Biology Reference
In-Depth Information
interesting electrical and optical properties [15,16]. Moreover,
interests and applications of the conjugated polymers have been
extended to the biological fields. In order to endow the conjugated
polymers with the biological functions derived from sugar residues,
e.g., the sugar-substituted conjugated polymers were synthesized
by using the conjugated main chain structures of polyaniline
[17], polyisocyanide [18], polythiophene [19], poly(
p
-phenylene)
[20,21], poly(
-phenylene
vinylene) [23]. In the series of these studies, the synthesis of poly(
p
-phenylene ethynylene) [22], and poly(
p
-
propargylamide) with galactose residues was investigated [24,25].
It contained a
N
-polyacetylene main chain and was obtained by the
Rh-catalyzed polymerization of a corresponding
cis
-propargylamide
monomer. On the basis of the aforementioned study, the polyacetylene
having graft saccharide chains with higher degree of polymerization
(DP), e.g., natural polysaccharides, would be functional polymers
with hybrid properties of polyacetylene and polysaccharide.
Therefore, the synthesis of the amylose-grafted polyacetylene by the
chemoenzymatic method as an effective preparation method for the
polyacetylene-polysaccharide hybrid was investigated.
Amylose-grafted polyacetylenes were synthesized by both the
macromonomer and polymer reaction methods (Fig. 5.4). In the
macromonomer method (Fig. 5.4a) [26], an acetylene-type macrom-
onomer having a maltooligosaccharide chain was polymerized by Rh
catalyst to give a polyacetylene with pendant maltooligosaccharide
graft chains. Moreover, the Rh-catalyzed copolymerization of the
macromonomer with another acetylene monomer was also carried
out. However, the DPs of the products obtained by both the afore-
mentioned polymerization and copolymerization were not high (ca.
10), probably owing to the steric hindrance of the bulky oligosac-
charide graft chains in the macromonomer and the produced poly-
acetylene derivatives. The phosphorylase-catalyzed enzymatic po-
lymerization of Glc-1-P from the maltooligosaccharide graft chains
on these polyacetylene derivatives was performed to yield two
types of the amylose-grafted polyacetylenes (homopolyacetylene
and copolyacetylene). These methods are indicated as the synthetic
route (ii)
N
→
→
(vi) in Fig. 5.1. The complex formation with iodine
has been a well-known characteristic property of amylose [27].
(iv)
