The synthesis, characterization, and reactivity of group 4 organometallics supported by β â€diketonates is reported. Sterically hindered β â€diketonates, such as 2,6â€dimesitylbenzoyl pinacolone ( L 1 ) and 2,6â€dimesitylbenzoyl acetylmesitylene ( L 2 ), preclude the formation of tetrakis†and trisâ€chelates, halting at cis â€octahedrally coordinated M( L n )...