Synthesis and crystal structures of tetra­meric [2-(4,4-dimethyl-2-oxazolin-2-yl)anilido]sodium and tris­[2-(4,4-dimethyl-2-oxazolin-2-yl)anilido]ytterbium(III)

Reaction of 2-(4,4-dimethyl-2-oxazolin-2-yl)aniline (H(2)-L1) with one equivalent of Na[N(SiMe(3))(2)] in toluene afforded pale-yellow crystals of tetra­meric poly[bis­[μ(3)-2-(4,4-dimethyl-2-oxazolin-2-yl)anilinido][μ(2)-2-(4,4-dimethyl-2-oxa­zolin-2-yl)aniline]tetra­sodium(I)], [Na(4)(C(11)H(13)N(2)O)(4)](n) or [Na(4)(H-L1)(4)](n) (2), in excellent yield. Subsequent reaction of [Na(4)(H-L1)(4)](n) (2) with 1.33 equivalents of anhydrous YbCl(3) in a 50:50 mixture of toluene–THF afforded yellow crystals of tris­[2-(4,4-dimethyl-2-oxazolin-2-yl)anilinido]ytterbium(III), [Yb(C(11)H(13)N(2)O)(3)] or Yb(H-L1)(3) (3) in moderate yield. Direct reaction of three equivalents of 2-(4′,4′-dimethyl-2′-oxazolin­yl)aniline (H(2)-L1) with Yb[N(SiMe(3))(2)](3) in toluene resulted in elimination of hexa­methyl­disilazane, HN(SiMe(3))(2), and produced Yb(H-L1)(3) (3) in excellent yield. The structure of 2 consists of tetra­meric Na(4)(H-L1)(4) subunits in which each Na(+) cation is bound to two H-L1 bridging bidentate ligands and these subunits are connected into a polymeric chain by two of the four oxazoline O atoms bridging to Na(+) cations in the adjacent tetra­mer. This results in two 4-coordinate and two 5-coordinate Na(+) cations within each tetra­meric unit. The structure of 3 consists of a distorted octa­hedron where the bite angle of ligand L1 ranges between 74.72 (11) and 77.79 (11) degrees. The oxazoline (and anilide) N atoms occupy meridional sites such that for one ligand an anilide nitro­gen is trans to an oxazoline nitro­gen while for the other two oxazoline N atoms are trans to each other. This results in a significantly longer Yb—N(oxazoline) distance [2.468 (3) Å] for the bond trans to the anilide compared to those for the oxazoline N atoms trans to one another [2.376 (3), 2.390 (3) Å].