Reactive metallocene cations as sensitive indicators of gas-phase oxygen and water

Joshi, Anuj; Donnecke, Sofia; Granot, Ori; Shin, Dongju; Collins, Scott; Paci, Irina; McIndoe, J. Scott

doi:10.1039/d0dt00798f

Cited by 8 publications

(12 citation statements)

References 45 publications

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“…However, species of this type may be responsible for formation of Me 2 AlF, especially in the absence of stronger donors such as OMTS [36] . As we have also seen ion fluorination in connection with other, unrelated reactions and it is definitely occurring in the gas phase [37] we cannot completely rule out formation of these fluorinated anions via ion‐molecule reactions in the source compartment, involving the solvent or another fluorinated impurity [38] …”

Section: Resultsmentioning

confidence: 94%

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Spectroscopic Studies of Synthetic Methylaluminoxane: Structure of Methylaluminoxane Activators

Joshi

Collins

Linnolahti

et al. 2021

Chemistry A European J

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Hydrolysis of trimethylaluminum (Me3Al) in polar solvents can be monitored by electrospray ionization mass spectrometry (ESI‐MS) using the donor additive octamethyltrisiloxane [(Me3SiO)2SiMe2, OMTS]. Using hydrated salts, hydrolytic methylaluminoxane (h‐MAO) features different anion distributions, depending on the conditions of synthesis, and different activator contents as measured by NMR spectroscopy. Non‐hydrolytic MAO was prepared using trimethylboroxine. The properties of this material, which contains incorporated boron, differ significantly from h‐MAO. In the case of MAO prepared by direct hydrolysis, oligomeric anions are observed to rapidly form, and then more slowly evolve into a mixture dominated by an anion with m/z 1375 with formula [(MeAlO)16(Me3Al)6Me]−. Theoretical calculations predict that sheet structures with composition (MeAlO)n(Me3Al)m are favoured over other motifs for MAO in the size range suggested by the ESI‐MS experiments. A possible precursor to the m/z 1375 anion is a local minimum based on the free energy released upon hydrolysis of Me3Al.

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Section: Resultsmentioning

confidence: 94%

“…[32]. The increased intensity of [ 16,5 ] − relative to [ 16,6 ] − in these spectra results in part from source‐induced fragmentation (see Supporting Information p. 2) [38] …”

Section: Resultsmentioning

confidence: 99%

Spectroscopic Studies of Synthetic Methylaluminoxane: Structure of Methylaluminoxane Activators

Joshi

Collins

Linnolahti

et al. 2021

Chemistry A European J

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“…76 Collecting spectra of extremely water-sensitive compounds can be negatively The collision gas also plays a significant role in getting reliable MS/MS spectrum. 77 When the system being studied is very sensitive to air and moisture, such as [Cp 2 Zr(μ-Me) 2 AlMe 2 ] + [B(C 6 F 5 ) 4 ] À , the collision gas employed is often passed through a gas drying unit. However, moisture can also be in the collision chamber inside the mass spectrometer, which is very difficult to remove.…”

Section: Electrospray Ionizationmentioning

confidence: 99%

“…Getting reliable MS/MS in such cases can be achieved by lowering the collision gas pressure. 77 Trace amounts of water in quadrupole ion traps (QIT) also complicate the analysis of moisture-sensitive compounds. 78,79 The desolvation gas employed for ESI-MS experiments is usually of very high purity (e.g., 99.995%).…”

Section: Electrospray Ionizationmentioning

confidence: 99%

Handling considerations for the mass spectrometry of reactive organometallic compounds

et al. 2022

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Mass spectrometry is a powerful tool in disparate areas of chemistry, but its characteristic strength of sensitivity can be an Achilles heel when studying highly reactive organometallic compounds. A quantity of material suitable for mass spectrometric analysis often represents a tiny grain or a very dilute solution, and both are highly susceptible to decomposition due to ambient oxygen or moisture. This complexity can be frustrating to chemists and analysts alike: the former being unable to get spec-

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“…Electrospray ionization mass spectrometry (ESI‐MS) is a convenient and useful technique for characterizing transition metal complexes including elemental composition and ligand‐to‐metal ratio as well as metal oxidation state 15–19 . Transition metal complexes in solution often coordinate with the solvents commonly used for ESI‐MS, such as methanol, acetonitrile and water, due to the presence of binding sites in the form of both oxygen and nitrogen donor atoms, resulting in the formation of solvent‐coordinated adduct ions during ESI‐MS 20–23 .…”

Section: Introductionmentioning

confidence: 99%

Investigating the exceptional adducts of alkoxides with Ru(II)–arene cations in alkyl alcohol solution using electrospray ionization mass spectrometry

Cao

Dong

et al. 2021

Rapid Comm Mass Spectrometry

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Rationale Exploring the formation mechanism of the exceptional adducts of alkoxides with Ru(II)–arene cations in alkyl alcohol solution using electrospray ionization mass spectrometry (ESI‐MS) is crucial for further understanding the physicochemical properties of Ru(II)–arene complexes in solution. Methods All mass spectra were collected with an AB SCIEX TripleTOF 5600+ mass spectrometer in positive mode. Theoretical calculations were carried out using the density functional theory method at the B3LYP level with a hybrid basis set consisting of 6‐31G(d,p) and LanL2DZ in the Gaussian 03 program. Results When ruthenated [15]paracyclophanes (Ru‐[15]PCPs) and Ru(II)–arene dimers were dissolved in alkyl alcohol solvents, the adducts of alkoxides with Ru(II)–arene cations were observed under positive ion mode ESI‐MS, which resulted from the coordination of alkyl alcohol molecules with the Ru(II)–arene cations followed by the deprotonation of O‐H bonds of the coordinated alcohols. Furthermore, the number of alkoxides binding to Ru‐[15]PCPs was regulated by the number of ruthenium atoms. Attributed to good solubility and small steric hindrance, the signal intensity of the adducts of methoxides with Ru(II)–arene cations was the strongest among the three alkyl alcohols used in this study. Conclusions The characteristic adducts of alkoxides with Ru(II)–arene cations were pervasively present in positive ion mode ESI‐MS of nine Ru(II)–arene complexes dissolved in alkyl alcohol solvents. Taking into consideration the solubility and signal response, methanol is the most suitable solvent for the ESI‐MS experiments with Ru(II)–arene complexes among the solvents studied, where almost only the diagnostic adducts of methoxides with Ru(II)–arene cations are present.

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Reactive metallocene cations as sensitive indicators of gas-phase oxygen and water

Abstract: Gas-phase oxidation of air-sensitive organometallic compounds does not proceed to a significant extent in mass spectrometric analysis unless a vacant coordination site is generated, making nitrogen generators a suitable source of desolvation gas.

Cited by 8 publications

References 45 publications

Spectroscopic Studies of Synthetic Methylaluminoxane: Structure of Methylaluminoxane Activators

Spectroscopic Studies of Synthetic Methylaluminoxane: Structure of Methylaluminoxane Activators

Handling considerations for the mass spectrometry of reactive organometallic compounds

Investigating the exceptional adducts of alkoxides with Ru(II)–arene cations in alkyl alcohol solution using electrospray ionization mass spectrometry

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