Dissertation

|3.3 NN-NHC-Ligand bbip: Toward Second Generation Catalysts|
bbip (see figure 84). Packing effects due to π-π-interactions between the two inequivalent bbipions
were found (d bbip
(π-π)
= 3.265 Å). The negatively charged bromide counter ions were found in
close proximity to the delocalized positively charged imidazolium moieties. Furthermore, as in
the case of bip, water molecules coordinate to the phenanthroline spheres via hydrogen bonds
with N-O distances between 2.878 and 3.141 Å.
3.3.4 N,N’-Coordinated ip-Type Complexes
To investigate whether the N,N-coordinating properties of the potential bridge are similar to
the parent phenanthroline, a series of new ruthenium complexes with the obtained ligands was
prepared (see figure 85).
N
N
H
N
N
N
N
N
N
N
N
N
N
Br
ip
bip
bbip
method C1 method C1 method C1
N
N
N
N
Ru 2+
N
N
H
N
N
N
N
N
N
Ru 2+
N
N
N
N
N
N
N
N
Ru 2+
N
N
N
N
Ru(ip)
Ru(bip)
Ru(bbip)
Figure85:Synthesis of the N,N’-coordinated ruthenium complexes of the prepared ligands through
reaction with [Ru(tbbpy) 2 Cl 2 ] and subsequent counter ion exchange.
The synthesis of the ruthenium complexes was performed according to the protocol method
C1 through stoichiometric reaction of one equivalent of [Ru(tbbpy) 2 Cl 2 ] and one equivalent
of ̂LL-ligand (ip, bip or bbip) in a solvent mixture of ethanol/water in a microwave reaction.
After counter ion exchange with NH 4 PF 6 , the complexes [Ru(tbbpy) 2 (ip)][PF 6 ] 2
(Ru(ip)),
[Ru(tbbpy) 2 (bip)][PF 6 ] 2 (Ru(bip)), and [Ru(tbbpy) 2 (bbip)][PF 6 ] 3 (Ru(bbip)) were obtained in
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