Synthesis and Properties of Sandwich Diimine-Coinage Metal Ethylene Complexes

摘要

Synthesis and full characterization of cationic isostructural “sandwich” diimine-coinage metal ethylene complexes are reported. Ethylene self-exchange kinetics proceeds by an associative exchange mechanism for Cu and Au complexes. The fastest ligand exchange was observed for Ag complex >8a. The upper limit of ΔG^‡, assuming associative ligand exchange, was found to be ca. 5.0 kcal/mol. Ethylene self-exchange in Cu complex >7b proceeds with ΔG298^‡ = 12.9 ± 0.1 kcal/mol, while the exchange is the slowest in Au complex >9, with ΔG298^‡ = 16.7 ± 0.1 kcal/mol. Copper complex >7b is unusually stable and can survive in air for years.