Synthesis, Structural Characterization, and Reactivity of 13-Vertex Lanthanacarboranes Bearing η⁷-<i>a</i><i>rachno</i>-Carboranyl Ligands

Treatment of 1-Me2NCH2CH2-1,2-C2B10H11 (1) with LnCl3 in the presence of excess Na metal gave, after recrystallization from a combination of different solvents, 13-vertex closo-lanthanacarboranes [{η1:η7-[(Me2NCH2CH2)C2B10H11]Er(THF)}{Na(THF)3}]2 (2), [{η1:η7-[(Me2NCH2CH2)C2B10H11]Y(MeCN)}{Na(MeCN)3}]2 (3), or [{η1:η7-[(Me2NCH2CH2)C2B10H11]Y(THF)}{Na(THF)2}]n (4), respectively. [{η1:η1:η7-[(Me2NCH2CH2)2C2B10H10]Y}{Na(MeCN)2}]n (6), [{η1:η1:η7-[(Me2NCH2CH2)(MeOCH2CH2)C2B10H10]Y}{Na(MeCN)}]n (8), and [{η1:η1:η7-[(Me2NCH2CH2)(MeOCH2CH2)C2B10H10]Er}{Na(MeCN)(THF)}]n (9) were prepared in a similar manner from 1,2-(Me2NCH2CH2)2-1,2-C2B10H10 (5) or 1-Me2NCH2CH2-2-MeOCH2CH2-1,2-C2B10H10 (7) and LnCl3 in the presence of excess Na metal in THF. These complexes underwent cation exchange reactions. Complex 2 reacted with KBr in the presence of 18-crown-6 ether or MgCl2 to afford [{η1:η7-[(Me2NCH2CH2)C2B10H11]Er(MeCN)}{K(18-crown-6)}]2 (10) or [η1:η7-{(Me2NCH2CH2)C2B10H11}Er(MeCN)]2[Mg(MeCN)6] (11), respectively. Complex 2 did not undergo carboranyl ligand exchange reactions and showed no reactivities toward LnCl3 and ZrCl4. Complex 4 reacted with AgBPh4 or Me2SiCl2 to give 1 or [YCl2(THF)5][YCl4(THF)2], respectively. The molecular structures of 2−4, 6, and 8−11 were confirmed by single-crystal X-ray diffraction studies.