Highly Efficient “Click” Functionalization of Poly(3-azidopropyl methacrylate) Prepared by ATRP

Abstract

To prepare polymers with pendant functionality capable of participating in highly efficient Cu I -catalyzed 1,3-dipolar cycloaddition of azide and alkynes, monomers with acetylene or azido groups were polymerized via controlled radical polymerization. Atom transfer radical polymerization (ATRP) of propargyl methacrylate (PgMA) resulted in high polydispersities (Mw/Mn > 3), multimodal molecular weight distributions, and cross-linked networks at moderate to high conversion. The poor results obtained with this monomer were presumably due to addition of the propagating radicals to the acetylene group, transfer reactions, and/or interference with the catalyst. A novel monomer, 3-azidopropyl methacrylate (AzPMA), was polymerized via ATRP with good control of the polymer molecular weight distribution and retention of chain functionality. Poly(3-azidopropyl methacrylate) was coupled with propargyl alcohol, propargyl triphenylphosphonium bromide, propargyl 2-bromoisobutyrate, and 4-pentynoic acid via a highly efficient "click" reaction in the presence of a Cu I catalyst. The azido-functionalized polymer demonstrated enhanced reactivity as compared to small molecules with comparable structures. The ability of the coupling reactions to be conducted at room temperature without significant excess of reagents makes this an attractive alternative to preparing (co)polymers with high degrees of functionalization.

Mechanically bonded macromolecules

“…Thus, a donor-acceptor type bistable [2]catenane containing the alkyne-derivatised CBPQT 4+ ring can then be subjected to the Cu(I)-catalysed Huisgen 1,3-dipolar cycloaddition 34 with the azide-terminated side-chains of polymer (M w = 55 000 g mol À1 and M n = 39 000 g mol À1 , PDI = 1.4), obtained by atom transfer radical polymerisation (ATRP). 32 Combining these two reactants in DMF-d 7 at 60 1C for 3 h with a stoichiometric amount of CuI gives the bistable sidechain poly [2]catenane 8Á4nPF 6 with 495% conversion-as determined from 1 H NMR spectroscopy-following precipitation of the polymer from a saturated aqueous solution of NH 4 PF 6 . End-group analysis of 8Á4nPF 6 reveals an M n value of 128 000 g mol À1 , while an M w value of 1 300 000 g mol À1 and an M n value of 870 000 g mol À1 (PDI = 1.5) were determined by size-exclusion chromatography with multi-angle light scattering analysis (SEC-MALS).…”

Synthesis of amphiphilic and thermoresponsive ABC miktoarm star terpolymer via a combination of consecutive click reactions and atom transfer radical polymerization

“…It has been established previously that the click reaction can be quite efficient even in the absence of any ligands if the solvent can facilitate sufficient solubility for copper catalyst. 39 Next, PEG-NHAN 3 (3) was transformed into PEG(AN 3 )ACl (4) by amidation with 2-chloropropionyl chloride. Figure 1(c) shows the 1 H NMR spectrum of 4.…”

Intramolecular Cross-linking of Polymers Using Difunctional Acetylenes via Click Chemistry

“…The Diels-Alder cycloaddition reac-tion [24][25][26] and thiol-ene chemistry [27,28] have recently been introduced as alternative click routes for providing new materials. Click reactions have been widely used for the synthesis of polymers with different compositions and topologies, ranging from linear (telechelic [29], macromonomer [30,31], macrophotoinitiator [32,33] and block co-polymer [34][35][36]) to nonlinear macromolecular structures (graft [37][38][39], star [40,41], miktoarm star [42,43], H-type [44], dendrimer [45][46][47], dendronized linear polymers [48,49], macrocyclic polymers [50,51], self-curable polymers [52][53][54], network systems [55,56] and polymeric nanoparticles [14,57]). Recently, the development and application of click chemistry in polymer and material science has been extensively reviewed [58][59][60][61][62][63].…”