bluuebunny/crossref_metadata_2025 huggingface dataset:
Perfluoro Compounds as Blood Substitutes
Authors: Riess Jean G. , Le Blanc Maurice
Published: December 2003

Inconceivable as it is, it has been proved that animals can survive after having had their blood massively or even totally replaced by emulsions of perfluorinated compounds in salines. “Bloodles” rats charged with an emulsion of perfluorotri‐n‐butylamine survived a five hour period in an atmosphere containing 50% oxygen and 50% carbon monoxide, i.e. in conditions where the transport of oxygen by the red cells is entirely blocked. This review discusses: (1) the experiments which have demonstrated the capability of blood substitutes based on perfluorinated compounds to sustain life; (2) the characteristics and preparation of the relevant perfluoro compounds and the production and handling of their emulsions; (3) their “physiology”, i.e. toxicity, life‐span in the blood‐stream, effect on the organs and their functions, and excretion properties. Obstacles remaining to be overcome in order to provide a safe blood substitute for medical practice include the availability of numerous series of well‐defined pure and inert perfluorinated chemicals, the production of stable emulsions, the optimization of fluid balance, and the attainment of reasonable excretion rates. The accent is placed upon the role of the chemist in the progress of this research.
Protein Biosynthesis: The Codon‐Specific Activation of Amino Acids
Authors: Holler Eggehard
Published: December 2003

At the start of protein biosynthesis the amino acids are chemically activated by esterification with transfer ribonucleic acids bearing the appropriate anticodons. The esterification is catalyzed with an exceptionally high specificity by aminoacyl‐tRNA synthetases. Current knowledge of the structural properties of the reactants, the course of the reaction, and the reasons for its specificity are summarized.
Polymeric Catalysts
Authors: Manecke Georg , Storck Winfried
Published: December 2003

The present‐day position in the field of polymeric catalysts is outlined. The following selected groups of polymeric catalysts are discussed: synthetic hydrolases, immobilized enzymes, phase‐transfer catalysts, nucleophilically active bases, polymers with conjugated π‐systems, photosensitizers, polymers as carriers for catalytically active metals or ions, and immobilized homogeneous catalysts. Polymeric catalysts have the following valuable properties: insoluble polymeric catalysts are readily separable from reaction solutions and can often be re‐used without loss of activity; a hydrophobic matrix protects the organometallic active center from deactivation by oxygen and water; by fixation of finely divided metals on an ion exchanger, multistage reactions may be effected successively in one reactor. Polymeric carriers may influence the catalytic properties; for example, in the case of immobilized enzymes on polyionic carriers the pH of the activity maximum may be shifted.
Organometallic Syntheses with Diazoalkanes
Authors: Herrmann Wolfgang A.
Published: December 2003

In recent years, aliphatic diazo compounds have proved to be more and more versatile as reagents in the preparative chemistry of organometallic complexes. As readily accessible compounds, they are not only suitable for the synthesis of known kinds of metal complexes but also open fresh routes to novel complex systems. The comparatively new field of diazoalkane complex chemistry exhibits numerous unexpected and novel reactions, and introduces interesting and promising aspects into the chemistry of carbonylmetal compounds.
Polyethylene Fibrids: Preparation and Properties
Authors: Gordon Wolfgang , Leugering Hans Joachim , Cherdron Harald
Published: December 2003

Polyethylene fibrids are small fibers having lengths of up to some millimeters, which are highly oriented and which have a morphology similar to that of cellulose fibers. The preparation of polyethylene fibrids is based on shear‐induced crystallization, a process in which the polyethylene crystallizes from solution under the influence of an elongated flow in the form of so‐called shish‐kebabs. Polymerization under shear conditions and the flash spinning of polyethylene solutions are the main processes for the preparation of PE fibrids. They may be hydrophilized by an additional process step.—Because of their cellulose‐like morphology, (hydrophilized) polyethylene fibrids have interesting properties, e.g. high adsorption capacity and the ability to form hydrogen bonds. In addition, the possibility of undertaking chemical reactions on the surface of the fibrids should be mentioned.
Unusual Selectivity in the Thermal Rearrangement‐Elimination Reaction of a Carbene Complex in Solution and in the Solid State
Authors: Fischer Helmut , Motsch Andreas , Kleine Willi
Published: December 2003

Halocarbene complexes such as (1) are potential intermediates in the synthesis of complexes containing MC bonds, thus conferring preparative interest upon the mechanism of the thermolysis of (1). On heating in solution (1) gives the carbyne complex (2); heating of the solid affords the isocyanide complex (3) among other products.
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Physical and Chemical Properties of Dissolved Electrons (Excess Electrons)
Authors: Schindewolf Ulrich
Published: December 2003

Electrons produced in a gaseous, liquid, or solid solvent are called dissolved electrons or excess electrons. These excess electrons can exist as quasi‐free particles of high mobility in a delocalized state, comparable with electrons in a metal; or as bound particles of low mobility they can be localized within narrow limits—in a solvent cavity formed by repulsive forces. Localized electrons can also be solvated like normal ions. Characteristically, such solvated electrons exhibit broad and extensive absorption spectra in the visible to near infrared spectral range. The localized and delocalized states of the excess electrons can be in equilibrium with each other, such that a continuous transition of the properties between the limiting extremes can be observed. The reactions of the excess electrons with suitable acceptors (substrates) are initiated by an attachment‐detachment equilibrium A + e− ⇌ A− which is followed by further chemical rearrangements. The rate constants of these reactions vary by more than 15 powers of ten depending on the substrates and the solvents. Most of the properties of excess electrons in solution can be interpreted by means of a model which is easily understandable but quantitatively evaluated only with considerable effort.
Structure and Bonding in Cyclic Sulfur‐Nitrogen Compounds
Authors: Roesky Herbert W.
Published: December 2003

The coordination number of sulfur is used in this review as a classification principle; cyclic sulfur‐nitrogen compounds in which the sulfur is di‐, tri‐, and tetracoordinated are discussed. Compounds with sulfur (and nitrogen) of coordination number 2 are electron‐rich combinations of elements whose π‐electrons are extensively delocalized. A correlation between the coordination number and the bond length can be observed in certain compounds containing tri‐ and tetracoordinated sulfur.
Di‐tert‐Butyl Acetylenedicarboxylate and Its Cyclotrimerization
Authors: Sucrow Wolfgang , Lübbe Fritz
Published: December 2003

Di‐tert—butylacetylenedicarboxylate (1)—surprisingly not synthesized before—is remarkable from a chemical standpoint. Its cyclotrimerization shows that the tert‐butyl groups do not exert strong steric hindrance. Ready cleavage (without base) of the esters obtained from (1) is of advantage.
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Synthesis and Properties of Tetrabutylammonium Octaiododirhenate(III),[(n‐C4H9)4N]2[Re2I8]
Authors: Preetz Wilhelm , Rudzik Lutz
Published: December 2003

Salts of the anion [Re2I8]2−, containing a ReRe quadruple bond, have hitherto defied preparation. However, they are accessible by reaction in nonaqueous solution. The HI used should be free from water and iodine (XCL, Br).
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Detection of Large‐Ring Sulfur Molecules in Liquid Sulfur: Simple Preparation of S12, α‐S18, and S20 from S8
Authors: Steudel Ralf , Mäusle Hans‐Joachim
Published: December 2003

The molecular composition of liquid sulfur has been a topic of discussion for generations. It was known to contain the homocyclic species S6 and S7, as well as S8. The isolation of S12, α‐S18, and S20, and the detection of Sx with x = 23—34 are new accomplishments.
An Example of the Equilibrium Ethylenehydridometal ⇌ Ethylmetal Complex
Authors: Werner Helmut , Feser Rainer
Published: December 2003

An understanding of the processes involved in the insertion of olefins into MH bonds is important for many catalytic processes. Equilibrium between an ethylenehydrido‐metal (1) and an ethyl‐metal complex (2) in solution has been demonstrated for the first time.
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Bis(dichloroboryl)silylamines and Tris(dichloroboryl)‐amine
Authors: Gasparis Theo , Nöth Heinrich , Storch Wolfgang
Published: December 2003

The first B‐perhalogenated di‐ and triborylamines have been synthesized from RN(SnMe3)2 and N(SnMe3)3. The weakest BN bonds yet encountered are found in Cl3SiN(BCl2)2 and N(BCl2)3.
Permeability of the Outer Membrane of Bacteria
Authors: Nikaido Hiroshi
Published: December 2003

The outer membrane of Gram‐negative bacteria is an attractive system for the study of the structure‐function relationships in biological membranes. This membrane has, inter alia, the task of regulating the inflow of nutrients and outflow of waste products. Investigations with the aid of mutants showed that there are at least two general pathways for the diffusion of small molecules across the outer membrane: one for hydrophobic and one for hydrophilic compounds. In the case of the “hydrophobic pathway” the hydrophobic compound dissolves in the interior of the membrane and then crosses the membrane in accordance with the partition coefficient. In wild‐type forms of enteric bacteria this pathway cannot be used—presumably owing to the absence of regions with phospholipid bilayers. Small hydrophilic molecules, on the other hand, penetrate the membrane through water‐filled pores.
Catalysis of Hydrogen Formation from an Organic Radical in Aqueous Solutions by Colloidal Silver
Authors: Henglein Arnim
Published: December 2003

Short‐lived radicals such as (1) can be compelled to undergo unusual reactions if they are generated in the presence of a metal colloid catalyst in aqueous solution. Instead of combining, disprotionating, or dismuting, the radicals (1) participate in a redox process leading to evolution of H2, according to the overall equation:
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The Sequences of the Membrane‐Modifying Peptide Antibiotic Trichotoxin A‐40
Authors: Brückner Hans , König Wilfried A. , Greiner Michael , Jung Günther
Published: December 2003

A possible model for nerve conduction is provided by the peptide antibiotic trichotoxin A‐40. The first complete sequence determination was accomplished once it had been recognized that the peptide can be fragmented highly selectively with anhydrous trifluoroacetic acid. The high content of aminoisobutyric acid (Aib) is remarkable.
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[2 + 4]‐Cycloadditions with Di‐tert‐butyl Acetylenedicarboxylate
Authors: Weber Gisela , Menke Klaus , Hopf Henning
Published: December 2003

Di‐tert‐butyl acetylenedicarboxylate is a valuable cycloaddition reagent—as has been confirmed for several examples. However, it is not quite so new as was stated on p. 149 of the February issue of this Journal. The first synthesis was published slightly earlier by Hopf et al. in Chemische Berichte.
Tellurium‐Catalyzed Reaction of Amines with Carbon Monoxide
Authors: Kambe Nobuaki , Kondo Kiyoshi , Ishii Hideo , Murai Shinji , Sonoda Noboru
Published: December 2003

Tellurium catalyze the formation of urea from amines and carbon monoxide. This is the first example of activation of CO by Te and also of the formation of equimolar amounts of ureas and H2.
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Simple Route to Li‐ or Zn‐Metalated η5‐Cyclopentadienyliron‐Olefin Complexes
Authors: Jonas Klaus , Schieferstein Ludwig
Published: December 2003

Some new reactions of ferrocene with lithium and olefins involve only replacement of a C5H5 ligand. The product, e.g.(1). DME and (1). TMEDA, can be metalated with ZnCl2 or CdCl2 and transformed into trinuclear complexes with olefinic ligands bonded to iron, such as(2). Reaction of (1) and trityl chloride produces the monomeric radical CpFe(COD)•.
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Adiabatic Photoreactions of Organic Molecules
Authors: Turro Nicholas J. , McVey Jeffrey , Ramamurthy V. , Lechtken Peter
Published: December 2003

An adiabatic photoreaction is a chemical process that occurs entirely on a single excited electronic energy surface. As a rule, most photoreactions of organic molecules start on an excited electronic surface but “jump” to a lower surface somewhere along the reaction coordinate. There are, however, exceptions to this general rule. For example, photoreactions involving small structural changes and minor alterations in covalent bonding (e.g., proton transfer and complex formation) are commonly found to occur adiabatically. The purpose of this review is to survey examples of more complicated adiabatic photoreactions such as fragmentation, electrocyclic rearrangements, and geometrical isomerizations. The concepts employed are presented in an introductory discussion.
Tris(trichlorophosphoranediylamino)carbenium Hexachloroantimonate, [C(NPCl3)3]+SbCl
Authors: Müller Ulrich , Lorenz Inge , Schmock Fritjof
Published: December 2003

The first photochemical reaction of the triazidocarbenium ion leads to a substituted guanidinium ion, in which the mutually equivalent bonds are shown to be practically equal in length by X‐ray structure analysis.
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1,1′‐Trimethylenebis(η5‐3‐tert‐butylcyclopentadienyl)‐titanium(IV)Dichloride, a Chiral ansa‐Titanocene Derivative
Authors: Schnutenhaus Horst , Brintzinger Hans H.
Published: December 2003

A configurationally stable chiral titanocene, of interest as a catalyst for asymmetric hydrogenation, contains tert‐butyl‐substituted Cp rings and a (CH2)3chain joining the two rings. The enantiomers of the title compound, synthesized for the first time, can be resolved by way of a diastereomeric (S)‐binaphtholate.
One‐Pot Syntheses of α‐Ferrocenylalkylamines
Authors: Herrmann Rudolf , Ugi Ivar
Published: December 2003

In order to carry out asymmetric peptide syntheses with 1‐ferrocenyl‐2‐methylpropylamine on a large scale a convenient entry to this amine and similar compounds has been developed. One‐pot syntheses in the trichloroacetic acid/fluorosulfuric acid solvent proved favorable(FcH = ferrocene).
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Raw Material‐Polymer Interrelationships — Today and Tomorrow
Authors: Weissermel Klaus
Published: December 2003

Against the background of increasing demand and limited availability of fossil, non‐regenerative fuel reserves and resources, ways are indicated of ensuring future supplies of raw materials and energy. The ambivalence of petroleum, natural gas, and coal in the energy and chemical sectors is demonstrated and opportunities for the gradual separation of their dual function are indicated. Taking into account the time factor, the necessary restructuring processes are analyzed critically with respect to their impact on the raw material–polymer relationship.
Coupling of Solvolysis and CC Linkage: A Promising Synthetic Route to Functionalized Carboxylic Acids, Aldehydes, and Ketones
Authors: Bott Kaspar
Published: December 2003

Numerous additions of carbocations to chloroolefins or acetylenes can be coupled with a solvolysis step when performed in a suitable acid; the products are variously substituted carboxylic acids, aldehydes, and ketones. Factors determining the success of these syntheses are the stability of the intermediate carbocations and suppression of the competing addition of protons to the unsaturated reaction component. Under the conditions of the Tscherniac‐Einhorn reaction, amidomethylation of chloroolefins and acetylenes, i.e. the introduction of acylaminomethyl groups, is shown not to involve a trigonal α‐chloro carbocation or a linear vinyl cation, but instead to proceed via a cyclic oxazinium ion intermediate.
Synthesis of Intermediates by Rhodium‐Catalyzed Hydroformylation
Authors: Siegel Hardo , Himmele Walter
Published: December 2003

The reaction of olefins with carbon monoxide and hydrogen to give aldehydes is referred to as hydroformylation (oxo reaction). As catalyst for this reaction rhodium is about three to four orders of magnitude more active than the more commonly employed cobalt. With special rhodium compounds, e.g. di‐ν‐chlorobis(ν‐1,5‐cyclooctadiene)dirhodium [RhCl(C8H12)]2, in the presence of chiral phosphanes, even asymmetric hydroformylations can be achieved; however, the enantiomeric purity of the products (20–30%) is not high enough for industrial‐scale syntheses.
Structure of Yellow Metal‐Free and Yellow Cobalt‐Containing Corrinoids
Authors: Schlingmann Gerhard , Dresow Bernd , Koppenhagen Volker B. , Becker Wulf , Sherldrick William S.
Published: December 2003

The biologically inactive yellow metal‐free corrinoids produced in large amounts by bacteria might be of use in the synthesis of vitamin B12 antimetabolites. X‐ray structure analysis of a “yellow” Co(CN)2‐containing model compound revealed that the side chain c forms a lactam ring. The yellow metal‐free corrinoids are probably similar in structure. Incorporation of Co and treatment with KCN transforms them into biologically active red corrinoids (with opening of the lactam ring).
Matrix Isolation of OSiS: IR Spectroscopic Evidence for the SiS Double Bond
Authors: Schnöckel Hansgeorg
Published: December 2003

The OSiS molecule has been isolated in an argon matrix and studied by IR spectroscopy. The force constants for SiS and SiO are 4.86 ± 0.06 and 9.0 ± 0.1 [102 N m−1], and the bond orders are 1.9 and 2.01, respectively. OSiS is the first SiIV compound with a SiS double bond.
Computer Simulation of the Kinetics of Complicated Gas Phase Reactions
Authors: Ebert Klaus H. , Ederer Hanns J. , Isbarn Gunther
Published: December 2003

Modern digital methods and powerful computers make it possible to simulate the time behavior of chemical reactions. These calculations can be performed on systems containing an almost unlimited number of elementary reactions. Generally, however, the reaction models used should contain only those elementary reactions which describe the bulk of the conversion. Such a reaction model may be obtained by reduction of the complete set of elementary reactions. Another possibility is analysis of the chemical system starting from conditions ensuring a simple chemistry, which is generally the case at low temperatures and low conversions. The reaction model may then be extended into the range of the reaction variables (temperature, time) of interest. Mathematical simulations may be helpful during the development of the reaction model, and sometimes even decisive. These methods were applied to the pyrolysis of ethylbenzene and n‐hexane, and to CO oxidation. They yield information on the reaction paths, the importance of particular elementary reactions, and reaction stability. Furthermore, quantitative data can be obtained concerning the influence of single elementary reactions on the product distribution. The sensitivity matrix shows, e.g., whether the determination of kinetic parameters of an elementary reaction from kinetic data of the overall reaction is possible in principle, and how high the accuracy of the rate constants should be for simulation of the reaction. Both results are important for modeling chemical reactions.
Differentiation between Chiral Pheromone Analogues by Chemoreceptors
Authors: Bestmann Hans Jürgen , Hirsch Hans Ludwig , Platz Hans , Rheinwald Marlies , Vostrowsky Otto
Published: December 2003

Insects can distinguish between the object and mirror image of chiral analogues of their (achiral) pheromones; thus the relative activities of (natural) (1):(R)‐(2): (R, S)‐(2): (S)‐(2) were 100:10:1:0.1 (electroantennogram test). These findings support the idea that the pheromone molecule is incorporated as a defined conformation into the receptor region.
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Are α‐Oxothioacyl Chlorides Formed in the Reaction of Methyl Ketones with Thionyl Chloride?
Authors: Adiwidjaja Gunadi , Günther Horst , Voss Jürgen
Published: December 2003

The answer to the question posed in the title is no; thus, previous claims in the literature have to be corrected. Work in this field has led to the new class of O‐alkyl α‐oxothiocarboxylates.
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The Influence of Density and Temperature on the Properties of Pure Molten Salts
Authors: Tödheide Klaus
Published: December 2003

Molten salts differ from most other types of liquids because of their high charge carrier density, which is responsible for a number of their extraordinary properties such as high ionic conductivity. Experimental and theoretical investigations during the past few years have provided information on the static and dynamic microscopic structures of this class of liquids and their relationship with the macroscopic properties. A consistent, albeit incomplete picture of the behavior of molten salts over wide ranges of temperature and density is now available including the transition from an insulator to an ionic conductor which a salt undergoes when it is compressed from vapor‐like to liquid‐like densities.
Vitamin B12 and a Vitamin B12 Model Compound as Catalysts of Reductive Removal of β‐Haloethyl Protecting Groups from Acids
Authors: Scheffold Rolf , Amble Erik
Published: December 2003

The transformation of β‐chloroethyl esters (1) into acids (2) under extremely mild conditions, i.e. removal of the protecting group Cl(CH2)2, can be accomplished with zinc dust/NH4Cl or electrochemically. The catalyst is vitamin B12 or a model compound. Even lactam rings remain intact during the deprotection.
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Cyclic Water Cleavage by Visible Light: Drastic Improvement of Yield of H2 and O2 with Bifunctional Redox Catalysts
Authors: Kiwi John , Borgarello Enrico , Pelizzetti Ezio , Visca Mario , Grätzel Michael
Published: December 2003

A further step on the road to utilization of solar energy by cleavage of water is made possible by a new catalyst which promotes both H2‐and O2‐formation in the (known) Ru(bpy)/methylviologen system. The catalyst consists of RuO2 (0.1%) in (Nb‐doped) n‐TiO2 charged with finely divided Pt. The rate of generation of H2 remains constant even after irradiation for 4 d with visible light.
Synthesis of the First Methylidyne‐Rhodium Cluster by Proton‐Induced H2/CH4‐Elimination from a μ‐Methylene Complex
Authors: Herrmann Wolfgang A. , Plank Johann , Guggolz Ernst , Ziegler Manfred L.
Published: December 2003

The transformation of a μ‐methylene‐dirhodium complex into a μ3‐methylidyne‐trirhodium complex (X‐ray structure analysis) has been accomplished in reaction (1) → (3). The first step is protonation of (1) to form the (isolable) μ‐hydrido complex (2).
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The Diphenylbismuthyl Group—A Potential New Auxiliary Group in Organic Synthesis
Authors: Steinseifer Fritz , Kauffmann Thomas
Published: December 2003

The PH2Bi group possesses a combination of favorable properties that is so far unique: Ph2Bi (like other organo‐heavy metal groups) stabilizes a carbanionic center; the alkyl‐Bi bond in alkyldiphenylbismuthanes is cleaved selectively by chlorine and bromine below 0°C; Ph2Bi can be replaced by H or Li under mild conditions if the resulting Li compound is stabilized.
Pharmaceutical Chemistry Today—Changes, Problems, and Opportunities
Authors: König Horst
Published: December 2003

Dissatisfaction with empirical methods, high expectations of the public, poorly harmonized international regulations, and rising costs have induced pharmaceutical research to search for new approaches. As a consequence, the medicinal chemist's professional activity is in a state of change. His synthetic strategy is being increasingly influenced by the reasoning of molecular biology. Novel classes of biologically active compounds demand the development of new synthetic methods beyond the scope of modern preparative organic chemistry: enzymes and microorganisms, cell cultures, and genetic engineering are harnessed to supply highly complex structures. Major efforts are devoted to the development of reliable structure‐activity relationships to rationalize his work. Thus the field of medicinal chemistry stretches from physical and physical organic chemistry far into the realm of biosciences, and the interdisciplinary character of this research is rapidly increasing. The author endeavors to convey an impression of this complex subject with the aid of selected examples.
UV Irradiation of Nucleic Acids and Their Components in the Presence of Air
Authors: Fahr Egon , Fecher Peter , Roth Georg , Wüstenfeld Peter
Published: December 2003

Pyrimidine bases can give different products on UV irradiation in the presence and the absence of air; hence the action of UV radiation in vivo cannot be deduced solely from in vitro experiments conducted with exclusion of air. A remarkable observation made on UV irradiation of cytosine, uracil, thymine, and similar bases in aqueous solution in the presence of air is the elimination of CO. Perhaps CO is formed in nature by such reactions.
Crystal and Molecular Structure of[Li(tmen)]3[Er(CH3)6]
Authors: Schumann Herbert , Pickardt Joachim , Bruncks Norbert
Published: December 2003

In the extremely sensitive polymethylated erbium complex (1), the central erbium atom is surrounded by six monohapto‐bonded methyl groups in a distorted octahedral configuration. The methyl groups are bridged pairwise by a lithium atom, which is co‐ordinated to the two nitrogen atoms of the N,N,N′,N′‐tetramethylethylenediamine ( = tmen) ligand.
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Structure of the Antibiotic Moenomycin A
Authors: Welzel Peter , Witteler Franz‐Josef , Müller Dietrich , Riemer Werner
Published: December 2003

The coupling of the (known) structural units, A‐B‐C and D‐E‐F‐G‐H‐I in moenomycin, has been explained by a combination of degradation, and high resolution mass‐ and 1H‐NMR‐spectroscopic studies. Moenomycin is one of the most active inhibitors of bacterial cell wall biosynthesis; now that the structure is known the determination of the important characteristics of its antibiotic activity should follow.
Preparative Separation of Lanthanoids by High‐Pressure Liquid Chromatography (HPLC)
Authors: Weuster Werner , Specker Hermann
Published: December 2003

The separation of the lanthanoids can be carried out on a preparative scale without the use of ion‐exchange, by high pressure liquid chromatography. As an example, the lanthanoids in a monazite sand (5.2 mg in total) were separated in 35 min using this method. From the 8.5 fractions collected, 4 contained pure Er, 2 pure Y, 6 pure Gd, 5 pure Sm, 10 pure Nd, 4 pure Pr, 12 pure Ce, and 18 pure La.
Protein Differentiation: Emergence of Novel Proteins during Evolution
Authors: Schulz Georg E.
Published: December 2003

The almost limitless number of proteins can be reduced to approximately 200 basic structures, i.e. geometries of polypeptide chains; these form, the set from which the tracable protein differentiation started. Protein differentiation begins with a gene duplication. One of the gene products is conserved since it must continue to fulfill the original function. The other gene product is conserved as soon as it has taken over a new function. Comparing amino acid sequences of equivalent proteins in two species yields the evolutionary distance between these species, which allows dating of their common ancestor (“molecular palaeontology”). These comparisons are now applied to the geometries of nonequivalent proteins, elucidating the pathways of protein differentiation.
Alkylsulfamoyl Chlorides as Key Units in the Synthesis of Novel Biologically Active Compounds for Crop Protection
Authors: Hamprecht Gerhard , König Karl‐Heinz , Stubenrauch Gerd
Published: December 2003

Due to their bifunctional character, alkylsulfamoyl chlorides are versatile units for the synthesis of heterocycles, polar sulfamates, and sulfonamides. In the last decade, synthetic methods of general preparative use have been developed, by means of which amine hydrochlorides, isocyanates, aziridines or tertiary alcohols can be reacted with suitable sulfuric acid derivatives to give novel, variously substituted alkylsulfamoyl chlorides. These compounds can subsequently be converted either to previously unobtainable N‐alkoxyalkyl‐N‐alkylsulfamoyl chlorides or to novel heterocycles of the type 1H‐2,1,3‐benzothiadiazin‐4‐one‐2,2‐dioxide, 2H‐1,2,6‐thiadia‐zin‐3‐one‐1,1‐dioxide and 2H‐1,2,4,6‐thiatriazin‐5‐one‐1,1‐dioxide; these compounds are examples of interesting models which illustrate the relation between the structure and the action of the compound, and in some cases lead to highly selective, ecologically unobjectionable herbicides. On the other hand, the alkylsulfamoyl chlorides themselves can be N‐acylated to give further 3‐ to 5‐atom bifunctional synthesis units, with which novel heterocyclic syntheses can be carried out. Further uses of the alkylsulfamoyl chlorides include the preparation of biologically active sulfamates, and cycloaddition reactions of N‐sulfonylamines prepared in situ.
Chloranil as a Catalyst for the Electrochemical Oxidation of NADH to NAD+
Authors: Huck Horst , Schmidt Hanns‐Ludwig
Published: December 2003

The development of enzyme electrodes for the determination or conversion of substrate NAD+‐dependent dehydrogenases requires that NADH can undergo direct electrochemical oxidation. A graphite electrode doped with chloranil is very well suited for this purpose—as is shown by cyclic voltammetry and coulometry.
The Transition Metal‐Nitrogen Multiple Bond
Authors: Dehnicke Kurt , Strähle Joachim
Published: December 2003

Numerous nitrido complexes of transition metals show very short metal‐nitrogen bond lengths, suggesting MN‐triple bonds. At present, compounds of this type are being intensively investigated. In particular the molybdenum complexes are considered as model substances for the study of at least an intermediate step of N2‐assimilation. This article contains a review of the structure and bonding, as well as syntheses and reactions of these complexes.
The Unusual Stereochemistry of the Cycloaddition of Vinyl Ethers with Sulfonyl Isothiocyanates
Authors: Schaumann Ernst , Bäuch Hans‐Günther , Adiwidjaja Gunadi
Published: December 2003

For corrigendum see DOI:10.1002/anie.198107021
RuCo2(CO)11 and Ru2Co2(CO)13, Two New “Pure” Carbonylmetal Clusters
Authors: Roland Eckehart , Vahrenkamp Heinrich
Published: December 2003

The air‐stable carbonyl‐ruthenium‐cobalt compound Ru, Co2(CO)13, prepared from the readily accessible, likewise novel cluster RuCo2(CO)11, contains a distorted Ru2Co2 tetrahedron with unsymmetrically distributed CO ligands. The polyhedron formed by the O atoms of the CO groups is the [13]‐polyhe‐dron of lowest energy. This is a further example illustrating that the structure of polynuclear carbonyl complexes depends on the spatial distribution of the ligands rather than on the localization of the bond relationships.
Phospha‐alkenes and Phospha‐alkynes, Genesis and Properties of the (p‐p)π‐Multiple Bond
Authors: Appel Rolf , Knoll Fritz , Ruppert Ingo
Published: December 2003

Just as the octet rule had prevented the discovery of the inert‐gas compounds, the systematic search for phosphorus‐carbon‐ and phosphorus‐nitrogen‐compounds having (p‐p)π‐multiple bonds was hindered by the double bond rule. The first successful synthesis of mesomeric‐stabilized phosphorus‐carbon compounds with coordination number 2, seventeen years ago, was followed nine years later by the preparation of the imino‐phosphanes whose intensive investigation has continued to the present day. A dramatic development has now begun in the phospha‐alkene and ‐alkyne fields, and a large variety of preparative methods have been found. Several compounds of this type are amazingly stable, however they do not participate in typical ylide reactions such as the Wittig reaction. In contrast, the PC double bond is more comparable to that of olefins, which has been confirmed by the occurrence of E,Z‐isomers and pericyclic reactions of phospha‐l,5‐hexadienes.
Crystallochemical Correlate to the Anomaly of Hydrofluoric Acid
Authors: Mootz Dietrich
Published: December 2003

Why does dilute hydrofluoric acid–in contrast to the other hydrohalic acids–exhibit low acid strength? A recent explanation is based on the particularly strong H‐bonds, indicated by IR spectroscopy, in the ion‐pair H3O+ · F−. This explanation now correlates results from X‐ray structure analyses: the compounds H2O · HF, H2O · 2HF, and H2O · 4HF, which melt between −36 and −100°C, are oxonium salts with very strong H‐bridges.
Triethanolamine: Dimerization via a Ring of Six Hydrogen Bonds
Authors: Brodalla Dieter , Mootz Dietrich
Published: December 2003

A particular type of dimerization was found in the title compound N(CH2CH2OH)3. The six hydroxy groups form a ring of six hydrogen bonds, producing a cage‐compound. In the crystal, the dimeric units are arranged according to the principle of cubic close packing.
α,ω‐Diisocyanatocarbodiimides, ‐Polycarbodiimides, and Their Derivatives
Authors: Wagner Kuno , Findeisen Kurt , Schäfer Walter , Dietrich Werner
Published: December 2003

Research in the field of low‐molecular weight, oligomeric and polymeric α,ω‐diisocyanatocarbodiimides and ‐polycarbodiimides has been fruitful, not only in connection with these compounds themselves, but also—as so often happens in chemistry—with quite different problems. Novel synthetic methods, discoveries concerning the properties of low‐molecular weight carbodiimides and phosphane imide derivatives, as well as results on the fragmentation reactions of four‐membered heterocyclic compounds containing oxygen, phosphorus, and nitrogen, and a better understanding of the diisocyanate polyaddition process are among the many by‐products of this research. The “high‐ and low‐temperature formation” of polycarbodiimides and the homogeneous and heterogeneous catalysis of this process are described, and the fundamental importance of four‐membered ring fragmentation mechanisms resulting in the formation of phosphane imide derivatives is outlined. Interesting building blocks for the diisocyanate polyaddition and polycondensation processes can be synthesized by many derivatization reactions of oligomeric and high‐molecular weight polycarbodiimides and polyuretonimines. The in situ production of polycarbodiimides via matrix reactions in flexible polyurethane foams leads to a cellular arrangement of the material due to the pronounced symmetrical growth processes. Combination‐foams with increased carbonation tendencies are formed in this way. Attention is drawn to several industrial applications of α,ω‐diisocyanatopolycarbodiimides, of high‐molecular weight cross‐linked polyuretonimines, and of polycarbodiimide foams.
Dodecamethyl‐1λ3,4λ3‐diphospha‐2,3,5,6,7,8‐hexastannabicyclo[2.2.2]octane, a Highly Symmetrical Cage Molecule
Authors: Dräger Martin , Mathiasch Bernd
Published: December 2003

White phosphorus reacts with 1,1,2,2‐tetramethyldislannane in the dark at 0°C to give the title compound, which according to an X‐ray structure analysis has D3‐symmetry. The bicyclo[2.2.2]octane framework with P in the bridgehead position is constructed from three Sn4P2 six‐membered rings which share three bonds with each other and adopt a distorted boat conformation.
Azaborolinyl‐Iron and ‐Cobalt Sandwich Complexes by Metal Atom Synthesis
Authors: Amirkhalili Saeid , Höhner Uwe , Schmid Günter
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 50. DOI:10.1002/anie.198200500
Activation of Silanes on a Ruthenium Cluster: Synthesis, Characterization, and Catalytic Action of the Cluster Anion [HRu3(CO)10(SiEt3)2]−
Authors: Süss‐Fink Georg
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 71. DOI:10.1002/anie.198200710
A Novel Type of Organic Conductor: One‐Dimensionally Polymerized Phthalocyaninatoiron(II)
Authors: Schneider Otto , Hanack Michael
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 41. DOI:10.1002/anie.198200410
The Norbornyl Cation: Prototype of a 1,3‐Bridged Carbocation
Authors: Grob Cyril A.
Published: December 2003

The protracted discussion of whether 2‐norbornyl cations are bridged or unbridged, i.e. nonclassical or classical, has lost most of its meaning, because these terms apply to the extremes of a graded series of structures. This is shown by a study of the solvolysis of stereoisomeric 6‐substituted 2‐norbornyl toluenesulfonates. Norbornyl and other bicyclic cations, to which nucleophiles have limited access, are stabilized by bridging between the cationic center and a saturated carbon atom in the β‐position. Bridging is reduced by electron‐attracting substituents and by bridging.
Umpolung of Carbonyl Reactivity via Acetoxyalkyl Radicals
Authors: Giese Bernd , Erfort Ulrich
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 250. DOI:10.1002/anie.198202500
Novel Chlorooxoaluminates
Authors: Thewalt Ulf , Stollmaier Friederike
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 209. DOI:10.1002/anie.198202090
Manganese Complexes with “End‐On” and Spirocyclic Bonded σ3,λ5‐Phosphazene Ligands
Authors: Scherer Otto J. , Kerth Jürgen , Balbach Barbara K. , Ziegler Manfred L.
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 169. DOI:10.1002/anie.198201690
Non‐Planar Structures of Allyl‐ and Pentadienylmetal Compounds: Pleating to Achieve a Better Charge Distribution?
Authors: Schlosser Manfred , Stähle Manfred
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 198. DOI:10.1002/anie.198201980
Selective Inclusion of Uncharged Guest Molecules by Neutral Hosts with Fence‐Shaped Side Arms
Authors: Vögtle Fritz , Müller Walter M.
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 185. DOI:10.1002/anie.198201850
Advances in Selective Chemical Syntheses of Complex Oligosaccharides
Authors: Paulsen Hans
Published: December 2003

A wide variety of complex oligosaccharides has now been made accessible as a result of methodological improvements in the sphere of chemical synthesis, which can be used for the study of conformations and interactions with protein‐receptor molecules. Such work is of particular importance because the oligosaccharide chains of glycoproteins and glycolipids anchored to the plasma membrane are important in cell‐cell interactions and are receptors for enzymes, hormones, proteins, and viruses; furthermore, they determine the antigen properties of cells. The methods of synthesis available for the production of selective linkages in oligosaccharides are dealt with, particular attention being paid to conversion of saccharides into oligosaccharides, which are important from the biological point of view.
Liquid Structure and Thermodynamics of Alkane Mixtures
Authors: Heintz Andreas , Lichtenthaler Rüdiger N.
Published: December 2003

Spectroscopic investigations and light scattering experiments with saturated, liquid hydrocarbons and their mixtures indicate a specific and distinct influence of the constitution, conformation, and flexibility of the molecule on the structure and macroscopic behavior of such liquids. Orientational order present in pure liquidn‐alkanes, for example, characteristically affects the thermodynamic mixing properties, such as the enthalpy of mixing ΔHMand the entropy of mixing ΔSM, when these liquids are mixed with each other, or with other liquids. Nowadays it is possible to determine thermodynamic mixing properties experimentally with such precision that systematic investigations of these properties allow the behavior of liquids to be studied qualitatively and–with molecular theories of liquids–to some extent also quantitatively. The latest results in this respect, exemplified by mixtures of alkanes, are discussed. These results not only demonstrate the progress made in understanding the relations between molecular (microscopic) and macroscopic properties, but are also of importance for industrial applications (e.g.separation processes) in which mixtures of hydrocarbons are involved.
[Fe6S9(SCH2C6H5)2]4−: A Hexanuclear Iron‐Sulfur Cluster Anion Containing the Square‐Pyramidal [(μ4‐S)Fe4] Unit
Authors: Henkel Gerald , Strasdeit Henry , Krebs Bernt
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 489. DOI:10.1002/anie.198204890
Arene‐Metal Clusters: Metal Atom‐Bis(arene)metal Solution Phase Chemistry
Authors: Ozin Geoffrey A. , Andrews Mark P.
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 381. DOI:10.1002/anie.198203810
A New Route to Pyridine Derivatives: Reaction of N‐Methylene‐tert‐butylamine with Enamine
Authors: Komatsu Mistsuo , Ohgishi Hideo , Takamatsu Shigeki , Ohshiro Yoshiki , Agawa Toshio
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 483. DOI:10.1002/anie.198204830
Resolution of D‐ and L‐Amino Acids by HPLC using Copper Complexes of N,N‐Dialkyl‐α‐amino Acids as Novel Chiral Additives
Authors: Weinstein Shulamith
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 425. DOI:10.1002/anie.198204250
The Reactivity of Primary Free Radicals and Radical Ions, Mass Transfer, and Electrosorption—The Fundamental Factors for Selectivity in Electrochemical Syntheses of Organic Compounds
Authors: Wendt Hartmut
Published: December 2003

In many cases the electrolytic synthesis of organic compounds is rather unselective. This is because the primary radical ions and/or radicals are very often so reactive that they are able to react competitively with several of the different species present in the electrolyte. The aim is to increase the selectivity by rationally altering the process parameters; this demands a knowledge,inter alia, of electrosorption effects and of the relationships between mass transfer and chemical reaction, at or in front of the electrodes (in the so‐called reaction layer). Four examples will be used to illustrate this theme:

The anodic synthesis of triarylsulfonium salts,

The addition of anodically generated N3‐radicals to olefins, producing “monomeric” 1,2‐diazides and “dimeric” 1,4‐diazides,

The cathodic synthesis of optically active 1‐(2‐pyridyl)ethanol,

The synthesis of 1,2‐ and 1,4‐diol ethers by anodic oxidation of vinyl compounds in alcoholic solutions.
A Simple, Highly Variable Route to (1,3‐Diynyl)amines
Authors: Himbert Gerhard , Feustel Michael
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 722. DOI:10.1002/anie.198207220
Novel Pseudooxocarbon Dianions of the C4 Series
Authors: Seitz Gunther , Sutrisno Rudianto , Gerecht Bernd , Offermann Guido , Schmidt Roland , Massa Werner
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 582. DOI:10.1002/anie.198205820
Synthesis and Properties of N‐[1‐(Arylcarbonyloxy)alkyl]pyridinium Salts
Authors: Anders Ernst , Gassner Thomas
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 675. DOI:10.1002/anie.198206750
Synthesis of 2‐Vinylphosphiranes
Authors: Richter Wolf Jürgen
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 739. DOI:10.1002/anie.198207390
Hydroxylation of Acyclic Alkanes by Oxygen Atoms O(3P)–Comparison of Ozone and O(3P) Oxidations of Alkanes
Authors: Zadok Elazar , Mazur Yehuda
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 606. DOI:10.1002/anie.198206060
Synthesis of Macromolecular Isocyanides with General Solvent Compatibility–Novel Polymer Supports for Solid‐Phase Syntheses
Authors: Arshady Reza , Ugi Ivar
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 761. DOI:10.1002/anie.198207610
Cu‐H2 Photochemistry in the Matrix; ESR, FTIR, UV/VIS Spectroscopic and Kinetic Studies
Authors: Ozin Geoffrey A. , Mitchell Steven A. , Prieto Jamie García
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 785. DOI:10.1002/anie.198207850
A Ternary Clathrate from Cryptand, Hydroquinone and Water—Selective Formation and X‐Ray Structural Analysis
Authors: Vögtle Fritz , Puff Heinrich , Friedrichs Edmund , Müller Walter M.
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 986. DOI:10.1002/anie.198209860
Polarity of Organic Glasses
Authors: Langhals Heinz
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 1138. DOI:10.1002/anie.198211380
Two Mild, Regioselective Methods of Degrading Biliprotein Chromophores
Authors: Kufer Werner , Krauss Corinna , Scheer Hugo
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 1050. DOI:10.1002/anie.198210500
The Resist Technique—A Chemical Contribution to Electronics
Authors: Steppan Hartmut , Buhr Gerhard , Vollmann Hansjörg
Published: December 2003

Besides its technical meaning, the word “electronics” signifies another industrial revolution. The driving force behind this development is the very rapid progress in the field of integrated semiconductor circuits. An ever‐increasing number of structures of ever‐decreasing size must be accommodated on the same surface of the semiconductor crystal. This trend towards miniaturization embraces not only the integrated circuit but also its mounting panel, the printed circuit board; integrated circuits with 65 536 storage spaces, i.e. more than 100 000 individual functions, on a semiconductor die of less than 1 cm2 are already standard today in industry. This micro‐world, the potential of which can hardly be fully appreciated even today, has a direct appeal to all those of scientific inclination. However, the role of chemistry in the creation of this world becomes clear only on closer examination of the manufacturing processes: no mechanical tool is fine enough and no machine is sufficiently precise and rapid to work out complicated structures in the micron range with the required perfection. Chemistry first made possible the mass production of electronic components and consequently their widespread use today, and it is chemistry which will also play a decisive role in the future. Whether in the field of photoresists for the production of printed circuit boards with conductor widths of less than 100 μm, or in overcoming the 1 μm barrier in the manufacture of semiconductors using electron beam‐ and X‐ray‐resists, photochemistry, radiation chemistry, and polymer chemistry will have to develop new manufacturing processes and provide industrially utilizable materials.
2‐Cyano‐3‐ethoxyacrylamides—Selective Synthons for the Synthesis of Heterocycles
Authors: Kampe Klaus‐Dieter
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 1213. DOI:10.1002/anie.198212130
Redox Reactions of a Ferrio‐arsane and ‐stibane with Chlorophosphanes: Synthesis of a Diferrioarsonium Chloride and a Stiborane with Asymmetric Iron Atoms[1]
Authors: Malisch Wolfgang , Kaul Hans‐Achim , Gross Elisabeth , Thewalt Ulf
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 1281. DOI:10.1002/anie.198212810
Support Effects on the Growth, Stabilization, and Agglomeration of Low Nuclearity Transition Metal Clusters Synthesized from Metal Atoms Vaporized into Liquid Aryl‐Substituted Polymers
Authors: Ozin Geoffrey A. , Andrews Mark P.
Published: December 2003

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 1255. DOI:10.1002/anie.198212550