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The porphyrin handbook - Kadish K.M.

Kadish K.M. The porphyrin handbook - Academic press, 2000. - 368 p.
Download (direct link): kadishsmishgulilard2000.djvu
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............................. 267
A. Calixpyrrole-Based
Sensors..................................................................
.......................... 267
B. Calixpyrrole-Modified HPLC
Media....................................................................
.................. 269
VIII. Expanded
Calixpyrroles............................................................
.................................... 271
IX. From Calixpyrroles to
Calixpyridines...........................................................
.......................... 272
X. Related Heterocalixarene
Analogues................................................................
....................... 274
A.
Calixindoles.............................................................
............................................. 274
B.
Azolophanes..............................................................
............................................. 276
XI.
Conclusion...............................................................
................................................ 276
Note Added in
Proof....................................................................
.................................. 276

References...............................................................
................................................ 277
I. Introduction
This chapter summarizes recent developments in the synthetic and
substrate recognition chemistry of the meso-octaalkylporphyrinogens.
Baeyer achieved the original synthesis of me.so-octamethylporphyrinogen
in the late nineteenth century,1 although it was only in the last decade
that the metal coordination chemistry of these macrocycles began to be
explored by Floriani and coworkers.2-20 Even more recently, a very
different research direction, namely
The Porphyrin Handbook
K.M. Kadish, K.M. Smith, R. Guilard, Eds.
Volume 6/Applications: Past, Present and Future
the use of /we.vo-octaalkylporphyrinogens as anion and neutral substrate
receptors, has begun to be explored. It is this work in particular that
is discussed here.
In recent years a number of research groups have been involved in
synthesizing receptors for anionic species that can coordinate to anions
via either hydrogen bonding alone,21-23 or hydrogen bonding in
combination with electrostatic interactions.24-26 However, many of these
anion receptors are challenging to synthesize, requiring multi-step
synthetic procedures.24-27-33 The work
Copyright (c) 2000 by Academic Press All
rights of reproduction in any form reserved.

ISBN 0-12-393200-9/S30.00
258
Sessler and Gale
summarized in this chapter demonstrates that meso-octaalkylporphyrinogens
are not only effective and selective anion binding agents but are also
easy-to-make, in one step, rendering them amenable to possible future use
in industrial applications.3435 Additionally, these macrocycles act as
receptors for neutral species.36-37 Based on these findings and other
work summarized in this chapter, it has been suggested that these systems
should be renamed calix[4]-pyrroles.38 Such a renaming serves to draw an
analogy to the calix[n]arenes,34-40 a class of polyphenolic macrocycle
consisting of n phenol rings linked via sp3 methylene carbon atoms,
thereby stressing the interesting conformational and inclusion properties
of the macrocycles. This chapter explicitly details the parallel between
calixpyrroles and calixarenes as molecular recognition units. Also
reviewed here are the syntheses of new functionalized calix[4]pyrroles
designed to perform specific functions.
II. Early Work
The story starts some fourteen years after Baeyer had initiated the first
study of phenol-formaldehyde condensation chemistry (which led to the
study of phenol-formaldehyde resins and subsequently to calixarene
chemistry)41-43 with the publication of his paper on the condensation of
pyrrole and acetone.1 Baeyer mixed pyrrole, acetone and hydrochloric acid
and obtained a white crystalline material, which later proved to be the
tetra-pyrrolic macrocycle, me.so-octamethylcalixpyrrole 1.

Dennstedt and Zimmermann subsequently studied this reaction using
"chlorzink" as the acid catalyst,44-46 and
1 2
Cl Cl
thirty years later Chelintzev and Tronov repeated these reactions and
proposed (correctly) a cyclic tetrameric calix[4]pyrrole structure for
the product.47 The latter authors also carried out successfully an acid-
catalyzed condensation between pyrrole and methyl ethyl ketone, a
reaction from which they isolated a small quantity of a single
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