ROMP azide

Block copolymers with organic polymers Block copolymers with polysiloxanes Comb copolymers Fuel cell membranes ROMP polymerizations Azide coupling to organic polymers ADMET polymerizations... 

ROMP ring-opening metathesis polymerization TMGA tetramethylguanidinium azide... 

More recently, ring opening metathesis polymerization (ROMP) has been used to prepare telechelic liquid crystalline polymers that carry azide end groups which can be crosslinked with a triacetylene species using the well known copper catalyzed click chemistry [22]. 

Binder and Kluger [41, 42] utilized the Hamilton wedge and THY as molecular recognition handles in the construction of side-chain-functionalized poly(oxanorbornene dicarboximides) using a ROMP/click methodology. Monomers functionalized with azido or alkynyl side chains were polymerized to either homopolymers or block copolymers and subsequently subjected to Cu-catalyzed azide-alkyne cycloaddition [72] to install the desired H-bonding motifs. 

Due to it s highly efficient and orthogonal nature, copper-catalyzed click chemistry is an attractive route to post-polymerization functionalization of ROMP copolymer backbones yielding amphiphilic micellar nanoparticles [103, 104]. However, it should be noted that post polymerization modification is necessary to yield azide or acetylene modified polymers, as azide and acetylene functionalities are not compatible with current ROMP catalysts. Ohe and coworkers [104] have synthesized amphiphihc triblock copolymers capable of assembly into discrete micellar nanoparticles by clicking an acetylene-modified hexaethylene... 

Figure 8.5 Strategies to combine AAC and ROMP, (a) A prefunctionalized monomer that contains a metathesis-compatible triazole can be employed, (b) Post-polymerization modification of a halogenated polymer with sodium azide and further elaboration...

The copper-catalyzed azide/alkyne click reaction has found the broadest application in the modification of ROMP polymers, with the first reported example in 2004 by Binder and Kluger [13]. Since then, the copper-catalyzed click reaction has been used for the preparation of block copolymers [24, 29, 37], stars [18, 26], cycles [23], networks [25], and graft copolymers [27, 28, 38, 56, 57], as well as for end- [16] and side-chain-functionalized polymers [13, 17, 19-22, 48]. The most often used catalysts and bases for the azide/alkyne click reaction include copper(l) iodide, copper(l) bromide, trisftriphenylphosphine) copper(l) bromide, or copperfll) sulfate/sodium ascorbate as catalyst and diisopropylethylamine (DIPEA), pentamethyldiethylenetriamine (PMDETA), or 2,2 -bipyridine (bPy) as base. 

Scheme 9.4 Route to hydrogen-bonded polymers by combining ROMP and azide/alkyne click chemistry, (a) Direct polymerization approach [13, 17], ONBEs with thymine and Hamilton-receptor functionalities, 22a and b via azide/alkyne click reaction, followed by polymerization...

Figure 3.9 (a, b) Synthetic strategies combining ROMP and the azide-alkine click reaction, (c) BCPs... 

Azides are traditionally hard to incorporate into monomers for ROMP because of their adverse interactions with the catalyst. However, postfunctionalization of an alkyl bromide may be used. As an example, a norbomene bearing a dendrimer capped with an alkyl bromine was successfully used to form diblocks, which upon polymerization was substituted for the azide. Click chemistry with Cgo formed dendritic side chains bearing up to three Cso units though only half of the potential sites were found to be reactive this was attributed to steric bulk of the Ceo groups as similar chemistry with zinc porphyrins went to completion (Figure 28). 

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