RESUMEN
The reaction of lithium hexa-methyl-disilyl-amide, [Li{N(Si(CH3)3)2}] (LiHMDS), with 4,4-dimethyl-2-phenyl-2-oxazoline (Phox, C11H13NO) in hexane produced colourless crystals of bis-(4,4-dimethyl-2-phenyl-2-oxazoline-κN)(hexa-methyl-disilyl-amido-κN)lithium, [Li(C6H18NSi2)(C11H13NO)2] or [Li{N(Si(CH3)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 C2/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 35.81â (5)°, while the phenyl substituents are approximately face-to-face, separated by 3.908â (5)â 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(CH3)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.
RESUMEN
The reaction between mononuclear [Ln(bbpen)Cl] [Ln = Gd or Dy; H2bbpen = N,N'-bis-(2-hy-droxy-benz-yl)-N,N'-bis-(pyridin-2-ylmeth-yl)ethyl-enedi-amine, C28H30N4O2] and potassium oxalate monohydrate in water/methanol produced the solvated centrosymmetric isostructural binuclear (µ-oxalato)bis-{[N,N'-bis-(2-oxidobenzyl-κO)-N,N'-bis-(pyridin-2-ylmethyl-κN)ethyl-enedi-amine-κ2 N,N']dilanthanide(III)}-methanol-water (1/4/4) complexes, [Ln 2(C28H28N4O2)2(C2O4)]·4CH3OH·4H2O, with lanthanide(III) = gadolinium(III) (Ln = Gd) and dysprosium(III) (Ln = Dy), in high yields (ca 70%) directly from the reaction mixtures. In both complexes, the lanthanide ion is eight-coordinate and adopts a distorted square-anti-prismatic coordination environment. The triclinic (P ) unit cell contains one dimeric unit together with four water and four methanol mol-ecules; in the final structural model, two of each type of solvating mol-ecule refine well. In each lanthanide(III) dimeric mol-ecule, the medium-strength Oâ¯H-O hydrogen-bonding pattern involves four oxygen atoms, two of them from the phenolate groups that are 'bridged' by one water and one methanol mol-ecule. These inter-actions seem to contribute to the stabilization of the relatively compact shape of the dimer. Electron densities associated with an additional water and methanol mol-ecule were removed with the SQUEEZE procedure in PLATON [Spek (2015 â¸). Acta Cryst. C71, 9-18]. These two new compounds are of inter-est with respect to magnetic properties.