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  • Wiley  (115)
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  • 1
    Electronic Resource
    Electronic Resource
    Rapid kinetic studies on the conformation of single-stranded DNA (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2365-2379 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational states of single-stranded calf thymus DNA were probed using the tmeperature-jump kinetic technique. A rapid decrease in transmission at 260 nm followed by a broad relaxation spectrum was observed for single-stranded DNA at 0.15M KCI, pH, 6.5 at 25°. The relaxation spectrum could also be detected as a hydrogen ion release. Sonicated samples of 103,000 daltons showed identical relaxation kinetics as unsonicated samples. The relaxation kinetics were studied as a function of temperature, pH, and salt concentration and could be interpreted as representing the melting of short, isolated folded segments. The rapid process that could not be kinetically resolved is interpreted as single-strand unstacking. Upon the addition of excess MgCl2 at pH 7.0, a hydrogen ion release from single-stranded DNA was observed that was 3.5 times greater than that observed for a comparable sample of native DNA. Evidence is presented which indicates that charge-pairs exist in folded segments that are A-T rich. There was no kinetic evidence of structures in single-stranded DNA other than single-stranded stacking and short isolated folded regions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111115
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  • 2
    Electronic Resource
    Electronic Resource
    Equilibrium studies on neutral red-DNA bindingA preliminary account of this work was presented in September, 1974, at the 168th National ACS Meeting in Atlantic City, New Jersey. (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 825-837 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spectrophotometric binding studies were undertaken on the interaction of neutral red with native and heat-denatured, sonicated, calf thymus DNA in a 0.2M ionic strength buffer containing Tris-sodium acetate-potassium chloride at 25°C. The pKA of neutral red was found to be 6.81. At pH 5 the binding of protonated neutral red was complicated even at low concentration ratios of dye to DNA. In the pH range 7.5-8.5 the tight binding process could be studied and it was found that both protonated and free base species of neutral red significantly bind with DNA having association constants (in terms of polynucleotide phosphate) of 5.99 × 103 M-1 and 0.136 × 103 M-1, respectively, for native DNA and 7.48 × 103 M-1 and 0.938 × 103 M-1, respectively, for denatured DNA. The pKA value of the neutral red-DNA complexes were 8.46 for native DNA and 7.72 for denatured DNA. These results are discussed in terms of possible binding mechanisms.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140411
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  • 3
    Electronic Resource
    Electronic Resource
    Übergangsmetall-Carbin-Komplexe, XXXVI. Nucleophile Substitution an trans-Tetracarbonyl (organylcarbin)-(tetrafluoroborato)-Komplexen des Chroms und Wolframs mit Triphenylphosphin, Cyanid und Rhodanid (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 2765-2773 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Carbyne Complexes, XXXVI. Nucleophilic Substitution on trans-Tetracarbonyl(organylcarbyne)(tetrafluoroborato) Complexes of Chromium and Tungsten with Triphenylphosphine, Cyanide and ThiocyanatePentacarbonyl[methoxy(phenyl)carbene]- and -[methoxy(methyl)carbene]tungsten(0) (1a, b) react in boron trifluoride dimethyletherate in the presence of a large excess of BF3 to form trans- (BF4)(CO)4WCR complexes (2a, b). In these two tungsten complexes 2a, b as well as in the analogous chromium complex mer-(BF4)(CO)3[P(CH3)3]CrCCH3 (4) the BF4 ligand is displaced easily by nucleophilic reagents. With thiocyanate, cyanide, and triphenylphosphine the corresponding neutral trans-isothiocyanato (6a, b) and trans-cyano complexes (7) as well as the cationic trans-(organylcarbyne)(triphenylphosphine)metal complexes (3, 5) are obtained similarly at low temperatures.
    Notes: Pentacarbonyl[methoxy(phenyl)carben]- und -[methoxy(methyl)carben]wolfram(0) (1a, b) reagieren in Bortrifluorid-dimethyletherat in Gegenwart eines großen Überschusses an BF3 zu trans- (BF4) (CO)4WCR-Komplexen (2a, b). Der am Metallatom koordinierte BF4-Ligand in den beiden Wolframkomplexen 2a, b sowie bei dem analogen Chromkomplex mer-(BF4)(CO)3-[P(CH3)3]CrCCH3 (4) kann durch nucleophile Reagentien leicht verdrängt werden. So lassen sich mit Rhodanid und Cyanid sowie Triphenylphosphin bei tiefen Temperaturen die entsprechenden neutralen trans-Isothiocyanato- (6a, b) und trans-Cyano-Komplexe (7) sowie die kationischen trans-(Organylcarbin)triphenylphosphin)metall-Komplexe (3, 5) erhalten.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110804
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Kenntnis von funktionellen Si-Heterocyclen, VI. 1-Oxa-2.6-disila-cyclohexane (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 1047-1056 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Umsetzung von 1.3 -Bis-brommethyl-tetramethyl-disiloxan mit Cyanessigestern in Gegenwart tert. Amine wurde ein neuer Weg zu 1-Oxa-2.6-disilacyclohexanen erschlossen. Reaktionen in 4-Stellung verlaufen unter Erhaltung des Ringsystems, wobei Derivate mit verschiedenen Konformationen resultieren; die 1H-NMR-Spektren werden diskutiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970416
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  • 5
    Electronic Resource
    Electronic Resource
    Übergangsmetall-Carben-Komplexe, XCVIII. Pentacarbonyl(halogenwasserstoff)wolfram-Komplexe (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1651-1658 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Carbene Complexes, XCVIII. Pentacarbonyl(hydrogen halide)tungsten ComplexesAt low temperatures and in nonbasic solvents, pentacarbonyl(methoxyphenylcarbene)tungsten(0) (1) reacts with excess hydrogen halide HX (X = Cl, Br, I) by cleavage of the metal-carbene-C bond to form pentacarbonyl(hydrogen halide)tungsten complexes 2-5 The new compounds are strong acids; their constitution was clarified by i. r., 1H n. m. r., and 13C n. m. r. spectroscopic data.
    Notes: Pentacarbonyl(methoxyphenylcarben)wolfram(0) (1) reagiert in nichtbasischen Lösungsmitteln bei tiefen Temperaturen mit überschüssigem Halogenwasserstoff HX (X = Cl, Br, I) unter Spaltung der Metall-Carben-C-Bindung zu Pentacarbonyl(halogenwasserstoff)wolfram-Komplexen 2-5. Die neuen Verbindungen zeigen stark saure Eigenschaften; ihre Konstitutionsermittlung erfolgte anhand IR-, 1H-NMR- und 13C-NMR-spektroskopischer Befunde.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100509
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  • 6
    Electronic Resource
    Electronic Resource
    Regioselektive Lewis-Säure-bedingte α-sek-Alkylierung von Carbonylverbindungen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 322-335 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regioselective Lewis Acid-mediated α-sec-Alkylation of Carbonyl CompoundsCarbonyl compounds such as ketones, aldehydes, acyloins, or carboxylic esters can be alkylated at the α-position via the corresponding O-silylated forms using activated alkyl halides or acetates in the presence of Lewis acids. In case of unsymmetrically substituted ketones regiospecificity is observed. The method is mild and does not afford undesired poly-alkylated products.
    Notes: Carbonylverbindungen wie Ketone, Aldehyde, Acyloine oder Carbonsäureester lassen sich über die entsprechenden O-silylierten Formen an der α-Stellung mit aktivierten Alkylhalogeniden oder Acetaten in Gegenwart von Lewis-Säuren alkylieren. Im Fall von unsymmetrisch substituierten Ketonen wird strenge Regioselektivität beobachtet. Die Methode ist mild und liefert keine unerwünschten Polyalkylierungsprodukte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170123
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  • 7
    Electronic Resource
    Electronic Resource
    Darstellung und chemisches Verhalten von S-(Trifluormethyl)-S,N-dihalogensulfimiden, (Trifluormethylthio)-(thiosulfinyl)amin und Bis(trifluormethyldithio)schwefeldiimid (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3248-3257 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Chemical Properties of S-(Trifluoromethyl)-S,N-dihalosulfimides, (Trifluoromethylthio)(thiosulfinyl)amine, and Bis(trifluoromethyldithio)sulfur DiimideOxidative halogenation of CF3SN(SiMe3)2 with F2 or Cl2 leads to CF3S(X)=NX (X=F, Cl) (2a,b). During the chlorination process CF3S(Cl)=NSiMe3 (3a) was isolated and characterized as an intermediate. It reacts with CF3SCl to give CF3S(Cl)=NSCF3 (3b) which was also obtained from (CF3S)2NH and Cl2 at -60°C. Similarly, CF3S(F)=NSCF3 (3c) was synthesized from (CF3S)2NH and F2 or from CF3SF3 and CF3SNH2. 3a - c decompose already at temperatures 〈20°C to form (CF3SN)4 and Me3SiCl or CF3SX (X=F, Cl), respectively. In the presence of quinoline or acridine CF3SNH2 condenses with S2Cl2 to CF3SN=S=S (4a). Its constitution was ascertained by chemical reactions and an 1,3-dipolar cycloaddition to cyclopentadiene (→5a,b). Analogously, CF3SN=S=NSCF3 (4b) reacts with cyclopentadiene to give 5c. Ringopening takes place during the reaction of [S3N2Cl]+ Cl- (6) with Hg(SCF3)2 with formation of CF3SSN=S=NSSCF3 (7) which was also obtained from (CF3SS)2NH and (ClSN)3 in the presence of pyridine. Physical and spectroscopic data of the compounds are reported.
    Notes: Die oxidative Halogenierung von CF3SN(SiMe3)2 (1) mit F2 bzw. Cl2 führt zu CF3S(X)=NX (X=F, Cl) (2a,b). Bei der Chlorierung kann die Zwischenstufe CF3S(Cl)=NSiMe3 (3a) isoliert und charakterisiert werden. Sie reagiert mit CF3SCl zu CF3S(Cl)=NSCF3 (3b), das auch aus (CF3S)2NH und Cl2 bei -60°C zugänglich ist. Analog wird CF3S(F)=NSCF3 (3c) aus (CF3S)2NH und F2 bzw. aus CF3SF3 und CF3SNH2 synthetisiert. 3a - c zerfallen schon unterhalb 20°C zu (CF3SN)4 und Me3SiCl bzw. CF3SX (X=F, Cl). In Abwesenheit von Chinolin oder Acridin kondensiert CF3SNH2 mit S2Cl2 zu CF3SN=S=S (4a), dessen Konstitution durch Folgereaktionen und eine 1,3-dipolare Cylcoaddition an Cyclopentadien (→5a,b) nachgewiesen wurde. Analog setzt sich CF3SN=S=NSCF3 (4b) mit Cyclopentadien zu 5c um. Unter Ringöffnung reagiert [S3N2Cl]+ Cl- (6) mit Hg(SCF3)2 zu CF3SSN=S=NSSCF3 (7), das sich auch aus (CF3SS)2NH und (ClSN)3 in Anwesenheit von Pyridin bildet. Physikalische und spektroskopische Daten der Verbindungen werden angegeben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180824
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  • 8
    Electronic Resource
    Electronic Resource
    Addition von Silylenen an Iminoborane (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1073-1078 
    Details
    ISSN: 0009-2940
    Keywords: Iminoboranes ; Silylenes ; Azasilaboriridin ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of Silylenes to Iminoboranes[1]Photolytically generated silylenes SiMe2 and SiMes2 are treated with iminoboranes XB≡NtBu [X = tBu, Me3Si(tBu)N, iPr2N: 1a-c]. The products from SiMe2 and 1a are the four-and six-membered rings [-B(tBu)=N(tBu)-SiMe2-SiMe2-] (3a) and [-B(tBu)=N(tBu)—B(tBu)N(tBu)-SiMe2-SiMe2-] (4a), depending on the conditions of the photolysis. SiMe2 reacts with 1b to give the six-membered ring [-BX=N(tBu)-SiMe2-BX=N(tBu)-SiMe2-] (4b). From SiMes2 and 1a,c the three-membered rings [-BX=N(tBu)-SiMes2-] are formed (2a: space group Pbca; 2c: space group P1): SiMes2 reacts with 1b to yield the unexpected four-membered BNSiN ring [B(Mes)N(tBu)-Si(Mes)(SiMe3)-N(tBu)] (5: space group P1).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250514
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  • 9
    Electronic Resource
    Electronic Resource
    Regioselektivität und sterischer Verlauf der Lewis-Säure-induzierten Ringerweiterung von Cyclohexadien-Komplexen mit Kohlenmonoxid (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3473-3489 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regioselectivity and Steric Course of Lewis Acid Promoted Ring Enlargement of Cyclohexadiene Complexes with Carbon MonoxideTreating the tricarbonyliron complexes 5 and 7 of substituted cyclohexadienes with AlCl3 yields complexes 6, 8, and 9 of seven-membered ring ketones, containing carbon monoxide inserted into one of the double bonds with high regioselectivity depending on the substitution pattern. The mechanism of this ring enlargement is discussed, and an X-ray analysis of 8e is carried out.
    Notes: Durch Behandeln der Tricarbonyleisen-Komplexe 5 und 7 substituierter Cyclohexadiene mit AlCl3 entstehen die Komplexe 6, 8 und 9 von Siebenringketonen, in denen Kohlenmonoxid in Abhängigkeit vom Substitutionsmuster mit hoher Regioselektivität in eine der Doppelbindungen eingeschoben ist. Der Mechanismus dieser Ringerweiterung wird diskutiert, und von 8e wird eine Röntgenstrukturanalyse ausgeführt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841171216
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  • 10
    Electronic Resource
    Electronic Resource
    Reaktionen cyclischer Oxalylverbindungen, 35. Untersuchung von Reaktionsmechanismen durch Isotopenmarkierung, 11. Zur Umsetzung von 4-Benzoyl-5-phenylfuran-2,3-dion mit S-Heterocumulenen  -  Präparative und mechanistische Aspekte (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2061-2067 
    Details
    ISSN: 0009-2940
    Keywords: Furan-2,3-diones ; Pyrrol-2,3-diones ; Cumulenes, S-hetero ; Cycloaddition reactions ; 17O Labeling ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of Cyclic Oxalyl Compounds, 35[1].  -  Mechanistic Investigation Aided by Isotopic Labeling, 11[2].  -  On the Reaction of 4-Benzoyl-5-phenylfuran-2,3-dione with S-Heterocumulenes  -  Preparative and Mechanistic Aspects[3]The furan-2,3-dione 1 combines with N-sulfinylamines or sulfur diimides to afford the pyrrole-2,3-diones 2, while with N-tosylsulfinylamine the (α-iminobenzyl)furandione 3 is obtained. (α-Iminobenzyl)pyrrolediones 4 are formed in the reaction of 2c with N-tosylsulfinylamine or from 3 with N-tosylsulfur diimides. Diisopropylcarbodiimide and the pyrroledione 2c or the (iminobenzyl)furandione 3a undergo [4 + 2] cycloaddition reactions accompanied by novel and surprising rearrangements to furnish the bicyclic compounds 5 and 6, respectively. The molecular skeleton of 6 was confirmed by an X-ray diffraction analysis. With the aid of 17O-labeling experiments and 17O-NMR spectroscopy mechanistic pathways including novel rearrangements were made evident.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260916
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