Synthesis of nonsymmetric chain end functionalized polyisobutylenes

We present the synthesis of nonsymmetric α-ω-functionalized polyisobutylenes (PIBs) bearing different functional moieties on their chain ends. Thus, on one chain end either, a short tri-ethylene oxide chain (TEO) or a phosphine oxide ligand is attached, whereas the other chain end is substituted by hydrogen bonding moieties (thymine/2,6-diaminotriazine). The nonsymmetric PIBs were synthesized via living cationic polymerization using methyl-styrene epoxide as initiator, followed by quenching reaction with 3-bromopropyl-benzene. Subsequent bromide/azide exchange and the use of the azide/alkyne click reaction allowed the synthesis of (a) (α)-TEO-(ω)-thymine-telechelic PIB (7a), (b) (α)-triethyleneoxide-(ω)-triazine telechelic PIB (7b), and (c) (α)-phosphinoxide-(ω)-thymine-telechelic PIB (13) with molecular weights Mn ∼ 4000 g mol-1 and low polydispersities (Mw/Mn = 1.3). The chemical identity of the final structures was proven by extensive 1H NMR investigations and matrix-assisted laser desorption/ionization-mass spectroscopy (MALDI). The presented method for the first time offers a simple and highly versatile approach toward supramolecular nonsymmetric α-ω-functionalized PIB. © 2011 Wiley Periodicals, Inc.