Date of Award

10-30-2020

Publication Type

Master Thesis

Degree Name

M.Sc.

Department

Chemistry and Biochemistry

First Advisor

John Trant

Keywords

aggregation-dependent fluorescence, bathochromic shift, bisbenzimidazole, concentration-dependent fluorescence, pseudorotaxane

Rights

info:eu-repo/semantics/openAccess

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Abstract

Mono and (bis)benzimidazoliums were evaluated both experimentally and computationally for their potential as building blocks of pseudopolyrotaxane axles. Their aggregation and optical behavior, along with the dependence of their supramolecular assembly with dibenzyl-24-crown-8 macrocycles on the protonation state of the axles, was studied through the synergistic application of 1D/2D and diffusion ordered NMR spectroscopy, ultraviolet-visible & fluorescence spectroscopy, and time-dependent density functional theory. Their unique optical behaviour was measured and modeled as a function of protonation state, solvent, and concentration. The axles show solvochromaticism and a very pronounced concentration dependent optical profile. All data supports that the complex adopts a more compact conformation than the free axle. By utilizing the axle with multiple recognition sites, it was possible to form pseudorotaxanes with tunable optical behavior.

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