Competition between the stabilizing effects of saturated alkyl substituents and pi bonds on complexes of silver ion (Ag<sup>+</sup>) with alkenes

Breton, Gary W.

doi:10.1002/poc.4301

Cited by 5 publications

(1 citation statement)

References 37 publications

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“…The soft acid/base chemistry between silver and olefins leads to a highly favorable interaction between the two. Electrostatically, during that interaction, the 2π orbital of the olefin donates electrons to the empty 5s and 5p orbitals of the silver ion while the silver back‐donates electrons from the 4d orbital to the empty 2π* orbital of the olefin 11,12 . This electrostatic interaction has been shown to increase in strength when the olefin contains a “bay region.” 13 This structural feature was demonstrated to significantly increase the abundance of [M + Ag] + detected in secondary ion mass spectrometry (SIMS) because of the increased strength of the interaction between silver and the multiple π bonds.…”

Section: Introductionmentioning

confidence: 99%

Improved detection in untargeted lipidomics through silver‐doped infrared matrix‐assisted laser desorption electrospray ionization

Eisenberg,

Muddiman

2024

Rapid Comm Mass Spectrometry

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RationaleSilver doping of electrospray is known to increase the abundance of olefinic compounds detected by mass spectrometry. While demonstrated in targeted experiments, this has yet to be investigated in an untargeted study. Utilizing infrared matrix‐assisted laser desorption electrospray ionization mass spectrometry imaging (IR‐MALDESI‐MSI), an untargeted lipidomics experiment on mouse liver was performed to evaluate the advantages of silver‐doped electrospray.Methods10 ppm silver nitrate was doped into the IR‐MALDESI solvent consisting of 60% acetonitrile and 0.2% formic acid. Using an Orbitrap mass spectrometer in positive ionization mode, MSI was performed, analyzing from m/z 150 to m/z 2000 to capture all lipids with potential silver adducts. The lipids detected in the control and silver‐doped electrosprays were compared by annotating using the LIPID MAPS Structural Database and eliminating false positives using the metabolite annotation confidence score.ResultsSilver‐doped electrospray allowed for the detection of such ions of lipid molecules as [M + H]+ or [M + NH4]+ and as [M + Ag]+. Among the ions seen as [M + H]+ or [M + NH4]+, the signal was comparable between the control and silver‐doped electrosprays. The silver‐doped electrospray led to a 10% increase in the number of detected lipids, all of which contained a bay region increasing the interaction between silver and alkenes. Silver preferentially interacted with lipids that did not contain hard bases such as phosphates.ConclusionsSilver‐doped electrospray enabled detection of 10% more olefinic lipids, all containing bay regions in their putative structures. This technique is valuable for detecting previously unobserved lipids that have the potential to form bay regions, namely fatty acyls, glycerolipids, prenol lipids, and polyketides.

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Section: Introductionmentioning

confidence: 99%

Improved detection in untargeted lipidomics through silver‐doped infrared matrix‐assisted laser desorption electrospray ionization

Eisenberg,

Muddiman

2024

Rapid Comm Mass Spectrometry

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Experimental and Theoretical Structure Elucidation of the [2 : 1] Complex Ion of Carbo[n]helicene with n=6, 7 and 8 and Ag⁺

et al. 2023

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Gas‐phase complexes of [n]helicenes with n = 6 ‐ 8 and the silver(I) cation are generated utilizing electrospray ionization mass spectrometry (ESI‐MS). Besides the well‐established [1:1] helicene/Ag+‐complex in which the helicene provides a tweezer‐like surrounding for the Ag+, there is also a [2:1] complex formed. Density‐functional theory (DFT) in conjunction with energy‐resolved collision‐induced dissociation (ER‐CID) experiments reveal that the second helicene attaches via π‐π stacking to the first helicene which is part of the pre‐formed [1:1] tweezer complex with Ag+. For polycyclic aromatic hydrocarbons (PAHs) of planar structure, the [2:1] complex with silver(I) is typically structured as a Ag+‐bound dimer (PAH‐‐‐Ag+‐‐‐PAH). For helicenes, the Ag+‐bound dimer is of similar thermochemical stability as the π‐π stacked dimer, however, it is kinetically inaccessible. Coronene (Cor) is investigated in comparison as an essentially planar PAH. In analogy to the π‐π stacked dimer of the helicenes, the Cor‐‐‐Ag+‐‐‐Cor‐‐‐Cor complex is also observed. Competition experiments using [n]helicene mixtures reveal that the tweezer complexes of Ag+ are preferably formed with the larger helicenes, with n = 6 being entirely ignored as the host for Ag+ in the presence of n = 7 or 8.

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Tandem mass spectrometry of π‐expanded triphenylamine and N‐heterotriangulene scaffolds: Radical cation versus silver(I) adduct

Kinzelmann,

Fröhlich,

Vogel

et al. 2024

J Mass Spectrom

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Triphenylamine (TPA) and N‐heterotriangulene (N‐HTA) scaffolds with up to three oligophenyl extensions are investigated by electrospray ionization (tandem) mass spectrometry (ESI‐[MS/]MS). Due to their low oxidation potentials, all molecules readily form radical cations in the electrospray process. The energy‐resolved collision‐induced dissociation behaviour of the molecular ions is contrasted to that of the silver(I) adducts. Complexation with Ag(I) leads to the expected [1:1] and [2:1] complexes (MAg+ and M2Ag+); however, even [1:2] complexes (MAg22+) can be detected for molecules with two and three large π‐expansions to allow stabilization of two charges. The TPA scaffolds decompose only at high collision energies through the loss of peripheral tert‐butyl groups. A general mechanism for this is proposed commencing with a methyl loss and followed by the release of isobutene and butyl radical moieties. The N‐HTA‐based scaffolds are considerably less stable and molecular ions fragment at low collision energies. This is caused by the facile loss of methyl radicals from the dimethylmethylene‐bridged triangulene core. In contrast, complexation with Ag+ leads to a dramatic stabilization. Most interestingly, dissociation eventually proceeds via the loss of neutral AgCH3, which is indicative of strong bidentate, tweezer‐like bonding of Ag+ to the molecules.

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Competition between the stabilizing effects of saturated alkyl substituents and pi bonds on complexes of silver ion (Ag⁺) with alkenes

Cited by 5 publications

References 37 publications

Improved detection in untargeted lipidomics through silver‐doped infrared matrix‐assisted laser desorption electrospray ionization

Improved detection in untargeted lipidomics through silver‐doped infrared matrix‐assisted laser desorption electrospray ionization

Experimental and Theoretical Structure Elucidation of the [2 : 1] Complex Ion of Carbo[n]helicene with n=6, 7 and 8 and Ag⁺

Tandem mass spectrometry of π‐expanded triphenylamine and N‐heterotriangulene scaffolds: Radical cation versus silver(I) adduct

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Competition between the stabilizing effects of saturated alkyl substituents and pi bonds on complexes of silver ion (Ag+) with alkenes

Cited by 5 publications

References 37 publications

Improved detection in untargeted lipidomics through silver‐doped infrared matrix‐assisted laser desorption electrospray ionization

Improved detection in untargeted lipidomics through silver‐doped infrared matrix‐assisted laser desorption electrospray ionization

Experimental and Theoretical Structure Elucidation of the [2 : 1] Complex Ion of Carbo[n]helicene with n=6, 7 and 8 and Ag+

Tandem mass spectrometry of π‐expanded triphenylamine and N‐heterotriangulene scaffolds: Radical cation versus silver(I) adduct

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Competition between the stabilizing effects of saturated alkyl substituents and pi bonds on complexes of silver ion (Ag⁺) with alkenes

Experimental and Theoretical Structure Elucidation of the [2 : 1] Complex Ion of Carbo[n]helicene with n=6, 7 and 8 and Ag⁺