Dissertation

|3.1 Brominated Phenanthrolines - A Gate to new Bridging Ligands|
extended 5,6-annulated aromatic systems play an important role in DNA binding and sensing
applications. [112] Important transformations of these positions represent electrophilic substitution
reactions such as nitration or oxidation to generate homo- and heteroditopic ligands such as
tpphz.
[113, 114, 115]
In order to further explore this interesting ligand class, concepts have to be implemented
which allow for the introduction of a multitude of potential connecting groups which can be
transformed selectively. But, according to the Bencini et al., it is more difficult to achieve synthetic
t Bu t Bu t Bu t Bu
N
N
N
N
N
N
Cl
[Pd]
t Bu
N
N
Ru
N
N
N
N
Ru
N
N
t Bu
N
N
Cl
[Pd]
t Bu
t Bu
N
N
t Bu
N
Ru
N
N
N
t Bu
OH
P
HO
O
b
N
Cl
Pt
N
Cl
a
t Bu
t Bu
N
N
Br
Br
[Pd]
N
N
N
Ru
N
N
N
S
S
CN
CN
c
Figure 37: Important examples of the use of 5- and 5,6- halogenated phenanthrolines in the
synthesis of bridging ligands for extended arrays with multiple chromophores e.g. for the
multi-photon uptake of efficient photocatalysts (a) [116, 117] , preparation of anchor ligands for
surface bound (e.g. TiO 2 ) chromophores for the application in dye-sensitized solar cells or
photoelectrochemical cells and heterogeneous catalysis (b), and ligands with thio-functionalities
for the application in [FeFe]-hydrogenase models [118] or for colloid binding (e.g. gold surfaces [119] )
in example (c).
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