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1.
It is shown that electrode catalysis of substitution reactions can operate even for systems with rather slow chemical steps and, furthermore, for those which are electrochemically irreversible. A procedure is described for synthesis of Fe(CO)(PPh3)(η5-C5H5)COCH3 from Fe(CO)2(η5-C5H5)CH3 and triphenylphosphine. A simplified mechanism for the catalytic chain, is given and discussed in terms of the structure of the reacting species. 相似文献
2.
Eulalia Ramirez-Oliva Jorge Cervantes Francisco Cervantes-Lee Ramesh N. Kapoor Keith H. Pannell 《Journal of organometallic chemistry》1996,510(1-2):57-62
A transition metal-substituted silylacetylene [(η5-C5H5)Fe(CO)2SiMe2C]2, [FpMe2SiC]2 (I) was synthesized and characterized spectroscopically and structurally. I crystallized in the monoclinic space group P21/n, A = 13.011(3) Å B = 12.912(3) Å, C = 13.175(5) Å, β = 94.95(2). The acetylene linkage is reactive toward Co2(CO)8 to form I. Co2(CO)6 (II) which was also characterized spectroscopically and by single crystal X-ray diffraction. II crystallized in the orthorhombic space group Pbca, A = 17.64(2) Å, B = 14.225(10) Å, C = 24.49(2) Å. 相似文献
3.
Salih S. Al-Juaid Peter B. Hitchcock Julian A. Johnson John F. Nixon 《Journal of organometallic chemistry》1994,480(1-2):45-50
The preparation of novel 1-arsa-3,4-diphospholyl and 3-arsa-1,4-diphospholyl anions of the type (C2tBu2AsP2)− is described. Spectroscopic and structural characterisation of mono-and bi-metallic complexes of these anions are also reported. 相似文献
4.
Darryl P. Klein N. Quir s M ndez Jeffery W. Seyler Atta M. Arif J. A. Gladysz 《Journal of organometallic chemistry》1993,450(1-2):157-164
The crystal structures of propionaldehyde complex (RS,SR)-(η5-C5H5)Re(NO)(PPh3)(η2-O=CHCH2CH3)]+ PF6− (1b+ PF6s−; monoclinic, P21/c (No. 14), a = 10.166 (1) Å, b = 18.316(1) Å, c = 14.872(2) Å, β = 100.51(1)°, Z = 4) and butyraldehyde complex (RS,SR)-[(η5-C5H5)Re(NO)(PPh3)(η2-O=CHCH2CH2CH3)]+ PF6− (1c+PF6−; monoclinic, P21/a (No. 14), a = 14.851(1) Å, b = 18.623(3) Å, c = 10.026(2) Å, β = 102.95(1)°, Z = 4) have been determined at 22°C and −125°C, respectively. These exhibit C
O bond lengths (1.35(1), 1.338(5) Å) that are intermediate between those of propionaldehyde (1.209(4) Å) and 1-propanol (1.41 Å). Other geometric features are analyzed. Reaction of [(η5-C5H5)Re(NO)(PPh3)(ClCH2Cl)]+ BF4− and pivalaldehyde gives [(η5-C5H5)Re(NO)(PPh3)(η2-O=CHC(CH3)3)]+BF4− (81%), the spectroscopic properties of which establish a π C
O binding mode. 相似文献
5.
The reductive electrochemistry of compounds of the type CpFe(CO)2L (Cp = η-C5H5, η-C5Me5; L = SP(S)(OEt)2, SP(S)(OiPr)2) has been examined by polarography, cylic voltammetry and coulometry. The first one-electron reduction step leads to a bond rupture process with formation of a mercury compound, [CpFe(CO)2]2Hg, at a mercury electrode and the corresponding dimer species at a platinum electrode. The second reduction step corresponds to the reduction of the dimer [CpFe(CO)2]2, except in the polarographic reduction of pentamethylcyclopentadienyl compounds. 相似文献
6.
Rainer Bartsch Peter B. Hitchcock John F. Nixon 《Journal of organometallic chemistry》1988,340(3):C37-C39
Syntheses of the novel sandwich compounds [Fe(η5-C5H5)(η5-C2R2P3)] and [Fe(η5-C5H5)(η5-C2R2P3)W(CO)5], (R = But), are described. The mode of attachment of the [W(CO)5] fragment in the latter compound has been determined by NMR and single crystal X-ray diffraction studies. 相似文献
7.
The mechanism of the transformation of (η5-C5H5)2NbCl2 to (η5-C5H5)2NbH3 by hydridoaluminate reducing agents has been investigated. Results suggest disproportionation of a niobium(IV) hydrite, leading to the trihydride product and a niobium(III) hydridoaluminate, (η5-C5H5)2NbH2AlR2, which in turn is converted to the trihydride on hydrolysis. (η5-C5H5)2NbH2AlH2 has been isolated; deuterium labelling shows that hydrogens exchange between ring and metal-bridging positions in this molecule. 相似文献
8.
Michael I. Bruce Peter Hinterding Edward R. T. TiekinkBrian W. Skelton Allan H. White 《Journal of organometallic chemistry》1993,450(1-2)
Reactions between [Ru(thf)(PPh3)2(η-C5H5)]+ and lithium acetylides have given further examples of substituted ethynylruthenium complexes that are useful precursors of allenylidene and cumulenylidene derivatives. From Li2C4, mono- and bi-nuclear ruthenium complexes were obtained: single-crystal X-ray studies have characterised two rotamers of {Ru(PPh3)2(η-C5H5)}2(μ-C4), which differ in the relative cis and trans orientations of the RuLn groups. Protonation of Ru(CCCCH)(PPh3)2(η-C5H5) afforded the butatrienylidene cation [Ru(C=C=C=CH2)(PPh3)2(η-C5H5)]+, which reacted readily with atmospheric moisture to give the acetylethynyl complex Ru{CCC(O)Me}(PPh3)2(η-C5H5), also fully characterised by an X-ray structural study. 相似文献
9.
Junes Ipaktschi Katja Reimann Michael Serafin Ansgar Dülmer 《Journal of organometallic chemistry》2003,670(1-2):66
Treatment of the η1-acetylide complex [(η5-C5H5)(CO)(NO)W---CC---C(CH3)3]Li (4) with 1,2-diiodoethane in THF at −78 °C, followed by the addition of Li---CC---R [R=C(CH3)3, C6H5, Si(CH3)3, 6a–6c] or n-C4H9Li and protonation with H2O, afforded the corresponding oxametallacyclopentadienyl complexes (η5-C5H5)W(I)(NO)[η2-O=C(CC---R)CH=CC(CH3)3] (7a–7c), 8c and (η5-C5H5)W(I)(NO)[η2-O=C(n-C4H9)CH=CC(CH3)3] (9). The formation of these metallafuran derivatives is rationalized by the electrophilic attack of 1,2-diiodoethane onto the metal center of 4 to form first the neutral complex [(η5-C5H5)(I)(CO)(NO)W---CC---C(CH3)3] (5). Subsequent nucleophilic addition of Li---CC---R 6a–6c or n-C4H9Li and a reductive elimination step followed by protonation leads to the products 7a–7c and 9. One reaction intermediate could be trapped with CF3SO3CH3 and characterized by a crystal structure analysis. The identity of another intermediate was established by infrared spectroscopic data. The oxametallacyclopentadienyl complex 10 forms in the presence of excess 1,2-diiodoethane through an alternative pathway and crystallizes as a clathrate containing iodine. 相似文献
10.
Stuart R. Berryhill 《Journal of organometallic chemistry》1989,370(1-3):C1-C4
The silyl group migration observed upon treating (R)(+)-(η5-C5H5)Fe(CO)2-SiMePh(1-Np) with n-BuLi occurs with retention of configuration at silicon. The anion resulting from the migration, (η5-C5H4SiMePh(1-Np))Fe(CO)2Li, is alkylated with MeI to give (R)-(−)-(η5-C5H4SiMePh(1-Np))Fe(CO)2Me (II). Compound II is independently prepared from (η5-C5H5)Fe(CO)2Me. A concerted mechanism for the migration involving frontside nucleophilic attack at silicon is suggested. 相似文献
11.
The complex [MoW(μ-CC6H4Me-4)(CO)2(η7-C7H7)(η5-C2B9H10Me)] reacts with diazomethane in Et2O containing EtOH to afford the dimetal compound [MoW(OEt)(μ-CH2){μ-C(C6H4Me-4)C(Me)O}(η7-C7H7)(η5-C2B9H10Me)]. The structure of this product was established by X-ray diffraction. The Mo---W bond [2.778(4) Å] is bridged by a CH2 group [μ-C---Mo 2.14(3), μ-C---W 2.02(3) Å] and by a C(C6H4Me-4)C(Me)O fragment [Mo---O 2.11(3), W---O 2.18(2), Mo---C(C6H4Me-4) 2.41(3), W---C(C6H4Me-4) 2.09(3), Mo---C(Me) 2.26(3) Å]. The molybdenum atom is η7-coordinated by the C7H7 ring and the tungsten atom is η5-coordinated by the open pentagonal face of the nido-icosahedral C2B9H10Me cage. The tungsten atom also carries a terminally bound OEt group [W---O 1.88(3) Å]. The 1H and 13C-{1H} NMR data for the dimetal compound are reported and discussed. 相似文献
12.
Won Seok Seo Youn Jaung Cho Sung Cheol Yoon Joon T. Park Younbong Park 《Journal of organometallic chemistry》2001,640(1-2):79-84
Reaction of ansa-cyclopentadienyl pyrrolyl ligand (C5H5)CH2(2-C4H3NH) (2) with Ti(NMe2)4 affords bis(dimethylamido)titanium complex [(η5-C5H4)CH2(2-C4H3N)]Ti(NMe2)2 (3) via amine elimination. A cyclopentadiene ligand with two pendant pyrrolyl arms, a mixture of 1,3- and 1,4-{CH2(2-C4H3NH)}2C5H4 (4), undergoes an analogous reaction with Ti(NMe2)4 to give [1,3-{CH2(2-C4H3N)}2(η5-C5H3)]Ti(NMe2) (5). Molecular structures of 3 and 5 have been determined by single crystal X-ray diffraction studies. 相似文献
13.
LI Xiu-juan ZENG Zheng-zhi 《高等学校化学研究》2006,22(1):6-10
IntroductionSince K pf[1]discovered that dicyclopenta die-nyltitanium dichloride possesses antitumour action in1979,a large number of cyclopentadienyltitanium com-plexes with different substituents have been synthe-sized[2,3].The experimental data reveal … 相似文献
14.
A high yield synthesis of the carbonyl dithiocarbamato derivative Fe(CO)2(η2-S2CNMe2)2 and Fe(η2-S2CNMe2)2 by photolysis with visible light of solutions containing Fe2(CO)9 or Fe3(CO)12 and [(η5-C5H5)(CO)3W(η1-SCSNMe2)] is reported. 相似文献
15.
16.
Slawomir Szafert Frdric Paul Wayne E. Meyer John A. Gladysz Claude Lapinte 《Comptes Rendus Chimie》2008,11(6-7):693-701
We report in this communication the synthesis and characterization of two Fe/Re heterodinuclear complexes 3n of formula (η5-C5Me5)Re(NO)(PPh3)(CC)n(η2-dppe)Fe(η5-C5Me5) (n = 3, 4) as well as the hexacarbonyl dicobalt adduct (4) of the hexatriynediyl complex 33. We show by cyclic voltammetry that the “electronic communication” between the organometallic endgroups and thereby the thermodynamic stability of the corresponding mixed-valent (MV) parent 3n+ is strongly influenced by bridge extension or by complexation of the [Co2(CO)6] fragment. In the case of the hexatriynediyl complex, the MV complex 33+ or 4 can be isolated by performing the chemical oxidation of 33 at low temperature. Spectroscopic studies of this compound and of other stable oxidized redox congeners should now help us to unravel how bridge extension modifies the electronic communication between the different redox-active endgroups in this family of unsymmetrically-substituted polyynediyl compounds. 相似文献
17.
It is shown that electrode catalysis of substitution reactions can operate even for systems with rather slow chemical steps and, furthermore, for those which are electrochemically irreversible. A procedure is described for synthesis of Fe(CO)(PPh3)(η5-C5H5)COCH3 from Fe(CO)2(η5-C5H5)CH3 and triphenylphosphine. A simplified mechanism for the catalytic chain, is given and discussed in terms of the structure of the reacting species. 相似文献
18.
The complex [Ir(σ-carb)(CO)(PhCN)(PPh3)], where carb = -7-C6H5-1,2C2B10H10, was found to be an effective catalyst for homogeneous hydrogenation of terminal olefins and acetylenes at room temperature and atmospheric or subatmospheric hydrogen pressure. Internal olefins are not hydrogenated, but simple alk-1-enes are readily converted into the corresponding alkanes. Isomerization of the double bond catalyzed by the metal complex occurs at very small extent. Catalytic hydrogenation of olefins having carboxylate substituents on the unsaturated carbon atoms is prevented by the formation of thermally stable chelate hydridoalkyl complexes of the type I(σ-CHRCHR′C(O)OR″) (σ-carb)(CO)(PPh3)]. Acetylenes are hydrogenated to alkenes. The alk-1-enes formed in the hydrogenation of the alkynes HCCR in turn undergo the more slow reactions either of hydrogenation to alkanes or isomerization to internal olefins which cannot be further hydrogenated. Hydrogenation of alkynes of the type RCCR′ is stereospecifically cis, yielding cis- olefins. Catalyzed cis → trans isomerization reaction of these internal olefins occurs only to a negligeable extent. 相似文献
19.
Takeo Yamamoto Chie Shikada Shojiro Kaita Tardif Olivier Yooichiroh Maruyama Yasuo Wakatsuki 《Journal of molecular catalysis. A, Chemical》2009,300(1-2):1-7
The Ni-methyl complex (η5-C5H5)Ni(CH3)(PPh3) (1) reacted with B(C6F5)3 to give an unstable contact ion-pair complex with a μ-methyl bridge between the Ni and B atoms. Formation of the B-CH3 bond was confirmed by the reaction of this complex with PPh3 to give [(η5-C5H5)Ni(PPh3)2][B(CH3)(C6F5)3] which was structurally characterized. Spontaneous decomposition of the contact ion-pair complex yielded (η5-C5H5)Ni(C6F5)(PPh3) which is very stable and does not show any reactions with norbornene with or without added B(C6F5)3. 19F NMR study showed that the polynorbornene obtained by the catalysis of 1/B(C6F5)3 system has the C6F5 end-group. A series of reactions, which includes CH3/C6F5 exchange between the Ni and B centers with concomitant dissociation of PPh3 to accept coordination of a norbornene monomer, is proposed as the route to active species that can initiate vinyl polymerization of norbornene. 相似文献
20.
The reactions of [Co(η-C5H5)(CO)(PR3)] or [Co(η-C5GH5)(CO)2]/R3P mixtures (R = alkyl or aryl) with CS2 in refluxing CS2 or CS2/toluene gives rise to [Co(η-C5H5)(PR3)(CS)], [Co(η-C5H5)(PR3)(CS2)], [Co(η-C5H5)(PR3)(CS3)], and [Co3(η-C5H5)3 (CS)(S)] in reasonable yields. The corresponding reactions using PhNCS give [Co(η-C5H5)(PPh3)(PhNCS)] and a polymeric species which appears to be [Co4(η-C5H5)4 (PhNCS)]. Similar products are obtained with [Co(η-C5H5)(CO)(CNR)] or [Co(η0C5H5)(CO)2]/RNC mixtures. 相似文献