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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 117 (2002), S. 1385-1394 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The effects of confining a polyelectrolyte solution containing a polyion and its counterions in spherical cavities of different sizes have been investigated by Monte Carlo simulations using a simple model system. Polyions of three different linear charge densities and counterions of three different valences have been examined. Structure, energy, and free energy properties of all systems have been determined as a function of the sphere radius. In nearly all cases, the free energy of confining the polyelectrolyte solution increases as the sphere radius is decreased. The free energy cost decreases as the linear charge density of the polyion is reduced and as the counterion valence is increased, although for completely different reasons. A strong consistency among the variations of the different structural and thermodynamic results on the linear charge density and counterion valence was found. The study provides information relevant for experimental systems of polyions confined to, e.g., viruses, vesicles, and zeolite cavities. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2018-09-13
    Description: An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy, using carbon monoxide and structurally different aliphatic diamines as N -nucleophiles, gives access, in one pot, to a new family of indole-based N -heterocyclic derivatives (hydropyrazinones, benzodiazepinones and hydroquinoxalines). Optimization of the reaction conditions towards double carbonylation ( P CO = 30 bar, T = 80°C, iodoindole/diamine ratio = 1 : 1.5, toluene as solvent) allowed the target cyclic products, which are formed in situ via intramolecular cyclization of the ketocarboxamide intermediates, to be obtained through a nucleophilic addition/elimination reaction with the pendant terminal amine groups. The structure of the diamine nucleophile was revealed to affect the reaction's selectivity, with the best yields for the cyclic products being obtained in the presence of (1 S , 2S )-(+)-cyclohexane-1,2-diamine ( a ) as the nucleophile, using either 5- or 7-iodoindole as the substrate. The reaction's selectivity was rationalized based on electronic structure calculations, which explain the effect of the diamine structure on the predominant formation of the cyclic products.
    Keywords: synthetic chemistry, computational chemistry, green chemistry
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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