d–d Dative Bonding Between Iron and the Alkaline-Earth Metals Calcium, Strontium, and Barium

Stegner P, Färber C, Oetzel J, Siemeling U, Wiesinger M, Langer J, Pan S, Holzmann N, Frenking G, Albold U, Sarkar B, Harder S (2020)

Publication Type: Journal article

Publication year: 2020

Journal

DOI: 10.1002/anie.202005774

Abstract

Double deprotonation of the diamine 1,1′-(tBuCH2NH)-ferrocene (1-H2) by alkaline-earth (Ae) or Eu^II metal reagents gave the complexes 1-Ae (Ae=Mg, Ca, Sr, Ba) and 1-Eu. 1-Mg crystallized as a monomer while the heavier complexes crystallized as dimers. The Fe⋅⋅⋅Mg distance in 1-Mg is too long for a bonding interaction, but short Fe⋅⋅⋅Ae distances in 1-Ca, 1-Sr, and 1-Ba clearly support intramolecular Fe⋅⋅⋅Ae bonding. Further evidence for interactions is provided by a tilting of the Cp rings and the related ¹H NMR chemical-shift difference between the Cp α and β protons. While electrochemical studies are complicated by complex decomposition, UV/Vis spectral features of the complexes support Fe→Ae dative bonding. A comprehensive bonding analysis of all 1-Ae complexes shows that the heavier species 1-Ca, 1-Sr, and 1-Ba possess genuine Fe→Ae bonds which involve vacant d-orbitals of the alkaline-earth atoms and partially filled d-orbitals on Fe. In 1-Mg, a weak Fe→Mg donation into vacant p-orbitals of the Mg atom is observed.

Authors with CRIS profile

Involved external institutions

Universität Kassel Germany (DE) Philipps-Universität Marburg Germany (DE) Shenzhen Institutes of Advanced Technology (SIAT) China (CN) Freie Universität Berlin Germany (DE)

How to cite

APA:

Stegner, P., Färber, C., Oetzel, J., Siemeling, U., Wiesinger, M., Langer, J.,... Harder, S. (2020). d–d Dative Bonding Between Iron and the Alkaline-Earth Metals Calcium, Strontium, and Barium. Angewandte Chemie International Edition. https://doi.org/10.1002/anie.202005774

MLA:

Stegner, Philipp, et al. "d–d Dative Bonding Between Iron and the Alkaline-Earth Metals Calcium, Strontium, and Barium." Angewandte Chemie International Edition (2020).

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