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Study on Cation and Fullerene Recognition by OxNx-Aza Crown Macrocyclic Ligands

Safar koopayeh, Barzin | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46439 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Ghanbari, Bahram
  7. Abstract:
  8. In this research, a new group of N2O2–azacrown macrocyclic ligands with different macroring size from 15 to 18 was synthesized using one-pot facile and high yield reaction. The products were characterized applying FT-IR, 1H and 13C NMR spectroscopies as well as elemental analysis. The single crystal structure of 18-membered macrocyclic ligand was also determined by x-ray crystallography. The crystallographic data showed such strong inter-molecular hydrogen bonding which excluded their nitrogen-donor groups, and initial investigation with UV-Vis spectroscopy shows no intraction with [60]fullerene, despite of presence of these interacrtions in their parent macrocycles. The result of Job’s method studies confirmed on 1:1 ratio of cation:ligand for 15- and 18-membered macrorings in their complex formation with Co(II), Ni(II)¬, Cu(II) cations while 1:2 ratio was found for 16-membered marcoring. Interaction of these ligands with these cations were monitored by UV-Vis spectroscopy applying Benesi-Hildebrand equation.¬ These results as well as the thermodynamic parameters measurements showed that Ka values observed for these new macrorings were generally lowered than their parent macrorings. Having these findings and their relative crystallographic data, confirmed on “exo-coordinating” property of these new macrorings. Futhermore, the interaction of these ligands with Zn(II)¬ were also observed by 1H NMR ¬spectroscopy to determine their most probable coordination sites. DFT calculations were applied for determination of relative geometric structures, hydrogen bonding, and other property of macrocycles using the B3LYP 6-31+G¬¬ ¬¬(d,p) method with Gaussian 09w software. The calculations showed that the hydrogen bond strength was ~50 kJ.mol-1. In the end, the ESI mass spectrometry of macrocycle mixture with Cu(II) in acetonitrile/water mixture as was determined. The ESI-MAS studies observations confirmed on the mentioned complex formations results with transition metal ions, independently
  9. Keywords:
  10. Fullerene ; Metals ; Computational Chemistry ; Macrocycle ; Azacrown ; Complexation ; Exo-Coordinating Macrocycle

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