Direct Observation of β‑Chloride Elimination from an Isolable β‑Chloroalkyl Complex of Square-Planar Nickel

Reported
here are the isolation, structural characterization, and
decomposition kinetics of the four-coordinate pentachloroethyl nickel
complex, NiCl­(CCl2CCl3)­(CNArMes2)2 (ArMes2 = 2,6-(2,4,6-Me3C6H2)2C6H3). This complex
is a unique example of a kinetically persistent β-chloroalkyl
in a system relevant to coordination–insertion polymerization
of polar olefins. Kinetic analysis of NiCl­(CCl2CCl3)­(CNArMes2)2 decomposition indicates
that β-chloride (β-Cl) elimination proceeds by a unimolecular
mechanism that does not require initial dissociation of a CNArMes2 ligand. The results suggest that a direct β-Cl elimination
pathway is available to four-coordinate, Group 10 metal vinyl chloride
polymerization systems.