The Syntheses and Applications of Squaraine-Based Molecular Switches
Date Issued
2010
Date
2010
Author(s)
Hsueh, Sheng-Yao
Abstract
This thesis consists of four parts. The first part is protecting a squaraine near-IR dye through its incorporation in a slippage-derived [2]rotaxane; the second part is to design and synthesize squaraine-based [2]rotaxanes that function as visibly active molecular switches; the third part is to develop efficient solvent-free syntheses of [2] and [4]rotaxanes; the last part is reporting the serendipitous discovery of an acid/base- and anion-controllable organogel formed from urea-based molecular switch.
Part Ⅰ：Protecting a Squaraine near-IR Dye through Its Incorporation in a Slippage-Derived [2]Rotaxane
We report high yield slippage synthesis of corresponding [2]rotaxanes according to previous works that unique Na+ ion-templated recognition system. The photophysical properties and chemical stability of a squaraine dye were enhanced by encirclement of a molecular cage.
Part Ⅱ：Squaraine-Based [2]Rotaxane that Function as Visibly Active Molecular Switches
We used Na+ ions to template a threading-followed-by-stoppering synthesis of a [2]rotaxane from the squaraine-containing pyridinium derivative and a molecular cage. This [2]rotaxane would function as a molecular switch in CD3CN if we could remove the templating Na+ ions and thereby move the molecular cage from the squaraine station to the pyridinium or bipyridinium one, this process should have the effect of decreasing the intensity of the [2]rotaxane’s long-wavelength-fluorescence emission.
Part Ⅲ：Efficient Solvent-Free Syntheses of [2]- and [4]Rotaxanes
We chose 1,8-diaminonaphthalene as a suitable diamine for the reaction with a threadlike moiety terminated with a formyl group through a new solid-state ball-milling reaction that produces both [2]- and [4]rotaxanes efficiently and in high yield.
Part Ⅳ：An Acid/Base- and Anion-Controllable Organogel Formed From Urea-Based Molecular Switches
We report the serendipitous discovery of a urea-based rotaxane that behaves as both a molecular switch and an organogelator, with both functions being mediated under acid/base and anion control.
Subjects
Squaraine
Molecular Manchine
Molecular Switch
Type
thesis
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