Mass spectrometry of metal‐organic negative ions

Gregor, I. K.; Guilhaus, Michael

doi:10.1002/mas.1280030103

Cited by 48 publications

(12 citation statements)

References 130 publications

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“…Except for 3a, mass spectral studies of these complexes have not been reported previously. The complexes are of interest because of the accessibility of the (111), (11), and (I) valence states of cobalt, which have varying hard/soft acid character. Furthermore, both the X = 0'and X = S series of complexes are stable and easily prepared (this is not so for several other metal ions).…”

Section: Introductionmentioning

confidence: 99%

Electron ionization mass spectrometry of cobalt(III) β-diketonates and monothio-β-diketonates possessing aryl and fluorinated alkyl substituents

Reimer¹,

Westmore²,

Das³

1992

Can. J. Chem.

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. Can. J. Chem. 70, 952 (1992).Electron ionization positive ion mass spectra of 15 substituted cobalt(II1) P-diketonates and monothio-P-diketonates, CO"'L,, where L = RCXCHCOR', R = phenyl, 2-thienyl, or 2-naphthyl; X = 0 or S; and R' = CHF2, CF,, C2FS, or n-C,F,, show a marked dependence on the ligand. Molecular ions, [CO"'L,]+', are observed only for some of the more highly fluorinated complexes (R' = C2FS or n-C3F7). The [Co1"L2] '' ion, possibly generated by ionization of CO"L forme! by thermal degradation, or by electron ionization of Col''L,, typically decomposes by elimination of a radical, i.e., L or R' , to yield ions containing Co(I1); subsequent decompositions proceed preferentially by loss of even-electron neutral species, also to yield ions containing Co(l1). Cobalt-containing ions in which fluorine has rearranged to the metal decrease in variety and abundance for the ligands with higher fluorine content. When metal-bonded oxygen is replaced by sulfur, fluorine migration to Co(III), rather than to Co(II), is preferred. These trends are consistent with a combination of several different concepts including the ability of the metal to undergo valency change, the principle of Hard and Soft Acids and Bases, and the inductive capabilities of the ligand donor atoms and of the R and R' groups. Ion decomposition pathways are proposed.Key words: mass spectrometry, cobalt complexes, P-diketonates, fluorinated chelate complexes. Mots clts : spectrometric de masse, complexes du cobalt, P-dicktonates, complexes de chelates fluorCs.[Traduit par la redaction] Introduction The significant volatility and stability of metal P-diketonates and their derivatives make them suitable for gas chromatography (1). When this technique is combined with mass spectrometry, analytical methods, based upon the use of isotopic tracers, can be devised for metals. Recently, metal P-diketonates were used as precursors for chemical vapor deposition (2-4), a promising technique for the preparation of thin films of high T, superconducting oxides (5), and the application of mass spectrometry to characterize the alkaline earth complexes for this purpose has been described (6).The mass spectra of these complexes are of interest in their own right because their wide variety permits assessment of the influence exerted by bonding and structure factors, i.e., (i) the central metal atom, (ii) the ligand donor atoms, and

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Section: Introductionmentioning

confidence: 99%

Electron ionization mass spectrometry of cobalt(III) β-diketonates and monothio-β-diketonates possessing aryl and fluorinated alkyl substituents

Reimer¹,

Westmore²,

Das³

1992

Can. J. Chem.

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“…Since reaction pathways (7) and (8) may be independent of the metal as is likely with 'CH insertion. It should be noted, however, that this effect is insufficient to account fully for differences in the degree of alkyl adduct formation as the metal is varied, particularly across the series 1-3, 4-6 and 10-12, and hence formation of these ions has been rationalized in terms of the metal-dependent oxidative addition mechanism.2…”

Section: Resultsmentioning

confidence: 99%

Adduct ion formation by metal complexes under methane negative chemical ionization conditions

Dillow

Gregor

Guilhaus

1986

Org. Mass Spectrom.

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Negative chemical ionization mass spectrometry is used as a probe to examine reactions between hydrocarbon radicals and metal complexes in the gas phase. The methane negative chemical ionization mass spectra of 27 complexes of cobalt(II), nickel(I1) and copper(n) in the presence of O,, OzN2 and N4 donor atom sets are characterized by two dominant series of adduct ions of the form [M+C,H,,]-and [M + CnHk+J at m / z values above the molecular ion, [MI-. Insertion of the 'CH radical into the ligand followed by radicallradical recombination and electron capture is proposed as the major mechanism leading to the formation of [M + C,H,]-adduct ions. A second pathway involves ligand substitution by 'C,H,+, radicals concomitant with H' elimination and electron capture. Oxidative addition at the metal followed by ionization is suggested as the principal pathway for the formation of [M + CnHk+J-adduct ions. ~ ~~ ~ ~

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“…The most probable structure of this adduct is either an ion molecule complex [η 5 -C 5 H 5 Fe(CO) 2 (CH 4 )] + or a product where the metal is inserted into the C-H bond, [η 5 -C 5 H 5 Fe(CO) 2 (CH 3 )(H)] + . Experiments using CD 4 and detailed scrutiny of the CID spectra may lead to assignment of this structure. 40 The CID spectrum of the product formed from CD 4 and [η 5 -C 5 H 5 Fe(CO) 2 ] + at m/z 197 consists of only five product ions that are easily explained.…”

Section: Methodsmentioning

confidence: 97%

Ion Molecule Reactions between Ligated Transition Metal Cations with Methane, Ethane and Propane in a High Pressure Ion Source

Ekeberg

Næss-Andresen

2011

Journal of Chemical Research

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The reactions of CH 4 , C 2 H 6 and C 3 H 8 with [η 5 -C 5 H 5 M(CO) n ] + (M = Fe, Co and Ni; 0 ≤ n ≤ 2) in the gas phase have been studied using a double focusing mass spectrometer with a high pressure ion source (HPIS). The products observed are mainly described as weakly bound ion molecule complexes. Carbon-hydrogen bond insertions were observed with propane and only to a minor extent with ethane. Methane was found to form ion molecule complexes only with ligated transition metal cations. The reactivity was influenced by the number of carbonyl ligands and the metal cations. The main adducts formed were obtained when one or no CO ligands were bound to the cyclopentadienyl metal cation. No adducts between the alkanes and naked transition metal cations or protonated metal compounds were found.

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Mass spectrometry of metal‐organic negative ions

Cited by 48 publications

References 130 publications

Electron ionization mass spectrometry of cobalt(III) β-diketonates and monothio-β-diketonates possessing aryl and fluorinated alkyl substituents

Electron ionization mass spectrometry of cobalt(III) β-diketonates and monothio-β-diketonates possessing aryl and fluorinated alkyl substituents

Adduct ion formation by metal complexes under methane negative chemical ionization conditions

Ion Molecule Reactions between Ligated Transition Metal Cations with Methane, Ethane and Propane in a High Pressure Ion Source

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