Liquid hydrogen chloride as an ionizing solvent. Part XI. Protonation and oxidation reactions of pentacarbonyliron

Iqbal, Zahoor; Waddington, T. C.

doi:10.1039/j19680002958

Cited by 19 publications

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“…Initial formation of Fe(CO) 4 F 2 or the ionized species [Fe(CO) 5 F] + and [Fe(CO) 4 F] + may be postulated, even though neither species is isolable . Related compounds such as Fe(CO) 4 X 2 , X = Cl, Br, or I, − or ions such as [Fe(CO) 5 X] + , X = Cl, Br, NO, are known. Attempts to obtain information on the intermediates in HF−SbF 5 solution by 13 C or 19 F NMR are hindered by line broadening on account of the presence of paramagnetic Fe 2+ species.…”

Section: Resultsmentioning

confidence: 99%

“…Nevertheless the synthetic approach used has produced the salts [M(CO) 6 ][AlX 4 ], M = Mn, Tc, Re, X = Br, with the first homoleptic metal carbonyl cations. − Equally erroneous has been the reported formation of [Fe(CO) 6 ] 2+ during the amine-catalyzed disproportionation of Fe(CO) 5 . Thus even though related cations of the type [Fe(CO) 5 X] + , X = Cl, Br, NO, H, are known, [Fe(CO) 6 ] 2+ as well as other multiply charged or “super electrophilic” homoleptic metal carbonyl cations has remained elusive until recently.…”

Section: Introductionmentioning

confidence: 99%

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Hexakis(carbonyl)iron(II) Undecafluorodiantimonate(V), [Fe(CO)₆][Sb₂F₁₁]₂, and -Hexafluoroantimonate(V), [Fe(CO)₆][SbF₆]₂, Their Syntheses, and Spectroscopic and Structural Characterization by Single Crystal X-ray Diffraction and Normal Coordinate Analysis

et al. 1999

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Hexakis(carbonyl)iron(II) undecafluorodiantimonate(V), [Fe(CO)6][Sb2F11]2, is conveniently prepared by the oxidative carbonylation of Fe(CO)5 with XeF2 as external oxidizer in the conjugate Brønsted-Lewis superacid HF−SbF5. The colorless compound crystallizes from the reaction medium in high purity. The molecular structure is obtained by single-crystal X-ray diffraction. The cation is a regular octahedron, while the vertex-shared di-octahedral [Sb2F11]- anion is distorted from D 4 h symmetry by bending and rotational processes, due to significant interionic interactions, primarily of the F···C type. Washing of [Fe(CO)6][Sb2F11]2 with anhydrous HF results in an unusual elution of SbF5 and the quantitative conversion to hexakis(carbonyl)iron(II) hexafluoroantimonate(V) [Fe(CO)6][SbF6]2. The molecular structure of the salt shows octahedral ions with slight tetragonal distortions for the cation (elongation) and the anion (compression). Both salts are thermally stable up to 150 °C. The averaged bond distances and the vibrational wavenumbers of [Fe(CO)6]2+ are nearly identical in both compounds. The [Fe(CO)6]2+ cation, the first and so far only isolated and structurally characterized dipositive, superelectrophilic carbonyl cation formed by a 3d-metal, is further characterized by a normal coordinate analysis (NCA). The obtained force constants are compared to those of the isoelectronic molecule Cr(CO)6. Changes in π-back-bonding affect the F CO/CO and F CO/MC interaction force constants more strongly than the stretching force constants F CO and F MC. All 13 fundamentals of [Fe(CO)6]2+ are detected and assigned with the help of the data obtained from the normal coordinate analysis and density functional calculations published previously. The electronic ground state 1A1g of the [Fe(CO)6]2+ cation is established by magnetic susceptibility measurements of polycrystalline [Fe(CO)6][SbF6]2 and [Fe(CO)6][Sb2F11]2 between 2 and 300 K. The magnetic impurity formed during synthesis is identified as Fe[SbF6]2 which has iron(II) in high spin (5T2g) ground state. Consistent with a diamagnetic ground state are the single line in the 57Fe Mössbauer spectrum (i.s. = −0.003(8) mm s-1 relative to α-Fe), obtained on polycrystalline samples and the single sharp line in the 13C NMR spectrum in DF solution at 178 ppm with J (57Fe-13C) of 19.2 Hz.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hexakis(carbonyl)iron(II) Undecafluorodiantimonate(V), [Fe(CO)₆][Sb₂F₁₁]₂, and -Hexafluoroantimonate(V), [Fe(CO)₆][SbF₆]₂, Their Syntheses, and Spectroscopic and Structural Characterization by Single Crystal X-ray Diffraction and Normal Coordinate Analysis

et al. 1999

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“…They include carbonylate anions of the type [M(CO) 5 Cl] -(M ) Cr, Mo, W 63 ), neutral species of the composition M(CO) 5 Cl (M ) Mn, Re [64][65][66][67] ), and the cation [Fe(CO) 5 Cl] + . 68 However, as the vibrational spectra [69][70][71] indicate, contribution from π-backbonding to the synergic M-CO bonding 7-9 becomes increasingly dominant with decreasing the oxidation state of the central atom from +1 to -1.…”

Section: Resultsmentioning

confidence: 99%

Syntheses, Molecular Structures, and Vibrational Spectra of Chloropentacarbonylrhodium(III) and -iridium(III) Undecafluorodiantimonate(V), [Rh(CO)₅Cl][Sb₂F₁₁]₂and [Ir(CO)₅Cl][Sb₂F₁₁]₂: An Experimental and Density Functional Study

Willner¹,

Bach²,

Wartchow³

et al. 2000

Inorg. Chem.

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The reactions of either bis(mu-chloro)tetracarbonyldirhodium(I), [Rh(CO)2(mu-Cl)]2, or chlorotricarbonyliridium(I), [Ir(CO)3Cl]n, in the conjugate Brønsted-Lewis superacid HF-SbF5 and in a CO atmosphere, produce [Rh(CO)5Cl][Sb2F11]2 or [Ir(CO)5Cl][Sb2F11]2, respectively. In these oxidative carbonylation reactions, antimony(V) fluoride functions as an oxidizing agent. The reduced product is identified as 6SbF3.5SbF5. [Rh(CO)5Cl][Sb2F11]2 is obtained in the form of single crystals. Crystal data: monoclinic, space group P2(1) (No. 4); a = 9.721(1), b = 12.602(1), c = 10.538(1) A; beta = 106.51(1) degrees; V = 1237.7(2) A3; Z = 2; T = 300 K; R1 [I > 3 sigma (I)] = 0.0367, wR2 = 0.0739. Single crystals of [Ir(CO)5Cl][Sb2F11]2 are produced in small amounts from a solution of mer-Ir(CO)3(SO3F)3 in magic acid, HSO3F-SbF5. The possible source of chlorine will be discussed. Crystal data for [Ir-(CO)5Cl][Sb2F11]2: monoclinic, space group P2(1) (No. 4); a = 9.686(2), b = 12.585(2), c = 10.499(2) A; beta = 106.59(2) degrees; V = 1226.5(4) A3; Z = 2; T = 294 K; R1[I > 3 sigma (I)] = 0.032, Rw = 0.031. The bond lengths and bond angles are nearly identical in the two isostructural salts; however, the cell volume of [Ir(CO)5Cl][Sb2F11]2 is slightly smaller than that of [Rh(CO)5Cl][Sb2F11]2. The cations (point group C4v) feature unusually long M-C bonds (M = Rh, Ir) and correspondingly short CO bonds, as well as high CO stretching wavenumbers and high CO stretching force constants. The [Sb2F11]- anions are not symmetry related, and their dihedral and bridge angles differ slightly in both salts. There are significant interionic contacts in [Ir(CO)5Cl][Sb2F11]2 exclusively of the C-F type (about 2 for each C atom of the five carbonyl groups) resulting in extended structures. The vibrational spectra for both [M(CO)5Cl]2+ cations (M = Rh, Ir) are assigned with the help of density functional calculations, which also provide intensities for IR and Raman bands. While [Rh(CO)5Cl]2+ is the first cationic carbonyl derivative of Rh(III), the vibrational and structural parameters for [Ir(CO)5Cl]2+ are compared to data for [Ir(CO)6]3+ and mer-Ir(CO)3(SO3F)3.

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“…Hypothetically, it could brominate the Hg–C bonds of Hg(phpy) 2 to afford 2-(2′-bromophenyl)pyridine followed by oxidative addition of iron(0) to the C–Br bond. Alternatively, Br 2 could target [Fe(CO) 5 ] to give [FeBr 2 (CO) 4 ] as in eq . − …”

Section: Resultsmentioning

confidence: 99%

“…Reaction is not a concerted process. The cationic intermediate [FeBr(CO) 5 ]Br can be formed, which then collapses to neutral [FeBr 2 (CO) 4 ], − but the latter does not seem to react with Hg(phpy) 2 . Therefore, we postulate that the cationic nature of [FeBr(CO) 5 ]Br is vital for the electrophilic substitution, as neutral complexes [FeBr 2 (CO) 4 ] and [Fe(CO) 5 ] are both unreactive.…”

Section: Resultsmentioning

confidence: 99%

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)₅: Synthesis, Properties, and Cytotoxicity of Bis(2-C₆H₄-2′-py-κC,N)dicarbonyliron(II)

et al. 2020

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Bis-cyclometalated iron(II) complex [Fe(κC,Nphpy) 2 (CO) 2 ] (1) (phpyH = 2-phenylpyridine) has been prepared in good yield from [Fe(CO) 5 ] and [Hg(phpy) 2 ] in the presence of dibromine, which is unexpectedly a crucial component of the reaction mixture. It is needed for the generation of short-lived reactive intermediate [FeBr(CO) 5 ]Br, which is actually involved in the electrophilic substitution reaction with [Hg(phpy) 2 ]. When irradiated by visible light, compound 1 readily affords bis(2-(pyridine-2-yl)phenyl)methanone ( 2) and iron oxides through the insertion of CO in the Fe−C bond of the cyclometalated moiety. Structures of iron complex 1 and ketone 2 were confirmed by X-ray crystallography. Activation of [Fe(CO) 5 ] by Br 2 represents a new approach for generating an iron intermediate, which is active in transmetalation reactions. Cytotoxic activity of 1 was tested against three gastric cancer cell lines, KATO III, AGS, and NUGC3. The activity against KATO III and NUGC3 cells is moderate, while complex 1 displayed excellent cytotoxicity against AGS cells. The molecular mechanism investigation showed that the cytotoxic activity of 1 appears independent of caspase 3 and the TP53 tumor suppressor gene, suggesting an apoptotic-independent process.

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Liquid hydrogen chloride as an ionizing solvent. Part XI. Protonation and oxidation reactions of pentacarbonyliron

Cited by 19 publications

References 0 publications

Hexakis(carbonyl)iron(II) Undecafluorodiantimonate(V), [Fe(CO)₆][Sb₂F₁₁]₂, and -Hexafluoroantimonate(V), [Fe(CO)₆][SbF₆]₂, Their Syntheses, and Spectroscopic and Structural Characterization by Single Crystal X-ray Diffraction and Normal Coordinate Analysis

Hexakis(carbonyl)iron(II) Undecafluorodiantimonate(V), [Fe(CO)₆][Sb₂F₁₁]₂, and -Hexafluoroantimonate(V), [Fe(CO)₆][SbF₆]₂, Their Syntheses, and Spectroscopic and Structural Characterization by Single Crystal X-ray Diffraction and Normal Coordinate Analysis

Syntheses, Molecular Structures, and Vibrational Spectra of Chloropentacarbonylrhodium(III) and -iridium(III) Undecafluorodiantimonate(V), [Rh(CO)₅Cl][Sb₂F₁₁]₂and [Ir(CO)₅Cl][Sb₂F₁₁]₂: An Experimental and Density Functional Study

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)₅: Synthesis, Properties, and Cytotoxicity of Bis(2-C₆H₄-2′-py-κC,N)dicarbonyliron(II)

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Liquid hydrogen chloride as an ionizing solvent. Part XI. Protonation and oxidation reactions of pentacarbonyliron

Cited by 19 publications

References 0 publications

Hexakis(carbonyl)iron(II) Undecafluorodiantimonate(V), [Fe(CO)6][Sb2F11]2, and -Hexafluoroantimonate(V), [Fe(CO)6][SbF6]2, Their Syntheses, and Spectroscopic and Structural Characterization by Single Crystal X-ray Diffraction and Normal Coordinate Analysis

Hexakis(carbonyl)iron(II) Undecafluorodiantimonate(V), [Fe(CO)6][Sb2F11]2, and -Hexafluoroantimonate(V), [Fe(CO)6][SbF6]2, Their Syntheses, and Spectroscopic and Structural Characterization by Single Crystal X-ray Diffraction and Normal Coordinate Analysis

Syntheses, Molecular Structures, and Vibrational Spectra of Chloropentacarbonylrhodium(III) and -iridium(III) Undecafluorodiantimonate(V), [Rh(CO)5Cl][Sb2F11]2and [Ir(CO)5Cl][Sb2F11]2: An Experimental and Density Functional Study

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)5: Synthesis, Properties, and Cytotoxicity of Bis(2-C6H4-2′-py-κC,N)dicarbonyliron(II)

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Hexakis(carbonyl)iron(II) Undecafluorodiantimonate(V), [Fe(CO)₆][Sb₂F₁₁]₂, and -Hexafluoroantimonate(V), [Fe(CO)₆][SbF₆]₂, Their Syntheses, and Spectroscopic and Structural Characterization by Single Crystal X-ray Diffraction and Normal Coordinate Analysis

Hexakis(carbonyl)iron(II) Undecafluorodiantimonate(V), [Fe(CO)₆][Sb₂F₁₁]₂, and -Hexafluoroantimonate(V), [Fe(CO)₆][SbF₆]₂, Their Syntheses, and Spectroscopic and Structural Characterization by Single Crystal X-ray Diffraction and Normal Coordinate Analysis

Syntheses, Molecular Structures, and Vibrational Spectra of Chloropentacarbonylrhodium(III) and -iridium(III) Undecafluorodiantimonate(V), [Rh(CO)₅Cl][Sb₂F₁₁]₂and [Ir(CO)₅Cl][Sb₂F₁₁]₂: An Experimental and Density Functional Study

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)₅: Synthesis, Properties, and Cytotoxicity of Bis(2-C₆H₄-2′-py-κC,N)dicarbonyliron(II)