Rare-Earth Metal Complexes Bearing Electrophilic Carbon and Strongly Polarized Metallacyclopropane Moiety: Synthesis and Diverse Reactivity toward Small Molecules.

Metallacyclopropanes are highly strained and very reactive organometallics; the rare-earth metal complexes bearing both highly reactive electrophilic carbon and strongly polarized metallacyclopropanes are extremely rare. This type of rare-earth metal complexes (κ 2 - L )RE(η 2 -C 2 B 10 H 10 )·(THF) 3 [ L = 1-(2-N-C 5 H 10 NCH 2 CH 2 )-3-(2,6- i Pr 2 C 6 H 3 N═CH)-C 8 H 4 N, RE = Lu( 1a ), Yb( 1b ), Er( 1c ), Y( 1d ), Dy( 1e )] bearing the indol-2-yl electrophilic carbon and carboryne-based strongly polarized metallacyclopropanes have been synthesized. Structures of complexes 1 are further confirmed by single-crystal X-ray diffraction and DFT theoretical calculations. It is found that complexes 1 have remarkable reactivity toward different polar unsaturated small molecules, elemental sulfur, and selenium to provide different products ( 2-15 ) through the selective reactions of the RE-C cage , and RE-C 2-ind bonds with the given small molecules, respectively. The reactivities of these complexes are different from those of the reported rare-earth metallacyclopropenes and d-block metal-carborynes.