Dual Ethylene and CS2 Insertion at an Amidoquinoline Nickel(II) Alkyl Complex Enables CS2-End-Capped Oligoethylene

Combining olefin and heteroallene (e.g., CO 2 and CS 2 ) migratory insertion during chain-growth polymerization could provide a powerful route to polyolefin-like materials bearing chemically addressable functionalities and defined degradation sites. Herein, we report a neutral Ni(II)-methyl complex 1 supported by an amidoquinoline ligand that exhibits dual reactivity, mediating both ethylene oligomerization at 1 bar and 70 °C and, separately, CS 2 insertion at the Ni–CH3 bond at ambient temperature to afford the corresponding κ 2 (S,S)-dithioacetate complex 2. DFT calculations rationalize the rapid CS 2 insertion mechanism, proceeding through an η 2 –CS 2 pentacoordinate transition state with an overall barrier of 15.3 kcal mol–1. Remarkably, sequential ethylene oligomerization followed by CS 2 addition provides spectroscopic evidence for dithioacetate end-capped oligoethylene, demonstrating that the Ni–C bonds generated during ethylene chain growth polymerization remain competent for heteroallene insertion. Together, these results provide an important step forward toward the synthesis of chemically addressable polyolefin-like materials directly from small-molecules building blocks.