Chemistry Reference
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monomer in order to attempt to template the polymerization of the adenine containing
monomer. However, a rate enhancement of the adenine monomer polymerization
reaction was observed. Similar rate enhancements were observed with the
addition of a thymine low molar mass molecule, suggesting that competitive coordi-
nation of the adenine groups to the copper ATRP catalyst occurred, which slowed the
reaction rates and was disrupted because of the hydrogen bonding association
to thymine.
Bazzi and Sleiman (2002) synthesized adenine-functionalized block copolymers
using ring-opening methathesis polymerization (ROMP) of substituted oxonorbor-
nene monomers (Fig. 4.3). The adenine containing block copolymers self-
assembled during evaporation from dilute solutions into cylindrical shaped structures
(Fig. 4.4). The ability to form these structures was attributed to the ability of adenine
to hydrogen bond in two directions with neighboring adenine molecules.
Surprisingly, low degrees of crystallinity in the adenine homopolymers were
observed from wide-angle X-ray scattering and differential scanning calorimetry.
Novel, noncovalent protecting chemistry involving the addition of complementary
succinimide was utilized to improve the conversion of the adenine containing
monomer.
Inaki (1992) synthesized a wide range of nucleobase-functionalized random and
homopolymers. In addition, Inaki et al. (1980) synthesized block copolymers con-
taining thymine and uracil groups in the main chain through ring-opening cationic
and anionic polymerization of cyclic derivatives of the nucleobases.
Figure 4.3 Synthesis of adenine containing block copolymers via a ROMP methodology.
Reprinted from Bazzi and Sleiman (2002). Copyright 2002 American Chemical Society.
