Synthesis of Pyridine- and 2-Oxazoline-Functionalized Vinyl Polymers by Alane-Based Frustrated Lewis Pairs

Abstract

Reported herein is the first example of polymerization of polar vinyl monomers bearing the C=C–C=N functionality by Frustrated Lewis pairs (FLPs). In particular, FLPs based on Al(C₆F₅)₃ and N-heterocyclic carbenes rapidly convert 2-vinyl pyridine and 2-isopropenyl-2-oxazoline into medium to high molecular weight, N-functionalized vinyl polymers. Activated monomer-alane adduct 1 and initiated zwitterionic intermediate 2 have been isolated and structurally characterized, providing strong evidence for the proposed bimolecular, activated monomer polymerization mechanism.

Key words

frustrated Lewis pairs - polymers - pyridines - nitrogen - monomers - polymerization

• References and Notes


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• 16 Selected crystallographic data for 1: C₂₅H₇AlF₁₅N, monoclinic, space group P2(1)/c, a = 10.6644(4) Å, b = 14.0645(5) Å, c = 16.5182(6) Å, β = 107.349(2)°, V = 2364.84(15) ų, Z = 4, D _calcd = 1.779 Mg/m³, GOF = 1.051, R ₁ = 0.0243 [I >2σ(I)], wR2 = 0.0659. CCDC 972837 contains the supplementary crystallographic data for this structure.
• 17 Selected crystallographic data for 2·CH₂Cl₂: C₃₇H₂₉AlCl₂F₁₅N₃, monoclinic, space group P2(1)/c, a = 11.6507(7) Å, b = 16.8033(10) Å, c = 19.1096(12) Å, β = 94.747(3)°, V = 3728.3 (4) ų, Z = 4, D _calcd = 1.601 Mg/m³, GOF = 1.060, R ₁ = 0.0512 [I >2σ(I)], wR2 = 0.1482. CCDC 972835 contains the supplementary crystallographic data for this structure.