Crystal structure of a three-coordinate lithium complex with monodentate phenyl-oxazoline and hexa-methyl-disilyl-amide ligands

• Published in: Acta crystallographica. Section E, Crystallographic communications Crystallographic communications, 2024-05, Vol.80 (Pt 6), p.620-624
• Main Authors: Carneiro Neto, José Severiano, Iwaya, Eduardo Mariano, Santana, Francielli Sousa, Soares, Jaísa Fernandes
• Format: Article
• Language: English
• Subjects: Research Communications
• ISSN: 2056-9890; 2056-9890
• DOI: 10.1107/S2056989024004237

The reaction of lithium hexa-methyl-disilyl-amide, [Li{N(Si(CH ) ) }] (LiHMDS), with 4,4-dimethyl-2-phenyl-2-oxazoline (Phox, C H NO) in hexane produced colourless crystals of bis-(4,4-dimethyl-2-phenyl-2-oxazoline-κ )(hexa-methyl-disilyl-amido-κ )lithium, [Li(C H NSi )(C H NO) ] or [Li{N(Si(CH ) ) }(Phox) ] in high yield (89%). Despite the 1:1 proportion of the starting materials in the reaction mixture, the product formed with a 1:2 amide:oxazoline ratio. In the unit cell of the 2/ space group, the neutral mol-ecules lie on twofold rotation axes coinciding with the Li-N(amide) bonds. The lithium(I) centre adopts a trigonal-planar coordination geometry with three nitro-gen donor atoms, one from the HMDS anion and two from the oxazolines. All ligands are monodentate. In the phenyl-oxazoline units, the dihedral angle defined by the five-membered heterocyclic rings is 35.81 (5)°, while the phenyl substituents are approximately face-to-face, separated by 3.908 (5) Å. In the amide, the methyl groups assume a nearly eclipsed arrangement to minimize steric repulsion with the analogous substituents on the oxazoline rings. The non-covalent inter-actions in the solid-state structure of [Li{N(Si(CH ) ) }(Phox) ] were assessed by Hirshfeld surface analysis and fingerprint plots. This new compound is attractive for catalysis due to its unique structural features.