The highly preorganized ligands 1,10-Phenanthroline-2,9-Dialdoxime and BIS-1, 10-Phenanthroline, and their complexing properties with metal ions

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Lindsay Leighton Boone (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Robert Hancock

Abstract: Preorganization is important in the recognition of metal ions by ligands. A ligand is more preorganized the more it is constrained as the free ligand to be in the conformation required to complex the target metal ion. Until the present time, high levels of preorganization have been achieved by cyclization of open-chain ligands to yield macrocycles and cryptands. A novel approach to designing highly preorganized ligands is followed where high levels of preorganization are achieved using the rigid 1,10-phenanthroline (1,10-phen) delocalized system as the backbone of the ligand. The highly preorganized ligands 1,10-phenanthroline-2,9- dialdoxime (PDOX) and bis-1,10-phenanthroline (DIPHEN) and their complexing properties with various metal ions have been studied.PDOX was synthesized by a literature method. Column chromatography of the product obtained by this method gave a product of improved purity, as shown by NMR and IR, and a considerably higher melting point. UV/VIS spectrometry was used in titrations to determine protonation constants of the free ligands and their stability constants with metal ions. Stability constants, logK1, for PDOX and DIPHEN with Ca(II), Cd(II), Cu(II), Gd(III), Pb(II), and Zn(II) have been determined. Fluorescence properties of PDOX and Ca(II), Cd(II), Pb(II), Hg(II), and Zn(II) were examined. The strong chelation enhanced fluorescence (CHEF) effect found with PDOX and metal ions such as Cd(II) and Pb(II) suggest that these ligands will have potential applications in biology, and in the development of sensors for these metal ions in the environment.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirement for the Degree of Masters of Science
Language: English
Date: 2009
Keywords
Ligands--Synthesis, Metal complexes, Metal ions--Analysis
Subjects
Metal ions -- Analysis
Ligands -- Synthesis
Metal complexes