Mass spectral studies of metal chelates. III. Mass spectra and appearance potentials of substituted acetylacetonates of trivalent chromium. Comparison with other trivalent metals of the first transition series

Bancroft, G. M.; Reichert, C.; Westmore, John B.; Gesser, H. D.

doi:10.1021/ic50073a014

Cited by 42 publications

(13 citation statements)

References 2 publications

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“…Evidence to support (a) is given by the appearance potential measurements to be discussed in this paper, and to support (b) is given later in this section. Evidence in favor of (c) has already been discussed (5). It is noteworthy that observation (c) is consistent with the relative stabilities of benzylic bonds meta or para to another functional group in the mass spectra of benzene derivatives and in which correlations with Hammett sigma constants have been made (14).…”

Section: Mass Spectrasupporting

confidence: 74%

“…However, differences in appearance potential values, although they should be easier t o assess than changes in absorption spectra (4), were not in agreement with those expected on the basis of Barnum's simple molecular orbital calculations and assuming Koopmans' theorem (10) t o hold. Yet the results have been consistent with the loss of a n electron from an orbital localized mainly o n the ligand, and the changes in appearance potentials for a number of substituted acetylacetonates (5) could be correlated with the bonding properties of the various substituents to a ring which has aromatic character.…”

Section: Introductionsupporting

confidence: 55%

“…In many cases, a one step process is indicated by the presence of a metastable peak for the transition. A mechanism for the elimination of CF, has been proposed previously (5) and involves the rearrangement of a fluorine atom to the metal. The elimination of L-F would also involve rearrangement of a fluorine atom to the metal.…”

Section: Mass Spectramentioning

confidence: 99%

“…Recent mass spectral studies of metal P-diketonates have been ~~s e f i i l in elucidating the bonding in these compounds (4)(5)(6)(7)(8)(9). However, differences in appearance potential values, although they should be easier t o assess than changes in absorption spectra (4), were not in agreement with those expected on the basis of Barnum's simple molecular orbital calculations and assuming Koopmans' theorem (10) t o hold.…”

Section: Introductionmentioning

confidence: 99%

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Mass spectral studies of metal chelates. V. Mass spectra and appearance potentials of some fluorine-substituted acetylacetonates

Reichert¹,

Bancroft²,

Westmore³

1970

Can. J. Chem.

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The mass spectra of the hexafluoroacetylacetonates (hfacac) and trifluoroacetylacetonates (tfacac) of Al(III), Cr(III), Fe(III), Fe(II), Cu(II), and Zn(II) are reported. The main features of the spectra are discussed. Compared with the spectra of the acetylacetonates (acac), substitution of CF3 for CH3 in these complexes leads to more extensive fragmentation of the molecular ions. For example, ions corresponding to loss of •CF3 radicals are more abundant than those corresponding to loss of •CH3 radicals. The appearance potentials (a.p.'s) of the molecular ions and, where possible, of fragment ions formed from the molecular ion by loss of •CF3, •CH3, or ligand radicals are reported. The a.p.'s of the molecular ions are more sensitive to the nature of the ligand than to the metal. Thus, for the metal chelates studied here the a.p.'s of the molecular ions from ML2 and ML3 (L stands for ligand) were 9.95 ± 0.25 V for L = hfacac, 9.05 ± 0.35 V for L = tfacac, and 8.3 ± 0.35 V for L = acac. The energy required to dissociate a •CF3 or •CH3 radical from the molecular ion is sensitive to the nature and valency of the metal M, being low (relatively) for Al(III) and Fe(III), and high (relatively) for Cr(III) (inferred) and Fe(II). This variation is discussed in terms of the effect of substituent, and of interaction of metal d orbitals with the ligands.

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Section: Mass Spectrasupporting

confidence: 74%

Section: Introductionsupporting

confidence: 55%

Section: Mass Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mass spectral studies of metal chelates. V. Mass spectra and appearance potentials of some fluorine-substituted acetylacetonates

Reichert¹,

Bancroft²,

Westmore³

1970

Can. J. Chem.

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“…These studies included the mass spectra of acetylacetonates (2-6), various Pdiketonates of chromium(111) (7), copper(I1) (8), various metal complexes of dibenzoylmethane (9), Ianthanide complexes of hexamethylacetylacetone (lo), and fluorine-substituted acetylacetonates (1 1). The effect of variation in metal or ligand upon appearance potentials has also been investigated (1, 5-8, 10, 12).…”

Section: Introductionmentioning

confidence: 99%

Mass spectral studies of metal chelates. VI. Mass spectra and appearance potentials of β-diketonates of copper(II)

Reichert¹,

Westmore²

1970

Can. J. Chem.

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The mass spectra of several copper complexes of e-diketones are discussed. The extent of fragmentation of the molecular ions depends upon the nature of the substituents on the chelate ring, being larger for electron-withdrawing, and smaller for electron-releasing subst~tuents. In a number of fragmentations, migration of an aryl group to the copper atom occurs. Hydrogen atom migrations are also observed in some fragmentations. Attempts are made to correlate the appearance potentials of the molecular ions with acid dissociation constants of the (3-diketones, formation constants and polarographic reduction potentials of the complexes, and Hammett o constants of the substituents.

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Electronic Structure and Magnetic Properties of a High‐Spin Mn^IIIComplex: [Mn(mesacac)₃] (mesacac=1,3‐Bis(2,4,6‐trimethylphenyl)‐propane‐1,3‐dionato)

et al. 2022

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Metal acetylacetonates of the general formula [M(acac) 3 ] (M III = Cr, Mn, Fe, Co) are among the best investigated coordination compounds. Many of these first-row transition metal complexes are known to have unique electronic properties. Independently, photophysical research with different β-diketonate ligands pointed towards the possibility of a special effect of the 2,4,6trimethylphenyl substituted acetylacetonate (mesacac) on the electron distribution between ligand and metal (MLCT). We therefore synthesized and fully characterized the previously unknown octahedral title complex. Its solid-state structure shows a Jahn-Teller elongation with two MnÀ O bonds of 2.12/ 2.15 Å and four MnÀ O bonds of 1.93 Å. Thermogravimetric data show a thermal stability up to 270 °C. High-resolution mass spectroscopy helped to identify the decomposition pathways. The electronic state and spin configuration of manganese were characterized with a focus on its magnetic properties by measurement of the magnetic susceptibility and triple-zeta density functional theory (DFT) calculations. The high-spin state of manganese was confirmed by the determination of an effective magnetic moment of 4.85 μ B for the manganese center.

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Mass spectral studies of metal chelates. III. Mass spectra and appearance potentials of substituted acetylacetonates of trivalent chromium. Comparison with other trivalent metals of the first transition series

Cited by 42 publications

References 2 publications

Mass spectral studies of metal chelates. V. Mass spectra and appearance potentials of some fluorine-substituted acetylacetonates

Mass spectral studies of metal chelates. V. Mass spectra and appearance potentials of some fluorine-substituted acetylacetonates

Mass spectral studies of metal chelates. VI. Mass spectra and appearance potentials of β-diketonates of copper(II)

Electronic Structure and Magnetic Properties of a High‐Spin Mn^IIIComplex: [Mn(mesacac)₃] (mesacac=1,3‐Bis(2,4,6‐trimethylphenyl)‐propane‐1,3‐dionato)

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Mass spectral studies of metal chelates. III. Mass spectra and appearance potentials of substituted acetylacetonates of trivalent chromium. Comparison with other trivalent metals of the first transition series

Cited by 42 publications

References 2 publications

Mass spectral studies of metal chelates. V. Mass spectra and appearance potentials of some fluorine-substituted acetylacetonates

Mass spectral studies of metal chelates. V. Mass spectra and appearance potentials of some fluorine-substituted acetylacetonates

Mass spectral studies of metal chelates. VI. Mass spectra and appearance potentials of β-diketonates of copper(II)

Electronic Structure and Magnetic Properties of a High‐Spin MnIIIComplex: [Mn(mesacac)3] (mesacac=1,3‐Bis(2,4,6‐trimethylphenyl)‐propane‐1,3‐dionato)

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Electronic Structure and Magnetic Properties of a High‐Spin Mn^IIIComplex: [Mn(mesacac)₃] (mesacac=1,3‐Bis(2,4,6‐trimethylphenyl)‐propane‐1,3‐dionato)