Conjugated Schiff-base macrocycles and their metal complexes

• Main Author: Hui, Joseph
• Format: Others
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/15276

The [3+3] Schiff-base macrocycles (37-40) were obtained by reacting 3,6- diformyl-l,2-dihydroxybenzene (31) and 4,5-diamino-l,2-dialkoxybenzene (33-36). The resulting macrocycles were characterized by ¹H and ¹³C NMR spectroscopy, IR spectroscopy, UV-Vis spectroscopy, ESI mass spectrometry, DSC and POM. The macrocycles with long alkoxy substituents have the potential to exhibit liquid crystallinity; however, no mesomorphic characteristics were observed. Macrocycle 37 was metallated with most of the first-row transition metals. The metal-containing [3+3] Schiff-base macrocycles (47-53) were characterized by ¹H NMR spectroscopy, IR spectroscopy, UV-Vis spectroscopy, and ESI and MALDI-TOF mass spectrometry. ESR spectroscopy has been performed on the vanadyl-containing macrocycle 47. The ESR spectrum shows that there appears to be a significant interaction between the unpaired electrons of the vanadium atoms, leading to a single broad ESR signal. Several attempts have been made to obtain the [6+6] Schiff-base macrocycle, but only a fragment of it (compound 65) could be synthesized successfully. === Science, Faculty of === Chemistry, Department of === Graduate