Pressurized Sample Infusion

Thomas, Gilian T.; Donnecke, Sofia; Chagunda, Ian C.; McIndoe, J. Scott

doi:10.1002/cmtd.202100068

Cited by 14 publications

(15 citation statements)

References 90 publications

(145 reference statements)

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“…The complexity of the mixture also increases due to the ligand-exchange equilibria, which creates a continuum of possible catalyst compositions. Electrospray ionization (ESI)-MS is a powerful tool for reaction mixture investigation, combining the perfect detection method with a “soft” ionization technique capable of ionizing metal complexes. , …”

Section: Resultsmentioning

confidence: 99%

Fully Automated Unconstrained Analysis of High-Resolution Mass Spectrometry Data with Machine Learning

et al. 2022

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Mass spectrometry (MS) is a convenient, highly sensitive, and reliable method for the analysis of complex mixtures, which is vital for materials science, life sciences fields such as metabolomics and proteomics, and mechanistic research in chemistry. Although it is one of the most powerful methods for individual compound detection, complete signal assignment in complex mixtures is still a great challenge. The unconstrained formula-generating algorithm, covering the entire spectra and revealing components, is a "dream tool" for researchers. We present the framework for efficient MS data interpretation, describing a novel approach for detailed analysis based on deisotoping performed by gradient-boosted decision trees and a neural network that generates molecular formulas from the fine isotopic structure, approaching the long-standing inverse spectral problem. The methods were successfully tested on three examples: fragment ion analysis in protein sequencing for proteomics, analysis of the natural samples for life sciences, and study of the cross-coupling catalytic system for chemistry.

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Section: Resultsmentioning

confidence: 99%

Fully Automated Unconstrained Analysis of High-Resolution Mass Spectrometry Data with Machine Learning

et al. 2022

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“…This is illustrated for the [(NHC 4 )( p -cym)RuCl] + cation that displays N-bound groups with C(sp 2 )–H and C(sp 3 )–H bonds amenable metalation upon CID. Together with the well-documented application of ESI-MS and its tandem version for mechanistic studies and the recent developments for “ in situ ” monitoring and kinetic analysis of the reaction intermediates by MS methods, , the development of new IM-MS-based approaches has the potential to have an important impact in mechanistic or speciation studies in catalysis. It is reasonable to consider that IM-MS could also be used to identify other site-selective C–X bond activation (X = halogen, CN, etc.)…”

Section: Discussionmentioning

confidence: 99%

Introducing Ion Mobility Mass Spectrometry to Identify Site-Selective C–H Bond Activation in N-Heterocyclic Carbene Metal Complexes

Mollar-Cuni

Ibáñez-Ibáñez

Guisado‐Barrios

et al. 2022

J. Am. Soc. Mass Spectrom.

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The activation of C−H bonds in a selective manner still constitutes a major challenge from a synthetic point of view; thus, it remains an active area of fundamental and applied research. Herein, we introduce ion mobility spectrometry mass spectrometry-based (IM-MS) approaches to uncover site-selective C−H bond activation in a series of metal complexes of general formula [(NHC)LMCl] + (NHC = N-heterocyclic carbene; L = pentamethylcyclopentadiene (Cp*) or p-cymene; M = Pd, Ru, and Ir). The C−H bond activation at the N-bound groups of the NHC ligand is promoted upon collision induced dissociation (CID). The identification of the resulting [(NHC-H)LM] + isomers relies on the distinctive topology that such cyclometalated isomers adopt upon site-selective C−H bond activation. Such topological differences can be reliably evidenced as different mobility peaks in their respective CID-IM mass spectra. Alternative isomers are also identified via dehydrogenation at the Cp*/p-cymene (L) ligands to afford [(NHC)(L-H)M] + . The fragmentation of the ion mobility-resolved peaks is also investigated by CID-IM-CID. It enables the assignment of mobility peaks to the specific isomers formed from C(sp 2 )−H or C(sp 3 )−H bond activation and distinguishes them from the Cp*/p-cymene (L) dehydrogenation isomers. The conformational change of the NHC ligands upon C−H bond activation, concomitant with cyclometalation, is also discussed on the basis of the estimated collision cross section (CCS). A unique conformation change of the pyrene-tagged NHC members is identified that involves the reorientation of the NHC ring accompanied by a folding of the pyrene moiety.

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“…Solid samples were dissolved in THF (∼2 m m ), deprotonated with an excess of KO t Bu/18‐crown‐6 and infused with a syringe pump at 8 μL min −1 . For live experiments, the reaction solution was fed into the instrument with a standard pressurized‐sample infusion setup at 30 mbar overpressure [23] …”

Section: Methodsmentioning

confidence: 99%

Live Monitoring of Anionic Living Polymerizations by Electrospray‐Ionization Mass Spectrometry

Eisele

Peters

Koszinowski

2023

Chemistry A European J

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Anionic polymerizations are of exceptional practical importance, but difficult to analyze due to the high reactivity of the growing polymer chains. Here, we demonstrate that electrospray‐ionization mass spectrometry (ESI‐MS) permits direct observation of the active carbanionic intermediates formed in the anionic ring‐opening polymerization of 1‐cyanocyclopropanecarboxylate in tetrahydrofuran. This includes the identification of a side product, as well as real‐time analysis of the polymerization reaction. From the mass spectra obtained, we can derive not only the mean molar mass and the polydispersity, but also the rate constants for the initiation and the individual propagation steps. The initiation proceeds significantly faster than the propagation steps. Accordingly, the examined reaction corresponds to a living polymerization, as we also confirmed by additional control experiments. Besides giving detailed insight into the reaction system probed here, we also expect the presented methodology to make possible the in‐situ analysis of further anionic polymerizations.

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Pressurized Sample Infusion

Cited by 14 publications

References 90 publications

Fully Automated Unconstrained Analysis of High-Resolution Mass Spectrometry Data with Machine Learning

Fully Automated Unconstrained Analysis of High-Resolution Mass Spectrometry Data with Machine Learning

Introducing Ion Mobility Mass Spectrometry to Identify Site-Selective C–H Bond Activation in N-Heterocyclic Carbene Metal Complexes

Live Monitoring of Anionic Living Polymerizations by Electrospray‐Ionization Mass Spectrometry

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