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A three body problem: a genuine heterotrimetallic molecule vs. a mixture of two parent heterobimetallic molecules
This work raises a fundamental question about the “real” structure of molecular compounds containing three different metals: whether they consist of genuine heterotrimetallic species or of a mixture of parent heterobimetallic species. Heterotrimetallic complex Li(2)CoNi(tbaoac)(6) (1, tbaoac = tert-...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Royal Society of Chemistry
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5982224/ https://www.ncbi.nlm.nih.gov/pubmed/29910924 http://dx.doi.org/10.1039/c8sc00917a |
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author | Han, Haixiang Wei, Zheng Barry, Matthew C. Carozza, Jesse C. Alkan, Melisa Rogachev, Andrey Yu Filatov, Alexander S. Abakumov, Artem M. Dikarev, Evgeny V. |
author_facet | Han, Haixiang Wei, Zheng Barry, Matthew C. Carozza, Jesse C. Alkan, Melisa Rogachev, Andrey Yu Filatov, Alexander S. Abakumov, Artem M. Dikarev, Evgeny V. |
author_sort | Han, Haixiang |
collection | PubMed |
description | This work raises a fundamental question about the “real” structure of molecular compounds containing three different metals: whether they consist of genuine heterotrimetallic species or of a mixture of parent heterobimetallic species. Heterotrimetallic complex Li(2)CoNi(tbaoac)(6) (1, tbaoac = tert-butyl acetoacetate) has been designed based on the model tetranuclear structure featuring two transition metal sites in order to be utilized as a molecular precursor for the low-temperature preparation of the LiCo(0.5)Ni(0.5)O(2) battery cathode material. An investigation of the structure of 1 appeared to be very challenging, since the Co and Ni atoms have very similar atomic numbers, monoisotopic masses, and radii as well as the same oxidation state and coordination number/environment. Using a statistical analysis of heavily overlaid isotope distribution patterns of the [Li(2)MM′L(5)](+) (M/M′ = Co(2), Ni(2), and CoNi) ions in DART mass spectra, it was concluded that the reaction product 1 contains both heterotrimetallic and bimetallic species. A structural analogue approach has been applied to obtain Li(2)MMg(tbaoac)(6) (M = Co (2) and Ni (3)) complexes that contain lighter, diamagnetic magnesium in the place of one of the 3d transition metals. X-ray crystallography, mass spectrometry, and NMR spectroscopy unambiguously confirmed the presence of three types of molecules in the reaction mixture that reaches an equilibrium, Li(2)M(2)L(6) + Li(2)Mg(2)L(6) ↔ 2Li(2)MMgL(6), upon prolonged reflux in solution. The equilibrium mixture was shown to have a nearly statistical distribution of the three molecules, and this is fully supported by the results of theoretical calculations revealing that the stabilization energies of heterotrimetallic assemblies fall exactly in between those for the parent heterobimetallic species. The LiCo(0.5)Ni(0.5)O(2) quaternary oxide has been obtained in its phase-pure form by thermal decomposition of heterometallic precursor 1 at temperatures as low as 450 °C. Its chemical composition, structure, morphology, and transition metal distribution have been studied by X-ray and electron diffraction techniques and compositional energy-dispersive X-ray mapping with nanometer resolution. The work clearly illustrates the advantages of heterometallic single-source precursors over the corresponding multi-source precursors. |
format | Online Article Text |
id | pubmed-5982224 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-59822242018-06-15 A three body problem: a genuine heterotrimetallic molecule vs. a mixture of two parent heterobimetallic molecules Han, Haixiang Wei, Zheng Barry, Matthew C. Carozza, Jesse C. Alkan, Melisa Rogachev, Andrey Yu Filatov, Alexander S. Abakumov, Artem M. Dikarev, Evgeny V. Chem Sci Chemistry This work raises a fundamental question about the “real” structure of molecular compounds containing three different metals: whether they consist of genuine heterotrimetallic species or of a mixture of parent heterobimetallic species. Heterotrimetallic complex Li(2)CoNi(tbaoac)(6) (1, tbaoac = tert-butyl acetoacetate) has been designed based on the model tetranuclear structure featuring two transition metal sites in order to be utilized as a molecular precursor for the low-temperature preparation of the LiCo(0.5)Ni(0.5)O(2) battery cathode material. An investigation of the structure of 1 appeared to be very challenging, since the Co and Ni atoms have very similar atomic numbers, monoisotopic masses, and radii as well as the same oxidation state and coordination number/environment. Using a statistical analysis of heavily overlaid isotope distribution patterns of the [Li(2)MM′L(5)](+) (M/M′ = Co(2), Ni(2), and CoNi) ions in DART mass spectra, it was concluded that the reaction product 1 contains both heterotrimetallic and bimetallic species. A structural analogue approach has been applied to obtain Li(2)MMg(tbaoac)(6) (M = Co (2) and Ni (3)) complexes that contain lighter, diamagnetic magnesium in the place of one of the 3d transition metals. X-ray crystallography, mass spectrometry, and NMR spectroscopy unambiguously confirmed the presence of three types of molecules in the reaction mixture that reaches an equilibrium, Li(2)M(2)L(6) + Li(2)Mg(2)L(6) ↔ 2Li(2)MMgL(6), upon prolonged reflux in solution. The equilibrium mixture was shown to have a nearly statistical distribution of the three molecules, and this is fully supported by the results of theoretical calculations revealing that the stabilization energies of heterotrimetallic assemblies fall exactly in between those for the parent heterobimetallic species. The LiCo(0.5)Ni(0.5)O(2) quaternary oxide has been obtained in its phase-pure form by thermal decomposition of heterometallic precursor 1 at temperatures as low as 450 °C. Its chemical composition, structure, morphology, and transition metal distribution have been studied by X-ray and electron diffraction techniques and compositional energy-dispersive X-ray mapping with nanometer resolution. The work clearly illustrates the advantages of heterometallic single-source precursors over the corresponding multi-source precursors. Royal Society of Chemistry 2018-05-08 /pmc/articles/PMC5982224/ /pubmed/29910924 http://dx.doi.org/10.1039/c8sc00917a Text en This journal is © The Royal Society of Chemistry 2018 http://creativecommons.org/licenses/by-nc/3.0/ This article is freely available. This article is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported Licence (CC BY-NC 3.0) |
spellingShingle | Chemistry Han, Haixiang Wei, Zheng Barry, Matthew C. Carozza, Jesse C. Alkan, Melisa Rogachev, Andrey Yu Filatov, Alexander S. Abakumov, Artem M. Dikarev, Evgeny V. A three body problem: a genuine heterotrimetallic molecule vs. a mixture of two parent heterobimetallic molecules |
title | A three body problem: a genuine heterotrimetallic molecule vs. a mixture of two parent heterobimetallic molecules
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title_full | A three body problem: a genuine heterotrimetallic molecule vs. a mixture of two parent heterobimetallic molecules
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title_fullStr | A three body problem: a genuine heterotrimetallic molecule vs. a mixture of two parent heterobimetallic molecules
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title_full_unstemmed | A three body problem: a genuine heterotrimetallic molecule vs. a mixture of two parent heterobimetallic molecules
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title_short | A three body problem: a genuine heterotrimetallic molecule vs. a mixture of two parent heterobimetallic molecules
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title_sort | three body problem: a genuine heterotrimetallic molecule vs. a mixture of two parent heterobimetallic molecules |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5982224/ https://www.ncbi.nlm.nih.gov/pubmed/29910924 http://dx.doi.org/10.1039/c8sc00917a |
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