1.1 Porphyrins - Friedrich-Alexander-Universität Erlangen-Nürnberg

3.2.6 Studying the Structure-Properties-Relations
O
N
NH HN
N
O
N
NH HN
N
Discussion and Results 3
As it has been a great surprise that such a kind of simple system like 53 can disclose the
previously presented extraordinary features, it needed further investigations on the
structure-properties-relationship (SPR) to reveal how characteristic features in the
cycloketo-porphyrin might be caused. So the next part of the work is strongly connected to
the study of similar systems with just minor changes and to investigate their behavior.
3.2.6.1 Possible Influences & Choice of Reference Systems
In principle, two features present in 53 are considered to have significant influence on the
chiral and photophysical behavior: On the one hand the seven-membered ring structure in
the keto-exocycle and, on the other hand, the opposite lying methyl group ortho in respect
to the porphyrin core. In order to figure out in how far these features contribute to the
overall performance of that system, two models (Scheme 41 middle and right) were chosen
lacking one or both of that structural features. The t-butyl substituent on the tethered
phenyl ring was also left out in the model compounds since it is not considered to have any
observable impact and as that eased the synthetic access to systems 57 and 58. Both were
then obtainable from methyl 2-formylbenzoate.
leave out
leave out
O
N
NH HN
N
Scheme 41. Mother compound 53 and simplified model compounds 57 and 58 with changes
marked with arrows.
The synthesis of the shown model compounds will be discussed within the following
paragraphs.
53
57 58
75