Rhodium(I) catalyzed cooligomerization of carbon monoxide with ethylene. direct evidence for a single mode of stepwise chain growth

Ligand Bite Angle Effects in Metal-catalyzed C−C Bond Formation

“…The kinetics for the overall reaction have not been reported, but it seems likely that the reaction is first order in alkene and that the order in CO depends on the pressure in such a way that CO suppresses the reaction at very high pressures. Undoubtedly, the rate of chain termination will also depend on the nature of the ligand, which will be the case for ionic mechanisms, but also for mechanisms involving β-hydride elimination and reinsertion . In the latter study it has been reported that the protonation of the alkyl chain end takes place after β-hydride elimination and reinsertion has taken place to give an enolate intermediate.…”

Polyketones

“…In the late 1940s, Reppe and Magin (BASF) showed that K 2 Ni(CN) 4 in water catalyzed the production of low melting polyketone oligomers in addition to diethyl ketone and propionic acid, albeit with a poor activity of ∼0.8 g PK-E/(g Ni·h) (6). Also, rhodium-based catalysts showed some activity (7,8). Palladium(II) systems were first disclosed by Gough (ICI).…”

Palladium-Catalyzed Alternating Copolymerization of Alkenes and Carbon Monoxide

“…Rhodium carbonyls are also active as catalysts for the production of alternating copolymers of ethene and carbon monoxide . The molecular weights of these polymers are low, as are the rates of formation.…”