Luminescent Probing of α-Amino Acids with Rare Earth Ions – a New Technique for Chiral Analysis
Доклады на конференциях
The overwhelming majority of racemates in the crystalline state have different physical properties comparing to pure enantiomers1 what can be revealed by a diversity of physical methods. Photoluminescent (PL) spectroscopy has been virtually disregarded for studying these fundamental homo- and heterochiral differences between enantiomers and racemates. It has been generally believed that application of PL spectroscopy for chiral analysis is limited to such chiroptical techniques as FD-CD and CPL.2 We revealed that luminescent probing with rare earth ions (europium, gadolinium, terbium) and an actinide ion (uranyl) can be used to differentiate enantiopure and racemic α-amino acids alanine, valine, threonine, aspartic acid and phenylalanine (Figure 1). In particular, we showed that using these achiral luminescent probes, small differences between pure L and DL alanine in the solid state were strongly amplified3 and can be used for chiral analysis.4 Formation of homo- and heterochiral complexes between enantiomers of amino acids and the metal ions was proposed as a plausible origin of chiral self-discrimination.
(1) J. Jacques, J.; Collet, A.; Wilen, S.H. Enantiomers, Racemates and Resolutions, Krieger, 1994. (2) Castiglioni, E.; Abbate, S.; Lebon, F.; Longhi, G. Methods and Applications in Fluorescence 2014, 2, 024006. (3) Tarasevych, A.V.; Kostyukov, A.I.; Baronskiy, M.G.; Rastorguev, A.A.; Guillemin J.-C.; Snytnikov, V.N. Chirality 2017, in print. (4) Rastorguev, A.A.; Tarasevych, A.V.; Snytnikov, V.N. A Method for Determination of Enantiomeric Excess. Patent RU 2 610 352 C1, priority date 15 Nov. 2015, published 09.02.2017.