Mass Spectrometry of Isomeric Ions

Project Information

IsoMS

Grant agreement ID: 682275

DOI

10.3030/682275

Project closed

EC signature date 22 June 2016

Start date 1 July 2016

End date 31 December 2021

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 612 500,00

EU contribution

€ 1 612 500,00

Coordinated by

STICHTING RADBOUD UNIVERSITEIT
Netherlands

Periodic Reporting for period 4 - IsoMS (Mass Spectrometry of Isomeric Ions)

Reporting period: 2020-01-01 to 2021-12-31

Summary of the context and overall objectives of the project

The IsoMS project focused on development of mass-spectrometry tools for studying reaction mechanisms. The pressure gap between the formation of reaction intermediates in solution and their gas-phase detection is one of the biggest questions in mass spectrometric approach to study reactions. To tackle this question, we have designed Delayed reactant labeling (DRL) method. We have shown that this method can be used to track reaction kinetics of intermediates in gold(I) catalyzed reactions (e.g. Chem. Sci. 2020, 11, 980) or in palladium-catalyzed reactions (Organometallics 2017, 36, 2072). In addition, we have developed a coupling of mass spectrometry with a flow reactor for monitoring reaction kinetics in solution (Angew. Chem. Int. Ed. 2021, 60, 7126 and Chem. Methods 2021, 1, 430). This approach is suitable for monitoring reactive, short-lived intermediates. We have highlighted our approached in an invited review (Chem. Sci. 2020, 11, 11960).
The second part of IsoMS was devoted to the implementing of ion spectroscopy as an analytical tool. We have shown that helium tagging infrared photodissociation (IRPD) spectroscopy can be used to characterize reactive hypervalent metal complexes (e.g. J. Am. Chem. Soc. 2017, 139, 2757 or Chem. Commun. 2017, 53, 8786). We have cooperated with several leading laboratories in bioinorganic and organometallic chemistry on further dissemination of this method and broadening of its analytical scope (e.g. Nat. Commun. 2019, 10, 901 or Angew. Chem. Int. Ed. 2021, 60, 23018). We have also used the IRPD approach to characterize short lived intermediates in photochemical reactions (e.g. Angew. Chem. Int. Ed. 2019, 58, 15412). The approach is summarized in an invited review (ChemBioChem. 2020, 21, 2232).
Another part of IsoMS was devoted to probing of chemical reactivity in our low temperature trap. We have made a breakthrough in the investigation of the prototypical system FeO+ + H2 for which we were able to measure the rate constants down to 5 K (ChemPhysChem. 2016, 17, 3723). We have also investigated photochemical reactions in the cold trap using irradiation in the vis and UV spectral range (J. Mol. Spec. 2017, 332, 52). For example, we have rationalized temperature dependent formation of iron(V)-nitrido complexes by investigating spin state dependent photofragmentation of iron(II) azide complexes (Angew. Chem. Int. Ed. 2017, 56, 14057).
In general, IsoMS project significantly contributed to the methods to bridge the gap between solution chemistry and mass spectrometry detection of species from the solution. IsoMS also fulfilled the goal to use ion spectroscopy as an analytical tool. The method is used in the field of metal chemistry and belongs to ultimate tools to detect highly reactive species. The project brought various methods developments in the field of kinetics, flow chemistry, gas-phase reactions and detections of highly reactive species in metal chemistry and in photochemistry.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The project was divided to four work packages. Three work packages were focused on reaction mechanisms or reaction intermediates. One work package was devoted to technological development of the cryotrapping instrumentation.
WP1: We have implemented Delayed reactant labeling for studying reaction mechanisms in the condensed phase. We have published several papers devoted to gold catalysis (e.g. Org. Biomol. Chem. 2017, 15, 7841; Faraday Discussions 2019, 220, 58; Chem. Sci. 2020, 11, 980). Further, we have developed an alternative approach to obtain solution kinetics of rapidly formed palladium complexes (Organometallics 2017, 36, 2072). Finally, we have developed coupling of flow chemistry with mass spectrometry for kinetics monitoring of highly reactive metal complexes (Angew. Chem. Int. Ed. 2021, 60, 7126; Chem. Methods 2021, 1, 430). We have also developed an open-source program to evaluate the MS data (https://gitlab.science.ru.nl/jzelenka/prasopes).
WP2: We have implemented helium tagging infrared dissociation (IRPD) spectroscopy as a common tool to investigate structure of reaction intermediates in all projects. We started to cooperate with a broad range of scientists from other fields to use IRPD spectroscopy as an analytical tool. We have published a methodology paper demonstrating correlation of gas-phase data with solution data and showed additional capabilities of our methods (J. Am. Chem. Soc. 2017, 139, 2757). The PI is regularly invited to conferences in the field of inorganic chemistry (bio-inspired catalysis and similar topics) to present the developed approach. The spectroscopic analysis of the structures of the intermediates (WP2) together with the correlation with solution chemistry and kinetics in solution (WP1) represent a powerful tool to understand mechanisms that are difficult to solve with other methods.
WP3: This work package was devoted to extending cryotrapping instrument with an ion mobility capability. This part of the project failed. We have tried some experiments that suggested that the ion mobility separation would be possible. However, the experiments were time-demanding and preventing us from the other work (other WPs). Therefore, we have decided to skip this part of the project.
WP4: This workpackage was devoted to the investigation of reactions in our cryogenic trap. We have investigated the FeO+ + H2 reaction. Until our work, the rate constants for this reaction were known in the temperature range down to 100 K. We were able to measure the rate constants down to 5 K. In addition, we have, for the first time, measured IRPD spectra of an in-trap formed reaction intermediate. It was possible to stabilize the initial reaction complex [H2FeO]+ and obtain its IRPD spectrum by the helium tagging method (ChemPhysChem. 2016, 17, 3723). Further, we have decided to broaden the program also for photochemical reactions. We have shown that we can study isomerizations (J. Mol. Spec. 2017, 332, 52) and photofragmentations (Angew. Chem. Int. Ed. 2017, 56, 14057).

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

We think that we went in all our key results well beyond the state of the art. We have developed methods to study processes in solution using mass spectrometry detection. It means that we can study independently different species in solution with an unprecedented detection sensitivity. This line of research develops further and we are preparing studies that demonstrate that our methods allow studying equilibria in complex reaction mixtures or comparison of various catalysts for a given reaction in one pot. Similar challenges are impossible to tack with other methods.
The achievements with helium tagging ion spectroscopy shifted the current state of the art in the field. Thanks to our results, we could have elucidate, how a molecule of oxygen gets activated with biomimetic copper complexes, how the binding between gold(I) and a proton works, or how do short-lived intermediates in photochemical reactions look like. These are just selected examples, how broad significance this spectroscopy of reactive species can have and how it can expand our knowledge in future.
Potential impact: The developed mass spectrometry methods provide more tools to investigate chemical reactions. They have brought and they will bring new knowledge about organic, organometallic, bioinorganic and other reactions. Further, the methods broaden the analytical method selection available for scientists working with reactive compounds.

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