basil, John D.,Aradi, Allen A.,Bhattacharyya, Nripendra K.,Rath, Nigam P.,Eigenbrot, Charles,Fehlner, Thomas P.
-
p. 1260 - 1270
(2008/10/08)
-
- Solvent Influence on Trifluoromethylation Reactions with Cd(CF3)2: One-pot Synthesis of Trifluoromethyl Iron Complexes
-
Bis(trifluoromethyl)cadmium complexes Cd(CF3)2*L (L=2CH3CN or CH3OCH2CH2OCH3) react as perfluoroalkyl Grignard reagents with carbonyl-iron halides in a one-pot reaction to yield Fe-CF3 compounds easily.A strong solvent influence is observed.The dependence of the direction of the reactions, either as a trifluoromethylation or a fluorination, is discussed.In the presence of CH3CN a ligand-exchange reaction is observed, yielding trifluoromethyl iron acetonitrile complexes, while carbonyl complexes are obtained in ethers.The compound has been prepared in 65percent yield, and its (19)F n.m.r., i.r., Raman, mass, and Moessbauer spectra recorded.The adventage of observing the (13)C satellites in the (19)F n.m.r. spectra for the analysis of trifluoromethyl metal compounds is established.If the appropriate reaction conditions are used, Cd(CF3)2 complexes react as fluorination reagents and CF2 sources.Thus, on reaction of the trifluoromethyl cadmium reagents with tetracarbonyliron halides in CH3CN, diamagnetic fluoroiron acetonitrile complexes are formed.
- Dukat, Wolfgang,Naumann, Dieter
-
p. 739 - 744
(2007/10/02)
-
- Characterization of open clusters with linked GeFe2 or SnFe2 triangles: Structures of Ge2Fe6(CO)23, Sn2Fe6(CO)23, and Ge2Fe7(CO)26
-
Reactions of GeH4 or Ge2H6 with Fe2(CO)9 in hexane at 68°C have revealed a rich system. Two new Ge-Fe clusters have been spectroscopically and structurally characterized; Ge2Fe6(CO)23 (3b) is the linked-triangle homologue of Ge[Fe2(CO)8]2 with four GeFe2 units [C23Fe6Ge2O23, a = 13.872 (1) A?, b = 14.5501 (7) A?, c = 9.2221 (7) A?, a = 96.875 (6)°, β = 97.152 (6)°, γ = 67.398 (6)°, triclinic, P1, Z = 2], while Ge2Fe7(CO)26 (4b) shows two μ-Ge[Fe2(CO)8] groups on adjacent sides of an Fe3 triangle [C26Fe7Ge2O26, a = 17.25 (1) A?, b = 17.14 (1) A?, c = 25.89 (4) A?, orthorhombic, Pbca, Z = 8]. The analogous tin complexes are formed with use of SnH4, and Sn2Fe6(CO)23 (3a) with four SnFe2 triangles has been structurally characterized [C23Fe6Sn2O23, a = 8.921 (1) A?, b = 12.551 (3) A?, c = 16.444 (5) A?, α = 95.65 (2)°, β = 104.53 (2)°, γ = 100.83 (2)°, triclinic, P1, Z = 2].
- Anema, Skelte G.,Mackay, Kenneth M.,Nicholson, Brian K.
-
p. 3158 - 3164
(2008/10/08)
-
- Reactivity of Fe(CO)4(H)MPh3 (M = Si, Ge) and mechanism of substitution by two-electron-donor ligands: Implications for the mechanism of hydrosilylation of olefins catalyzed by Fe(CO)5
-
cis-Fe(CO)4(H)MPh3 (M = Si, Ge) complexes undergo carbonyl displacement with nucleophilic ligands (phosphines, phosphites) to give Fe(CO)3(H)(L)MPh3. With M = Si the geometry of these complexes depends on the nature of the solvent; in nucleophilic solvents the mer-OC-6-43 isomer is formed, while in nonnucleophilic solvents the mer-OC-6-23 isomer is obtained (the cis positions of H and Si are retained). These two isomers undergo concerted reductive elimination of silane with PPh3. The mer-OC-6-43 isomer reacts 183 ± 19 times faster than the mer-OC-6-23 isomer in toluene at 26.0°C, giving the same 16-electron intermediate; the calculated equilibrium constant for the interconversion of OC-6-43 and OC-6-23 is 823 ± 192 at 26.0°C in toluene. Owing to the strong acidity of Fe(CO)4(H)MPh3 (pKa estimated as 3CN) and of Fe(CO)3(H)(PPh3)MPh3 (pKa estimated as ≤8.94 in CH3CN), reaction with basic two-electron-donor ligands [P(alkyl)3, P(cycloalkyl)3, NR3] leads to the formation of the anionic trigonal-bipyramidal complexes [Fe(CO)4MPh3]- and [Fe(CO)3(L)MPh3]-. cis-Fe(CO)4(H)SiPh3 reacts with isoprene to give [Fe(CO)4SiPh3]2; this reaction is not observed with Fe(CO)3(H)(L)SiPh3. The versatile reactivity of these complexes sheds some light on the mechanism of hydrosilylation of olefins and conjugated dienes. Under thermal conditions previous coordination of the olefin to the metal in this reaction seems to be excluded.
- Bellachioma, Gianfranco,Cardaci, Giuseppe,Colomer, Ernest,Corriu, Robert J. P.,Vioux, André
-
p. 519 - 525
(2008/10/08)
-
- Thiolate, Thioether, and Thiol Derivatives of Iron(0) Carbonyls
-
A new series of anionic complexes of iron tetracarbonyl monofunctionalized with the ligand ->,-> (R = Ph, Et, Me, H), have been synthesized and characterized.The compound was formed in the reaction of and PhSSPh.The -> anion was characterized by X-ray diffraction as its +> salt and found to be a typical trigonal-bipyramidal complex in which the phenylthiolate ligand occupies an axial position with a Fe-S bond distance of 2.332(5) Angstroem and Fe-S-C(Ph) = 111.3(6) deg.The salt crystallized inthe orthorhombic space group Pbc21, with a = 9.529(4) Angstroem, b = 21.493(9) Angstroem, c = 20.185(9) Angstroem, V = 4134(3) Angstroem3, and Z = 2.Other members of the series of complexes, ->, were best obtained by ligand exchange of -> and the labile thioether complex (PhSMe)Fe(CO)4.The latter was produced from the low-temperature alkylation of the ->.Protonation of the thiolates (R = Ph, Et, Me, H) ultimately leads to formation of H2 and Fe2(μ-SR)2(CO)6; however, the intermediate thiol, (RSH)Fe(CO)4, could be observed at -78 to -40 deg C for R = Et, Me.The PhSH and HSH derivatives were unstable even at -78 deg C.
- Liaw, Wen-Feng,Kim, Christine,Darensbourg, Marcetta Y.,Rheingold, Arnold L.
-
p. 3591 - 3597
(2007/10/02)
-
- Synthesis, characterization, and reactivity of iron carbonyl clusters containing bismuth or antimony. Crystal structures of isomorphous [Et4N][BiFe3Cr(CO)17] and [Et4N][SbFe3Cr(CO)17] and the ring complex Bi2Fe2(CO)8Me2
-
The reaction of [Et4N]2[Fe2(CO)8] with BiCl3 or SbCl3 forms compounds (Ia, E = Bi; Ib, E = Sb) that are proposed to be the previously characterized [Et4N] [EClFe3(CO)12] based on elemental analyses and spectroscopic data. Treatment of Ia or Ib with Cr(CO)5(THF) produces [Et4N] [EFe3Cr(CO)17] (11a and 11b, respectively), while the methylation of Ia affords Bi2Fe2(CO)8Me2 (III). Refluxing Ia and Ib in acetonitrile gives the previously known [Et4N]2[Bi2Fe4(CO)13] and [Et4N]2[Sb2Fe5(CO)17], respectively. IIa, IIb, and III have been characterized by X-ray crystallography. IIa crystallizes in the centrosymmetric triclinic space group P1 (no. 2) with a = 12.297 (3) ?, b = 15.154 (3) ?, c = 9.791 (1) ?, α = 107.60 (1)°, β = 95.24 (2)°, γ = 92.02 (2)°, V = 1727.9 (6) ?3, and Z = 2. The structure was refined to R = 4.5% and Rw = 5.3% for those 5114 reflections with I > 3σ(I). The core framework of IIa consists of a distorted tetrahedral BiFe3Cr cluster in which a central bismuth atom is bonded to isolated Fe(CO)4 and Cr(CO)5 groups and a metal-metal-bonded Fe2(CO)8 fragment. The Fe-Fe bond distance is 2.608 (2) ?, and the Fel-Bil-Fe2 angle is 56.91 (4)°. IIb is isomorphous with IIa: centrosymmetric triclinic space group P1 (no. 2), a = 12.233 (1) ?, b = 15.108 (5) ?, c = 9.742 (3) ?, α = 107.23 (3)°, β = 94.61 (2)°, γ = 92.37 (1)°, V = 1710.0 (9) ?3, and Z = 2. Diffraction data were refined to R = 4.2% and Rw = 5.7% for those 6100 reflections with I > 3σ(I). The Fe-Fe bond distance in IIb is 2.598 (1) ?. III crystallizes in the centrosymmetric triclinic space group P1 (no. 2) with a = 7.571 (4) ?, b = 8.734 (4) ?, c = 7.136 (3) ?, α = 107.02 (4)°, β = 108.41 (4)°, γ = 79.89 (4)°, V = 426.3 (4) ?3, and Z = 1. Refinement converged at R = 4.1% and Rw = 5.3% for those 1355 reflections with I > 3σ(I). III consists of a Bi2Fe2 parallelogram situated about a crystallographic inversion center. There is one Me group bonded to each bismuth atom. The Fe(CO)4 groups are pseudooctahedral with an average Bi-Fe distance of 2.786 ?. The Bi-C distance is 2.28 (1) ?.
- Whitmire, Kenton H.,Shieh, Minghuey,Cassidy, Juanita
-
p. 3164 - 3170
(2008/10/08)
-
- 1,5-Dihydropyrrol-2 ones from (1,4-diaza-1,3-diene)tricarbonyliron, (DAD)Fe(CO)3, and alkyne. 5. Spectroscopic and X-ray structural characterization of a bicyclo[2.2.1] complex resembling the initial cycloadduct. The C=N-Fe fragment in (DAD)Fe(CO)3 as an isolobal analogue of the classical 1,3-dipole azomethine ylide in 1,3-dipolar cycloaddition
-
In solution, [biacetyl bis(4-methoxyanil)]Fe(CO)3 (1a) reacts instantly with dimethyl acetylenedicarboxylate, even at -90°C. Depending on the additional ligand offered, different products are isolated. Under 1 atm of CO, the expected 1,5-dihydropyrrol-2-one complex 3a is formed at room temperature from which the coordinated heterocycle can be displaced by using CO pressure (180 bar) at elevated temperature. When P(OMe)3 is offered instead, a ferrabicyclo[2.2.1] complex, 4a, can be isolated which is spectroscopically characterized (IR, FD-MS, and 1H, 13C, and 31P NMR). Above -20°C, 4a transforms into 5a, C28H33-N2O11PFe, of which the structure has been determined by single-crystal X-ray diffraction: space group P1, a = 11.833 (4) A?, b = 13.740 (2) A?, c = 11.607 (3) A?, α = 102.94 (2)°, β = 106.79 (2)°, γ = 76.54 (2)°, V = 1732.0 A?3, Z = 2, R = 0.048 (Rw = 0.075) for 5862 reflections with I > 2.5σ(I). In 5a the bicyclo[2.2.1] core of 4a is retained, while the phosphorus ligand has changed from a trivalent, 2e-donating phosphite in 4a to a covalently bound, pentavalent phosphonate in Sa. With the bicyclo[2.2.1] structure being established, the initial step in the reaction of (diazadiene)Fe(CO)3 complexes with dipolarophilic acetylenes is formulated in terms of an oxidative 1,3-dipolar cycloaddition of the alkyne to the C=N-Fe fragment. The isolobal analogy between the latter and the classic Huisgen 1,3-dipole R2C=N(R)-CR2 is demonstrated.
- Frühauf, Hans-Werner,Seils, Frank,Stam, Casper H.
-
p. 2338 - 2343
(2008/10/08)
-
- Multiple Bonds Between Main-Group Elements and Transition Metals, LIX. - Bridging Tin Atoms in Organomanganese Complexes. Formation, Structures, and Reactivity of Manganese-Tin Multiple Bonds
-
Organomanganese complexes with tin atoms in linear and trigonal-planar coordination environments are accessible by means of two different synthetic methods.Sequential treatment of the complex (η5-C5H4CH3)Mn(CO)2(THF (1a) with tin(II) chloride and zinc dust yields (μ3-Sn)5-C5H4CH3)Mn(CO)2>3 (2a); 2a is also formed from 1a and monostannane, SnH4.The pentamethylcyclopentadienyl derivative 1b yields analogously the two compounds (μ3-Sn)5-C5Me5)Mn(CO)2>3 (2b) and (μ-Sn)5-C5Me5)Mn(CO)2>2 (3b). 2a formally contains two Mn-Sn single bonds and a Mn-Sn double bond (X-ray diffraction study). - Keywords: Bridging tin atoms/ Organomanganese complexes
- Herrmann, Wolfgang A.,Kneuper, Heinz-Josef,Herdtweck, Eberhardt
-
p. 437 - 444
(2007/10/02)
-
- Synthesis of Alkyl(alkoxycarbonyl)tetracarbonyliron Complexes : the First Evidence of their Relevance to the Catalytic Cycle in the Carbonylation of Organic Halides induced by Pentacarbonyliron
-
Reaction of (1-) (1) (R = Me or But) with BrCH2CO2Me produces stable complexes (3) which thermally decompose to yield Fe(CO)5 and malonic esters under a CO atmosphere; these reactions provide the first demonstration of possible key steps in the catalytic cycle of the carbonylation of reactive halides into esters with Fe(CO)5 and an alkoxide anion.
- Laurent, Pascale,Sabo-Etienne, Sylviane,Larsonneur, Anne-Marie,Abbayes, Herve des
-
p. 929 - 930
(2007/10/02)
-
- Improved syntheses of M2 (M=Si, Ge or Sn) and the X-ray crystal structure of Si2
-
The reaction of MH4 (M=Si, Ge) with Fe2(CO)9 in hexane gives Si2 or Ge2 in 61 or 43 percent yield, respectively.A reproducible synthesis of Sn2 from 2- and SnCl4 in thf is also described.The X-ray crystal structure of Si2 shows two mutually perpendicular SiF2 triangles linked at the common spiro-silicon atom, with each iron atom carrying four terminal CO ligands.Average bond length are: Fe-Si 2.345(4), Fe-Fe 2.795(3) Angstroem.
- Anema, Skelte G.,Barris, Glen C.,Mackay, Kenneth M.,Nicholson, Brian K.
-
p. 207 - 216
(2007/10/02)
-