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Synthesis and Study on Complexation of Naphthalene Azacrown Macrocycle Ligands with [60] Fullerene and Metal Cations Like Cu2+

Zarepour-jevinani, Morteza | 2017

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 49919 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Ghanbari, Bahram
  7. Abstract:
  8. In the present research, two series of N2O2- and N4O2-naphthadiaza-crown macrocyclic ligands with different macroring size, 15-21 memberd (L1-L7) were synthesized using direct method. The products were characterized by applying 1H and 13C NMR, IR spectroscopy, mass spectrometry and elemental analysis and in some cases by X-ray crystallography. Firstly, to study on emission properties of naphthadiaza-crown macrocyclic ligands as a fluorophore, we employed different amines as fluorescence quencher. It was observed that the quenching effects of 3o aliphatic amines like triethylamine were more pronounce than other group of amines. Also, the quenching constants for interactions of macrocyclic ligands with amines were obtained by using stern-volmer equation at different temperatures. Based on increasing the stern-volmer constants (KSV) by increasing temperature, a dynamic mechanism suggested for quenching of the ligands in interaction with amines. The supramolecular interaction of these ligands with [60]Fullerene were also monitored by fluorescence as well as UV-vis spectroscopy and applying Benesi-Hildebrand equations. The binding constants (KBH) of these interactions were calculated and compared with N2O2 macrocyclic ligands in our previous experiments. Using Stern-Volmer equation, the quenching constants for interaction of N2O2-macrocyclic ligands and [60]Fullerene were obtained. For the macrocycles, [60]Fullerene act as fluorescence quencher and based on decreasing the stern-volmer constants with increasing temperature, a static mechanism for quenching was proposed. In these experiments, the 18-memberd macrocycle showed the maximum interaction with [60]Fullerene in terms of both binding and quenching constants as ̴ 156000 M-1. The interaction of these macrocycles with different metal cations were also studied as chemosensors. According to the results, macrocyclic ligands L1, L2, L3, L4, and L5 showed good selectivity and sensitivity for Zn2+, Cu2+, Cu2+, Zn2+, and Hg2+, respectively in the presence of other metal cations. Showing low values of limit of detections (LOD) (L1/Zn2+ = 5×10-7, L2/Cu2+ = 1×10-7, L3/Cu2+ = 5×10-8, L4/Zn2+ = 5×10-8, L5/Hg2+ = 1×10-9 in ethanol, L5/Hg2+ = 1×10-11 M in water) as well as good quantum yields were obtained for interaction of macrocyclic ligands as sensor with metal cations. Moreover, modeling and optimization studies applying SPARTAN software, gaussian program, and DFT calculations using B3LYP/6-31G* basis set showed that, the supramolecular interaction of macrocyclic ligands with [60]Fullerene occurred in terms of HOMO and LUMO orbitals situated on the ligands and [60]Fullerene, respectively. Besides, the interaction of N4O2-naphtha-diaza-crown macrocyclic ligands with different metal cations were studied as chemosensors in ethanol by fluorescence spectroscopy. In these interactions, macrocyclic ligands L6, and L7 showed high selectivity and sensitivity for Al3+ cation in the presence of other metal cations showing very low LOD, L6/Al3+ = 1×10-11, L7/Al3+ = 5×10-11 M). It is concluded that naphthadiaza-crown macrocyclic ligands, with emissive naphthalene rings, provided applying fluorescence spectroscopy method with high sensitivity than UV-vis Spectroscopy. The macrocycles, also used both as chemosensors for different metal cations and as good host molecules with extened π system for [60]Fullerene which in both aspects have advantage rather than benzoaza-crown macrocyclic ligands.
  9. Keywords:
  10. Fullerene ; Macrocyclic Ligand ; Azacrown ; Naphthalene ; Aza-Ether ; Metal Cations

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