biostudies-literatureHierlmeier GDeutsche ForschungsgemeinschaftEuropean Research CouncilEuropean CommissionVerband der Chemischen Industrie776-784https://www.ebi.ac.uk/biostudies/studies/S-EPMC8965875biostudies-literatureUnknown41(6)The modification of cyclopentadienyl ligands with carefully selected substituents is a widely used strategy for tuning their steric and electronic properties. We describe the synthesis of an extremely bulky penta-terphenyl cyclopentadienyl ligand (Cp^T5) by arylation of cyclopentadiene. Deprotonation reactions with various group 1 metals and bases afforded a complete series of alkali metal salts MCp^T5 (M = Li-Cs). The compounds were isolated as solvate-free salts, which were characterized by multinuclear nuclear magnetic resonance spectroscopy, ultraviolet-visible spectroscopy, and elemental analysis. Single-crystal X-ray diffraction studies of LiCp^T5, NaCp^T5 (crystallized as a solvate with one tetrahydrofuran molecule per formula unit), and KCp^T5 revealed the formation of metallocene-like sandwich structures in the solid state.OrganometallicsBulking up Cp^BIG: A Penta-Terphenyl Cyclopentadienyl Ligand.PMC8965875ERC CoG 772299772299426795949Wolf RHierlmeier GfalseBulking up Cp^BIG: A Penta-Terphenyl Cyclopentadienyl Ligand.The modification of cyclopentadienyl ligands with carefully selected substituents is a widely used strategy for tuning their steric and electronic properties. We describe the synthesis of an extremely bulky penta-terphenyl cyclopentadienyl ligand (Cp^T5) by arylation of cyclopentadiene. Deprotonation reactions with various group 1 metals and bases afforded a complete series of alkali metal salts MCp^T5 (M = Li-Cs). The compounds were isolated as solvate-free salts, which were characterized by multinuclear nuclear magnetic resonance spectroscopy, ultraviolet-visible spectroscopy, and elemental analysis. Single-crystal X-ray diffraction studies of LiCp^T5, NaCp^T5 (crystallized as a solvate with one tetrahydrofuran molecule per formula unit), and KCp^T5 revealed the formation of metallocene-like sandwich structures in the solid state.2022-01-01T00:00:00Z2022 Mar2025-04-19T09:20:08.838Z2025-04-19T09:20:08.838ZS-EPMC89658753536871410.1021/acs.organomet.2c00009