Synthesis and crystal structures of tetra-meric [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-) with one equivalent of Na[N(SiMe)] in toluene afforded pale-yellow crystals of tetra-meric poly[bis-[μ-2-(4,4-dimethyl-2-oxazolin-2-yl)anilinido][μ-2-(4,4-dimethyl-2-oxa-zolin-2-yl)aniline]tetra-sodium(I)], [Na(CHNO)] or [Na(H-)] (), in excellent yield. Subsequent reaction of [Na(H-)] () with 1.33 equivalents of anhydrous YbCl 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(CHNO)] or Yb(H-) () in moderate yield. Direct reaction of three equivalents of 2-(4',4'-dimethyl-2'-oxazolin-yl)aniline (H-) with Yb[N(SiMe)] in toluene resulted in elimination of hexa-methyl-disilazane, HN(SiMe), and produced Yb(H-) () in excellent yield. The structure of consists of tetra-meric Na(H-) subunits in which each Na cation is bound to two H- 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 tetra-mer. This results in two 4-coordinate and two 5-coordinate Na cations within each tetra-meric unit. The structure of consists of a distorted octa-hedron where the bite angle of ligand 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 nitro-gen is to an oxazoline nitro-gen while for the other two oxazoline N atoms are to each other. This results in a significantly longer Yb-N(oxazoline) distance [2.468 (3) Å] for the bond to the anilide compared to those for the oxazoline N atoms to one another [2.376 (3), 2.390 (3) Å].