Unexpected structural isomers of AlFe<sub>2</sub>O<sub>4</sub><sup>+</sup> and AlCo<sub>2</sub>O<sub>4</sub><sup>+</sup>: vibrational spectroscopy and ion mobility combined with quantum chemistry
The structure and reactivity of the mixed metal oxide clusters Al<sub>2</sub>MO<sub>4</sub> <sup>+</sup> and AlM<sub>2</sub>O<sub>4</sub> <sup>+</sup> (M = Fe, Co), formally obtained by transition metal ion substitution from Al<sub>3</sub>O<sub>4</sub> <sup>+</sup>, are studied using infrared photodissociation (IRPD) spectroscopy, ion-mobility mass-spectrometry (IM-MS) and quantum chemistry. We use density functional theory (DFT) in combination with global structure optimization to identify low energy structures and to connect them to the IRPD and IM-MS data. Insights into anharmonic and temperature effects are obtained from machine learning-based molecular dynamics simulations. While all metal ions are equal in the cone-shaped structure of M<sub>3</sub>O<sub>4</sub> <sup>+</sup>, the mixed metal oxide clusters attain different, more stable structures, in which the metal ions are either in different oxidation states (Al<sub>2</sub>MO<sub>4</sub> <sup>+</sup>) or have different coordination numbers (AlM<sub>2</sub>O<sub>4</sub> <sup>+</sup>). The present results illustrate that different DFT functionals may accurately describe local minimum structures, but reliable relative energies of isomers with differently coordinated transition metal ions require multi-reference wavefunction calculations.
Authors
- Tatiana C. Penna (ORCID: https://orcid.org/0000-0001-5279-0639)
- Keijiro Ohshimo (ORCID: https://orcid.org/0000-0002-2397-6896)
- Naoyuki Ishida (ORCID: https://orcid.org/0000-0001-7603-1151)
- Knut R. Asmis (ORCID: https://orcid.org/0000-0001-6297-5856)
- Fuminori Misaizu (ORCID: https://orcid.org/0000-0003-0822-6285)
- Arghya Chakraborty (ORCID: https://orcid.org/0000-0002-6643-9169)
- Stephen Leach (ORCID: https://orcid.org/0000-0002-0875-729X)
- Fabian Berger (ORCID: https://orcid.org/0000-0002-5463-3159)
- Fabian Müller (ORCID: https://orcid.org/0000-0002-1774-6373)
- Joachim Sauer (ORCID: https://orcid.org/0000-0001-6798-6212)
- Francine Horn (ORCID: https://orcid.org/0000-0002-7296-3549)
- Henning Windeck (ORCID: https://orcid.org/0000-0003-2482-9748)
- Xavier R. Advincula (ORCID: https://orcid.org/0009-0001-5343-0456)
- Yake Li (ORCID: https://orcid.org/0000-0002-7421-6643)
- Winni Schwedland (ORCID: https://orcid.org/0009-0008-2126-3981)
Institutions
- Tohoku University (JP)
- University of Cambridge (GB)
- Fritz Haber Institute of the Max Planck Society (DE)
- Humboldt-Universität zu Berlin (DE)
- Leipzig University (DE)
Publication Details
- Journal
- Chemical Science
- Published
- 2025-01-01
- DOI
- https://doi.org/10.1039/d5sc02681d
- Citations
- 2
- Primary Topic
- Inorganic and Organometallic Chemistry
- Type
- article
- Field-Weighted Citation Impact
- 1.87
Funders
- Alexander von Humboldt-Stiftung
- International Max Planck Research School for Environmental, Cellular and Molecular Microbiology
- Fonds der Chemischen Industrie
- European Commission
- University of Edinburgh
- Deutsche Forschungsgemeinschaft
- Isaac Newton Trust
- Engineering and Physical Sciences Research Council
- European Research Council