Single-walled carbon nanotubes are grafted with polystyrene chains employing a graft-to protocol. Thermogravimetric analysis allows calculation of the grafted chain density and average interchain separation on the nanotube surface as a function of molecular weight. The separation scales with molecular weight as a power law with an exponent of ca. 0.588, showing the grafted chains to be in a swollen random walk conformation. This implies that chain packing is controlled by coil size in solution. In addition, the dispersed concentration of functionalized nanotubes scales with the size of the steric potential barrier that prevents aggregation of polymer functionalized nanotubes. It is also shown that the molecular weight of the grafted chains significantly affects the mechanical properties of nanotube films.

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.

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Tris(pentafluorophenyl)boron B(C6F5)3 is an effective catalyst for the hydrosilylative reduction of tertiary and N-phenyl secondary amides. It allows for the mild reduction of a variety of these amides in near quantitative yield, with minimal purification, at low temperatures, and with short reaction times. This reduction shows functional group tolerance for alkenes, nitro groups, and aryl halides, including aryl iodides.

2,7-Dibromoazadibenzocyclooctyne (DIBAC-Br 2 ) was prepared as a pro-monomer unit that could be modified by the metal-free strain-promoted azide−alkyne cycloaddition (SPAAC). Click cyclization of DIBAC-Br 2 with five different benzyl azides produced a homologous series of monomers with different functionality on the resulting triazole ring, ranging from electron-withdrawing to electron-donating substituents. Using this series of monomers, in combination with 2,7-dialkylfluorene as a comonomer, five different conjugated polymers were prepared via Suzuki polycondensation, each having different electronic properties. The resulting copolymers exhibited M w values ranging from 5 to 10 kDa and PDI values in the 1.5−2 range. These polymers were characterized by 1 H NMR spectroscopy, optical spectroscopy, and cyclic voltammetry. Finally, a coumarin-containing oligomer was synthesized and used to demonstrate a photo-cross-linking scheme via [2 + 2] cycloaddition.