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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of a Dinuclear ZnII-Calix[4]arene Enzyme Model with Additional General Base Groups - Catalytic Activity in Phosphate Diester Transesterification (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 3269-3275 
    Details
    ISSN: 1434-193X
    Keywords: Calixarenes ; Enzyme mimetics ; Phosphatases ; Transesterification ; Zinc ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Calix[4]arenes modified at the upper rim with two pairs of functional groups were synthesized and were used as starting materials for the synthesis of an enzyme model 3-Zn2 that has two ZnII centers and two dimethylamino groups. Under neutral conditions, this dinuclear metallo-enzyme model is catalytically active in the cleavage of the phosphate diester bond of the RNA model substrate 2-hydroxypropyl-p-nitrophenyl phosphate (HPNP). The kinetics of 3-Zn2 were compared with a mononuclear complex 1-Zn and a dinuclear complex 2-Zn2 that lack the dimethylamino groups. A catalysis mechanism is proposed where the ZnII centers of 3-Zn2 cooperate in the activation of the phosphoryl group while one of the dimethylamino groups acts as a general base in the deprotonation of the hydroxyl group of HPNP.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of (Hemi)Carceplex Adsorbates for Self-Assembly on Gold (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 269-274 
    Details
    ISSN: 1434-193X
    Keywords: Cage compounds ; Calixarenes ; Cavitands ; Carcerands ; Gold ; Interfaces ; Monolayers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The synthesis of sulfide-functionalized (hemi)carceplexes suitable for self-assembly on gold is described. A noncentrosymmetrical carceplex 9 (guest DMF) was synthesized by the combination of calix[4]arene 4 and resorcin[4]arene 3, while a noncentrosymmetrical hemicarceplex 12 (guest NMP) was prepared by the combination of two different resorcin[4]arenes, 3 and 10. These adsorbates form ordered self-assembled monolayers on gold with their quasi C4v axis perpendicular to the surface. The two positions possible for the incarcerated guest lead to diastereotopic surfaces.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    High Hyperpolarizabilities of Donor-π-Acceptor-Functionalized Calix[4]arene Derivatives by Pre-organization of Chromophores (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 1089-1098 
    Details
    ISSN: 1434-193X
    Keywords: Calixarenes ; Chromophores ; Nonlinear optics ; Pre-organization ; Supramolecular chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A systematic investigation of the conceptofpre-organization of nonlinear optical (NLO) active chromophoric groups in calix[4]arene derivatives and the influence on the absolute second-order nonlinear optical coefficients is reported. Several calix[4]arenes were synthesized by modification of the electron-withdrawing groups at the upper rim of the aromatic and extension of the conjugated π system of the pre-organized chromophoric groups. Electrical field induced second harmonic generation (EFISH) experiments showed high μβ(0) values up to 1165·10-48 esu. Compared with the corresponding reference compounds, enhancements of the μβ(0) values varying up to 2.5 times per chromophore were observed which proves the benefit of pre-organization of NLO-active units in a multi-chromophoric system. Another important advantage is that the increase in NLO activity observed for these systems is not accompanied with a shift of the absorption band to longer wavelengths exceeding 20 nm. This makes these calix[4]arene derivatives promising building blocks for the development of stable, NLO-active materials that are suitable for frequency doubling.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
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