Luminescent N2-Modified Guanosines: Synthesis, Self-Assembly and Metal ion Interactions

dc.contributor.authorMartic, Sanelaen
dc.contributor.supervisorWang, Suningen
dc.contributor.supervisorWu, Gangen
dc.date2009-09-22 16:02:20.934's University at Kingstonen
dc.descriptionThesis (Ph.D, Chemistry) -- Queen's University, 2009-09-22 16:02:20.934en
dc.description.abstractThe objective of this thesis was to synthesize N2-modified guanosines (N2G) in order to introduce fluorescent and chelating ligands, such as diphenylamino, 2,2’-dipridylamino, 2-(2’-pyridyl)benzimidazolyl and p-pyrenylphenyl functionalities. Their photophysical properties were examined in order to gain further knowledge about the effect of guanine modification on its electronic structure. The impact of N2-modification was first studied in terms of self-assembly of the luminescent guanosines in solution and gas phase. Extensive NMR and ESI MS studies provided evidence that these N2-modified guanosines self-assemble exclusively into octamers with high-fidelity, in the presence of Group 1 and Group 2 metal ions. In addition, the first example of “empty” G-octamer (free of metal cations) was identified by ESI MS. Experimental results suggested that N2-substituents provide additional electronic and steric effects which drive the diastereoselectivity of self-assembly and provide additional stability. Hydrogen bonding of N2Gs with cytidine was monitored using fluorescence and NMR. In addition to GC base pair formation, the G-quartet-to-GC base pair structural transformation was studied using CD, fluorescence, and NMR spectroscopy. Due to the luminescent and chelating nature of some of the N2G derivatives, their interactions with a number of metal ions, such as Zn2+, Cd2+, Hg2+, La3+, Tb3+ and Eu3+ ions, were probed by using various spectroscopic methods. The overall optical response in the presence of metal ions was highly dependent on the nature of N2-substituent, and it varied from “turn-on” to “turn-off” response, clearly indicating that the modification at the N2-site of guanosine can be used to finely tune the optical response of these nucleosides. Finally, synthesis of a phosphorescent N2-arylguanosine containing the Ru2+ metal center was achieved and its photophysical and electrochemical properties were examined.en
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dc.relation.ispartofseriesCanadian thesesen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.titleLuminescent N2-Modified Guanosines: Synthesis, Self-Assembly and Metal ion Interactionsen
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