Lewis Acidic Cationic Strontium and Barium Complexes

Thum K, Martin J, Elsen H, Eyselein J, Stiegler L, Langer J, Harder S (2021)

Publication Type: Journal article

Publication year: 2021

Journal

European Journal of Inorganic Chemistry Wiley-VCH Verlag

DOI: 10.1002/ejic.202100345

Abstract

Lewis acidic (BDI)Ae+ cations of the heavier metals Sr and Ba, which are not stabilized by polar solvents, have been obtained by double deprotonation of (BDI)H2+ with either SrN’’2 or BaN’’2; BDI = HC[C(Me)N(DIPP)]2, DIPP = 2,6-diisopropylphenyl, Ae = alkaline earth, N’’ = N(SiMe3)2. Due to clathrate formation [(BDI)Ae+][B(C6F5)4−] could not be crystallized, but pyrene addition gave crystalline [(BDI)Ae+ ⋅ pyrene][B(C6F5)4−] which was structurally characterized for Ae = Mg, Ca, Sr, Ba. (R2N)Ae+ cations of the heavier metals Sr and Ba were obtained by reaction of Ae(NR2)2 with [Ph3C+][B(C6F5)4−] or [PhNMe2H+][B(C6F5)4−]. Following complexes were structurally characterized: [N’’Ba+ ⋅ (tol)2][B(C6F5)4−], [N*Sr+ ⋅ PhNMe2][B(C6F5)4−], [N*Ba+ ⋅ tol][B(C6F5)4−] and [N*Ba+ ⋅ C6H6][B(C6F5)4−]; tol = toluene and N* = N(SiiPr3)2. DFT calculations show that Sr⋅⋅⋅PhNMe2 coordination is preferred over Sr⋅⋅⋅toluene bonding. The (R2N)Ae+ cations can be used as Brønsted bases (reaction with (BDI)H gave (BDI)Ae+) and may be useful precursors for a variety of Lewis base-free RAe+ cations. DFT calculations, limited to monomeric model systems including B(C6F5)4− (ωB97XD/def2tzvpp//ωB97XD/def2svp), show that there is negligible electron transfer from the pyrene or toluene ligands to the Ae2+ cation. Electrostatic attraction originates from charge-induced polarization of the (Formula presented.) -electron density in the toluene and pyrene ligands.

Authors with CRIS profile

Katharina Thum Lehrstuhl für Anorganische und Metallorganische Chemie Johannes Martin Lehrstuhl für Anorganische und Metallorganische Chemie Holger Elsen Lehrstuhl für Anorganische und Metallorganische Chemie Jonathan Mai Lehrstuhl für Anorganische und Metallorganische Chemie Lisa Stiegler Lehrstuhl für Organische Chemie II Jens Langer Lehrstuhl für Anorganische und Metallorganische Chemie Sjoerd Harder Lehrstuhl für Anorganische und Metallorganische Chemie

How to cite

APA:

Thum, K., Martin, J., Elsen, H., Eyselein, J., Stiegler, L., Langer, J., & Harder, S. (2021). Lewis Acidic Cationic Strontium and Barium Complexes. European Journal of Inorganic Chemistry. https://doi.org/10.1002/ejic.202100345

MLA:

Thum, Katharina, et al. "Lewis Acidic Cationic Strontium and Barium Complexes." European Journal of Inorganic Chemistry (2021).

BibTeX: Download