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RSC Advances
potentials of ligand 7 and the corresponding complex 8
underlines further the effective communication along the
conjugated path as an anodic shi of more than 600 mV is
observed for the reduction of the diazauorene and the ethy-
nylbipyridine units. The different nature of metal binding sites
within the molecule allows for selective coordination of metal
centres, a topic of continuing interest in different elds such as
photo-driven catalytic reactions.
In total, the persistent electronic communication in pre-
sented ligand design alongside the exible synthetic modica-
tion of peripheral substituents allow for manipulating the
properties of such ligand systems. In particular, the different
nature of imine binding sites provided in ligand 7 paves the way
to chemoselective control of coordination chemistry for various
applications.
Fig. 5 Cyclic and differential pulse voltammogram of 8, performed in
CH2Cl2 solution at room temperature containing 0.1 M nBu4NPF6 with
Ag/AgCl as reference electrode, Pt wire as counter electrode and
glassy carbon as working electrode; scan rate: 100 (CV)/50 (DPV) mV
Conflicts of interest
s
ꢁ1; all data referenced against external Fc+/Fc.
There are no conicts to declare.
Acknowledgements
respectively, that can be assigned to the reduction of both dia-
zauorene and ethynylbipyridine units. Remarkable is the
anodic shi of more than 600 mV for both events compared to
the reduction potential of the ligand 7, which underlines the
¨
We are grateful to Dr Sven Furmeier for his assistance in
preparing the manuscript.
electron-withdrawing nature of the Ru centers promoting the Notes and references
reduction of the respective ligand units. Another reversible
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the latter points towards simultaneous reduction of several
bipyridine units considering the higher current detection.
The photophysical and electrochemical properties of the
synthesized ligand and the corresponding Ru complex support
previous ndings in similar cross-p-conjugated systems. As
such, ligand 7 is of possible use for the design of catalytic
ensembles as it provides different binding moieties for indi-
vidual metal centers, while offering electronic communication
between the different units.
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