14375-85-0Relevant academic research and scientific papers
Triphenyl-phosphine and -arsine analogues which facilitate the electrospray mass spectrometric analysis of neutral metal complexes
Decker, Corry,Henderson, William,Nicholson, Brian K.
, p. 3507 - 3513 (2007/10/03)
The six triarylphosphines PPhn(C6H4OMe-p)3-n and PPhn(C6H4NMe2-p)3-n (n = 0-3) and the arsine As(C6H4OMe-p)3 (L) have been synthesized and examined for their use in the electrospray mass spectrometric (ESMS) study of metal complexes. This has been tested with selected examples of the complexes [Mo(CO)4L2], [Fe(CO)3L2], [Fe(CO)4L], [Ru3(CO)9L3], cis-[PtCl2L2], [PdCl2L2] and [AuCl(L)]. All of the metal carbonyl complexes of these ligands gave [M + H]+ ions in their spectra, while in contrast the analogous PPh3 complexes do not, suggesting that these electrospray-friendly ligands should be useful for the characterisation of a wide range of complexes by ESMS. The incorporation of the ligands into metal halide complexes however does not allow the observation of [M + H]+ ions, with ions formed by the previously reported halide-loss mechanism being the only ones observed. The Royal Society of Chemistry 1999.
Phosphorus-phosphorus coupling constants in mixed-phosphine tricarbonyl iron complexes, Fe(CO)3LL′. Crystal structure of trans-Fe(CO)3(PEt3) (PPh3)
Keiter, Richard L.,Benson, John William,Keiter, Ellen A.,Harris, Travis A.,Hayner, Matthew W.,Mosimann, Laura L.,Karch, Eric E.,Boecker, Carol A.,Olson, Donna M.,Vanderveen, Jennaver,Brandt, Douglas E.,Rheingold, Arnold L.,Yap, Glenn P.A.
, p. 2246 - 2253 (2008/10/08)
Mixed-ligand complexes, trans-Fe(CO)3LL' (L = PPh2Me, L' = PPh2Me, PPhMe2, PMe3, PPh2-Et, PEt3, PPh2CH=CH2, PPh2H, AsPh3, P(OPh)3; L = PMe3, L' = PEt3, PPh2Et, PCy3, PPh2Me, PPhMe; L = PEt3, L' = PPh2Me; L = PPh2H, L' = PPh2CH=CH2, PPh2Et; L = AsPh3, L' = PPhMe2, P(OPh)3, P(OMe)3, P(OEt)3), have been obtained from the stepwise reaction of phosphines with Fe(CO)3(BDA) (BDA = benzylideneacetone) or Fe(CO)3(AsPh3)2 and from the reaction of phosphine with Fe(CO)4PPh3 in the presence of base. A strong negative correlation exists between 2Jpp coupling constant values and the sum of the phosphine pKa values. By application of quantitative analysis of ligand effects, it has been shown that 2Jpp for the mixed-ligand complexes correlates strongly with both γ and Ear, but not with θ. Although a near perfect fit is obtained from the three-parameter equation, a statistical analysis suggests that for this small data set there are no predictive advantages over the one-parameter pKa model. It is possible to calculate reliable 2Jpp values for transFe(CO)3L2 complexes with either model. An X-ray structure of solid-state frans-Fe(CO)3-(PEt3)(PPh3) shows equal Fe-PEt3 and Fe-PPh3 bond distances, implying that bond strength equalization may occur when two rather different phosphines occupy trans coordination sites.
Transition Metal-carbonyl, -hydrido and -η-Cyclopentadienyl Derivatives of the Fullerene C60
Douthwaite, Richard E.,Green, Malcolm L. H.,Stephens, Adam H. H.,Turner, John F. C.
, p. 1522 - 1523 (2007/10/02)
Monoadduct derivatives of the fullerene C60, namely 2-C60)>, 2-C60)> (R = H, Bun), 2-C5H5)2(η2-C60)H> and 2-C60)H>, are described.
Enthalpies of reaction of (diene)- and (enone)iron tricarbonyl complexes with monodentate and bidentate ligands. Solution thermochemical study of ligand substitution in the L2Fe(CO)3 complexes
Luo, Lubin,Nolan, Steven P.
, p. 2410 - 2415 (2008/10/08)
The enthalpies of reaction of (BDA)Fe(CO)3 (BDA = (C6H5)CH=CHO(CH3), benzylideneacetone) with a series of mono- and multidentate ligands, leading to the formation of (η4-L)Fe(CO)3, (L′)2Fe(CO)3, and (L″)Fe(CO)3 complexes (L = diene, enone; L′ = monodentate arsines; L″ = bidentate ligands), have been measured by solution calorimetry in THF at 50°C. The range of reaction enthalpies spans some 44 kcal/mol. The overall relative order of stability established is as follows: for monodetate ligands, AsPh3 3 a relative order of complex stability for these compounds in the iron tricarbonyl system. These data allow the calculation of the enthalpy associated with the geometric isomerization process (axial-equatorial/ diaxial) present in the (L′)2Fe(CO)3 system (5.4 ± 0.5 kcal/mol) as well as for a quantitative analysis of ring strain energies in the (L″)Fe(CO)3 system. The four-membered metallacycle is the only cyclic structure exhibiting significant strain energy (12.6 kcal/mol). Comparisons with other organometallic systems and insight into factors influencing the Fe-L bond disruption enthalpies are also discussed.
DIENE-METAL ? BONDING. SOME UNEXPECTED EFFECTS OF GROUP 5 DONOR LIGANDS ON CARBON-13 NUCLEAR MAGNETIC RESONANCE PARAMETERS AND X-RAY CRYSTAL STRUCTURES
Pearson, Anthony J.,Raithby, Paul R.
, p. 884 - 891 (2007/10/02)
A number of η4-cyclohexadiene-Fe(CO)2L and η4-2-methoxycyclohexadiene-Fe(CO)2L complexes have been prepared and their 13C n.m.r. spectra recorded.Methoxy-substituent effects suggest a depopulation rather than the expected enhanced population of the diene l.u.m.o. (lowest unoccupied molecular orbital) as the ?-acceptor strength of L decreases.X-Ray crystal-structure determinations for L = PPh3 were in agreement, and an explanation is proposed.Complexes (7) and (8) both crystallise in the monoclinic space group P21/c with Z = 4.The cell parameters are a = 10.289(4), b =24.651(10), c = 9.282(4) Angstroem, and β = 109.37(3)deg for (7) and a = 14.444(7), b =18.052(10), c = 9.229.(4) Angstroem and β = 100.57(4)deg for (8).The structures were solved by a combination of Patterson and Fourier-difference techniques, and refined by blocked-cascade least squares to R = 0.053 for 3 325 unique observed reflections (7) and to R = 0.062 for 2 952 reflections (8).
Oxidation of substituted iron carbonyl complexes in acetonitrile, acetone, and dichloromethane at mercury and platinum electrodes
Blanch,Bond,Colton
, p. 755 - 761 (2008/10/08)
The oxidative electrochemistry of the substituted iron carbonyl complexes Fe(CO)4L and Fe(CO)3L2, where L is a monodentate tertiary phosphine, arsine, or stibine ligand, has been studied in acetone, dichloromethane, and acetonitrile at both Hg and Pt electrodes. At platinum electrodes, for L = AsPh3 or SbPh3 the initially generated 17-electron cations [Fe(CO)4L]+ and [Fe(CO)3L2]+ are unstable in all solvents while with phosphorus ligands the species [Fe(CO)3(PPh3)2]+ has some stability in dichloromethane. Reactions leading to decomposition are considered. In marked contrast, at mercury electrodes, the cations appear to be substantially more stable than at platinum, and chemically reversible behavior can be observed where the response is completely irreversible at platinum. The data are explained in terms of a chemically modified pathway at mercury electrodes giving rise to mercury stabilized cations.
Mechanism and equilibrium constants of the reaction between η4-heterodieneiron tricarbonyl complexes and group 5 ligands
Cardaci,Bellachioma
, p. 3099 - 3104 (2007/10/12)
The complexes Fe(CO)3(η2-C6H4XCH=CHCHO)L (where L = CO, X = 4-NMe2, 4-OMe, 3-OMe, 4-Me, 4-Cl; L = SbPh3, X = 3-OMe, 4-Cl) and Fe(CO)2(η4-C6H4XCH=CHCHO)L (where L = CO, X = 4-NMe2, 4-OMe, 3-OMe, 4-Me, 4-Cl; L = PPh3, X = H, 4-Cl, 4-Me, 4-OMe, 3-OMe) have been prepared and characterized. The reaction between Fe(CO)3(η4-C6H4XCH=CHCHO) (where X = H, 3-OMe, 4-Cl) and SbPh3 has been studied and the equilibrium constants and forward and reverse rate constants for this reaction have been measured. From the results obtained, it is concluded that the mechanism of this reaction proceeds via a dissociative equilibrium of the η4 complexes to η4 unsaturated complexes. The reaction between Fe(CO)3(η4-C6H4XCH=CHCHO) (where X = H, 4-NMe, 3-OMe, 4-OMe, 4-Me, 4-Cl) and PPh3 has also been studied. The kinetic law, the activation parameters, and the substituent effect indicate a reaction mode proceeding in two parallel directions. One of these is the same as that found for SbPh3 and the other corresponds to an associative process with the phosphine ligand. These results may be generalized to other diene complexes of iron tricarbonyl.
