Transition Metal Carbonyl Anions Research Articles

A halogenophilic pathway in the reactions of transition metal carbonyl anions with [(η⁶-iodobenzene)Cr(CO)₃

The paper provides the first example of formal nucleophilic substitution by the halogenophilic pathway in Cr(CO)3 complexes of haloarenes with metal carbonyl anions. All metal carbonyl anions examined attack [(η(6)-iodobenzene)Cr(CO)3] at halogen, which is shown by aryl carbanion scavenging with t-BuOH. The reaction with K[CpFe(CO)2] gives only the dehalogenated arene, but the reaction with K[Cp*Fe(CO)2] (Cp* = η(5)-C5Me5) results in nucleophilic substitution to give [(η(6)-C6H5FeCp*(CO)2)Cr(CO)3]. Reaction with Na[Re(CO)5] quantitatively gives the iodo(acyl)rhenate anion Na[(η(6)-C6H5C(O)ReI(CO)4)Cr(CO)3] and in the case of K[Mn(CO)5] a mixture of σ-aryl complexes [(η(6)-C6H5Mn(CO)5)Cr(CO)3] and K[(η(6)-C6H5Mn(CO)4I)Cr(CO)3]. An analogous rhenium complex Na[(η(6)-C6H5Re(CO)4I)Cr(CO)3] is formed from the initial iodo(acyl)rhenate upon prolonged standing at 20 °C, and its structure (in the form of [NEt4](+) salt) is established by X-ray diffraction analysis. The reaction of [(η(6)-chlorobenzene)Cr(CO)3] with K[CpFe(CO)2], in contrast, proceeds by the common S(N)2Ar mechanism.

Predicting the direction of nucleophilic attack in vinyl halides: halogenophilic versus carbophilic reactivity of metal carbonyl anions

Transition metal carbonyl anions ([M(CO)nL]‐, L=CO, Cp) were previously shown to react with activated vinyl halides (VinHal) via two distinct mechanistic pathways: ‘carbophilic’ addition–elimination substitution (AdNE) and halogenophilic mechanism. Such competition between attack at carbon and halogenophilic attack is relevant for many other reactions of soft nucleophiles with aryl, vinyl, and alkyl halides. As descriptors of the experimentally observed reaction pathway, various quantum‐chemical parameters (π* and σ*C‐Hal molecular orbital and reaction energies, Fukui coefficients ) and their combinations were examined. Correlation of the computational parameters with the kinetic data allowed to develop separate models for VinHal reactivity in AdNE and halogenophilic reactions, and to predict the direction of [M(CO)nL]‐ attack for the whole set of VinHal with reasonable accuracy. The lg(k) of ‘carbophilic’ AdNE reactions were found to roughly correlate with π* lowest unoccupied molecular orbital energies, but a three‐parameter model was required for a more accurate description. The lg(k) of halogenophilic reactions does not correlate with the energy of the corresponding σ*C–Hal molecular orbital, but is well described by a linear combination of density functional theory energies of Hal+ abstraction from VinHal and Hal+ affinity of [M(CO)nL]–. The developed approach can be also used to create a semiquantitative dual electrophilicity scale of vinyl halides (at carbon and at halogen) including the cases, when one of the reaction pathways is experimentally unobservable, because of the much higher rate of competing process. Copyright © 2012 John Wiley & Sons, Ltd.

Reactions of transition metal carbonyl anions with 2-(1-bromoalkylidene)thiazolidin-4-ones: halogenophilic attack or deprotonation

Bromophilic attack by the transition metal carbonyl anion, [Re(CO)5]Na (pKa=21.1), on 2-(1-bromoalkylidene)thiazolidin-4-ones is significantly faster than abstraction of an acidic lactam hydrogen (pKa ∼17–18), when the generated carbanion is stabilized by an α-CN or α-PhCO group. The bromophilic reaction of 2-(1-bromoalkylidene)thiazolidin-4-one, having an α-CN electron-withdrawing group, resulted in formation of a new metallacyclic anionic complex. With less reactive vinyl bromides, containing an α-CONHPh or α-CO2Et group, only deprotonation is observed. The role of the metal carbonyl anion is highlighted by a comparison with the 9-methylfluorenide carbanion (pKa of 9-methylfluorene is 22.3), which reacts exclusively via a deprotonation pathway.

Nucleophilic vinylic substitution with transition metal carbonyl anions—a rare case of a halophilic reaction mechanism: Formation of halo(acyl)rhenate complexes and X-ray structure of cis-[CF 2CF(CO)Re(CO) 4Br]Na

Reactions of polyfluorinated alkenyl halides Z-(CF 3) 3CCFCFHal (Hal=Cl, I- Cl, Hal=Br, I- Br) and CF 2CFBr ( II- Br) with [CpFe(CO) 2]K (FpK) and [Re(CO) 5]Na proceed through the initial attack of metal carbonyl anion on halogen. Reaction with FpK gives minor amounts of σ-alkenyl complexes Z-R f CFCFFe(CO) 2Cp ( I- Fe, II- Fe) (3–30%), but primarily leads to dimer [CpFe(CO) 2] 2. Reaction with [Re(CO) 5]Na produces anionic halo(acyl)rhenates cis-[ Z-R f CFCF(CO)Re(CO) 4Hal]Na ( V- Cl, V- Br, VI) (70–90%) which were isolated, and halo(acyl)rhenate VI (R f =F) was characterized by X-ray structure analysis. Halo(acyl)rhenates result from the attack of the intermediate carbanion [R f CFCF] − on the carbonyl ligand of Re(CO) 5Hal. The involvement of [R f CFCF] − is demonstrated by their trapping with t-BuOH or CH-acid, which gives the protodehalogenated alkenes I- H and II- H, and suppresses the nucleophilic substitution reaction leading to I- Fe, II- Fe or V- Cl. Arguments against a radical/SET mechanism for the substitution reaction are also advanced.

Halophilic reactions of pentafluorohalobenzenes with transition-metal carbonyl anions

In the present work we widen the scope of the halophilic mechanism of nucleophilic aromatic substitution, which we found earlier for the reaction of pentafluorochlorobenzene with [CpFe(CO) 2] − anion, to reactions of pentafluorohalobenzenes (Hal=Cl, Br, I) with various metal carbonyl anions [Re(CO) 5] −, [Mn(CO) 5] − and [CpFe(CO) 2] −. Nucleophilic aromatic substitution with the [CpFe(CO) 2] − anion yields C 6F 5Fe(CO) 2Cp, while with [Re(CO) 5] − and [Mn(CO) 5] − anions the halo(acyl)metallates cis-[C 6F 5(CO)M(CO) 4Hal]Na (M=Mn, Re) are obtained.

A density functional theory study on boundary of “superreduced” transition metal carbonyl anions [M(CO) n] z− (M=Cr, n=5, 4, 3, z=2, 4, 6; M=Mn, n=5, 4, 3, z=1, 3, 5; M=Fe, n=4, 3, 2, z=2, 4, 6; M=Co, n=4, 3, 2, z=1, 3, 5)

A nonlocal density functional theory (DFT) method has been applied to the calculations on optimized geometry, Mulliken atomic net charges and interatomic Mulliken bond orders as well as total bonding energies ( E) in the binary transition metal carbonyl anions with different reduced states [M(CO) n ] z− (M=Cr, n=5, 4, 3, z=2, 4, 6; M=Mn, n=5, 4, 3, z=1, 3, 5; M=Fe, n=4, 3, 2, z=2, 4, 6; M=Co, n=4, 3, 2, z=1, 3, 5). For comparison of relative stability, a relative stabilization energy D is defined as D= E([M(CO) n ] z− )− nE(CO). The calculated C–O distances are lengthened monotonously with the increase of the anionic charge, but the M–C distances are significantly lengthened only in the higher reduced states. The relative stabilization energy calculated is a considerable negative value in the lower reduced states, but a larger positive value in the higher reduced states. The DFT calculations show that with the increase of the anionic charge, the Mulliken net charges on the M, C, and O atoms all increase, however, an excess of the anionic charge is mainly located at the central metal atom. The calculated C–O Mulliken bond orders decrease consistently with the increase of the anionic charge, but the M–C bond orders exhibit an irregular behavior. However, the total bond orders calculated clearly explain the higher reduced states to be considerably unstable. From analysis of the calculated results, it is deduced that the stability of the binary transition metal carbonyl anions [M(CO) n ] z− studied are associated with the coordination number n and the anionic charge z, further, it is possible for the anions studied to be stable if n≥z, conversely, it is impossible when n< z.

Gas‐phase reactions of transition metal carbonyl anions and atomic metal anions with nitrous oxide and dioxygen: Oxygen atom transfer and ligand exchange in reactions with nitrous oxide

AbstractThe gas‐phase reactions of a series of metal carbonyl anions M(CO) (M=Cr, n=2–5; M=Mn, n=1–5; M=Fe, n=1–4) with nitrous oxide and dioxygen have been studied by use of Fourier‐transform ion cyclotron resonance (FTICR) mass spectrometry. With nitrous oxide, most of the metal carbonyl ions react by oxygen atom transfer leading to oxo‐metal anions and oxo‐metal carbonyl anions. The Cr− and Fe− ions also react relatively easily with nitrous oxide by oxygen atom abstraction to form CrO− and FeO−, respectively. Experiments with N15NO reveal that loss of a CO molecule from a collision complex is a significant ligand exchange channel for the Mn(CO), Mn(CO) and Fe(CO) ions. The nitrous oxide molecule remains intact in the resultant product ions, M(CO)n(N2O)− with M=Mn, n=2 and 3; and M=Fe, n=2. The losses of 15NN and 15NN + CO in the collision‐induced dissociations of the Mn(CO)3(N15NO)− ions, in combination with the relatively facile occurrence of oxygen atom transfer, are taken to mean that coordination of the metal centre to the oxygen atom is preferred over bond formation to the terminal nitrogen atom of the nitrous oxide molecule. The metal carbonyl anions react readily with dioxygen to form mainly oxo‐metal ions as well as oxo‐ and dioxo‐metal carbonyl anions in relative yields which depend on the nature of the metal and the number of CO ligands in the reactant ion.

The synthesis of heteronuclear transition metal clusters derived from alkylidyne tricobalt cluster precursors: I. The reaction of (μ 3-CCl)Co 3(CO) 9 with transition metal carbonyl anions. The crystal and molecular structure of (μ 3-CCl)Co 2Mo(CO) 8(η 5-C 5H 5)

Metal exchange reactions were used to produce heterometallic clusters derived from alkylidyne tricobalt precursors. Reaction of the cluster (μ 3-CCl)Co 3(CO) 9 with the potassium salt of (η 5-C 5H 5)Mo(CO) 3 − produced (μ 3-CH)CoMo 2(η 5-C 5H 5) 2(CO) 7, and (μ 3-CH)Co 2Mo(η 5-C 5H 5)(CO) 8 in an overall yield of 35%. The use of the bis(triphenylphosphine)iminium cation as the counterion leads, after work-up, to products with the reactive apical group intact. The structure of (μ 3-CCl)Co 2Mo(η 5-C 5H 5)(CO) 8, ( 1), has been determined. Use of (η 5-C 5H 5)Cr(CO) 3 − or (η 5-C 5H 5)W(CO) 3 − also gives substituted products, but in lower yields. The Mn(CO) 5 − anion effects reduction of the starting cluster rather than yielding substituted products.

The chemistry of transition metal–germanium compounds. Part 2. Synthesis, characterization, structure and reactivity of transition-metal carbonyl-substituted germacyclopent-3-enes

A number of transition-metal carbonyl-substituted germacyclopent-3-ene compounds have been prepared by metathesis between 1,1-dibromogermacyclopent-3-enes and sodium salts of transition-metal carbonyl anions. These species have been characterized by a variety of spectroscopic techniques and in the case of 3,4-dimethyl-1,1-bis(tetracarbonylcobaltio)-1-germacyclopent-3-ene 5, 1-bromo-3,4-dimethyl-1-(pentacarbonylmanganio)-1-germacyclopent-3-ene 7 and 1-bromo-3,4-dimethyl-1-(tetracarbonylcobaltio)-1-germacyclopent-3-ene 11 by low-temperature single-crystal X-ray diffraction. Compound 5 crystallizes in the space group P21/n with the cell parameters a= 15.556(3), b= 6.691(1), c= 17.726(2)A, β= 104.23(1)° and Z= 4, 7 in the space group P21/c with a= 14.825(2), b= 6.781(1), c= 14.765(2)A, β= 103.43(0)° and Z= 4, and 11 in the space group P21/c with a= 6.441(1), b= 30.040(7), c= 7.472(1)A, β= 106.38(1)° and Z= 4. All three compounds exhibit a puckered germacyclopent-3-ene ground-state conformation, the origin of which is discussed. In solution the symmetrically substituted compounds exhibit a degenerate equilibrium which involves a planar germacyclopent-3-ene transition state. Reaction of 1-halogeno-1-(transition metal carbonyl)-substituted germacyclopent-3-enes with different transition metal carbonylate anions results in formation of mixed-metal carbonyl derivatives and reduction with LiAlH4 results in formation of a germanium hydride. Thermolysis of 5 results in loss of a carbonyl ligand and formation of a compound which possesses and intramolecular carbonyl-bridged Co–Co bond. Kinetic data for this decarbonylation reaction, measured by variable-temperature 1H NMR spectroscopy, reveal activation parameters at an average temperature of 70 °C of ΔG‡=+25.9 kcal mol–1, ΔH‡=+27.6 kcal mol–1 and ΔS‡=+5 cal K–1 mol–1.

Ligand substitution reactions of 17-electron transition-metal carbonyl anions: an electron-transfer mechanism

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLigand substitution reactions of 17-electron transition-metal carbonyl anions: an electron-transfer mechanismYing H. Pan and Douglas P. RidgeCite this: J. Am. Chem. Soc. 1989, 111, 3, 1150–1151Publication Date (Print):February 1, 1989Publication History Published online1 May 2002Published inissue 1 February 1989https://doi.org/10.1021/ja00185a067RIGHTS & PERMISSIONSArticle Views82Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (305 KB) Get e-Alerts Get e-Alerts

Some transition-metal complexes of 1,3,2-dithiarsolane

Reaction of a range of transition-metal carbonyl anions [M]– with 2-chloro-1,3,2-dithiarsolane results in the formation of the metalloarsines [M–A[graphic omitted]]{M–=[Mo(CO)3(η-C5H5)]–, [W(CO)3(η-C5H5)]–, [Fe(CO)2(η-C5H5)]–, [Mn(CO)5]–, or [Re(CO)5]–}. There is no indication on an n.m.r. time-scale of pyramidal inversion about the arsenic atom in these complexes. Photolysis of [Mo(σ-A[graphic omitted])(CO)3(η-C5H5)] causes elimination of carbon monoxide and formation of [Mo(η2-A[graphic omitted])(CO)2(η-C5H5)] in which the dithiarsolane ring behaves as a dihapto, formally, three-electron donor. The reaction of 2-chloro-1,3,2-dithiarsolane with [Co(CO)4]– produces the dihapto product [Co(η2-[graphic omitted])(CO)3] directly.

Reactions of transition-metal carbonyl anions with dioxygen in the gas phase

Reactions donnant plusieurs nouveaux exemples d'anions d'oxydes metalliques produits a temperature ordinaire. Nature radicalaire de l'oxydation primaire

Reactions of group VIII metal carbonyl anions with 1,2-dichlorotetramethyl-disilane

Reactions of 1,2-dichlorotetramethyldisilane with transition metal carbonyl anions, NaCo(CO) 4 and Na 2Fe(CO) 4, proceed easily to give monodisplacement products. Thus, reaction with NaCo(CO) 4 yields a neutral chlorodisilanyl cobalt complex, Cl(CH 3) 2Si(CH 3) 2SiCo(CO) 4, and the analogous reaction chlorodisilanyltetracarbonylferrate salt, [Cl(CH 3) 2Si(CH 3) 2SiFe(CO) 4] −Na +. The β-chloride of Cl(CH 3) 2SiCo(CO) 4 was unreactive toward BCl 3. Prolonged reaction with CaCo(CO) 4 resulted in formation of the cluster compound, (CO) 9Co 3COSi(CH 3) 2Si(CH 3) 2Co(CO) 4 and of bis(μ-dimethylsilylene)bis(tricarbonylcobalt)(CoCo).

Nucleophilic displacement of transition metal carbonyl anions from metal-metal bonded compounds

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNucleophilic displacement of transition metal carbonyl anions from metal-metal bonded compoundsJames M. BurlitchCite this: J. Am. Chem. Soc. 1969, 91, 16, 4563–4564Publication Date (Print):July 1, 1969Publication History Published online1 May 2002Published inissue 1 July 1969https://doi.org/10.1021/ja01044a051RIGHTS & PERMISSIONSArticle Views51Altmetric-Citations22LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (276 KB) Get e-Alerts Get e-Alerts

Additions and Corrections - Transition Metal Carbonyl Anions. I. The Course of the Reduction of Chromium Hexacarbonyl

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdditions and Corrections - Transition Metal Carbonyl Anions. I. The Course of the Reduction of Chromium HexacarbonylWilliam KaskaCite this: J. Am. Chem. Soc. 1969, 91, 9, 2411Publication Date (Print):April 1, 1969Publication History Published online14 April 2004Published inissue 1 April 1969https://doi.org/10.1021/ja01037a603RIGHTS & PERMISSIONSArticle Views24Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (150 KB) Get e-Alerts Get e-Alerts

Transition metal carbonyl anions. I. Course of the reduction of chromium hexacarbonyl

Transition metal carbonyl anions. I. Course of the reduction of chromium hexacarbonyl