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

The reaction of lithium hexa-methyl-disilyl-amide, [Li{N(Si(CH 3 ) 3 ) 2 }] (LiHMDS), with 4,4-dimethyl-2-phenyl-2-oxazoline (Phox, C 11 H 13 NO) in hexane produced colourless crystals of bis-(4,4-dimethyl-2-phenyl-2-oxazoline-κ N )(hexa-methyl-disilyl-amido-κ N )lithium, [Li(C 6 H 18 NSi 2 )(C 11 H 13 NO) 2 ] or [Li{N(Si(CH 3 ) 3 ) 2 }(Phox) 2 ] 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 C 2/ c 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 3 ) 3 ) 2 }(Phox) 2 ] were assessed by Hirshfeld surface analysis and fingerprint plots. This new compound is attractive for catalysis due to its unique structural features.