Chemistry Reference
In-Depth Information
REDOX AND FLUORESCENT OPEN
CORE DENDRIMERS
A
NGEL
E. K
AIFER
Center for Supramolecular Science and Department of Chemistry, University of Miami,
Coral Gables, FL 33124-0431, USA
7.1 INTRODUCTION
Dendrimers offer a large number of molecular design possibilities. Inmany cases their
molecular frameworks can be described using a relatively small branching unit that
contains perhaps one or two simple functional groups. For instance, one can consider
that the commercially available poly(amidoamine) (PAMAM) dendrimers [1] are
composed of many repeating units of the type -CH
2
CH
2
N(CH
2
CH
2
CONH-)
2
,in
which a branching bifurcation exists at the tertiary nitrogen atom in the middle.
The corresponding functional groups, tertiary amine and amide, are integral
constituents of the molecular framework in this class of dendrimers. The internal
structure of the macromolecule becomes thus rather repetitive, although this does
not detract from some of their many fascinating properties. However, one of the
most interesting aspects of dendrimer chemistry is the possibility of placing
additional functional groups in well-defined locations within the dendrimer struc-
ture [2-7]. Of particular concern in this chapter are functional groups with redox
active or fluorescent properties.
The covalent attachment of redox active or fluorescent residues is in fact one of
the many possibilities involved in dendrimer functionalization. The most commonly
used methods involve either the functionalization of the dendrimer periphery with
multiple copies of the same residue or the functionalization of the core, from which
