14649-69-5Relevant academic research and scientific papers
Kinetics and Electron Paramagnetic Resonance Evidence of an Electron-transfer Chain Mechanism for PPh3 Substitution of
Luo, Feng-Hurng,Yang, Shehngh-Rur,Li, Chen-Shun,Duan, Jiun-Pey,Cheng, Chien-Hong
, p. 2435 - 2440 (1991)
Rapid PPh3 substitution of to give occurs in tetrahydrofuran at ambient temperature.The reaction is independent of the complex concentration.An electron-transfer-catalysed mechanism is operative in this reaction, with .- as the catalytically active species.The EPR studies indicate that .- is produced rapidly at the beginning of the reaction and its concentration is maintained at a constant value during the reaction.The substitution rate is equal to k.-> with k = (2.7 +/- 0.1)*10-3 s-1.Dissociation of a CO ligand from this radical to yield .- is the rate-limiting step for this electron catalysis.It is believed that .- is formed from a fast disproportionation for induced by an impurity in PPh3.The impurity is likely PPh3O and its concentration is proportional to that of the PPh3 used.
A MILD PHASE TRANSFER SYNTHESIS OF THE YLID ADDUCT (CO)4FeCH2P(C6H5)3 FROM IRON PENTACARBONYL AND DICHLOROMETHANE: EVIDENCE FOR THE TRANSIENT GENERATION OF THE TETRACARBONYL FERRATE ANION Fe(CO)42-
Weiberger, Bernd,Tanguy, Guy,Abbayes, Herve Des
, p. C31 - C33 (1985)
The ylid adduct (CO)4FeCH2P(C6H5)3 (i) was rapidly produced (along) with (CO)4FeP(C6H5)3) by introducing iron pentacarbonyl into the following phase transfer system under nitrogen: CH2Cl2/P(C6H5); H2O/NaOH 1 M, Bu4N+2SO42-.Production of I goes through the transient generation of the tetracarbonyl ferrate anion Fe(CO)42-, which reacts with the dichloromethane
Acrylic acid derivatives of group 8 metal carbonyls: A structural and kinetic study
Li, Bo,Kyran, Samuel J.,Yeung, Andrew D.,Bengali, Ashfaq A.,Darensbourg, Donald J.
, p. 5438 - 5447 (2013)
The synthesis, spectroscopic, and X-ray structural studies of acrylic acid complexes of iron and ruthenium tetracarbonyls are reported. In addition, the deprotonated η2-olefin bound acrylic acid derivative of iron as well as its alkylated species were fully characterized by X-ray crystallography. Kinetic data were determined for the replacement of acrylic acid, acrylate, and methylacrylate for the group 8 metal carbonyls by triphenylphosphine. These processes were found to be first-order in the concentration of metal complex with the rates for dissociative loss of the olefinic ligands from ruthenium being much faster than their iron analogues. However, the ruthenium derivatives afforded formation of primarily mono-phosphine metal tetracarbonyls, whereas the iron complexes led largely to trans-di-phosphine tricarbonyls. This difference in behavior was ascribed to a more stable spin crossover species 3Fe(CO)4 which undergoes rapid CO loss to afford the bis phosphine derivative. The activation enthalpies for dissociative loss of the deprotonated η2-bound acrylic acid ligand were found to be larger than their corresponding values in the protonated derivatives. For example, for dissociative loss of the protonated and deprotonated acrylic acid derivatives of iron(0) the ΔH? values determined were 28.0 ± 1.2 and 34.1 ± 1.5 kcal·mol-1, respectively. Density functional theory (DFT) computations of the bond dissociation energies (BDEs) in these acrylic acids and closely related complexes were in good agreement with enthalpies of activation for these ligand substitution reactions, supportive of a dissociative mechanism for olefin displacement. Processes related to catalytic production of acrylic acid from CO2 and ethylene are considered.
Intuitive Quantifiers of Charge Flows in Coordinate Bonding
Couzijn, Erik P. A.,Lai, Yu-Ying,Limacher, Armin,Chen, Peter
, p. 3205 - 3214 (2017)
ETS-NOCV charge and bond energy analyses have been carried out for a broad range of transition-metal carbonyl complexes L-[M], comprising different ligand classes, transition metals, and coordination geometries. The resulting electronic redistributions are visually assigned to σ donation, π backbonding, and related interactions. We propose a Hirshfeld partitioning of these electronic redistributions to afford the corresponding charge flow contributions Δqσ, Δqπ, etc. Taken together, a detailed picture of the dative bonding arises, in terms of both energetics and the extent of σ-electron donation and π-electron backbonding. The charge flows Δqσ and Δqπ appropriately quantify trends in the ligand σ-donor and π-acceptor abilities and are transferable across the transition-metal complexes studied and thus promise to be suitable descriptors for ligand knowledge bases. As a case in point, the TEP is well reproduced by the calculated νCO(A1) frequencies and is 3 times more strongly affected by Δqσ than by Δqπ, with an additional modest steric influence. Further, empirical relationships are derived among the charge flows Δqσ and Δqπ, the (L)W(CO)5 carbonyl stretching frequencies, and the ligand's steric volume %Vbur, which allow estimating the σ-donor and π-acceptor abilities of phosphines from experimental observables. On the other hand, direct Cl:→L-σ? interactions are identified in several cis-(L)Ir(CO)2Cl complexes, which compromises the use of these species as experimental probes for ligand parameters.
Chemistry of vinylidene complexes. XX. Intramolecular carbonylation of vinylidene on the MnFe center: Spectroscopic and structural study. X-ray structure of the new trimethylenemethane type MnFe complex
Antonova, Alla B.,Chudin, Oleg S.,Vasiliev, Alexander D.,Rubaylo, Anatoly I.,Verpekin, Victor V.,Sokolenko, William A.,Pavlenko, Nina I.,Semeikin, Oleg V.
, p. 963 - 970 (2011)
Reactions of Fe2(CO)9 with Cp(CO)2MnCCHPh (1) and Cp(CO)(PPh3)MnCCHPh (3) gave the heterometallic trimethylenemethane complexes η4-{C[Mn(CO)2Cp](CO) CHPh}Fe(CO)3 (2) and η4-{C[Mn(CO)(PPh 3)Cp](CO)CHPh}Fe(CO)3 (4), respectively. The formation of the benzylideneketene [PhHCCCO] fragment included in complexes 2 and 4 occurs via intramolecular coupling of the carbonyl and vinylidene ligands. The structures of 3 and 4 were determined by single crystal XRD methods. The influence of the nature of the L ligands at the Mn atom on the structural and spectroscopic characteristics of η4-{C[Mn(CO)(L)Cp](CO)CHPh} Fe(CO)3 (L = CO (2), PPh3 (4)) is considered. According to the VT 1H and 13C NMR spectra, complex 2 reversibly transforms in solution into μ-η1:η1-vinylidene isomer Cp(CO)2MnFe(μ-CCHPh)(CO)4 (2a), whereas complex 4 containing the PPh3 ligand is not able to a similar transformation.
Substitutional reactivity of dodecacarbonyltrimetal complexes of iron and osmium
Shojaie, Abdolrasul,Atwood, Jim D.
, p. 187 - 190 (1985)
The kinetics of the substitution reactions of Fe3(CO)12 and Os3(CO)12 have been investigated for L = PPh3, PBu3, P(OPh)3, and P(OMe)3 in hydrocarbon solution. The substitution of the iron cluster leads to both substitution and fragmentation products with a very small dependence on the entering ligand, typical of a CO dissociative interchange mechanism. Substitution of Fe3(CO)11PPh3 leads only to fragmentation at a rate which is faster than substitution on Fe3(CO)12. Substitution on Os3(CO)12 occurs in an entering ligand independent reaction to Os3(CO)9L3. The reactivities of these clusters are compared to the ruthenium analogue and to the mononuclear complexes M(CO)5.
Light-enhanced displacement of methyl acrylate from iron carbonyl: Investigation of the reactive intermediate via rapid-scan fourier transform infrared and computational studies
Muhammad, Sohail,Moncho, Salvador,Li, Bo,Kyran, Samuel J.,Brothers, Edward N.,Darensbourg, Donald J.,Bengali, Ashfaq A.
, p. 12655 - 12660 (2013)
The thermal displacement of methyl acrylate from Fe(CO)4(η 2-CH2=CHCOOMe) by phosphine ligands is a relatively slow reaction requiring several hours at elevated temperatures. In the present study, it is observed that photolysis of the tetracarbonyl complex with UV light activates the process such that the reaction is complete within a few seconds. This rate enhancement is due to the formation of an intermediate η4 complex where the organic C=O and C=C units of methyl acrylate occupy axial and equatorial coordination sites on the Fe center, respectively, following photochemical CO loss. The displacement of methyl acrylate from this photolytically generated intermediate is facile with a remarkably low barrier of 8.7 kcal/mol. Density functional theory calculations support these experimental observations.
Darstellung von Dreikernclustern durch Umwandlung von Fe3(CO)112- und Fe4(CO)132-
Deck, W.,Powell, A. K.,Vahrenkamp, H.
, p. 431 - 443 (1991)
Reactions of the cluster compounds and 2 with organotransition metal halides are described.In all cases a fragmentation of the Fen cluster framework occurs.A common side product resulting from hydride abstraction is , the structure of which was determined.Both starting clusters yield (M = Mn, Re) with (CO)5MnBr and (CO)5ReBr, respectively.The structure of suffers from the same disorder problem as that of Fe3(CO)12.With Cp(PPh3)NiCl the starting clusters form , the structure of which was also determined.
Uebergangsmetall-Silyl-Komplexe. XL. Umsetzung von cis-Fe(CO)4(SiCl3-nMen)2 (n = 1-3) mit Phosphinene: Konkurrenz von CO-Substitution, SiR3-Abspaltung und Bildung zweikerniger, SiR2-verbrueckter Komplexe
Schubert, Ulrich,Knorr, Michael,Strasser, Carmen
, p. 75 - 87 (1991)
Upon reaction of benzene solutions of the bissilyl complexes cis-Fe(CO)4(SiCl3-nMen)2 (n = 1-3) with triphenylphosphine no disilane elimination takes places.Instead, formation of phosphine-substituted bissilyl or hydrido silyl complexes, disiloxanes and F
THE SYNTHESIS OF SOME BI- AND TRI-METALLIC CLUSTERS CONTAINING RHODIUM; X-RAY CRYSTAL STRUCTURES OF 3-CO)3(CO)3(PPh3)3(η-C5H5)>*CH2Cl2 AND
Farrugia, Louis J.,Miles, Anthony D.,Stone, F. Gordon A.
, p. 2415 - 2422 (1984)
Treatment of the complexes (M=Mo or W) with in tetrahydrofuran at room temperature affords the tetranuclear 56 valence-electron cluster compounds 3-CO)3(CO)3(PPh3)3(η-C5H5)>.The structure of the molybdenumtrirhodium species, which crystallises with a molecule of CH2Cl2, has been established by a single-crystal X-ray diffraction study.The metal-atom core approximates to a regular tetrahedron, with Rh-Rh separations 2.710(1)-2.729(1) Angstroem, and Mo-Rh distances 2.764(1)-2.778(1) Angstroem.The molybdenum atom carries the η-C5H5 ligand, and a CO and a PPh3 group are attached to each rhodium atom.These terminal carbonyl ligands are directed below the Rh3 triangle, and the three ligated phosphorus atoms lie above.In addition, a CO group triply bridges each of the MoRh2 faces of the cluster.The reaction between and and .The structure of the 44 valence-electron trimetal compound has been determined by X-ray diffraction.The three metal atoms form a triangle , the molybdenum atom carries the η-C5H5 ligand, and the platinum and rhodium atoms are co-ordinated by PPh3 groups.The three edges of the metal triangle are bridged; the Mo-Rh edge by two CO ligands, the Mo-Pt by PPh2, and the Rh-Pt by a C6H5 group .One carbon of the phenyl group is a ? bonded to platinum and together with an adjacent carbon is η2-co-ordinated to the rhodium.The n.m.r. data (1H, 13C-(1H), and 31P-(1H) for the new compounds are reported and discussed.
