bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photochemie substituierter Cycloheptatriene. III. Sigmatrope Wasserstoffverschiebung an Arylcycloheptatrienen
Authors: Abraham W. , Buck K. , Csongár Ch. , Henke E. , Kreysig D. 
Published: December 2004

Photochemistry of Substituted Cycloheptatrienes. III. Sigmatropic Hydrogen Shift in Arene CycloheptatrienesThe monochromatic photoexcitation of substituted phenylcycloheptatrienes 1–8 exclusively gives rise to 1, 7‐hydrogen shift. The sequences of photoreactions of the isomeric compounds are discussed. The qualities and quantities of the hydrogen shifts of dimethylamino‐phenyl‐ycloheptatrienes 4–7 depend on the wavelengths of photoexcitations.
Synthese von 3 verkürzten, mehrfach durch Ala substituierten Analogen der Insulin‐B‐Kette in geschützter Form
Authors: Losse Günter , Stange Hans 
Published: December 2004

Synthesis of 3 Shortened, Repeatedly by Ala Substituted Analogues of the Insulin B Chain in Protected FormStarting from the previously described fragments of the insulin B chain with native or partielly modified amino acid sequence, the 3 terminal shortened, additionally in several positions by Ala respectively in position 6 by Val substituted analogues B1‐27(Ala9, Ala10, Ala27), B4‐27‐(Ala4, Ala9, Ala10, Ala27) (1) and B4‐27(Ala4, Val6, Ala9, Ala10, Ala27) were prepared in protected form.
Zur Konstitution der Farbform der photochromen ortho‐Nitrobenzylverbindungen
Authors: Klemm E. , Klemm D. 
Published: December 2004

Constitution of the Coloured Form of Photochromic o‐NitrobenzylpyridinesThe reversibly highly coloured photochromic forms of dinitrobenzyl pyridines and tetranitro diphenylmethanes have structure of polymethines as evidenced by u.v.‐vis, i.r. and 1H‐n.m.r. spectra. There exists an analogy to the polymethines formed from 1‐methyl‐2‐(2′,4′‐dinitrobenzyl)‐pyridinium iodid and tetranitrodiphenylmethane and potassium hydroxide. The structure of the coloured form of the dinitrobenzylpyridines and tetranitrodiphenylmethanes are in agreement with their photochromic properties, especially with the u.v.‐vis‐absorption, the photochromism in substance and the influence of substituents on the photochromism.
Kurzzeitspektroskopische Untersuchungen an photochromen N‐substituierten Dinitrobenzylpyridinen
Authors: Klemm D. , Klemm E. , Graness A. , Kleinschmidt J. 
Published: December 2004

Short‐Time Spectroscopic Investigations of Photochromic N‐Substituted DinitrobenzylpyridinesBy means of nanosecond laser absorption spectroscopy of N‐substituted photochromic dinitrobenzylpyridines is shown that in polar solvents the long wave absorbing polymethin coloured form forms independently on the electronic properties of the substituents at the pyridine nitrogen. The polymethin is formed either directly or via the nitronic acid immediately after irradiation by the laser impulse (20 ns). In nonpolar solvents, on the other hand, the polymethin is only produced if the substituent (e.g. in N‐oxide 6) is able to bind the hydrogen splitted from the methylen group by photoreaction. If this is impossible (e.g. N‐Methyl‐compound 5) only absorption of nitronic acid occur.
Modellrechnungen zum Gegenioneneinfluß auf die kationische Polymerisation; Geometrieoptimierung und Verhalten gemischter Halogenoantimonate SbClnBr
Authors: Hallpap Peter , Spange Stefan , Heublein Günther , Zwanzinger Heinz , Reinhold Joachim 
Published: December 2004

Model Calculations on the Counterion Effect in the Cationic Polymerization; Geometry Optimization and Behaviour of the Mixed Halogenoantimonates SbClnBr.The CNDO/2 method including geometry optimization with respect to the energy has been applied to calculate the structure and the electronic properties of the complex anions SbClnBr. Independently on the composition of the anions the bond lengths Sb‐X (X = Cl, Br) remain those of the pure antimonates.The HOMOs are delocalized over the ligand sphere. They mainly contain components of Br and are lifted by increasing Br amount. The LUMOs have central atom character and are lowered by Br. Charge distribution and Wiberg bond indices indicate extra easy cleavage of the Sb‐Br bond if Cl holds a trans position to Br. The computed data agree with spectral properties, the acceptor behaviour and the decay trend of the antimonates SbClnBr.
New possibilities of applying of 1,1,1‐trichloro‐2,2‐bis‐(4‐chlorophenyl)ethane for the synthesis of self‐extinguishing and thermo‐resistant polyurethane or polyurea resins
Authors: Lesiak T. , Nowakowski J. 
Published: December 2004

Neue Möglichkeiten zur Verwendung von 1,1,1‐Trichlor‐2,2‐bis(4‐chlorophenyl)ethan für die Darstellung von selbstlöschenden und wärmebeständigen Polyurethan‐ und PolyharnstoffharzenEs werden Reaktionen zur Darstellung von 1,1,1‐Trichlor‐2,2‐bis(4‐chlor‐3‐aminophenyl)ethan, 1,1‐Dichlor‐2,2‐bis(4‐chlor‐3‐isocyanatophenyl)ethylen und 1,1,1‐Trichlor‐2,2‐bis(4‐chlor‐3,5‐diaminophenyl)ethan aus 1,1,1‐Trichlor‐2,2‐bis(4‐chlorphenyl)ethan beschrieben. Die Polyadditionsprodukte der Diisocyanate mit Diolen und Diaminen werden durch Derivatographie charakterisiert.
Spectroscopy and photochemistry of indigoid compounds. VI. Direct Trans → cis Photoisomerization of Indigoid Dyes
Authors: Haucke G. , Paetzold R. 
Published: December 2004

Spektroskopie und Photochemie indigoider Verbindungen. VI. Direkte trans → cis Photoisomerisierung indigoider FarbstoffeWir haben die Fluoreszenz und die photochemische trans → cis Isomerisierung einiger indigoider Farbstoffe in flüssigen Lösungen bei 300 K und festen Gläsern bei 77 K, die Temperaturabhängigkeit der Fluoreszenzquantenausbeute und die Löschung der trans → cis Isomerisierung durch Elektronendonatoren in Benzen und Iodbenzen und durch O2 in Benzen untersucht. Diese und andere Ergebnisse werden vorgestellt und diskutiert. Es wird angenommen, daß die direkte trans → cis Photoisomerisierung — zumindest im ersten Schritt — über einen Singulett‐Zustand verläuft.
Aluminiumalkyle mit Heteroatomen. X. Elektronenstoßinduzierte Fragmentierung von Trimethylsilylalkanonen
Authors: Sonnek G. , Baumgarten K.‐G. , Habisch D. 
Published: December 2004

Aluminium Alkyls with Heteroatoms. X. Electron Impact Fragmentation of TrimethylsilylalkanonesIt has been shown that the fragmentation of trimethylsilyl alkanones on electron impact proceeds with a uniform mechanism which differs from that of silicon‐free ketones by the fact, that no α cleavage is observed.It consists of a McLafferty rearrangement at the silicon‐free alkyl group, followed by a McLafferty‐type cleavage involving migration of the silyl group to yield the radical ion of the respective trimethylsilyl enolether.
Computeranalyse chemischer Reaktionsgleichungen mit Stöchiometriekorrektur
Authors: Weise Alfons 
Published: December 2004

Computerized Analysis of Chemical Reaction Equations with Correction of StoichiometryA computer programme (SYNKL, synthonclassifier) was developed, which recognizes and separates synthon equations from reaction equations. The algorithm of the programme is based on an extensive silimarity proof and overlay of the most similar partial structures to encircel the synthon substructures. The programme is able to discern synthon substructures from nonstoichiometric appendants and to correct the stoichiometric differences in many cases.
Zur Reaktion von Cyanodithioformiaten mit primären Aminen
Authors: Kibbel H. U. , Kücken M. , Peters E. , Weber H. 
Published: December 2004

Reactions of Cyanodithioformates with Primary AminesN‐Alkyldithiooxamides 3 and N,N ‐dialkyldithiooxamides 4 were synthesized in good yields by reaction of cyanodithioformates 1 with primary aliphatic amines. N‐Alkylcyanothioformamides 2, intermediates in these reactions were obtained in very low yields only. The reaction of 1 and diaminoethane or 1.3‐diaminopropane afforded imidazolidine‐2‐thione 5a respectively perhydropyrimidine‐2‐thione 5b. The reaction of 1 with 1‐chloro‐2‐aminoethane did gave 2‐thiocarbamoylthiazoline 7.
1,2,3‐Triazabutadiene. XII. Abhängigkeit der 13C‐15N‐Kopplungskonstanten von der Z/E‐Isomerie der 1‐Phenyl‐3‐[3‐ethylbenzthiazolinyliden‐(2)]‐triazene und 1‐Phenyl‐1‐ethyl‐3‐[3‐ethylbenzthiazolinyliden‐(2)]‐triazenium‐ tetrafluoroborate
Authors: Fanghänel E. , Simova S. , Radeglia R. 
Published: December 2004

1,2,3‐Triazabutadienes. XII. Dependence of the 13C‐ 15N Coupling Constants on the Z/E‐Isomerism of the 1‐Phenyl‐3‐[3‐ethylbenzthiazolinyden‐(2)]‐triazenes and 1‐Phenyl‐1‐ethyl‐3‐[3‐ethylbenzthiazolinyliden‐(2)]‐triazenium‐tetrafluoroborates13C‐ and 15N spectra have been measured for the 15N‐labelled triazene 1 and triazenium salt 2. The 13C‐15N coupling constants are discussed in the light of the Z/E‐isomerism of the compounds. A significant nitrogen lone pair effect of the Z/E isomers on the magnitude of the coupling constant 1J(15N113C1·) was observed and discussed.
Derivate des Phosphorsäure‐o‐phenylenesters. 23. Verhalten von Brenzkatechylphosphortrichlorid gegenüber O‐funktionellen P(III)‐Verbindungen
Authors: Gloede J. 
Published: December 2004

Derivatives of o‐Phenylene Phosphates. 23. Behaviour of Catechyl Phosphorus Trichloride towards Phosphites and PhosphinitesCatechyl phosphorus trichloride (1) reacts with triethyl phosphite (4), triphenyl phosphite (9), and the o‐phenylene phosphites (16a–d) by ligand exchange and with isopropyl diphenyl‐phosphinite (21) by ligand exchange and oxidation.
Über die SiN‐Bindung. XXXIX [1]. Kinetische Untersuchungen zur spontanen Hydrolyse, Alkoholyse und Phenolyse von Aminosilanen
Authors: Kaufmann K.‐D. , Gisbier D. , Grosse‐Ruyken H. , Rühlmann K. 
Published: December 2004

Silicon‐Nitrogen Bonds. XXXIX. Kinetic Studies on the Spontaneous Hydrolysis, Alcoholysis, and Phenolysis of SilylaminesIt could be shown by polarimetric and DC‐metric methods that hydrolysis, alcoholysis, and phenolysis of silylamines are of second order and lead to equilibria.The rate of equilibrium establishment is determined by the position of a preceding protonation equilibrium and by steric effects. The position of the equilibria depends on inductive and steric effects. The enthalpy of activation for the ethanolysis of Me3SiNHPh was determined to 27,2 kJ/mol and the entropy of activation to –231 J/K · mol. The mechanism of the reactions is given.
Gibberellins. LXXXIII. Molecular and crystal structure of “Hydrogeno I”, a hydrogenolysis product of gibberellin A3 methyl ester
Authors: Kutschabsky L. , Reck G. , Adam G. , Argay G. , Czugler M. 
Published: December 2004

Gibberellins. LXXXIII. Molekül‐ und Kristallstruktur von „Hydrogeno I”︁, einem Hydrierprodukt von Gibberellin‐A3‐methylesterIm Zusammenhang mit stereochemischen Untersuchungen an Gibberellinverbindungen wurde die Molekül‐ und Kristallstruktur von „Hydrogeno I”︁ 2, einem Produkt der katalytischen Hydrierung von Gibberellin‐A3‐methylester, durch Röntgenstrukturanalyse bestimmt. Verbindung 2 kristallisiert in der orthorhombischen Raumgruppe P212121 mit den Gitterkonstanten a = 10,316, b = 17,214 und c = 10,341 Å. Die Verfeinerung erfolgte bis zu einem R‐Wert von 0,074.
α‐Substituierte Phosphonate. 37. α‐Pyrrolomethanphosphonsäurederivate und N‐Vinylpyrrole
Authors: Gross H. , Beisert S. , Costisella B. 
Published: December 2004

α‐Substituted Phosphonates. 37. Derivatives of α‐Pyrrolomethanephosphonic Acid and N‐VinylpyrrolesDiethyl α‐aminomethanephosphonate 5a and its α‐aryl derivatives 5b–d react with 2,5‐diethoxytetrahydrofuran 1 to give diethyl α‐pyrrolomethanephosphonate 9a and the α‐aryl derivatives 9b–d, respectively. The pyrrolo derivatives 9 can be converted into the lithium salts 15 and 16, respectively, which with carbonyl compounds undergo the HORNER reaction yielding E/Z‐mixtures of N‐vinylpyrroles 18. In certain cases the intermediate of the HORNER reaction, the β‐hydroxyphosphonate 17, can be isolated. The pyrrolo‐analogue of stilbene, 18a, is formed only as E‐isomer. On treating the lithium salts 15 and 16 with 9 or with alkyl halides α‐C‐alkylated pyrrolo‐phosphonates 22 and 23, respectively, are obtained.
N, N‐Dialkylamide der 2‐Hydroxy‐2‐phenyl‐cyclopropan‐1‐carbonsäure – photochemische Darstellung und Strukturuntersuchung
Authors: Henning H.‐G. , Berlinghoff R. , Mahlow A. , Köppel H. , Schleinitz K.‐D. 
Published: December 2004

N,N‐Dialkylamides of 2‐Hydroxy‐2‐phenyl‐cyclopropan‐1‐carboxylic Acid – Photochemical Synthesis and Determination of the StructureIrradiation of N,N‐dialkylamides of β‐benzoylpropionic acid 2a, b in ether by n,π*‐excitation leads to the corresponding amides of the hitherto unknown 2‐hydroxy‐2‐phenyl‐cyclo‐propancarboxylic acid 3a, b, 4a, b. The photocyclization yields diastereomeric mixtures E:Z = 2.5–3:1. The determination of the relative configurations is based on the different tendency of dimerization of the E and Z diastereomers.
Über die Autoxidation einiger asymmetrischer p‐Dialkylbenzene
Authors: Blau K. , Pritzkow W. 
Published: December 2004

The Autoxidation of Some Asymmetric p‐DialkylbenzenesThe autoxidation mixtures of p‐ethyltoluene, p‐isopropyltoluene, and p‐ethylcumene were reduced with lithium alanate and the alcohols formed analyzed gaschromatographically. From the results obtained the relative reaction rates of primary, secondary, and tertiary CH‐bonds with the chain‐propagating peroxy radicals were estimated to 1 : 7 : 15.
d‐NMR‐Untersuchungen der behinderten Rotation am NC(X)‐Bindungsfragment. XV. Beeinflussung der Rotationsbarriere im NR2C(X)R1‐Bindungsfragment durch elektronische und sterische Substituenteneffekte
Authors: Kleinpeter E. , Behrendt S. , Beyer L. , Dietzsch W. , Borsdorf R. 
Published: December 2004

d‐N.M.R. Investigations of the Restricted Rotation at the NC(X)‐Bonding Fragment. XV. Influence of the Rotational Barrier in the NR2C(X)–R1‐Bonding Fragment by Electronic and Steric Substituent Effects.The rotational barriers ΔG≠ of the restricted rotation about partial C,N‐double bonds are determined for 4 series of urea‐derivatives, and analogous compounds by complete lineshape analysis and approximation equations. Some general conclusions are drawn about the validity range of the approximations independence on the low temperature splitting Δν, the possible corrections within the margin of error and the internal temperature measurement. The dependence of the determined free enthalpies of activation about the effect of heteroatoms X, the NR2‐substituents and the electronic and steric influence of the substituents R1 are discussed.
Effektivität der photochemischen Co‐C‐Bindungsspaltung in σ‐Alkyl‐Co(III) (salen)‐ und ‐Co(III) (salphen)‐Komplexen
Authors: Roewer G. , Kempe G. , Kolle B. , Just R. 
Published: December 2004

Efficiency of the Photochemical Co‐C‐Bond Cleavage in σ‐Alkyl‐Co(III)(salen)‐and‐Co(III)(salphen)‐Complexes.The photodealkylation rate of RCoIII(chel) X complexes (R = methyl, ethyl; chel = salen, salphen; X = H2O, py, PPh3) depends on the nature of ligands and solvents as well as on the concentration of oxygen and scavengers for alkyl radicals. The rapid recombination of the fragments R. and Co(chel)X is responsible for the low quantum yields of the anaerobic dealkylation. The quantum yields may reflect the H‐donating ability of the solvents used. Lewis bases X in the trans position generally cause a decrease of quantum yields relative to the pentacoordinated species RCo (chel). The anaerobic photolysis can be accelerated by the addition of scavengers for alkyl radicals (e. g. Koelsch radical, nitrosodurene, styrene). The quantum yield also increases in the presence of oxygen, preventing the recombination of the fragments of the cobalt‐carbon bond scission by forming alkyl‐peroxocomplexes ROOCo(chel)X.α‐Hydroxyalkylradicals arising from the decomposition of the ROOCo(chel)X complexes via secondary reactions probably react with the starting σ‐alkyl complexes and cause the dependence of quantum yields on the light intensity.
Chemie angeregter Zustände. XII. MO‐Berechnungen zum Elektronenspektrum des Pyridin‐N‐Oxid – Eine kritische Analyse
Authors: Scholz Manfred 
Published: December 2004

Chemistry of Excited States. XII. MO Calculation of the Electronic Spectrum of Pyridin‐N‐Oxid – A Critical AnalysisMO calculations (ab initio, HAM/3, INDO‐, CNDO‐ and PPP‐Typ including CI) are reported with regard to the interpretation of the u.v. spectrum of the title compound.The different semiempirical methods show similar results concerning the energies of the ππ* transitions.For the absorption at 5.72 eV, differences are found between the ab initio and all semiempirical calculations concerning the interpretation of this transition (A1 or B2).None of the methods yields results exactly enough to predict the dipole forbidden (A2) and allowed (B1) nπ* transition energies.
Substituenteneinfluß auf die T1‐ Energie und auf S1‐T1‐Energiegap bei ω‐Phosphor‐substituierten trans‐Styrenen
Authors: Gloyna D. , Berndt K.‐G. , Wegener W. 
Published: December 2004

Influence of Substituents on the T1 Energy and the S1‐T1 Energy Gap in ω‐Phosphorus Substituted trans‐StyrenesThe fluorescence and the phosphorescence of 4‐substituted ω‐diphenylphosphinyl trans‐styrenes 1 and analogous diphenylthiophosphinyl trans‐styrenes 2 at 77 K indicate together with some oxygen‐induced singlet‐triplet absorption spectra a bathochromic shift of the lowest singlet (S1) and the lowest triplet level (T1) relatively to the S1 and T1 level of the unsubstituted compounds 1a and 2a, respectively. Donor substituents X in 4‐position give rise to a shift of S1, which is in the most cases much greater than that of T1, so that the S1–T1 energy gap decreases. P(Y)R1R2 groups (Y = O, S) in ω‐position of 1 and 2 effect a small bathochromic shift of the T1 energy level only (130–900 cm−1 relatively to unsubstituted styrene). S1 is shifted 860–2080 cm−1 to lower energies, however.
Reactions with 3,1‐Benzoxazin‐4‐ones. II. Behaviour of 6,8‐dibromo‐2‐methyl‐3,1‐benzoxazin‐4‐one towards Friedel‐Craft and Grignard reactions
Authors: Ismail M. Fekry , Shams Nabil A. , Salem M. R. , Emara S. A. 
Published: December 2004

Reaktionen mit 3,1‐Benzoxazin‐4‐onen. II. Verhalten von 6,8‐Dibrom‐2‐methyl‐3,1‐benzoxazin‐4‐on in Friedel‐Craft's und Grignard‐Reaktionen6,8‐Dibrom‐2‐methyl‐benzoxazin‐4‐on (1) reagiert mit verschiedenen aromatischen Kohlenwasserstoffen unter Friedel‐Crafts‐Bedingungen zu O‐Acetylaminobenzophenon‐Derivaten 2.Die Reaktion von 1 mit Organomagnesiumhalogeniden führt durch Addition von einem Mol des Reagenzes zu den Ketonen 2 und 5 bzw. durch Addition von zwei Mol zu den Carbinolen 4. Diese unterliegen in einigen Fällen einer gleichzeitigen Dehydratisierung, die zu den Benzoxazin‐Derivaten 6 führt.
Konfigurative Zuordnung über sterisch definierte Epoxidringe. VIII. Glycidonitrile. I. Synthese von 4‐Aryl‐1‐oxaspiro(2,5)octan‐2‐nitrilen und 4‐Aryl‐1‐oxaspiro(2,5)octan‐2‐carbonsäureestern
Authors: Fischer F. , Palitzsch P. 
Published: December 2004

Determination of Configurations by the Aid of Sterically Corresponding Epoxides. VIII. Glycidic Nitriles. I. Synthesis of 4‐Aryl‐1‐oxaspiro(2,5)octane‐2‐nitriles and 4‐Aryl‐1‐oxaspiro(2,5)octane‐2‐carboxylic Acid Methyl EstersThe condensation of 2‐aryl‐cyclohexan‐1‐ones (1–5) with ClCH2CN or ClCH2CO2CH3 at 80°C in the presence of NaH and in dimethoxyethane yields the corresponding glycidic nitriles and the glycidic esters, respectively. The configuration and the preferred conformation of the two isomeric 1‐oxaspiro‐[2,5]octane derivatives (12 A and 12 B) formed have been determined by 1H‐n.m.r. spectroscopy. Some earlier results from BOEKELHEIDE and SCHILLING and from SCHWARTZMAN and WOODS have been corrected.
Zum Konformationsverhalten substituierter Benzoesäurephenylester ‐ Molekül‐ und Kristallstruktur der nematogenen Verbindung 4‐n‐Pentoxybenzoesäure‐4′‐(ß‐cyanethyl)‐phenylester
Authors: Baumeister U. , Brandt W. , Hartung H. , Jaskólski M. 
Published: December 2004

On the Conformational Behaviour of Substituted Phenylbenzoates ‐ Molecular and Crystal Structure of the Nematogenic Compound 4′‐(ß‐Cyanoethyl)‐phenyl‐4‐n‐pentoxybenzoateThe title compound crystallizes in the monoclinic space group P21/n with a = 1567.6(2) pm, b = 915.5(1) pm, c = 1459.1(1) pm, β = 115.30(1)°, and four molecules per unit cell. The structure has been solved by direct methods and refined to R = 0.104. The molecules adopt a markedly stretched form and show a parallel arrangement of their long axes in the crystal lattice. The molecular and crystal structure is discussed in relation to the mesomorphic behaviour of the compound.A theoretical conformational analysis has been performed for the isolated phenylbenzoate molecule using the EPEN/2 method, its results are compared with the experimental torsion angles in a series of substituted phenylbenzoates.
Extraction of copper from acid sulphate solutions by 2‐hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐benzaldehyde,‐acetophenone and ‐benzophenone oximes
Authors: Szymanowski J. , Sobczyńska A. , Stepniak‐Biniakiewicz D. , Borowiak‐Resterna A. 
Published: December 2004

Abstract2‐Hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐benzaldehyde E‐oxime (1), 2‐hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐acetophenone E‐oxime (2) and 2‐hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐benzophenone E‐oxime (3) were synthesized and used for copper extraction from acidic sulphate solutions. The dissociation constants of the phenolic group of the oximes and the stability constants for their complexes with copper were determined. An extraction model is discussed taking under consideration the association of the oxime and the solvation of the complex.It was found that 1 can extract copper more efficiently from acidic aqueous solutions and at a higher rate than 2 and 3. 1 is a stronger acid than 2 and 3. However, it is a weaker acid than the Z isomer of 3.The proposed model fits the experimental data well. When the oxime is used in excess, solvation of the copper complex seems probable.
Komplexkatalyse. XV. Kationische η3‐Allyl‐bis(triorganylphosphit)nickel(II)‐Komplexe als Katalysatoren für die stereoreguläre Butadienpolymerisation
Authors: Taube R. , Schmidt U. , Gehrke J.‐P , Anacker U. 
Published: December 2004

Complex Catalysis. XV. Cationic η3‐Allyl‐bis(triorganylphosphite)nickel(II) Complexes as Catalysts for the Stereoregular Butadiene PolymerisationSynthesis and catalytic properties of [C3H5NiL2]PF6 complexes 1a–f with L = tri‐ethyl‐, ‐isopropyl‐, ‐phenyl‐, ‐o‐tolyl‐, ‐thymyl‐ and o‐biphenylylphosphite are described. It is shown how electronic and steric effects of the phosphite ligands in these complexes control their catalytic activity and selectivity in 1,4‐polymerization of butadiene.
Ionisation und Dissoziation von Triphenylmethylhalogeniden in Methylenchlorid
Authors: Heublein Günther , Bauerfeind Dietmar 
Published: December 2004

Ionization and Dissociation of Triphenylmethyl Halides in MethylendichlorideThe Winstein scheme is valid for triphenylmethyl halides in methylendichloride. The equilibrium of ionization and dissociaton has been determined by investigation of the ratio between the sum of concentrations of ionic species and the covalent form. Tritylbromide in methylendichloride shows an exothermic ionization but endothermic dissociation. In the case of tritylchloride ionization and dissociation are nearly independent on the temperature.
4′‐tert‐Alkylbenzo[15]krone‐5‐ether. Synthesen und Kaliumthiocyanat‐Komplexe
Authors: Beger J. , Meerbote M. 
Published: December 2004

4′‐tert‐Alkylbenzo[15]Crown‐5‐Ether. Syntheses and Complexes with Potassium ThiocyanateThe title compounds 4 are synthesized either by alkylation of pyrocatechole 1 in 4‐position and followed by ring closure with 1,11‐dichloro‐3,6,9‐trioxaundecane or by alkylation of benzo[15]‐crown‐5 3. In most cases the way first mentioned gives better results. Analytical samples of the alkylated benzo[15]crown‐5 ethers 4 are obtained through complexing with KSCN.Physical data and 1H‐n.m.r.‐spectra of 5 new pyrocatecholes 2 and 6 new benzo[15]crown‐5 ethers 4 are given.