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Synthesis and Comparative Study on Complex Formation of Azo-bearing Nitrogen-Donor Macrocyclic Ligands with Fullerene C60 and Cu(II) Cation

Mahdavian, Mahsa | 2017

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 50377 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Ghanbari, Bahram
  7. Abstract:
  8. In the present research, a series of bimacrocyclic tweezer anchored through azobenzene moiety were synthesized and characterized by applying IR spectroscopy, 1H and 13C{1H} NMR, fluorescence spectroscopy, UV-visible spectroscopy, mass spectrometry and elemental analysis and in some cases by X-ray crystallography. Firstly, UV-visible spectroscopy established that the irradiation of the tweezers with UV light promoted the trans to cis isomerization. On the other hand, thermal cis-trans isomerization behavior of the azobenzene moiety in tweezers was surveyed in which the cis isomers were formed of the heating at 50 oC for 5 minutes. Where the -OH group was replaced with 4-toluenesulfonyl chloride in the azobenzene ring, however, there was no observable change in the spectrum of the tweezer even after irradiation with UV light or heating for two hours, confirming on its resistance to the trans-cis isomerization in chloroform. The obtained electron spectra were confirmed using TDDFT studies. The supramolecular interaction of these tweezers with C60 which was obtained by Benesi-Hilderbrand equation and T1TS-bz showed the remarkable Kb value (Kb=56689). Moreover, transformations of 1H NMR spectra of the tweezers in the presence of C60 were explored. The appearance of new signals in the 1H NMR spectra of T1ph-bz and T1ph-py indicated the role of the azobenzene moiety in these tweezers on the suparmolecular interaction with C60. The aromatic signal changes for the macrocycle ring of T1TS-bz signified the priority of the macrocycle interaction with C60 for this tweezer. Moreover, the intracting site of C60 in tweezers confirmed by employing DFT calculation. In the following, the interaction of the side-armed naphthodiaza-crown macrocycles and T2ph-bz tweezer with different metal cations were also studied as chemosensors. According to the results, 2mbz and 2dbz showed good selectivity and sensitivity for Al3+ and T2ph-bz showed good selectivity and sensitivity for Cr3+ and Cu2+ in the presence of other metal cations. However, the T2ph-bz in cis isomer did not show selectivity for any metal ion. Showing low values of limit of detections (LOD) (2dbz/Al3+=5×10-7M in ethanol, 2dbz/Al3+ =7×10-6M in ethanol/water and T2ph-bz/Cr3+ =10-8M in ethanol) were found for the interaction of this compounds as sensor with metal cations. For instance, employing fluorescence titration showed binding constant values 105 M-1, 2.6×106 M-1 and 1.5×108 M-2 for 2mbz/Al3+, 2dbz/Al3+and T2ph-bz/Cr3+, respectively. Moreover, by detecting the effect of pH, these 2mbz, 2dbz and T2ph-bz act as chemosensors at pH=7. From the reaction between T1ph-py and ZnTPP new tweezer T3 was synthesized. 1H NMR spectroscopy, fluorescence and UV-vis spectroscopy and X-ray crystallography is confirmed axial connection of pyridine rings T1ph-py to porphyrin. Further, the interaction of this new tweezer with fullerene was investigated, which showed 1.1×109 M-2 of K value for this interaction to the best of knowledge
  9. Keywords:
  10. Tweezer ; Fullerene ; Spectrofluorometry ; Tetraphenyl Porphyrin ; Fluorescence Sensors ; Ultra Violet-Visible ; Isomerization-Cis-Trans ; Chemosensor

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