Zweikernige Lanthanoidkomplexe als Katalysatoren für die Hydrolyse von Bis(<i>p</i>‐nitrophenyl)phosphat und von doppelsträngiger DNA

Ragunathan, Kaliappa G.; Schneider, Hans‐Jörg

doi:10.1002/ange.19961081116

Cited by 13 publications

References 23 publications

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Supramolekulare Katalyse der Spaltung von Estern und Amiden durch einen zweikernigen Bariumkomplex

et al. 1999

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Fünf Komponenten lagern sich spontan zusammen zum reaktiven Komplex 1. In diesem überträgt eines der Bariumatome ein Ethanolation auf die Carbonylgruppe eines Amids (Substrat), das über eine distale Carboxylatgruppe am anderen Bariumatom verankert ist. Das katalytische System zeichnet sich durch hohe Substratspezifität, einigermaßen hohe Reaktionsgeschwindigkeiten und kompetitive Hemmung durch inerte Substrate aus.

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Supramolekulare Katalyse der Spaltung von Estern und Amiden durch einen zweikernigen Bariumkomplex

et al. 1999

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Evidence for Cooperativity in the Disproportionation of H2O2 Efficiently Catalyzed by a Tetranuclear Manganese Complex

2000

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Die Base bestimmt den Verlauf der katalytischen Disproportionierung von Wasserstoffperoxid durch einen gemischtvalenten MnIII(MnIV)3‐Komplex. Das Vorhandensein der Base 1,4,7‐Trimethyl‐1,4,7‐triazacyclononan führt zu einem Wechsel der Reaktionskinetik von einem Michealis‐Menten‐Verhalten (Hill‐Koeffizient n=1.03) zu einem kooperativen Verhalten (Hill‐Koeffizient n=1.58; siehe Bild). Die Geschwindigkeitskonstante für diese kooperative Katalyse ist die bislang größte für einen synthetischen Mangankomplex.

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Affinity and Nuclease Activity of Macrocyclic Polyamines and Their Cu^IIComplexes

et al. 2000

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The stability constants of CuII complexes that consist of either an oxa‐aza macrocycle with two triamine moieties linked by dioxa chains, or two macrocyclic ligands with a polyamine chain which are connecting the 2 and 9 positions of phenanthroline, have been determined by means of potentiometric measurements. The results are compared to those reported for other ligands with a similar molecular architecture. Of the complexes that contain phenanthroline in their macrocycle, the CuII ion of the complex with the smallest and most rigid macrocycle (L3) has an unsaturated coordination sphere, while in the complex with the largest macrocycle (L5) the CuII ion is coordinatively almost saturated. These results are corroborated by the crystal structure of the [CuL5](ClO4)2 complex. The affinity of the ligands and the complexes towards nucleic acids was studied by measuring the changes in the melting temperature, which showed that the affinity of the macrocyclic ligands towards double‐stranded DNA or RNA is generally smaller than that of their linear analogues that bear a similar charge, with a strong preference for polyA–polyU, a model for RNA. However, the complexes of two of the changed macrocyclic ligands which contain a phenanthroline unit (L4, L5) showed a distinctly larger increase in their melting temperature ΔTm with DNA (polydA–polydT), which is reversed again in favor of RNA upon metallation to the dinuclear copper complex with L5. Experiments with supercoiled plasmid DNA showed a particularly effective cleavage with a mononuclear CuII complex that contains a phenanthroline unit (L6). Related ligands showed less activity towards DNA, but not so towards the biocidic bis(p‐nitrophenyl)phosphate (BNPP). In both cases (with DNA and BNPP) the activity seemed to increase with decrease of coordinative saturation of the CuII ion, with the exception of one particular ligand (L6). Experiments with radical scavengers in the DNA experiments showed some decrease in cleavage, which indicates the participation of redox processes.

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Zweikernige Lanthanoidkomplexe als Katalysatoren für die Hydrolyse von Bis(p‐nitrophenyl)phosphat und von doppelsträngiger DNA

Cited by 13 publications

References 23 publications

Supramolekulare Katalyse der Spaltung von Estern und Amiden durch einen zweikernigen Bariumkomplex

Supramolekulare Katalyse der Spaltung von Estern und Amiden durch einen zweikernigen Bariumkomplex

Evidence for Cooperativity in the Disproportionation of H2O2 Efficiently Catalyzed by a Tetranuclear Manganese Complex

Affinity and Nuclease Activity of Macrocyclic Polyamines and Their Cu^IIComplexes

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Zweikernige Lanthanoidkomplexe als Katalysatoren für die Hydrolyse von Bis(p‐nitrophenyl)phosphat und von doppelsträngiger DNA

Cited by 13 publications

References 23 publications

Supramolekulare Katalyse der Spaltung von Estern und Amiden durch einen zweikernigen Bariumkomplex

Supramolekulare Katalyse der Spaltung von Estern und Amiden durch einen zweikernigen Bariumkomplex

Evidence for Cooperativity in the Disproportionation of H2O2 Efficiently Catalyzed by a Tetranuclear Manganese Complex

Affinity and Nuclease Activity of Macrocyclic Polyamines and Their CuIIComplexes

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Affinity and Nuclease Activity of Macrocyclic Polyamines and Their Cu^IIComplexes