Tuck-in_complex
In organometallic chemistry, a tuck-in complex usually refers to derivatives of Cp* ligands wherein a methyl group is deprotonated and the resulting methylene attaches to the metal. The C5–CH2–M angle is acute. The term "tucked in" was coined to describe derivatives of organotungsten complexes.[1] Although most "tucked-in" complexes are derived from Cp* ligands, other pi-bonded rings undergo similar reactions.