Gallatabenzene Ligands Emerging from Open Lutetocene and Yttrocene Methyl Complexes

Utilizing ternary mixtures [LnMe3]n/K(2,4‐dtbp)/GaMe3 (Ln=Lu, Y; 2,4‐dtbp=2,4‐di‐tert‐butyl‐pentadienyl), a series of metallacycles is accessible via tandem salt metathesis/deprotonation. Depending on the precursor molar ratio, both gallatabenzene and lutetacyclic moieties with fully planar metallacycles are obtained, which were further analyzed using DFT calculations. The precursor molar ratio affects the extent of pentadienyl C−H‐bond activation and oligomerization to tetra‐ and pentametallic arrays. Reacting a 1 : 2 : 2 mixture at −40 °C gave the open sandwich methyl complex (2,4‐dtbp)2Lu(CH3), displaying a vital intermediate for subsequent ring‐closure reactions. Fully open metallocene (2,4‐dtbp)2LuMe (I) is isolable and stable only at low temperatures and features a superbasic vital intermediate for subsequent ring‐closure reactions. So accessible bis(gallatabenzene) complexes (1‐Me‐3,5‐tBu2‐C5H3Ga)(μ‐Me)Ln(1‐Me‐3,5‐tBu2‐C5H3Ga) (Ln=Y, Lu (II)) exhibit almost planar metallacycles, while the respective aluminatabenzene chemistry follows distinct reaction pathways.