On the 18th of November, 2022, Alo Rüütel successfully defended his PhD thesis titled Design principles of synthetic molecular receptors for anion-selective electrodes.

Alo’s thesis starts by expanding a fundamental question asked by Otto S. Wolfbeis back in 2013: when so much research is done on binding anions with various molecular receptors, why do we see so few real sensors that could be used in real-life applications?

In response to this, Alo has outlined a sensor development strategy flowchart and identified a “dead zone” – space between receptor evaluation and prototype fabrication stages – on the sensor development pathway where the research most often gets stuck. Alo’s dissertation connects the research fields of receptor design and sensor preparation. The thesis demonstrates the challenges of creating new ion-selective electrodes for carboxylate sensing. This process is accompanied by several scientific challenges at the fundamental level of supramolecular chemistry. To address these problems, influencing factors are explored, such as improving binding, lipophilicity, biphasic binding environments etc. A big outcome of the thesis was a compilation of accurate binding constants of one hundred (!) anion receptors. Perhaps the most tangible result of the thesis were real sensor prototypes, capable of sensing carboxylate anions (e.g. benzoate).

Alo’s performance at the defence was one of the best we have seen. He single-handedly and seemingly effortlessly answered all the (numerous!) questions from the opponent, as well as from the committee.

Please accept our big congratulations, Alo!