Title

Self-assembled platinum(II) complexes for anion recognition.

Date of Award

2005

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Chemistry and Biochemistry

Keywords

Chemistry, Inorganic.

Rights

CC BY-NC-ND 4.0

Abstract

The focus of this thesis is the development of novel anion receptors possessing conformational flexibility through the use of a simple inorganic framework. The complex cation, [PtL4]2+, can adopt four conformations inspired by calix[4]arene-based receptors: 'cone', 'partial cone', '1,2-alternate' or '1,3-alternate'. The first part of the thesis involves the synthesis, characterization and examination of the binding properties of three generations of anion receptors using 1H NMR spectroscopy and X-ray crystallography. The first generation receptor is [PtL4]2+ where L = 3-nbutylnicotinamide. Solution studies show moderate binding constants in polar solvents with preference for 1:2 binding of planar bidentate anions such as CH3CO2- and NO3-. Conformational flexibility is removed in the second generation receptor. The receptor is preorganized for 1:2 binding of planar bidendate anions with two bis-3,5-nbutylnicotinamide ligands coordinated to [Pt(2,2'-bipy)]2+. The results show diminished receptor:anion interactions in both solution and solid state. The third generation receptor consists of [PtL4]2+ where L = 8nbutylureaisoquinoline. The association constants are high in very polar solvent with the 1,2-alternate conformation preferred for the binding of spherical halide anions. The cone conformation is seen when binding tetrahedral shaped oxo-anions. This trend is also confirmed by X-ray crystal structure data. The second part of the thesis investigates the conformational stability and interconversion barriers of several rotameric model complexes using 1H NMR spectroscopy and molecular mechanics. The number of possible conformations in most of the compounds is simplified to two, syn and anti. The anti conformation is the most stable and interconversion barriers range from 69 - 76 kJ/mol. Finally, the last section of the thesis explores the use of mass spectrometry and fluorescence spectroscopy as tools for qualitative analysis of the binding interactions between our third generation receptor and several different anions. Trends in anion selectivity are monitored. Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 5971. Thesis (Ph.D.)--University of Windsor (Canada), 2005.