LITHIUM AND LANTHANOID(III) COMPLEXES OF THE CHELATING DIMETHYL-N'-TRIMETHYLSILYLETHANE-1,2-DIAMINATE(1-) LIGAND

Deprotonation of N,N-dimethyl-N'-trimethylsilylethane-1,2-diamine (HL1 ) with LiBun in hexane yielded solvent-free LiL1, whilst in diethyl et her the dinuclear complex [(LiL2Li)-Li-1(OEt2)] was obtained. A single -crystal structure determination of the etherate showed one four-co-or dinate Li atom bound to two chelating amide ligands which were further bound, through the amide nitrogens, to a three-co-ordinate lithium ce ntre which also has a coordinated diethyl ether molecule. The complex [{(LiLLiClLiL1)-Li-1(thf)}(2)] (thf = tetrahydrofuran) was formed as a side product of a reaction of [LiL1(thf)(n)] with [LuCl3(thf)(2)] in thf. In the solid state the structure shows a LICl bonded between LiL1 and LiL1(thf) units generating a 'three-rung ladder', which is furthe r connected, by Li-Cl bonds, to a second (LiLLiClLiL1)-Li-1(thf) moiet y. The dimer has two rare Li,CI units. Three equivalents of [LiL1(thf) (n)], prepared in situ in thf, reacted with [LuCl3(thf)(2)], anhydrous LnCl(3) (Ln = Er, Eu, Sm or Nd) or [LaBr3(thf)(3)] to form the hexane -soluble [LnL(3)(1)]. Monomeric six-co-ordinate, distorted-octahedral complexes with three chelating L-1 ligands in a fac orientation were f ound for Ln = Lu, Er or Eu by single-crystal X-ray studies. Reaction o f 2 equivalents of LiL1 with ErCl3 in thf generated heteroleptic [(ErL 2Cl)-Cl-1].