Click Functionalization of a Dibenzocyclooctyne‐Containing Conjugated Polyimine

Abstract

A conjugated poly(phenyl-co-dibenzocyclooctyne) Schiff-base polymer, prepared through polycondensation of dibenzocyclooctyne bisamine (DIBO-(NH2)2) with bis(hexadecyloxy)phenyldialdehyde, is reported. The resulting polymer, which has a high molecular weight (M(n)>30 kDa, M(w)>60 kDa), undergoes efficient strain-promoted alkyne-azide cycloaddition reactions with a series of azides. This enables quantitative modification of each repeat unit within the polymer backbone and the rapid synthesis of a conjugated polymer library with widely different substituents but a consistent degree of polymerization (DP). Kinetic studies show a second-order reaction rate constant that is consistent with monomeric dibenzocyclooctynes. Grafting with azide-terminated polystyrene and polyethylene glycol monomethyl ether chains of varying molecular weight resulted in the efficient syntheses of a series of graft copolymers with a conjugated backbone and maximal graft density.

“Click” generation of a conjugated polymer library for SWNT dispersion

“…Consistent with our previous work, we found that the apparent molecular weight of the product polymer decreased upon SPAAC coupling, changing from 26.1 kDa (M n ) to a range between 17.8 and 22.0 kDa ( Table 1). The observed decrease in molecular weight is consistent with our previous studies, 23 where computational modeling, including density functional theory (DFT) and semi-empirical calculations, showed a conformational change in the polymer backbone that resulted in its "accordion-like" contraction upon click functionalization. 23 This contraction is manifested in an apparent decrease in hydrodynamic volume for most of the polymers.…”

“…The strained alkyne‐containing polymer, P0 , was synthesized following previously reported procedures . Azides for P1 , P2 , and P7 (Fig.…”

“…The strained alkyne-containing polymer, P0, was synthesized following previously reported procedures. 23 Azides for P1, P2, and P7 ( Fig. 1) were prepared by azidification of the corresponding commercially-available halides with sodium azide.…”

“…Recently, we reported a polymerizable dibenzocyclooctyne diamine (DIBO-NH 2 ) derivative that could be polymerized with a dialdehyde via Schiff base formation. 23 The resulting conjugated polyimine was shown to undergo efficient strainpromoted azide-alkyne cycloaddition (SPAAC) at each cyclooctyne repeat unit of the polymer backbone ( Fig. 1).…”

Orthogonal Click Postfunctionalization of Alternating Copolymers Prepared by Nitroxide‐Mediated Polymerization

“…The resulting poly(HFIPA‐ alt ‐OVE) was orthogonally postfunctionalized via radical thiol–ene click reaction and subsequent amidation . It is well known that the properties of polymers can be altered significantly by chemical postfunctionalization and numerous recent reports deal with the modification of polymers by thiol click chemistry, Cu‐catalyzed alkyne–azide click reaction (CuAAC), amidation reactions, and many others, including combinations thereof. Our conceptual approach introduced allowed for preparation of a small library of alternating copolymers using a single type of parent copolymer and diversifying subsequent orthogonal postmodification.…”