Dalton transactions | 2019
Versatility of cyclooctatetraenyl ligands in rare earth metal complexes of the [M2(COT)3(THF)2] (M = Y and La) type.
Abstract
Two new organometallic cyclooctatetraenyl complexes of the type [M2(COT)3(THF)2] (M = Y and La) have been prepared, using optimized synthetic procedures, and fully characterized by X-ray diffraction analysis, IR and 1H NMR spectroscopies. The structures can be represented as formed by the double-decker [M(COT)2]- anion with an asymmetrically bound cationic [M(COT)(THF)2]+ unit. The COT rings in the anionic sandwich are not equidistant from the metal with the M-COTcentroid distances measuring at 1.991(5) Å and 2.074(5) Å for [Y(COT)2]-vs. 2.045(4) Å and 2.154(5) Å for [La(COT)2]-. The sandwich fragments are η2-coordinated to the second metal center with the average M-C distances of 2.837(4) Å and 2.879(5) Å for yttrium and lanthanum complexes, respectively. The M-COTcentroid distances in the cationic unit are 1.962(4) Å for the former and 2.009(2) Å for the latter.