Narrowly distributed homotelechelic polymers in 30 minutes: Using fast in situ pre-functionalized ROMP initiators

Abstract

Today's olefin metathesis catalysts show high reactivity, selectivity, and functional group tolerance, and allow the design of new syntheses of precisely functionalized polymers. Here we describe a general "one-pot" synthesis for narrow polydispersity bis-end-functional (5homotelechelic) ROMP polymers exploiting the propagating ruthenium complex inherent selectivity for strained norbornenes over acyclic internal olefins. This approach represents a straightforward general method of homotelechelic polymers carrying almost any functional end group (within the limitations of the catalyst's functionality tolerance). Complete pre-functionalization of the initiator is realized in situ within minutes and without the need of further purification steps. The excess acyclic olefin re-enters the catalytic cycle after monomer consumption is complete giving a homotelechelic polymer. 1 H NMR spectroscopic and MALDI-ToF-MS analysis show highly efficient end group functionalization. V C 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4183-4190

Catalytic living ring-opening metathesis polymerization

“…Our group has carried out extensive investigations into end functionalizations of ROMP polymers [54][55][56][57] . Based on our experience, we designed CTA1, which contains a cyclohexene ring.…”

Dye-functionalized polymers via ring opening metathesis polymerization: principal routes and applications

“…In most cases, protecting groups need to be applied to make sure the initiator does not change its reactivity [87]. Since this is no issue in the termination step, more functionalities can be introduced at this stage in an unprotected form.…”

Degradable precision polynorbornenes via ring‐opening metathesis polymerization

“…While this is readily feasible with most common radical and ionic polymerizations, precise functionalization in ROMP can be achieved with different pathways that usually result in high yields, but often come with their own challenges . Perhaps, the most common approach involves the use of a chain transfer agent that allows the introduction of a functional group onto the polymer chain end, however often results in broad molecular weight distributions as such reactions are dominated by chain transfer thus resulting in secondary metathesis products . Typically, Ru‐catalyzed ROMP is quenched by the addition of a large excess of a vinyl ether, thus simultaneously rendering the catalyst inactive and adding a functional group onto the polymer chain end.…”