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Comparative study on the effect of nitrogen-donor groups versus macro-ring size in O2Nx-azacrowns on the complexation with [60]fullerene

Ghanbari, B ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1080/1536383X.2012.684185
  3. Abstract:
  4. The interaction of [60]fullerene with a newly synthesized series of 17-to 21-membered macrocyclic ligands containing an O2N3-donor set has been investigated. The formation constants (K) arising from their complexation with [60]fullerene macrocycles, having various ring size, were measured in CHCl3 media by UV-visible spectroscopy applying Benesi-Hildebrand (BH) equation and their stoichiometries were also determined by the Job method. The best K value was measured for 20-membered ring macrocycle in which a 1:1 complexation stoichiometry with [60]fullerene was dominant. Furthermore, 1H NMR spectroscopy data reveled that the macrocylic ligand coordinates [60]fullerene via the nitrogen-donor groups. Evaluation of the thermodynamic parameters, for example, formation enthalpies (ΔH O f) and entropies (ΔS O f) confirmed on these complexations as both enthalpy and entropy favorite processes. Comparing with our previous observation for similar [60]fullerene complexation with the O 2N2-donor macrocylic ligands, we concluded that increasing the number of nitrogen-donor groups on the macrocycle had rather more pronounce effect on these complexation than the macro-ring size
  5. Keywords:
  6. Azacrown ; Host-guest ; Macrocycle ; [60] fullerene ; Azacrowns ; Formation constants ; Host-guests ; Macro-cyclic ligands ; Macrocycles ; Thermodynamic parameter ; UV visible spectroscopy ; Enthalpy ; Entropy ; Fullerenes ; Ligands ; Nitrogen ; Stoichiometry ; Ultraviolet visible spectroscopy ; Complexation
  7. Source: Fullerenes Nanotubes and Carbon Nanostructures ; Vol. 22, issue. 4 , 2014 , pp. 322-331 ; ISSN: 1536383X
  8. URL: http://www.tandfonline.com/doi/abs/10.1080/1536383X.2012.684185?journalCode=lfnn20#.VeP_mrXBZoo