Alkaline-Earth Metal Complexes Based on Tridentate β-Diketiminate Ligands Bearing a Tethered Secondary Amine: Synthesis and Characterization

Rösch B, Guzmán J, Bauer H, Pahl J, Wiesinger M, Escalona A, Harder S (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Book Volume: 652

Article Number: e70135

Journal Issue: 11

DOI: 10.1002/zaac.70135

Abstract

The alkaline-earth (Ae) metal chemistry of a β-diketiminate (BDI) ligand with a bulky Ar-substituent and a pendant amine arm was investigated. The ligand precursor HC[C(Me)N(H)DIPP][C(Me)NCH2CH2N(H)tBu], abbreviated as LH2, carries two N—H groups that can potentially be deprotonated (DIPP = 2,6-diisopropylphenyl). We improved the literature-known synthesis for LH2 and increased the product yield and purity. Reactions of this pro-ligand with AeN″2 (Ae = Mg, Ca, Sr) led to selective single deprotonation resulting in a series of (LH)AeN″ complexes (N″ = N(SiMe3)2). Crystallization from hexane gave solvent-free (LH)MgN″ and (LH)CaN″, but due to poorer solubility, the Sr analog was crystallized from hexane/THF to give the THF adduct (LH)SrN″·THF. All complexes crystallized as monomers with a monoanionic tridentate LH¯ ligand. Coordination of the pendant arm results in the formation of a chiral center at N and a chiral coordination environment around the metal. This gives rise to disorder in some of the crystal structures. Heating benzene solutions of the (LH)AeN″ complexes did not result in deprotonation of the pendant arm and formation of (L)Ae, even under microwave conditions (170°C, 12 h). Under these conditions, all complexes also showed a surprisingly high stability toward ligand exchange by the Schlenk equilibrium.

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How to cite

APA:

Rösch, B., Guzmán, J., Bauer, H., Pahl, J., Wiesinger, M., Escalona, A., & Harder, S. (2026). Alkaline-Earth Metal Complexes Based on Tridentate β-Diketiminate Ligands Bearing a Tethered Secondary Amine: Synthesis and Characterization. Zeitschrift für Anorganische und Allgemeine Chemie, 652(11). https://doi.org/10.1002/zaac.70135

MLA:

Rösch, Bastian, et al. "Alkaline-Earth Metal Complexes Based on Tridentate β-Diketiminate Ligands Bearing a Tethered Secondary Amine: Synthesis and Characterization." Zeitschrift für Anorganische und Allgemeine Chemie 652.11 (2026).

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