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Graphical Abstract (Angew. Chem. Int. Ed. Engl. 91994)

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A Journal of the
Gesellschaft
Deutscher Chemiker
International Edition in English
1994
3319
Pages 903- 1014
The German Bunsen Society for Physical Chemistry celebrates its centenary in Berlin
in May. Angeivandte Clzemie extends its congratulations and therefore dedicates this
issue, which includes a review by John M. Thomas, to the topic of catalysis. Physical
chemistry continues to offer a wide variety of attractive research topics-highresolution spectroscopy, electron transfer, clusters, catalysis. and thin layers, to
name a few. By publishing many reviews Angewandtr Chemie has informed chemists
of new developinents in physical chemistry and will continue to d o so. Communications and highlights provide a forum for the rapid presentation of important new
results. The manuscripts that we receive testify that Angewandte Chemie has recently
become even more attractive to physical chemists, and we are happy that we can
accommodate these fine papers thanks to our expanded volume.
COVER PICTURE
Catal~sisplays such an integral role in the histor! of physical chemistry that i t is only
fitting to >et this topic in the forct'ront of thi, "anniversary issue''. John M . Thomas
begins his; perwnal j o u r n q through the increasingly better charted territor!t of
pure and ;ipplicd catal!sis with ;I d i x o w r > , from 1823. At that time IXbcreiner.>
dram;ttic dcmonstration o f the pl;itinuni-cstullzed synthesi, of \\Liter -u,hich hc
Jevzlopcd into Ihc tinder box - \ v ; i h the basis foi the first cummcrcial application of
catallsi\. ,\n cspecidly fine specimen o f hi.; appxratus is depicted on our cover: the
picture n ; t \ \upplied b! Prol.. Dr. 0. Krlit/ from the Germun Museum in Munich.
The description 01' the industriiil innwations and ac;idcmic :id\.anceh i n c;iIal! h i 5
3iiitc Diibcrtiner's invention should be ple;is;int rs;iding Ihr all chcniists (szc
p. 91 1 K.)
REVIEWS
Contents
Everything is interesting but not everything is important-this fact has to be borne in
mind during the study of catalysis, since with the multitude of efficient techniques
available nowadays a vast amount of information on catalysts under operational
conditions or about model systems can be obtained. The first part of this review
highlights aspects from the history of catalysis, which are still interesting and entertaining( !) today, for example, that catalytic cracking was pioneered by a motor-racing enthusiast. In the second part recent results on solid catalysts are presented and
discussed in connection with biocatalysts and the challenges of clean technology.
J. Meurig Thomas* ....................
Is a particular reaction between an electrophile and a
nucleophile feasible? This question often arises in
synthesis design (symbolically represented on the
right). Here electrophilicity and nucleophilicity
scales are proposed that can give helpful answers.
However, setting up an electrophilicity scale that is
independent of the nucleophile contradicts the reactivity-selectivity principle. This is recognized as a
special case.
H. Mayr,*
M. Patz ......................................
913-937
Turning Points in Catalysis
938-958
Scales of Nucleophilicity and Electrophilicity: A System for Ordering Polar Organic
HMR,
EH
?
HIGHLIGHTS
0
A milestone in natural product chemistry is the first total synthesis of
taxol achieved independently of each
other by the groups of R. A. Holton
and K . C. Nicolaou. Taxol is at
present the most promising anti-cancer agent, and its synthesis is extremely demanding. It is highly unlikely that this climax will be the end
of probably the greatest worldwide
effort yet to synthesize a single compound.
Ph
L. Wessjohann * .........................
.
3'
A
O-:?-
OH
15
,
OH
The First Total Syntheses of Taxol
B
k i D O
2
1,
dEk
6Ac
2o
Taxol, R' = Ph, R2 = OAc
The benzene radical cation is not a regular hexagon. This statement, previously only
substantiated with photoelectronic spectra of benzene, ESR spectra of C,H; in a
freon matrix, or the laser-induced fluoresence halogen-substituted benzenes, was
strongly supported by the results of ZEKE-PE experiments by Miiller-Dethlefs et al.
These results should lead soon to a quantification of the Jahn-Teller geometric
distortion in C,HZ and the energy stabilization derived therefrom.
T. A. Miller* ..............................
The metal-metal bonds are stable without bridging ligands in the heterodinuclear
complexes 1 and 2. The combination of one metal center in a high oxidation state
and one in a low oxidation state causes these bonds to be strongly polarized. The
reactivity of such systems promises to be interesting- recently the direct insertion of
CO, into the Zr-Fe and Zr-Ru bond of related complexes has been achieved.
R = p-tolyl.
M. Heherhold,*
G.-X. Jin ....................................
[(tBuN),Re-M(CO),Cp]
1, M
=
Mo
959 -961
[HC(SiMe,NR),Ti-M(CO),Cpl
962-964
Molecular Distortion in Reactive Chemical
Intermediates
964-966
Heterodimetallic Complexes with an Unbridged, Polar Metal-Metal Bond
2, M = Fe, Ru
COMMUNICATIONS
Transfer of methyl groups from 2 to 1 leads to the first Zr,AI,C, cluster 3 [Eq. (a)],
in which six metal atoms form an open cube shielded by Al and C atoms. The Zr-Al
distances in the cube are remarkably short. Zr/AI/C compounds are of interest with
regard to Ziegler-Natta catalysts.
-
+ Me,AIF + CH,
[(C,Me,)ZrF,]
I
+ AIMe,
906
(3 VCH Verlagsgesrllscliu{fmbH, 0-69451 Weinheim. 1994
2
[((C,Me,)Zr},Al,Me,(CH),(CH,),I
3
(a)
A. Herzog,
H. W. Roesky,* 2. Zak,
M. Noltemeyer ..........................
967-968
Reactions of [(C,Me,)ZrF,] with AIMe,- Synthesis and Structure of a ZirconiumAluminum -Carbon Cluster
0570-0833j94i0909-0YW $10.00+.255/0
AnKen. Chem. Int. Ed. Engl. 1994, 33. N o . Y
An almost ideal planar AI,N, ring as a central unit
and the lowest degree of oligomerization for the
cp*
SiMe,
MeSi-N
class of compounds is shown by the dimeric iminoalane 1, which is formed from (Cp*AI), and
Me,SiN,. The fact that no heterocubane results is
attributed to the steric demand of the Cp* and
SiMe, groups.
cp*
/
I
\
,A',
AI-N
& 'ti'
,N
Me,Si
N-AI
\
/
SiMc,
1
Neither a helical structure nor a spiral j-bend ribbon structure. but a flat 8-bend
ribbon is formed by the title compound. Peptides with 2.3-didehydroamino acid
esters (x$-didehydroamino acid esters) such as dehydrophenylalanine (APhe) are of
great interest as model compounds for the study of structure- function relationships,
since the dehydroamino acids strongly influence the conformation and the enzymatic degradation of peptides. The comparison of the structure of the title compound
with that of corresponding Aib-containing peptides is informative.
A description as a cyclopropenyliocyclononatetraenide (that is, as the dipolar structure 1 with a planarized
nine-membered ring) for the title
compound 1 is valid, according to
N M R investigations, for the temperature range - 50 to + 50 "C and even
in nonpolar solvents.
'
'1
CN
f
N
J
C
\
N4
N
S. Schulz. L. Hiiming,
R. Herbst-Trmer,
H. W. Roesky,"
G. M. Sheldrick ..........................
969-970
Synthesis and Structure of the First Dimeric Iminoalane Containing an A1,N2 Heterocycle
K . R . Rajashankar,
S. Ramakumar, T. K. Mal,
V. S. Chauhan* ..........................
970-973
Synthesis. Crystal and Molecular Structure
of Boc-Pro-APhe-Ala-APhe-Ala-OMe ; A
Pentapeptide with a Novel 8-Bend Ribbon
Structure
s.
M.Chai,
Neuenschwander* ....___....._...
973-975
1 1,12-Bis(diethylamino)nonatriafulvalene.
the First "Aromatic" Nonafulvene
'
Colorless and only stable up to -4O"C, the new
bromine oxide Br,O, (1) has been characterized by
X-ray crystallography. The molecule has a symmetrical structure with an eclipsed arrangement of terminal oxygen atoms; in I,O, these are staggered.
.
I
D . Leopold,
K. Seppelt * ................................
1
975-976
Dibromine Pentoxide Br,O,
One alkylbismuth(v) compound stable up to 150 OC and three other unstable ones were
prepared and structurally characterized for the first time, namely, BiMe:CF,SO;
(the stable species). BiMe,CI,, BiMe,, and [Li(thf),]'BiMe,.
The tetramethyl compound. the hexamethyl compound, and the dichloride are, as expected, tetrahedral.
octahedral, and trigonal bipyramidal, respectively. However. based on the blue-violet color, a square pyramid was expected for BiMe,, and not the observed trigonal
bipyramid.
S. wdllenhauer,
K. Seppelt * ___...___...___...____.___._....,...
976-978
Reconstruction, not decomposition. was used to determine the composition of the
pigment from the blue petals of cornflowers. protocyanin. Comparison of optical
and mass spectra of natural and reconstructed protocyanin revealed it to be a
complex of an anthocyanin and a malonylflavone with iron(1n) and magnesium ions.
T. Kondo,* M. Ueda,
H. Tamura, K . Yoshida,
M. Isobe, T. Goto ........__..._._..._..
978-979
Methylbismuth(v) Compounds
Composition of Protocyanin, A Self-Assembled Supramolecular Pigment from the
Blue Cornflower, Centaicrea cycmus
Excellent endolexo selectivity and very good induced diastereoselectivity are achieved
by hetero-Diels-Alder reactions of oxabutadienes such as 1, accessible from chiral
oxazolidinones. with the enol ether 2 in the presence of Lewis acids. The facial
selectivity can be reversed by varying the Lewis acid. The endo product is formed
almost exclusively from I and 2 with Me,AICI as promotor. In contrast. the other
endo product 4 predominates with trimethylsilyltriflate (TMS-OTf) as initiator.
L. E Tietze, * C. Schneider.
A. Montenbruck ___..___....__...._...__
980 -982
Asymmetric 1,6-Induction in Hetero-Diels-Alder Reactions of Chiral Oxabutadienes
for a De Novo Synthesis of EnantiomericalIv Pure Carbohydrates : Lewis Acid Depen-
W. Schilbach,
V. von der Gonna,
D. Gudat, M. Nieger,
E. Niecke* .................................
982-983
As receptors and catalysts in host-guest chemistry
the title compounds can be recommended. The
stereoselective ring closure of aminonitriles is the
key to the synthesis of this new type of axially chiral
cation. The chiral center of the side chain, which
stems from an x-amino acid, transfers its absolute
configuration to the biaryl skeleton. This principle
provides access to a wide variety of target structures
such as 1.
S. Lehr, K. Schutz,
M. Bauch,
M. W. Gobel* ............................
984-986
pH or Cu" concentration can be used to tune the supramolecular structure obtained
by self-assembly of the amphiphilic gluconamide 1. Vesicles form at pH 4.5, whereas
fibers and hollow tubuli are generated at pH 8.5; in the presence of Cu" ions, helices
are produced.
R. J. H. Hafkamp,
M. C. Feiters,*
R. J. M. Nolte* ..........................
Interesting trapping products with phosphanes and chlorotrimethylsilane result from
reactions with the novel intermediate phosphoranylidene carbenoid 1 : These lead to
the phosphoniomethanide 2 with PPh,, the dihydrodiphosphete 3 with PMe,, and
the imino(methy1ene)phosphorane 4 with CISiMe,. R = 2,4,6-tBu3C,H,, R' = Ph,
Me.
2
1
3
4
Axially Chiral Amidinium Ions with a
Biaryl Skeleton: A New Class of Structure
in Host-Guest Chemistry
986-987
Tunable Supramolecular Structures from a
Gluconamide Containing Imidazole
Golden lustrous crystals of the semiconductor
Me,SbI, contain free ordered iodine chains (picture
shown on the right), which are stabilized by the
coordination of three Me,Sb+ ions to every second
I atom of the chain. These chains break if the octaiodide is dissolved. Me,SbI, can be prepared readily
from Me,SbI and I,.
U. Behrens,
H. J. Breunig,* M. Denker,
K. H. Ebert ................................
Only an ethylene bridge braces the
Cp,Ru unit in the first [2]ruthenocenophane. This leads to a highly
strained
molecular
framework
(shown on the right) and makes
[2]ruthenocenophanes suitable starting materials for thermal ring-opening polymerization to give poly(ruthenocenyIethy1ene)s.
J. M. Nelson, A. J. Lough,
908
<
V C H Verlug~gesellschu/fmbH 0-69451 Wernheim 1994
987-989
Iodine Chains in (Me,Sb),I, and Discrete
Triiodide Ions in Me,AsI,
I. Manners* ................................
,
989 -991
Synthesis and Ring-Opening Polymerization of Highly Strained, Ring-Tilted
[2]Ruthenocenophanes
0570-0R33/94j0909-0908$10 00 f 25'0
A n g m Chrni I n t Ed Engl 1994. 33. No 9
U. Kolle,* T. Riither,
N. Le Narvor, U. Englert,
W. Klaui .....................................
The stabilization of high oxidation states by sixfold
oxygen coordination is achieved with the dianionic
tripod ligand 1. With this ligand and the methyl
analogues. B, Si, Ti, Nb, Co, and Ru complexes
were synthesized. According to the electronic spectrum of the Co“ complex, the ligand 1 has a lower
ligand-field strength than water.
Deviations from the usual reaction pattern of strained olefins and
epoxides occur in the reactions of the
title compounds with methyllithium.
tive 2forforms
in the
a indene
nucleophilic,
Thus,
example,
deriva-
transannular homo-l,4-addition from
I ; an analogous transannular substitution takes place for its epoxide.
(oEt)a
:’ pE’Eap(oEt)z
A New Oxygen Tripod Ligand and Its First
II
o
!
0
Complexes with p- and d-Block Elements
1
Qj$lg=??jg
R. Herges,* H. Neumann,
F. Hampel ..................................
993-995
Transannular Addition of Methyllithium to
cyclooctene
5,12:6,1l-Di[l,2]benzenodibenzo[a,e]and Its 5,6-Epoxy Derivative
2 H+
1
991 -993
2
C,,, C,,,, ...,diamond, graphite. The accurate calorimetric determination of the
standard heats of formation of highly pure C,, and C,, confirms the fundamental
statements concerning the stability in the series of the allotropic forms of carbon
predicted from calculations. MM3 force-field calculations provide the best prediction of the experimental values.
H.-D. Beckhaus, S. Verevkin,
C. Riichardt,*
F. Diederich,* C. Thilgen,
H.-U. ter Meer, H. Mohn,
W. Miiller ...................................
996-998
C,, Is More Stable than C6,: Experimental
Determination of the Heat of Formation of
The highly diastereoselective formation of unsaturated a-amino acids 2 by rearrangement of 1 has now been achieved under mild conditions and in very good yields by
using metal enolates. The Ireland variant, which makes use of silylketene acetals, is
hereby supplemented and in some cases the yield and selectivity are even improved.
Z = benzyloxycarbonyl.
U. Kazmaier* ............................
Grignard compounds and amines were converted into “dimagnesylamines” RN(MgX), as long ago as 1903.Now for the first time a crystalline compound has been
obtained from a PhN(MgBr), solution in ether and characterized by X-ray structure
analysis. The title compound has a Mg,N, adamantanyl framework; each Mg2+ion
is solvated by an ether molecule, and the four Br- ions are located above the four
hexagonal faces of the Mg,N, cage.
T. Hascall, M. M. Olmstead,
P. P. Power* ..........................
Absorption maxima shifted to the near IR region are observed for the cations 1. These
cations can be synthesized by the reaction of
benzothiazolium iodides and squaric acid in
the ratio 3:2 without the addition of a base.
The chromophore of 1 is a polymethine
chromophore and not a triarylmethane one.
R = Bu. Pr, Et.
A n p v . Clwii?. In!. Ed. Engl. 1994. 33, N o . 9
R,
0
#(CVCH Verk~i~sgeselkschafr
m b H , 0-69451 Wknheim, 1994
998 -999
Synthesis of Unsaturated Amino Acids
by [3,3]-Sigmatropic Rearrangement of
Chelate-Bridged Glycine Ester Enolates
1000-1001
Synthesis and Structural Characterization
of [{(Et,O)Mg},(NPh),Br,]: A Magnesium
h i d e Cage Species Derived from a Dimagnesylamine Solution
H. Nakazumi,*
K. Natsukawa, K. Nakai,
K. Isagawa ............................
1001 -1003
Synthesis and Structure of New Cationic
Squarylium Dyes
0570-0833,!94,tOY09-090Y $ 10.00
+ .25:0
909
Contents
How many more ways can three C, ligands and two metal atoms be arranged? In
addition to the classical triple-decker A and the Cp-bridged binuclear complex B, the
first preparation of a metallabenzene sandwich complex of type C exemplifies a third
structural isomer.
U. Bertling, U. Englert,
A. Salzer* ..............................
1003- 1004
From Triple-Decker to Metallabenzene: A
New Generation of Sandwich Complexes
A
The recognition of sequences consisting of a total of 48 nucleotides is
achieved by a structure which contains only 35 nucleotides. The design,
synthesis. and binding properties of
the circular 3Smer oligodeoxynucleotide (in the center of the picture on
E. Rubin,
E. T. Kool* ............................
5.-
c
T
T A T
T A T
the right) are described herein. The
design of the oligonucleotide illustrates ways to control binding properties in D N A molecules by varying
more than just the primary sequence
of nucleotide bases.
C G C
T A T
T A T
__
-
T
TT
T
c -
C
T
T
T
T
-
T
1004-1007
Strong, Specific Binding of Six Different
DNA Sequences by a Single Conformation-Switching D N A Macrocycle
c'
T A T
"C G
T
T
C
T
T
T
A
A
G
A
A
T
T
C
T
T
S C
* Author to uhorn correspondence should be addrevscd
BOOKS
Half a Century of Free Radical Chemistry
-
D. H. R. Barton, S. I. Parekh
Supramolecular Architecture. Synthetic Control in Thin Films and Solids
Electrochemical and Electrocatalytic Reactions of Carbon Dioxide
K. Krist. H. E. Guard
Chemistry of Iron
-
. T. Bein
. B. P. Sullivan,
J. Silver
Photodissociation Dynamics
*
R. Schinke
Biocatalysts in Organic Synthesis
Liquid Crystal Polymers
*
*
J. Halgas
N. A. Plate
Chirotechnology. Industrial Synthesis of Optically Active Compounds
R. A. Sheldon
Author Tndex A 4 3
Resources A-39
B. Givse ...........................................
1009
N . Herron ........................................
1009
W Leitnrr ........................................
1010
s. Polzl .............................................
1011
P. Wicsen .........................................
1011
W - D . Fessner ..................................
1012
H . Kresse .........................................
1013
H.-J. Federst1 ...................................
1013
Preview A 4 4
The following reviews will appear in future issues:
A Three-Dimensional Model for Taste Utilizing Stereoisomeric Peptides and Peptidomimetics
T. Yamazaki. E. Benedetti, D. Kent. M. Goodman
Molecular Catalysts for Multielectron Redox Reactions of Small Molecules: The Cofacial Metallodiporphyrin Approach
J. P. Collman, P. S. Wagenknecht, J. E. Hutchinson
Alkene. Alkyne. and Alkylidene Ligands as Sensors of Tc-Donor Capacity in Tetrahedral and Pseudo-Tetrahedral Transition Metal
Complexes
V. C. Gibson
Split Genes and RNA Splicing (Nobel Lecture)
P. A. Sharp
An Amazing Distortion in DNA Induced by a Methyltransferase (Nobel Lecture)
R. J. Roberts
The Polymerase Chain Reaction (Nobel Lecture)
K . B. Muilis
Synthetic DNA and Biology (Nobel Lecture)
M. Smith
Scientific Committee
K. Danzer, Jena
G. Gauglitz, Tubingen
M. Otto, Freiburg
H. W. Zwanziger, Merseburg
Sclentlflc Topics
Chemometrics
Analytical Data Evaluation
Automization in Analytical Chemistry
CHEMOMETRIK
DATENVERARBEITUNG
-
October 4 6,1995
S. Ebel, Wurzburg
D. L. Massart, Brussel
W. Wegscheider, Graz
Wiirzburg, Germany
FIRSTANNOUNCEMENT
AND lNVlTATlON
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Chromatography
ElectroanalyticalTechniques
Spectroscopy
and other methods in Analytical Chemistry
Application Flelds:
Chemistry
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Pharmacy and other fields
Exhibition:
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Compana '95 will be held in the campus of the University of
Wuerzburg, Am Hubland in the main building of the Faculty
of Chemistry and Pharmacy
Organized by
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FachgruppeAnalytische Chemie
Arbeitskreis Chemometrik und
Labordatenverarbeitung
in cooperation with
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Angru.. Chwii. In!.
Ed. Engl. 1994, 33. No. 9
CIVCH
Conference Secretariat
Contact address for scientific problems. for papers and for
posters:
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Contact address for all other questions and registration:
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Verlugsgesellschufi m h H , 0-69451 Wrinheim. 1994
0570-0833194jO909-0911$10.00+ .2SIO
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