102-54-5Relevant articles and documents
Homoleptic complexes of cobalt(0) and nickel(0,I) with 1,1′- bis(diphenylphosphino)ferrocene (dppf): Synthesis and characterization
Pilloni, Giuseppe,Toffoletti, Antonio,Bandoli, Giuliano,Longato, Bruno
, p. 10321 - 10328 (2006)
Reduction of Co(dppf)Cl2 with 2 equiv of sodium naphthalenide in THF, in the presence of dppf, affords the homoleptic complex Co(dppf) 2, 1, isolated in 65% yield as a brick red solid, extremely air sensitive. In solution, under inert atmosphere, 1 slowly decomposes into Co and dppf, following a first-order kinetic law (t1/2 = 21 h at 22°C). Similarly to the Rh and Ir congeners, 1 undergoes a one-electron reversible reduction to [Co(dppf)2]-. Attempts to obtain this d 10 species by chemical as well as electrochemical reduction of 1 lead to the hydride HCo(dppf)2, 2, as the only product that can be isolated. Reduction of Ni(dppf)Cl2 with sodium in the presence of dppf and catalytic amounts of naphthalene affords Ni(dppf)2, 3, isolated in 60% yield as a yellow air stable solid. The stoichiometric oxidation of 3 with [FeCp2]PF6 forms the d9 complex [Ni(dppf)2]PF6, 4, which represents the second example of a structurally characterized Ni(I) complex stabilized by phosphines. A single-crystal X-ray analysis shows for the metal a distorted tetrahedral environment with a dihedral angle defined by the planes containing the atoms P(1), Ni, P(2) and P(3), Ni, P(4) of 78.2° and remarkably long Ni-P bond distances (2.342(3)-2.394(3) A). The EPR spectroscopic properties of 1 (at 106 K in THF) and 4 (at 7 K in 2-methyl-THF) have been examined and g tensor values measured (1, gx = 2.008, gy = 2.182, gz = 2.326; 4, gx = 2.098, gy = 2.113, gz = 2.332). A linear dependence between the hyperfine constants and the Ni-P bond distances has been evidenced. Finally, the change with time of the EPR spectrum of 4 indicates that it very slowly releases dppf.
Reactivity of an early-late heterobimetallic complex toward phosphines: Synthesis, structure, and reactivity of a cationic tantalum-palladium compound with a free cyclopentadienyl counteranion
Butts, Matthew D.,Bergman, Robert G.
, p. 4269 - 4271 (1993)
Treatment of Cp2Ta(CH2)(CH3) with CpPd-(C3H5) led to Cp2Ta(μ-CH2)2PdCp(1). Reaction of 1 with 1 equiv of either PMe3 or P(OMe)3 in CH2Cl2 resulted in the formation of Cp2Ta(μ-CH2)2Pd(PR3)(Cl) (R = Me, 2; R = OMe, 3) and 0.5 equiv of Cp2(CH2). The reaction of 1 with 2 equiv of PMe3 or P(OMe)3 or 1 equiv of Me2P(CH2)2PMe2 (DMPE) led to the isolation of [Cp2-Ta(μ-CH2)2PdL2]Cl (L2 = 2 PMe3, 4; L2 = 2 P(OMe)3, 5; L2 = DMPE, 6). Addition of P(OMe)3 to 1 in CH3CN gave the product Cp2Ta(μ-CH2)2Pd(P(OMe)3)(CH 2CN) (7). Each of these reactions of 1 with phosphorus compounds implicates the intermediacy of free cyclopentadienyl onion. In support of this hypothesis, the stable naked Cp complex [Cp2Ta(μ-CH2)2Pd(DMPE)]Cp (8) was isolated from the reaction of 1 with DMPE in CH3CN and was characterized by X-ray crystallography. The shortest distance between the free anionic Cp group and the bimetallic fragment in 8 is 3.46(3) A. Addition of FeCl2 to 8 resulted in the formation of 1/2 equiv of Cp2Fe and 6. Treatment of 8 with 1,2-dibromoethane led to the quantitative formation of 1/2 equiv of spiro[2.4]hepta-4,6-diene together with the bromide salt of 8.
Unusual reactivities of (μ-η2:η2-FP-CC-H)Co2(CO)6, the adducts of FP-CC-H to Co2(CO)8: photolysis, thermolysis and reduction with hydrosilanes giving polynuclear complexes, (CP)2Fe2Co3(μ5-C=CH)(CO)10, (μ-CH=CH)3-C)Co3(CO)9>2 and CpFeCo3(μ-C=CH2)(CO)9
Akita, Munetaka,Terada, Masako,Ishii, Naomi,Hirakawa, Hideki,Moro-oka, Yoshihiko
, p. 175 - 186 (1994)
The properties and reactivities of (μ-η2:η2-FP-CC-H)Co2(CO)6 (3) C-H adducts to Co2(CO)8: 3a (FP = Fp), 3b (FP = Fp*)> have been compared with those of alkyne adducts (μ-η2:η2-R-CC-R)Co2(CO)6 and the Ph analogue (μ-η2:η2-Fp-CC-Ph)Co2(CO)6 (5).Compound 3 has been shown to serve as a building block for polynuclear complexes. 13CO-labelling experiments on 3a and 5 have revealed an intramolecular exchange between the Fe-CO and Co-CO ligands.Photolysis of 3a, b produces pentanuclear clusters (CP)2Fe2Co3(μ5-C=CH)(CO)10 (11a,b), respectively, via an apparent addition reaction of a (CP)FeCo(CO)n fragment to 3.On the other hand, thermolysis of 3a gives the Fe-free hexacobalt cluster compound (μ-C=CH)3-C)Co3(CO)9>2 (13) which consists of two alkylidyne tricobalt units linked by the CH=CH bridge, whereas 3b is thermolyzed to give the Fe-Co dimer without the C2H ligand, Cp*Fe(CO)(μ-CO)2Co(CO)3 (14), in addition to the photolysis product 11b.Reduction of 3 with hydrosilanes gives a mixture containing 1,2-disilylethylene (16) and the tetranuclear μ-vinylidene cluster CpFeCo3(μ4-C=CH2)(CO)9 (12) formally by way of hydrosilylation and hydrometallation (with a HCo(CO)n species) of the C2H ligand, respectively.In the case of the Pauson-Khand reaction and catalytic cyclotrimerization 3a exhibits reactivities similar to alkyne adducts to give the tricyclic cyclopentenone derivatives 18 (from norbornene and norbornadiene) and triphenylbenzenes, respectively. Key words: Iron; Cobalt; Carbonyl; Polynuclear
Oxidatively induced nucleophilic capture vs. degradation of cyclopentadienyl iron derivatives of simple carboxylic acids and of α-amino acids. A comparative study
Amiens, C.,Balavoine, G.,Guibe, F.
, p. 207 - 219 (1993)
The electrochemical behaviour and the chemical oxidation of various cyclopentadienyl iron complexes of simple carboxylic acids and of amino-protected α-amino acids have been studied in relation to several factors including the nature of the ligands on the metal (Cp, Cp*, CO, PPh3), the nature of the oxidizing agent (one-electron oxidants such as Cu(OTf)2, FcOTf and CAN or a two-electron oxidant such as NBS) and the medium effects (especially the presence or absence of nucleophilic species).With simple carboxylic acid derivatives either homolytic dissociation (leading to alkyl radicals) or nucleophilic capture of the first-formed iron radical cations is observed, depending on the reaction conditions.With α-amino acid derivatives, an oxidative degradation to aldehyde is observed invariably, which is likely to proceed through the successive and transient formation of N-acyl α-amino radicals and N-acyl iminium ions.
Multinuclear complexes derived from ferrocenylphosphines and triruthenium dodecacarbonyl
Zheng, Tu Cai,Cullen, William R.,Rettig, Steven J.
, p. 3594 - 3604 (1994)
Pyrolysis of Ru3(CO)11(PFc2Ph) in hexanes for 15 h gave the trinuclear cluster Ru3(CO)8-(μ-CO)(μ-H)[μ-η 3-(η5-C5H3PFcPh)Fe(η 5-C5H5)] (11) in 20% yield. Pyrolysis of Ru3(CO)12 with PFc2Ph in octane for 3.5 h gave the tetranuclear cluster Ru4(CO)11(μ3-PFc)(μ-η 1:η5-C5H4 (12) in 12% yield and the previously known 8, Ru4(CO)10(μ-CO)μ4-PFc)(μ 4-C6H4), in 10% yield: the mild conditions are noteworthy. Pyrolysis of Ru3(CO)12 with PEt2Fc in octane for 18 h gave the hexanuclear cluster complexes Ru6C(CO)14(μ-PEt2)2 (13) and Ru6C(CO)13(μ-PEt2)-(η5-C 5H5) (14) in 15% and 25% yields, respectively, and the pentanuclear derivative Ru5-(CO)9(μ-CO)(η6-C6H 6)2(μ4-PEt) (15) (low yield). Pyrolysis of Ru3(CO)12 with PEtFc2 in toluene for 10 h gave the pentanuclear cluster Ru5(CO)12(μ4-PEt)(η6-C 7H8) (16) in ～5% yield. Crystal data: 8, monoclinic, space group P21/c, a = 14.725(3) A?, b = 9.024(2) A?, c = 22.719(1) A?, β = 92.078(8)°, Z = 4; 11, triclinic, P1, a = 12.7671(9) A?, b = 13.284(1) A?, c = 10.2212(8) A?, α = 93.006(6)°, β = 98.561(6)°, γ = 83.665(6)°, Z = 2; 12, monoclinic, space group P21/c, a = 10.463(2) A?, b = 16.412(1) A?, c = 17.903(2) A?, β = 103.85(1)°, Z = 4; 13, monoclinic, space group C2/c, a = 12.566(2) A?, b = 16.326(2) A?, c = 17.001(2) A?, β = 105.43(1)°, Z = 4; 14, monoclinic, space group P21/c,a = 12.638(2) A?, b = 9.911(3) A?, c = 24.743(5) A?, β = 91.33-(2)°, Z = 4; 15, orthorhombic, space group Cmc21, a = 16.239(1) A?, b = 13.754(2) A?, c = 11.895(2) A?, Z = 4; 16, monoclinic, space group C2/c, a = 31.831(3) A?, b = 9.904(2) A?, c = 17.536(2) A?, β = 99.36(1)°, Z = 8. The structures were solved by direct or Patterson methods and were refined by full-matrix least-squares procedures to R = 0.042, 0.024, 0.027, 0.024, 0.028, 0.032, and 0.026 for 4943, 8583, 5279, 3650, 6357, 1302, and 5711 reflections with I ≥ 3σ(I), respectively.
AZOLE ANIONS AS ONE-ELECTRON REDUCERS OF FERRICINIUM SALTS
Babin, V. N.,Belousov, Yu. A.,Lyatifov, I. R.,Materikova, R. B.,Gumenyuk, V. V.
, p. C11 - C12 (1981)
Azole anions are capable of reducing ferricinium cation to ferrocene in solution at room temperature.Th formation of azolyl radicals under these conditions is detected.
Ferrocenylaluminum-pyridine adducts, lithium tetra(ferrocenyl)alanate, and the molecular structure of tri(ferrocenyl)aluminum-pyridine
Wrackmeyer, Bernd,Klimkina, Elena V.,Ackermann, Tamara,Milius, Wolfgang
, p. 3941 - 3948 (2009)
Aluminum compounds with up to four ferrocenyl groups (Fc) linked to aluminum were prepared and characterized in solution by NMR spectroscopy (1H, 13C, 27Al NMR), and in one case, tri(ferrocenyl)aluminum-pyridine Fc3/
THE APPLICATION OF 13C AND 1H NMR SPECTROSCOPY TO THE INVESTIGATION OF THE DINITROGEN FIXATION PROCESS IN THE SYSTEM (η-C5H5)2TiCl2-Mg
Sobota, Piotr,Janas, Zofia
, p. 35 - 44 (1983)
The N2 reduction reaction in the system (η-C5H5)2TiCl2-Mg in tetrahydrofuran was examined.The 13C and 1H NMR results as well as the chemical properties of the products formed revealed that the reaction yielded a mixture of compounds in which the titanium atom was bonded both to the μ-(η5: η5-fulvalene) ligand and to the cyclopentadienyl ligands.In this system dinitrogen undergoes reduction to N3-, which then forms M3N bridges (M = Ti, Mg).The nitride nitrogen may readily be oxidized to imide nitride N-1, which may react further, e.g. with carbon monoxideto produce isocyanates, or, with excess oxidizing agent N2.THF in this system undergoes polymerisation.In addition, a - OC4H9 alkoxy group is formed which makes the substitution of the cyclopentadienyl group bonded to the titanium atoms possible.
Oxidation and Protonation of Transition Metal Hydrides: Role of an Added Base as Proton Shuttle and Nature of Protonated Water in Acetonitrile
Alessandra Quadrelli,Kraatz, Heinz-Bernhard,Poli, Rinaldo
, p. 5154 - 5162 (1996)
The Cp2Fe+ oxidation and the protonation of CpMoH(CO)2L (L: PPh3, 1; PMe3, 2) in MeCN have been investigated. In the dry solvent, the oxidation of both compounds consumes 1 mol of oxidant/mol of hydride with production of [CpMo(CO)2L(MeCN)]+ (L: PPh2, [3]+; PMe3, [4]+) and H2. The stoichiometry changes toward the consumption of 2 mol of oxidant in the presence of excess water when the oxidizing equivalents are added rapidly, either chemically or electrochemically. However, 1 oxidizing equiv is again sufficient to consume the hydride material completely under conditions of slow oxidation. Under comparable conditions, the more basic 2 leads to a lower [ox]/M-H stoichiometry. Protonation of 1 and 2 with HBF4·Et2O in dry MeCN results in rapid H2 evolution and formation of [3]+ and [4]+, respectively, whereas the presence of excess water suppresses the H2 evolution and gives rise to protonated water. However, this process is followed by slow and irreversible delivery of the proton back to 1 or 2 to afford [CpMoH2(CO)2L]+, which ultimately decomposes to [3]+ or [4]+ and H2. The dihydride complex is too unstable to be isolated, even when the protonation of 1 or 2 is carried out in a noncoordinating solvent. The proton delivery is faster for the more basic 2 and slower for the less basic 1. Thus, water operates as a proton shuttle , whose speed depends on the basicity difference between the hydride complex and water. The identity of the protonated water in MeCN as [H(H2O)32]+ is suggested by an independent 1H-NMR experiment in CD3CN.
δ-Ferrocenyl-Komplexe des Rutheniums
Herberhold, Max,Feger, Wolfgang,Koelle, Ulrich
, p. 333 - 350 (1992)
The reactions of lithioferrocene (fcLi) and 1,1'-dilithioferrocene (FcLi2) with the halfsandwich ruthenium complexes CpRu(CO)2Cl, Cp*Ru(CO)2Cl and (C6Me6)Ru(CO)Cl2 have been used to prepare the ferrocenyl compounds CpRu(CO)2Fc (1), Cp*Ru(CO)2Fc (2) and (C6Me6)Ru(CO)(Cl)Fc (3), as well as the ferrocenylene compounds 2fc (4) and *Ru(CO)2>2fc (5), respectively. Photodecarbonylation of 1 and 2 in the presence of two-electron ligands (L = CNtBu (a), PPh3 (b), PMe3 (c)) leads to chiral complexes of the type Cp(*)Ru(CO)(L)Fc (1a-c, 2a-c); in the case of L = CNtBu, further CO-substitution takes place to give Cp(*)Ru(CNtBu)2Fc (1d, 2d).Photo-induced reaction of 3 with excess trimethylphosphane, PMe3 (c), produces the octahedral complex mer- (6), whereas organolithiums (nBuLi and p-TolLi, but not FcLi) react with 3 to give (C6Me6)Ru(CO)(R)Fc (R = nBu (7a), p-Tol (7b)).Oxidation of 1, 2 and 3 by AgBF4 leads to paramagnetic salts such as (*)Ru(CO)2Fc>BF4 (1e, 2e) and BF4 (3e).All new complexes were characterized by IR, 1H and 13C NMR, and mass spectroscopy; the Cp and Cp* compounds were also studied by cyclovoltammetry.
