Multidentate aminoalkoxides. Synthesis and complexation behavior to lithium and sodium

摘要

The tris(dimethylaminomethyl)-substituted alcohol (R2NCH2)(3)COH (R = Me: 1) was synthesized by reaction of 1-chloro-2,3-epoxy-2-chloromethylpropane with a large excess of 40% aqueous HNMe2 in 95% yield as colorless liquid (b.p. 87 degreesC/1 mbar). Similar syntheses led to the respective amino alcohols with R = Et, CH2Ph. The dimethylamino, alcohol 1 was characterized crystallographically as hydrochloride salt 2. Reaction of I with elemental sodium in toluene gave the tetrameric alcoholate [(Me2NCH2)(3)CONa](4) (3) which has a heterocubane structure in the solid state. In addition to three oxygen atoms, each sodium atom is coordinated by two amino groups from two different adjacent ligands (Na-N 2.529(3)/2.628(3) A). Reaction of 1 with LiNMe2 afforded the lithium alcoholate which crystallized as dimeric mixed-anion aggregate [(Me2NCH2)(3)COLi.LiNMe2](2) (4). It has a four-rung ladder structure consisting of two four-membered Li(NMe2)LiO rings connected through a central LiOLiO ring. All ligand amino groups are lithium-coordinated (Li-N 2.117(6)/2.101(6)/2.218(6) A) as is the amido, nitrogen atom (Li-N 1.964(6)/2.027(6) A). Reaction of 1 with LitBu in n-hexane also led to deprotonation at oxygen. In addition, in one ligand one methyl group is deprotonated, in a second one two methyl groups are lithiated leading to doubly and triply charged anions, respectively. The product crystallizes as the dimeric mixed-anion aggregate [(-H2CN(Me)CH2)(Me2NCH2)(2)CO-.5 Li+. (-H2CN(Me)CH2)(2)(Me2NCH2)CO-](2) (5) having a core of 10 Li+ cations, 4 alcoholate oxygen atoms, and 6 N(Me)-CH2- groups.