Chemistry Reference
In-Depth Information
11.2 DENDRIMERS WITH A SINGLE LUMINESCENT UNIT
ASACORE
In the present case, fluorescence anisotropy measurements shine light on the
hydrodynamic properties of the dendrimers as a function of generation, and on
the local motion of the core chromophore, that is, the rigidity of its connections to the
dendrons. In particular, the rotational behavior depends on the dimension and form of
the rotor, interactions between probe and solvent, viscosity of the solvent, and
temperature. Interaction of the dendrimer with solvent can indeed lead to changes
in the dendrimer structure, depending on the nature of the core and the dendrons.
11.2.1 Dendrimers with a p-Terphenyl Core
These dendrimers are constituted by a p-terphenyl core appended with two n-octyl
units and two oligosulfonimide branches of increasing size from G0T up to G2T
(Scheme 11.2). Their absorption and emission bands are slightly red-shifted com-
pared to those of p-terphenyl T [13]. In dichloromethane the fluorescence quantum
yield of the dendrimers is similar and very high (0.7-0.8) and the fluorescence decay is
short (
t ΒΌ
0.8 ns).
O
O
S
S
O
O
N
O
O
O
O
O
S
S
NH
HN
S
O
O
O
O
N
S
S
N
O
T
S
G0
T
O
O
G1
T
O
N
O
S
S
O
O
O
O
S
N
O
S
O
O
O
O
O
O
O
S
S
S
S
O
N
O
O
N
O
N
S
O
S
O
O
O
S
S
O
O
N
O
O
S
O
O
O
N
S
S
N
O
O
O
S
S
O
O
O
O
O
S
N
N
S
O
S
O
O
O
N
O
S
S
O
O
O
S
O
N
N
O
O
S
S
O
S
O
O
O
O
O
S
S
O
N
N
O
S
S
O
O
O
O
G1.5
T
G2
T
SCHEME 11.2
Dendrimers with a p-terphenyl core
T
.
