Aromatic borate anions and thiophene derivatives for sensor applications
1University of Oulu, Faculty of Science, Department of Chemistry
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|Persistent link:|| http://urn.fi/urn:isbn:9789514286575
|Publish Date:|| 2007-11-28
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic dissertation to be presented, with the assent of the Faculty of Science of the University of Oulu, for public defence in Auditorium IT115, Linnanmaa, on December 8th, 2007, at 12 noon
Professor Jouko Kankare
Professor Jouko Vepsäläinen
This study was part of a project targeted at developing chemical sensors for organic cations and metal ions by exploiting the interactions between cations and anionic borate derivatives. As well, the chemical synthesis of thiophene monomers with charged or neutral ion-recognition sites was investigated.
The primary task in the first part of the work was to prepare anionic receptor molecules based on synthesized borate derivatives and study their complexation with N-heteroaromatic and tropylium cations. The complexation was studied in solution by 1H NMR and ESIMS techniques and in solid state by X-ray crystallography. Crystal structures showed evidence of weak noncovalent interactions–hydrogen bonding, cation···π interactions, and π-stacking. In addition, the crystal structure of the alkali metal complex of tris[3-(2-pyridyl)pyrazolyl]hydroborate was determined. Stability constants of borate complexes were measured by 1H NMR titration in methanol/acetonitrile (1:1) solution at 30 °C. Various derivatives of aromatic borate anions synthesized within this project, some commercially available derivatives, and two neutral carriers containing aromatic anthryl groups were also studied as recognition sites for aromatic cations where N-methylpyridinium was used as primary ion in PVC membrane-based all-solid-state ion sensors. The results showed that borate derivatives offer new possibilities for molecular recognition by ion-selective electrodes (ISEs).
The aim of the second part of the study was to develop chemical ion sensor materials where the ion-recognition unit and the charge-compensating ion are covalently coupled to the backbone of a conductive polymer. Sulfonated thiophenes were used as doping ions for the fabrication of Ag+-ISEs. More than 15 differently substituted monomers were synthesized. The materials differed with respect to the receptor unit, extent of oxidation, counteranion, and length of the chain.
Acta Universitatis Ouluensis. A, Scientiae rerum naturalium
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