Polyolefin-supported recoverable/reusable Cr(III)-salen catalysts.

The design of functional soluble polyolefins for use as supports for salen ligands and metal complexes is described. Examples and applications that use both polyisobutylene (PIB)- and polyethylene (PE(Olig))-bound recoverable/recyclable salen ligands/metal complexes are detailed. In the case of using PIB as a support, the polymer-bound complexes can be recovered through the use of latent biphasic or a thermomorphic mixed solvent systems.

Polyisobutylene-anchored N-heterocyclic carbene ligands.

The synthesis of polyisobutylene (PIB)-supported N-heterocyclic carbenes (NHCs) that are useful as ligands for recoverable/recyclable organometallic complexes is described. Both PIB-bound carbenes analogous to SIMes and IMes as well as carbene precursors bound to PIB via 1,2,3-triazoles by alkyne-azide couplings are described. Both Ag(I) and Ru(II) complexes of these carbenes are shown to be phase selectively soluble in heptane.

A phase separable polycarbonate polymerization catalyst.

Polyisobutylene is shown to be a nonpolar phase tag that separates a highly colored salen Cr(III) complex from products but is otherwise kinetically similar to a low molecular weight salen Cr(III) complex in polycarbonate formation by Cr(III)-catalyzed copolymerization of CO2 and cyclohexene oxide.

Heptane-soluble ring-closing metathesis catalysts.

Terminally vinyl-functionalized polyisobutylene (PIB) oligomers can be easily transformed into end-functionalized PIB-bound Ru metathesis catalysts. The nonpolar catalysts so prepared can be used as solutions in heptane and recycled by a gravity-based extraction after addition of a heptane-immiscible polar solvent. This paper describes the synthesis and the recycling of a PIB-supported second-generation Hoveyda-Grubbs catalyst for Ru-catalyzed ring-closing metathesis and ring-opening metathesis polymerizations.