Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Charles Pedersen  (1)
  • O2 activation  (1)
  • Recognition of coordination structure  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Structure and O2 uptake properties of a novel nickel(II) complex of pyridyl-pendant dioxocyclam [1-(2-pyridyl)methyl-5,7-dioxo-1,4,8,11-tetraazacyclotetradecane] (1997)
    Springer
    JBIC 2 (1997), S. 74-82 
    Details
    ISSN: 1432-1327
    Keywords: Key words Nickel complex ; DNA cleavage ; O2 activation ; Biomimetic chemistry ; Macrocyclic polyamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract  Novel potentially five-coordinate pyridyl–pendant dioxocyclam [1-(2-pyridyl)methyl-5,7-dioxo-1,4,8,11-tetraazacyclotetradecane (H2L) and its homologs (6-methyl and 6,6-dimethyl derivatives)] have been synthesized to study nickel(II) complexation. A purple nickel(II) complex with a deprotonated amide (NiHL) was isolated from aqueous equimolar solution of H2L and Ni(ClO4)2. A yellow nickel(II) complex with two deprotonated amides (NiL) was crystallized from an H2O/CH3CN solution of H2L and Ni(OH)2. The X-ray crystal study of NiL showed a square-planar nickel(II) complex with the pyridyl–pendant remaining uncoordinated. It is concluded from the visible absorption and NMR study of NiL in aqueous solution that the four-coordinate NiL is in equilibrium with a five-coordinate square-pyramidal nickel(II) complex with the apical coordination of the pyridyl–pendant. A voltammetric study disclosed a low nickel(II/III) redox potential of +0.29 V vs SCE for NiL at pH 9.5 and 25  °C with 0.10 M Na2SO4. The nickel(II) complex NiL absorbed an equimolar amount of O2 at pH 9.5 and 25  °C, and the O2 was activated to cleave plasmid DNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007750050108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    X-ray structural study of a zinc(II) inclusion complex of a phenolate-pendant cyclam (1992)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 12 (1992), S. 377-387 
    Details
    ISSN: 1573-1111
    Keywords: Charles Pedersen ; crown ethers ; phenol-pendant cyclam-zinc(II) complex ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The molecular structure of phenol-pendant cyclam-zinc(II) complex,4a, has been determined by X-ray structure analysis. Crystals of4a · ClO4 · CH3OH (C16H27N4OZn · ClO4 · CH3OH) are monoclinic, space groupP21/nn, with four molecules in the unit cell of dimensionsa=31.198(2) Å,b=8.426(1) Å,c=8.214(1) Å, andβ=93.96(1)°. The structure was solved by the heavy atom method and refined anisotropically toR=0.044,R w=0.062 for 1551 independent reflections. The complex assumes a five-coordinate, square pyramidal geometry, where zinc(II) is surrounded by the cyclam moiety in a planar fashion with the pendant phenolate anion occupying an axial position. An extremely short Zn-O(phenolate) bond distance of 1.983(5) Å, in conjunction with the 0.288 Å displacement of Zn(II) above the cyclam N4 plane toward the phenolate, accounts for the extremely low pK a value of 5.8 for the pendant phenol. These facts about4a, in comparison with the previous findings for the Ni(II) (4b) and Cu(II) complexes (4c) with the same ligand, illustrate well the characteristics of zinc(II) ion coordination properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01053875
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Potentiometric discrimination between planar and octahedral anionic metal cyano complexes by liquid membrane electrodes based on lipophilic macrocyclic dioxopolyaminesDedicated to the memory of Prof. Dr. Wilhelm Simon, who has made major contributions to the field of analytical chemistry, particularly by introducing the use of antibiotics as well as of synthetic compounds as sensory elements for ion-selective electrodes. (1993)
    Weinheim : Wiley-Blackwell
    Electroanalysis 5 (1993), S. 731-738 
    Details
    ISSN: 1040-0397
    Keywords: Macrocyclic polyamines ; Ion-selective electrodes ; Metal cyano complexes ; Recognition of coordination structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel type of poly(vinyl chloride) matrix liquid membrane electrodes that are capable of discriminating between planar and octahedral anionic metal cyano complexes has been developed by exploiting as the sensory elements lipophilic derivatives of macrocyclic dioxopolyamines (13-hexadecyl-1,4,8,11-tetraaza-12,14-dioxocyclotetradecane, 15-hexadecyl-1,4,7,10,13-pentaaza-14,16-dioxocyclohexadecane). Potentiometric response behaviors of these electrodes for a series of anionic metal cyano complexes were compared with those of the electrodes based on the corresponding nondioxo macrocyclic pentaamine (15-hexadecyl-1,4,7,10,13-pentaazacyclohexadecane) as well as a conventional anion exchanger (Capriquat®). The electrodes based on the dioxopolyamines displayed strong potentiometric responses at pH 4.0 to the metal cyano complexes having a planar structure ([Ni(CN)4]2-, [Pt(CN)4]2-). In contrast, the responses to the metal cyano complexes having an octahedral structure ([Fe(CN)6]3-, [Fe(CN)6]4-) were only negligible. On the other hand, for all of the guests tested, the electrodes based on the nondioxo macrocyclic pentaamine or the anion exchanger showed strong linear responses to both planar and octahedral complexes. These results represent a new mode of potentiometric discrimination displayed by dioxo-type macrocyclic polyamines having both amine and amide moieties.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140050905
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...