07.06.2016
Doctoral Dissertation

16 June 2016, M.Sc. Toni Mäkelä (Faculty of Mathematics and Science, Organic Chemistry)

Time:

16.6.2016 12:00 — 15:00


Location: Ylistonrinne , KEM 4
Release: Ion Pair Recognition by Ditopic Crown Ether Based bis-Urea and Uranyl Salophen Receptors
M.Sc. Toni Mäkelä defends his doctoral dissertation in Organic Chemistry "Ion Pair Recognition by Ditopic Crown Ether Based bis-Urea and Uranyl Salophen Receptors" on 16 June 2016.

M.Sc. Toni Mäkelä defends his doctoral dissertation in Organic Chemistry "Ion Pair Recognition by Ditopic Crown Ether Based bis-Urea and Uranyl Salophen Receptors". Opponent Professor Anthony P. Davis  (University of Bristol, UK) and custos Academy Professor Kari Rissanen (University of Jyväskylä). The doctoral dissertation is held in English.

This work describes the synthesis of ditopic crown ether based ion pair receptors and their recognition behaviour towards various ion pairs in solid-state, solution, and gas-phase. The receptors consist of crown ether scaffolds for cation recognition and bis-urea or uranyl salophen as anion recognition functionality. As the introduction to the topic, a short description of supramolecular chemistry is given. Then examples of ditopic receptors based on crown ethers and uranyl salophens are presented to give an overview of their ion pair binding behaviour. This is followed by a description of the use of ditopic receptors in further examples of different receptor types, and finally a few examples of more complicated multitopic receptor systems are discussed. The Results and Discussion section summarizes the results obtained and reported in three published journal articles and one manuscript. In the course of this work, four new crown ether bis-urea receptors and two new crown ether uranyl salophen receptors were prepared. The solid-state ion pair binding behaviour of the crown ether bis-urea receptors was studied in extensive single-crystal X-ray crystallography studies of 33 crystal structures revealing the general characteristics of their ion pair complexation. In addition, the solution behaviour of the receptors revealed strong positive cooperativity toward anion binding when the receptors were complexed with alkali metals. The solution-state behaviour of the receptors was supported by solid-state studies. Lastly, the gas-phase studies by mass spectrometry strongly supported the ion pair complexation behaviour seen in solution. The two crown ether uranyl salophen receptors were studied in comprehensive solid-state studies with single crystal X-ray crystallography (19 structures) revealing three general interaction motifs in ion pair complexation that depend on the crown ether size and the nature of the ion pair. Interestingly one obtained crystal structure constituted of coordination polymer with repeating ···O=U=O···Na+···O units, presenting the intriguing possibility of utilizing these types of receptors in building magnetic materials.      

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Toni Mäkelä

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toni.p.l.makela@jyu.fi