Märt Lõkov works in our group focusing on investigations of acid-base equilibria – first of all, determination of acidity and basicity constants (pKa values) of molecules – in nonaqueous solutions. This is a core research direction in our group and he is one of the key people in advancing it.
He has made significant contributions to the self-consistent acidity scale and self-consistent basicity scale in acetonitrile, containing pKa values 231 acids and pKaH values of 279 bases, respectively. Because of how these values have measured (“multiple overlapping” relative spectrophotometric measurements), these scales are widely regarded as the most reliable sets of pKa values in acetonitrile. Thus, assembling those scales was to a large extent also a revision of existing pKa values for many compounds and assigning new values to them.
Märt has mastered the art of pKa measurements in nonaqueous media to the highest degree and is right now one of the most skilful people on planet Earth in performing nonaqueous pKa measurements. Besides doing these measurements himself, he has supervised and is supervising numerous master’s and doctoral students who measure pKa values in their degree projects. Thus, indirectly, via the supervised students, his contribution is even larger.
Perhaps the most ambitious endeavour that Märt is now engaged in is a large-scale re-evaluation and revision of pKa values of carboxylic acids in three nonaqueous solvents – acetonitrile, DMSO, dimethylformamide. The analysis of available pKa data that we have carried out in the framework of the IUPAC project 2015-020-2-500 Critical compilation of acid pKa values in polar aprotic solvents reveals that the non-aqueous pKa values available in the literature for this very important compound class are often significantly in error, sometimes by several orders of magnitude. The revision will involve measurements and analysis of literature data. Märt has assembled a group of people involving several students and the expected outcome will be a large amount of high-quality nonaqueous pKa data of carboxylic acids.
These contributions have been noticed by the International Union of Pure and Applied Chemistry (IUPAC) and Märt has been awarded the Balarew Award for an Outstanding Young Scientist working in the field of critical evaluation of solubility and/or related chemical equilibria!
Märt, please accept our warm congratulations!
