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Graphical Abstract Angew. Chem. Int. Ed. 172003

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Contents
Web Sites
Separation Science:
separationsNOW
United in Separation
F. Svec
Dennis J. Paustenbach
reviewed by H. Hulpke
Gordon A. Gallup
reviewed by M. Goez
1888
Books
Human and Ecological Risk Assessment
Theory and Practice
1889
Valence Bond Methods
1889
Highlights
Gold Clusters
P. Schwerdtfeger*
Gold is not as noble as it is widely
assumed—at least in the form of nanostructured gold clusters or the depicted
multiwalled nanotubes. Recent progress
shows the potential use of such structures, for example, in catalysis, molecular
electronics, or as bioconjugate probes for
gene analysis.
1892 – 1895
Gold Goes Nano—From Small Clusters to
Low-Dimensional Assemblies
Molecular Mousetrap
M. Sch/fer*
1896 – 1899
Supramolecular Crown Ether Adducts in
the Gas Phase: From Molecular Recognition of Amines to the Covalent Coupling of
Host/Guest Molecules
The diazomalonic acid diester of
[18]crown-6-methanol forms a noncovalent complex (see picture) with doubly
protonated 1,6-diaminohexane which can
be transferred intact into the gas phase.
After collision-induced dissociation, the
reactive carbene intermediate reacts as a
molecular mousetrap. The successful
formation of an intermolecular covalent
coupling between the host and the guest
molecule can be observed by subsequent
MS/MS experiments.
Reviews
Cross-Metathesis of Olefins
S. J. Connon, S. Blechert*
1900 – 1923
Recent Developments in Olefin CrossMetathesis
1880
It’s all in the catalyst! The development of
new catalysts has catapulted olefin crossmetathesis (see scheme) to the forefront
of modern synthetic methods in organic
2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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chemistry. This reaction is one of the most
practical and versatile methods for the
formation of CC bonds.
Angew. Chem. Int. Ed. 2003, 42, 1880 – 1885
Angewandte
Chemie
Communications
An electrical detection method was used
to monitor a three-step reaction at the
single-molecule level as it occurs within a
protein pore (see picture). The reaction
involved the breakdown of a protected
carbamic acid and was initiated with light.
Rate constants for the reaction could be
determined by measuring the current
multiple times. This approach reveals
reactive intermediates, uncovers minor
pathways, and quantifies the kinetics
of steps invisible in conventional kinetic
techniques.
Unlike the original form of SiB3, which has
a huge compositional spread in its Si/B
ratio and a crystal structure with Si atoms
randomly distributed over all its B12 cages,
the new form of SiB3 (b form; see structure) is stoichiometrically and crystallographically ordered. The clear segregation
of Si and B atoms in the new form is
believed to be responsible for its
enhanced oxidation resistance observed
at high temperatures.
Angew. Chem. Int. Ed. 2003, 42, 1880 – 1885
T. Luchian, S.-H. Shin,
H. Bayley*
1926 – 1929
Kinetics of a Three-Step Reaction
Observed at the Single-Molecule Level
An Oxidation-Resistant Semiconductor
J. R. Salvador, D. Bilc, S. D. Mahanti,
M. G. Kanatzidis*
1929 – 1932
Stabilization of b-SiB3 from Liquid Ga:
A Boron-Rich Binary Semiconductor
Resistant to High-Temperature Air
Oxidation
Connecting Individual Polymer Chains
“Move-connect-prove” is the sequence
that is employed to join and shape two
individual strands of dendronized
polymers. A scanning force microscope
is used to move and shape the strands
(picture a!b); the connection is
obtained by UV irradiation of the sample,
and tested by pulling on the connected
polymer chains.
For the USA and Canada:
ANGEWANDTE CHEMIE International
Edition (ISSN 1433-7851) is published weekly
by Wiley-VCH PO Box 191161, D 69451 Weinheim, Germany. Air freight and mailing in the
USA by Publications Expediting Inc. 200 Meacham Ave., Elmont, NY 11003. Periodicals
Reaction Kinetics in a Pore
J. Barner, F. Mallwitz, L. Shu,
A. D. Schl@ter,* J. P. Rabe* 1932 – 1935
Covalent Connection of Two Individual
Polymer Chains on a Surface: An
Elementary Step towards Molecular
Nanoconstructions
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2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1881
Contents
Arenes on Metal Clusters
J. P.-K. Lau, Z.-Y. Lin,
W.-T. Wong*
1935 – 1937
The Molecular Structure of
[Os3Rh4(m3-h1:h1:h1-C6H5CH3)(CO)13]:
A Face-Capping Bonding Mode for Arenes
in Organometallic Clusters
Rhodium gets a new flat cap: A novel facecapping mode of toluene on the title
{Os3Rh4} cluster is observed (see structure; Os blue, Rh green, C gray, O red,
H white). The cluster is obtained from
the reaction of [Os3Rh(m-H)3(CO)12] with
toluene in the presence of an excess
amount of 4-vinylphenol under reflux for
2 h. The new cluster has relatively short
metal–metal bonds and an electron count
of only 92, which is four electrons less
than expected.
Inorganic–Organic Hybrid Materials
A Chinese-vaselike cage, depicted, is
contained within the crystalline nanoporous [Ga2(VO)3K2(OH2)3(C2H4P2O6)4(H2O)13] structure, NCHU-3, and is
thermally stable up to 550 8C. NCHU-3
exhibits a highly reversible lithium-ionintercalation and de-intercalation cycle
between + 3 and + 5 volts. Such cyclability is a key aspect of rechargeable
lithium battery cathode materials.
C.-Y. Cheng, S.-J. Fu, C.-J. Yang,
W.-H. Chen, K.-J. Lin,* G.-H. Lee,
Y. Wang
1937 – 1940
NCHU-3: A Crystalline Inorganic-Organic
Hybrid Molecular Sieve with Extra-Large
Cages
Self-Assembled Cu-Based Capsule
M. A. Alam, M. Nethaji,*
M. Ray*
1940 – 1942
Synthesis of a Self-Assembled Molecular
Capsule that Traps Pyridine Molecules by
a Combination of Hydrogen Bonding and
Copper(ii) Coordination
Tunable Cavity of Titania Spheres
Z. Yang,* Z. Niu, Y. Lu,* Z. Hu,
C. C. Han
1943 – 1945
Templated Synthesis of Inorganic Hollow
Spheres with a Tunable Cavity Size onto
Core–Shell Gel Particles
1882
Copper(ii) complexes of a tetradentate
ligand self-assemble in pyridine to form
two slightly different tetrameric units.
Hydrogen bonding between the tetramers
forms a capsular cavity that traps four
molecules of pyridine (see picture).
Titania/polymer capsules and hollow
titania spheres are prepared by using
sulfonated-polystyrene core–shell gel
particles as templates. The titania shell
thickness and the cavity size are controlled in the entire particle radius range. If an
electric field is applied during synthesis,
hollow spheres with pillared surfaces
(depicted) are produced.
2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Angew. Chem. Int. Ed. 2003, 42, 1880 – 1885
Angewandte
Chemie
Order from disorder: Highly ordered
nanocrystal super-lattices accommodating identical tin particles spontaneously
crystallize from a dispersion displaying no
order. Two structure types were identified,
a noncompact one displaying uniform
orientations of the particles atomic
planes, and an unprecedented one containing monodisperse larger and more
anisotropic particles (see electron micrographs). Which structure is formed
depends on the reaction conditions used.
Tin Superstructures
K. Soulantica, A. Maisonnat,
M.-C. Fromen, M.-J. Casanove,
B. Chaudret*
1945 – 1949
Spontaneous Formation of Ordered 3D
Super-Lattices of Nanocrystals from
Polydisperse Colloidal Solutions
Novel Azine Reactivity
R. Cohen, B. Rybtchinski, M. Gandelman,
L. J. W. Shimon, J. M. L. Martin,*
D. Milstein*
1949 – 1952
An unprecedented reaction: Dinitrogen
pincer Rh complexes react with azines in a
moderately catalytic fashion by “nonsym-
Novel Azine Reactivity: Facile NN Bond
Cleavage, CH Activation, and NN
Coupling Mediated by RhI
metrical” NN bond cleavage to the
corresponding nitriles and imines (see
scheme).
Variations in the structural parameters of
the analogous [UO2]2+ and [UO2]+ compounds, [UO2(OPPh3)4](OTf)n (n = 1, 2;
picture shows the cation of the n = 1
complex), allow a direct comparison of
the observed data with that obtained from
EXAFS studies in solution, and from
theoretical studies.
Structures of Uranyl Complexes
J.-C. Berthet,* M. Nierlich,
M. Ephritikhine
1952 – 1954
Isolation of a Uranyl [UO2]+ Species:
Crystallographic Comparison of the
Dioxouranium(v) and (vi) Compounds
[UO2(OPPh3)4](OTf)n (n = 1, 2)
Palladium-Catalyzed Reactions
S. Ma,* Z. Yu
Taking the bond for a walk: An w-1-alkenyl
group was introduced at the b position of
butenolides by the PdII-catalyzed coupling/cyclization of 2,3-allenoic acids with
w-1-alkenyl halides (see scheme). The
Angew. Chem. Int. Ed. 2003, 42, 1880 – 1885
active PdII catalyst was regenerated
through the combination of cyclic
oxypalladation–carbopalladation with
repeated dehydropalladation/hydropalladation–dehalopalladation.
www.angewandte.org
1955 – 1957
“Walking” of the CC p Bond over Long
Distances in Pd-Catalyzed Reactions of
2,3-Allenoic Acids with w-1-Alkenyl
Halides
2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1883
Contents
A Disappearing Polymorph
Missing in action: Neutron and X-ray
diffraction studies at low temperatures
reveal the delicate balances of attractive
and repulsive intermolecular interactions
in the dimorphs of 1,2,3,5-tetra-O-acetylb-d-ribofuranose (the less stable polymorph is shown, O red, H blue, C gray).
Very short intermolecular H···H contacts
which are only present in the less stable
crystal form are responsible for the disappearance of this polymorph.
P. Bombicz, M. Czugler, R. Tellgren,
A. KRlmRn*
1957 – 1960
A Classical Example of a Disappearing
Polymorph and the Shortest Intermolecular H···H Separation Ever Found
in an Organic Crystal Structure
Crystal Engineering with Acetylene
Different phases: Molecular complexes of
acetylene and acetone or DMSO are
formed simultaneously in different
phases. Crystalline acetylene:actone
1:2 (A) and 1:1 (B), as well as acetylene:DMSO 2:1 (C) complexes have been
obtained by in situ cocrystallization under
pressure in a capillary with the use of an IR
laser. The crystal structures may be interpreted as a “frozen” situation of the
liquids.
R. Boese,* M. T. Kirchner, W. E. Billups,
L. R. Norman
1961 – 1963
Cocrystallization with Acetylene:
Molecular Complexes with Acetone and
Dimethyl Sulfoxide
Crystal Structure Predictions
Too difficult to predict? The second
polymorph of the title compound, is
presented. A comparison of hydrogenbond patterns and lattice energies suggests that the previously obtained form
(see picture, left) is a kinetic polymorph,
while the second polymorph (right) is
most likely to represent the more
thermodynamically stable form. The new
polymorph, however, has two symmetryindependent molecules, which rendered it
beyond the limit of previous structural
predictions.
R. K. R. Jetti, R. Boese,* J. A. R. P. Sarma,*
L. S. Reddy, P. Vishweshwar,
G. R. Desiraju*
1963 – 1967
Searching for a Polymorph: Second
Crystal Form of 6-Amino-2-Phenylsulfonylimino-1,2-Dihydropyridine
Tumor-Specific Transport
W. Mier,* R. Eritja, A. Mohammed,
U. Haberkorn, M. Eisenhut 1968 – 1971
Peptide–PNA Conjugates: Targeted
Transport of Antisense Therapeutics into
Tumors
Tumor-specific accumulation of antisense
therapeutics: The conjugation of a receptor-binding peptide allows for the first
time the selective transport of oligonucleotide analogues into tumor tissue.
By using the tert-butyloxycarbonyl (Boc)
1884
2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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protecting group stratergy, hybrids of
peptide nucleic acids and peptides are
accessible that accumulate in tumor
tissue at a tenfold higher concentration
than the free peptide nucleic acid.
Angew. Chem. Int. Ed. 2003, 42, 1880 – 1885
Angewandte
Chemie
Metalloid Gallium Cluster
Like “inverse” P4O10, a nearly tetrahedral
Ga4P10 shell encloses a gallium-rich core
with a distorted tetrahedral Ga4 center in
the neutral metalloid cluster compound
[Ga16(PtBu2)10].
J. Steiner, G. StTßer,
H. SchnTckel*
1971 – 1974
[Ga16(PtBu2)10]: A Gallium Phosphide
Sheathed Core of Four Naked Ga Atoms?
Os in the Sharpless Dihydroxylation
D. V. Deubel*
1974 – 1977
Reactivity of Osmium Tetraoxide Towards
Nitrogen Heterocycles: Implications for
the Molecular Recognition of DNA
Mismatch
A chameleon oxidant: In Sharpless dihydroxylation of C¼C bonds osmium tetraoxide is shown to be a chameleon oxidant.
Quantum chemical studies show that
osmium tetraoxide attacks the C¼C bond
of nucleobases either as an electrophile
(blue) or a nucleophile (red) depending
upon the nature of the substrate (see
scheme; CT = charge transfer).
Communications labeled with this symbol have been judged by two referees as being “very important papers”.
The publication of Communications labeled with this symbol has been accelerated because of their topical or highly competitive
nature.
The issues for April 2003 appeared online on the following dates
Issue 13: April 7. · Issue 14: April 10. · Issue 15: April 16.
Service
Angew. Chem. Int. Ed. 2003, 42, 1880 – 1885
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Keywords
1978
Authors
1979
Sources
A25
Vacancies
1886
Preview
1981
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1885
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