Berlin 2015 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 69: Biomaterials and Biopolymers (joint session CPP, BP)
CPP 69.11: Talk
Thursday, March 19, 2015, 17:45–18:00, C 264
Kinetics of mutarotation in fucose-saccharides as monitored by dielectric and infrared spectroscopy — •Wilhelm Kossack1, Wycliffe Kiprop Kipnusu1, Mateusz Dulski2, Karolina Adrjanowicz2, Olga Madejczyk2, Emanuel Urandu Mapesa1, Martin Tress1, Kamil Kaminski2, and Friedrich Kremer1 — 1University of Leipzig, Linnestr. 5, Leipzig, Germany — 2University of Silesia, Katowice, Poland
Fourier Transform Infrared Spectroscopy and Broadband Dielectric Spectroscopy are combined to trace kinetics of mutarotation in L-fucose. After quenching molten samples to temperatures between T = 313 K and 328 K, the concentrations of two anomeric species change according to a simple exponential time dependence, as seen by the increasing absorbance of specific IR-vibrations. In contrast, the dielectric spectra reveal a slowing down of the structural (α-) relaxation according to a stretched exponential time dependence (stretching exponent of 1.5± 0.2). The rates of change in the IR absorption for α- and β-fucopyranose are (at T = 313 K) nearly one decade faster than that of the intermolecular interactions as measured by the shift of the α-relaxation. This reflects the fact that the α-relaxation monitors the equilibration at a mesoscopic length scale, resulting from fluctuations in the anomeric composition.