10.07.2015 Views

Jozef Hodyl PhD Thesis - Theses - Flinders University

Jozef Hodyl PhD Thesis - Theses - Flinders University

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3.2.3 Job’s plots for host-guest complexes formed with[Cd(TracHP12)](ClO 4 ) 2 , 49Job’s plots for [Cd(TracHP12)](ClO 4 ) 2 , 49, with various different aromatic anions p-nitrophenolate, p-nitrobenzoate, acetate, phenoxyacetate, D-histidinate and L-histidinate, were produced by maintaining, in an NMR tube, the total concentrationof the two components at 12 µM in 700 µL of DMSO-d 6 and varying the moles ofeach constituent from 0 to 8.4 mmol to achieve mole fractions ranging from 0 to 1.Changes in the chemical shift of the guest resonances as the host-guest complexformed were monitored by 1 H NMR spectroscopy at 298 K. Each difference in thechemical shift of one particular resonance at the appropriate mole fraction was thenmultiplied by that mole fraction to obtain a value of χ G ∆δ G which was plotted againstthe mole fraction χ G to give an inverted parabola. In all cases the maximum occurredat χ G = 0.5. This is shown, for example, for the inclusion of phenoxyacetate in thecavity of [Cd(TracHP12)](ClO 4 ) 2 , 49, in Figure 3.3 and for p-nitrophenolate inFigure 3.4.χG∆δ∆δGFigure 3.3 Job's Plot for phenoxyacetate inclusion in the cavity of [Cd(TracHP12)](ClO 4 ) 2 , 49,showing 1:1 composition.χ G56

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