30 research outputs found

    Le maomegas en 1984 Plus dition n erlandaise

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    SIGLEBSE B225257V / UCL - Université Catholique de LouvainBEBelgiu

    Maomegasgids C.I.P.F. 1986

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    SIGLEBSE B226064N / UCL - Université Catholique de LouvainBEBelgiu

    Le maomegas en 1985

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    SIGLEBSE B226063U / UCL - Université Catholique de LouvainBEBelgiu

    Guide du maomegas 1987

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    SIGLEBSE B226423L / UCL - Université Catholique de LouvainBEBelgiu

    Quenching Dynamics of the Photoluminescence of [Ru(bpy) 3 ]

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    The Stern-Volmer quenching constants (K sv ) for poly(amidoamine)- (PAMAM-) based dendrimers (generations G0-G4) modified with (4, 8, 16, 32 and 64) pendant [Ru(bpy) 3 ] +2 (bpy is 2,2- bipyridine) chromophores have been measured in the presence of three nitroaromatic quenchers (2,4,6trinitrotoluene ) TNT, 2,4-dinitrotoluene ) DNT, nitrotoluene ) NT), two negatively charged quenchers (K 3 Fe(CN) 6 ,Na 4 Fe(CN) 6 ), and one energy transfer type quencher (Fe(C 5 H 5 ) 2 ). The quenching efficiencies were calculated for the dendrimers (G0-G4) in the presence of TNT and were found to peak for dend16 -Ru(bpy) 3 . The generation dependence of the quenching efficiency mirrors the calculated crowding factor and the variations were attributed to changes in the 3-dimensional structure with generation (size) and the associated changes in the accessibility of the [Ru(bpy) 3 ] -pendant groups. Electrostatic attractions between the positively charged dendrimers and the negatively charged quenchers resulted in larger K sv values when compared to the reference complex, [Ru(bpy) 3 ] . The addition of electrolyte to an ionic strength of 0.1 M (KCl or NaCl) caused a diminution of the K sv values by 60%, consistent with electrostatic interactions and charge screening effects
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