The Gas‐Phase Chemistry of Transition‐Metal Ions with Organic Molecules

Allison, John

doi:10.1002/9780470166352.ch7

Cited by 108 publications

(9 citation statements)

References 151 publications

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“…The ECD spectrum of the [Cu II (L) 3 ] 2ϩ complex of 6:0/6:0GPCho ( Figure 1a) represents an example of how capture of the electron at the metal center can result in a vibrationally excited-state complex, which then fragments via loss of a neutral phosphocholine ligand (to give m/z 969). It is worth noting that the vibrational excitation of independently generated [Cu I (L) 3 ] ϩ complex also results in fragmentation via phosphocholine ligand loss (for the CID spectrum of the [Cu I (L) 3 ] ϩ complex of 6:0/6:0GPCho see Supplemental Figure S2). …”

Section: Overview Of Ecd Fragmentation Chemistry Ofmentioning

confidence: 99%

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Electron capture dissociation of complexes of diacylglycerophosphocholine and divalent metal ions: Competition between charge reduction and radical induced phospholipid fragmentation

James

Perugini

O’Hair

2008

J. Am. Soc. Mass Spectrom.

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Divalent metal complexes of phosphocholines, [Metal II (L)n] 2ϩ (where Metal ϭ Cu 2ϩ , Co 2ϩ , Mg 2ϩ , and Ca 2ϩ , L ϭ 1,2-dihexanoyl-sn-glycero-3-phosphocholine [6:0/6:0GPCho] and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine [16:0/18:1GPCho] and n ϭ 2-5), were formed upon electrospray ionization mass spectrometry (ESI/MS) of 8 mM solution of phosphocholine (L) with 4 mM metal salt (Metal). The electron capture dissociation (ECD) reactions of these [Metal II (L) n ] 2ϩ complexes were examined via Fourier-transform ioncyclotron resonance mass spectrometry. A rich and complex chemistry was observed, including charge reduction and fragmentation involving losses of a methyl radical, trimethylamine, and the acyl chains. The predominant reaction channel was dependent on the size (n) of the complex, the metal and ligand used, and the size of the acyl chain. Thus charge reduction dominates the ECD spectra of the larger phosphocholine, 16:0/18:1GPCho, but is largely absent in the smaller 6:0/6:0GPCho. For complexes of 16:0/18:1GPCho, n ϭ 4 -5, fragmentation from the head group mainly occurs via loss of the methyl radical and trimethylamine. At n ϭ 3, the relative abundance of fragments due to loss of acyl chain radicals increases. The abundances of ions arising from these radical losses increase further for the n ϭ 2 complexes, thereby providing information on the composition and position of the 16:0 and 18:1 acyl groups. Thus ECD of metal complexes provides structurally useful information on the phosphocholine, including the nature of the head group, the acyl chains, and the positions of the acyl chains. complexes of L ϭ 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, which allows distinction of acyl chains [9]. We were thus intrigued by the possibility of using electron capture dissociation (ECD) on divalent metal complexes of phospholipids to gain additional structural information, since recent studies suggest that divalent metal ions not only can direct the fragmentation of peptides under conditions of ECD [10 -13], but also act as charge tags to allow the use of ECD on other biomolecules that may not undergo multiple protonation under electrospray ionization (ESI) conditions [13].

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Section: Overview Of Ecd Fragmentation Chemistry Ofmentioning

confidence: 99%

“…any previous studies have highlighted the promise of metal ions as reagents in analytical and bioanalytical chemistry [1][2][3]. As part of a series of studies on the use of mass spectrometry-based approaches to examine lipid-lipid interactions [4], we have become interested in understanding how metal ions may influence fragmentation chemistry.…”

mentioning

confidence: 99%

Electron capture dissociation of complexes of diacylglycerophosphocholine and divalent metal ions: Competition between charge reduction and radical induced phospholipid fragmentation

James

Perugini

O’Hair

2008

J. Am. Soc. Mass Spectrom.

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“…Survey work has subsequently shown that none of the other third-row, none of the first-row, and only Zr + of the second-row transition-metal cations activate methane at room temperature . A host of additional studies have confirmed these results − and demonstrated that the Zr + reaction is slightly endothermic and therefore inefficient . Guided ion beam studies have extended this work to higher collision energies, thereby providing quantitative information about the reactivity and energetics of these reactions across the periodic table. ,− More recently, it has been reported that cationic gold clusters will activate methane, although initial reports of catalytic activity to form ethene have been proven erroneous …”

Section: Introductionmentioning

confidence: 85%

Infrared Spectroscopy of Gold Carbene Cation (AuCH₂⁺): Covalent or Dative Bonding?

et al. 2019

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The present work explores the structure of the gold carbene cation, AuCH2 +, using infrared multiple photon dissociation action spectroscopy and density functional theory (DFT). Unlike several other 5d transition-metal cations (M+ = Ta+, W+, Os+, Ir+, and Pt+) that react with methane by dehydrogenation to form MCH2 + species, gold cations are unreactive with methane at thermal energies. Instead, the metal carbene is formed by reacting atomic gold cations formed in a laser ablation source with ethylene oxide (cC2H4O) pulsed into a reaction channel downstream. The resulting [Au,C,2H]+ product photofragmented by loss of H2 as induced by radiation provided by the free-electron laser for intracavity experiments in the 300–1800 cm–1 range. Comparison of the experimental spectrum, obtained by monitoring the appearance of AuC+, and DFT calculated spectra leads to the identification of the ground-state carbene, AuCH2 + (1A1), as the species formed, as previously postulated theoretically. Unlike the covalent double bonds formed by the lighter, open-shell 5d transition metals, the closed-shell Au+ (1S, 5d10) atom binds to methylene by donation of a pair of electrons from CH2(1A1) into the empty 6s orbital of gold coupled with π back-bonding, i.e., dative bonding, as explored computationally. Contributions to the AuC+ appearance spectrum from larger complexes are also considered, and H2CAu+(c-C2H4O) seems likely to contribute one band observed.

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“…The use of transition metals in catalyzing organic bond fragmentation reactions is well documented. − Gas phase experiments, where careful control of the environment and energy content of the system is possible, provide an understanding of the energy lowering ability of transition metal active sites and the associated reaction mechanism. Ion cyclotron resonance mass spectrometry, − tandem mass spectrometry, − and crossed beam studies − are such gas phase experiments.…”

Section: Introductionmentioning

confidence: 99%

Co⁺-Assisted Decomposition of h₆-Acetone and d₆-Acetone: Acquisition of Reaction Rate Constants and Dynamics of the Dissociative Mechanism

2012

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Reaction rate constants have been acquired for the gaseous unimolecular decomposition reaction of the Co(+)(OC(CH(3))(2)) cluster ion and its deuterium labeled analog. Each rate constant is measured at a well resolved cluster internal energy within the range 12,300-16,100 cm(-1). The weighted, averaged kinetic isotope effect (KIE), k(H)/k(D) = 1.54 ± 0.05, is about three times smaller than the KIE measured for the rate-determining rate constants in the similar Ni(+)(OC(CH(3))(2)) decomposition reaction. These reactions likely follow the same oxidative addition-reductive elimination mechanism. Thus, this unexpected change in the KIE magnitudes is not due to differences in the dissociative reaction coordinates. Rather, we propose that the unique dissociation dynamics of these two similar systems is due to differences in the low-lying electronic structure of each transition metal ion.

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The Gas‐Phase Chemistry of Transition‐Metal Ions with Organic Molecules

Cited by 108 publications

References 151 publications

Electron capture dissociation of complexes of diacylglycerophosphocholine and divalent metal ions: Competition between charge reduction and radical induced phospholipid fragmentation

Electron capture dissociation of complexes of diacylglycerophosphocholine and divalent metal ions: Competition between charge reduction and radical induced phospholipid fragmentation

Infrared Spectroscopy of Gold Carbene Cation (AuCH₂⁺): Covalent or Dative Bonding?

Co⁺-Assisted Decomposition of h₆-Acetone and d₆-Acetone: Acquisition of Reaction Rate Constants and Dynamics of the Dissociative Mechanism

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The Gas‐Phase Chemistry of Transition‐Metal Ions with Organic Molecules

Cited by 108 publications

References 151 publications

Electron capture dissociation of complexes of diacylglycerophosphocholine and divalent metal ions: Competition between charge reduction and radical induced phospholipid fragmentation

Electron capture dissociation of complexes of diacylglycerophosphocholine and divalent metal ions: Competition between charge reduction and radical induced phospholipid fragmentation

Infrared Spectroscopy of Gold Carbene Cation (AuCH2+): Covalent or Dative Bonding?

Co+-Assisted Decomposition of h6-Acetone and d6-Acetone: Acquisition of Reaction Rate Constants and Dynamics of the Dissociative Mechanism

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Infrared Spectroscopy of Gold Carbene Cation (AuCH₂⁺): Covalent or Dative Bonding?

Co⁺-Assisted Decomposition of h₆-Acetone and d₆-Acetone: Acquisition of Reaction Rate Constants and Dynamics of the Dissociative Mechanism