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金虫 (正式写手)

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专业: 无机非金属类电介质与电解

[交流] 这篇论文是美国著名高分子科学家Percec发表在chemical review 上的文章

高分子化学前沿
Introduction: Frontiers in Polymer Chemistry
The word polymer was introduced by Berzelius in
1833. About 100 years later, during the classic period
of polymer science, Wallace Carothers reviewed the
entire field of polymer chemistry including that of
biological polymers and of polymer physics in a single
article in Chemical Reviews (Carothers, W. H. Polymerization.
Chem. Rev. 1931, 8, 353). Today, the
field of synthetic and biological polymers is impacting
extensively various areas of chemistry, biochemistry,
molecular biology, nanotechnology, electronics, medicine,
life sciences, materials, etc., and is reviewed in
almost every individual and thematic issue of Chemical
Reviews. The present thematic issue is focused
only on a very selected series of subjects in an
attempt to avoid overlap with very recent thematic
issues such as 揘anostructures?(Vol. 99, No. 7, 1999),
揊rontiers in Metal-Catalyzed Polymerization?(Vol.
100, No. 4, 2000), 揅hemical Sensors?(Vol. 100, No.
7), and 揚rotein Design?(Vol. 101, No. 10, 2001).
Living polymerizations and iterative synthesis are
the two most advanced synthetic methods in the field
of polymer synthesis. Anionic, cationic, and metathesis
living polymerizations are already well-established
methods for the synthesis of well-defined and
monodisperse polymers that have a narrow molecular
weight distribution and complex topology and architecture.
Their mechanisms have been relatively well
elucidated both in the case of ring opening and of
vinyl polymerization reactions and therefore will not
be reviewed in this thematic issue. However, living
radical polymerization and other methods to produce
well-defined polymers by radical reactions are currently
being developed and are investigated extensively
in many laboratories, in spite of the fact that
this is a topic of old concern (Otsu, T. Iniferter Concept
and Living Radical Polymerization. J. Polym.
Sci., Part A: Polym. Chem. 2000, 38, 2121). This issue
begins with an article by Fischer, who discusses
the concept of the persistent radical effect and explains
the mechanism via which this concept provides
access both to selective radical organic reactions and
to various methods used to accomplish living radical
polymerization. Gridnev and Ittel follow with an
analysis of the catalytic chain transfer in free-radical
polymerization and its application to the design of
various classes of well-defined polymers. Hawker,
Bosman, and Harth review the synthesis of new polymers
by nitroxide-mediated living radical polymerization.
The contribution by Kamigaito, Ando, and
Sawamoto provides an extensive review of metal-catalyzed
living radical polymerization. Today, the most
versatile method for the synthesis of polymers with
complex architecture is based on living anionic polymerization.
A very comprehensive review on this
topic is presented by Hadjichristidis, Pitsikalis, Pispas,
and Iatrou.
Synthetic methods that are borrowing the tools of
biology are being actively developed for the synthesis
of nonbiological and biological macromolecules. Enzymatic
polymerization is one of the most recent
entries to this field and is reviewed by Kobayashi,
Uyama, and Kimura.
Iterative synthesis is the only synthetic method
available for the preparation of biological (peptides,
nucleic acids, and polysaccharides) and nonbiological
oligomers with well-defined sequences and molecular
weight free of chain length distribution. One of the
most powerful illustrations of the utility of this
synthetic strategy is in the preparation of dendrimers.
They represent a class of synthetic macromolecules
that have impacted dramatically the field of
organic and polymer chemistry in the past decade.
A contribution by Grayson and Fre碿het details the
convergent iterative synthesis and the applications
of dendrons and dendrimers. Another relevant example,
the preparation of rod-coil block copolymers,
relies on a combination of iterative synthesis and
living polymerizations. The self-assembly of supramolecular
structures from rod-coil block copolymers is
analyzed by Lee, Cho, and Zin.
Folding and chirality (including its transfer and
amplification) are two of the most important events
that determine the correlation between the primary
structure of biological macromolecules and their
tertiary and quaternary structures that ultimately
are responsible for their functions and properties.
Biological macromolecules know how to fold in very
specific secondary structures that determine their
3-dimensional architecture and their large diversity
of functions. While the understanding of folding
processes in biological macromolecules is still incomplete,
it is believed that its complete elucidation relies
on the ability to produce synthetic nonbiological
macromolecules that will exhibit the same mecha-
nism of folding, formation of 3-dimensional structure,
functions, and properties at the level of sophistication
displayed by the natural compounds. Hill, Mio,
Prince, Hughes, and Moore provide a very comprehensive
review that discusses for the first time all
classes of biological and nonbiological foldamers. On
related topics, Nakano and Okamoto detail the
synthesis and properties of helical polymers. This
theme is further developed by Cornelissen, Rowan,
Nolte, and Sommerdijk in their analysis of chiral
architectures from macromolecular building blocks.
Both in biological and nonbiological macromolecules
the intramolecular folding process is determined
by a combination of primary structure and
noncovalent directional and nondirectional interactions.
Most recently, combinations of various noncovalent
interactions were also used to self-assemble
supramolecular polymers in which the repeat
units are interconnected via noncovalent rather than
covalent bonds. The field of supramolecular polymers
is reviewed by Brunsveld, Folmer, Meijer, and
Sijbesma.
Progress in the field of chemical and biological
sciences is continually impacted by the development
of novel methods of structural analysis. Sheiko and
Mo╨ler review a field that started to develop only in
the past several years, i.e., visualization of biological
and synthetic macromolecules including individual
macromolecules and their motion on surfaces with
the aid of scanning force microscopy (SFM). Brown
and Spiess analyze the most recent advances in solidstate
NMR methods for the elucidation of the structure
and dynamics of molecular, macromolecular, and
supramolecular systems. Finally, Ungar and Zeng
discuss the use of linear, branched, and cyclic model
compounds prepared mostly by iterative methods in
the elucidation of the polymer crystallization mechanism
by using the most advanced X-ray diffraction
methods.
Although I completely agree with the following
statement made by one of the pioneers of the field of
polymer science: ?..there is no substitute for reading
every reference, cited-second-hand citations are incredibly
unreliable...?(Morawetz, H. Polymers. The
Origins and Growth of a Science; Wiley: New York,
1985), I hope that our readers will find that the outstanding
work done by the authors mentioned above
will provide an excellent and state of the art report
for the Frontiers in Polymer Chemistry at the beginning
of the 21st century. The field of polymer chemistry
was born at the interface between many disciplines
and today is more interdisciplinary than ever.
Finally, I express my great appreciation for the
cooperation on this thematic issue to all contributing
authors and reviewers and to the Editorial Office of
Chemical Reviews.
Virgil Percec
Roy & Diana Laboratories,
Department of Chemistry,
University of Pennsylvania,
Philadelphia, Pennsylvania 19104-6323
3580 Chemical Reviews, 2001, Vol. 101, No. 12 Editorial

[ Last edited by faunhelf on 2005-12-15 at 15:38 ]

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