-Tetraethyl-'-tetrapyridin-4-yl Porphyrins, Their
N-Methylated Tetracations, and Heterodimers with
ms-Tetraphenylsulfonato Porphyrins
-Tetraethyl-'-tetrapyridin-4-yl Porphyrins, Their
N-Methylated Tetracations, and Heterodimers with
ms-Tetraphenylsulfonato Porphyrins
and
Contribution from the Institut für Organische Chemie and Institut für Kristallographie, der Freien Universität Berlin, Takustrasse 3, D-14195 Berlin, Germany, and Technische Universität Berlin, Max-Volmer-Institut für Physikalische Chemie, Strasse des 17, Juni 135, D-10623 Berlin, Germany
Received December 5, 1995
Abstract:
A mixture of the four regioisomers of
-tetraethyl-'-tetrapyridin-4-yl porphyrins and their
N-methylated
tetracations has been synthesized. The crystal structure of
regioisomer I is determined by complicated edge-on
interactions between the pyridinyl substituents, which arrange as a
"bowl". The nonseparable mixture of regioisomers
III+IV is extremely well soluble in chloroform and, as
tetramethylated tetracation, in water (
10-1 M).
It forms
well-defined and water-soluble (5 × 10-4 M)
heterodimers with ms-tetraphenylsulfonatoporphyrin as a free base,
a
zinc and a copper complex (Kdimer = 1.3 ×
108 M-1). Dimers containing one copper
porphyrinate show no
fluorescence. Cofacial porphyrin-porphyrin distances were
estimated from transition dipole interaction as 7-8 Å.
Tetracationic zinc porphyrinates are stable against acid
demetalation, the corresponding free base is not
protonated
down to pH 1. NH-Deprotonation has been achieved with sodium
hydroxide and leads to chain-like assemblies in
water. Application of the new porphyrins in vesicle entrapment
measurements, formation of electron donor-acceptor
pairs, and molecular assemblies is shortly discussed.