Marek Szczepaniak

University of Wroclaw | WROC · Faculty of Chemistry

We have applied the CCSD(T)-F12a/cc-pVTZ-F12//CCSD(T)/cc-pVTZ level of theory to calculate energies for 22 reactions pertinent to the stability and reactivity of hardly isolable cyanoform (HC(CN)3). A number of exothermic processes has been indicated, especially the hydration. In the predicted mechanism for the gas-phase hydration of cyanoform, the...

The rheological behavior of concentrated oil-in-water emulsions containing carotenoids (2% (w/w) with different polarity (polarity order: lycopene LY < beta-carotene BC < apocarotenal AC ≪ lutein LU) and its relationship with the microstructural changes caused by three-month storage at 4 °C and 30 °C was studied. The smallest particle size and the...

Although an isolation of elusive tricyanomethane HC(CN)3 (1) was recently reported, the existence of other HC4N3 species has yet to be confirmed. In this work, the relative stabilities, spectroscopic features and rearrangements of (1) and its isomers (2-5) are examined using single- (CCSD(T), CCSD(T)-F12) and multi-reference (MCSCF, MRPT2) methods....

We present a comprehensive benchmark computational study which has explored a complete path of the anomerization reaction of bare d-erythrose involving a pair of the low-energy α- and β-furanose anomers, the former of which was observed spectroscopically (Cabezas et al., Chem. Commun. 2013, 49, 10826). We find that the ring opening of the α-anomer...

D-erythrose is a C4 monosaccharide with a biological and potential astrobiological relevance. We have investigated low-energy structures of D-erythrose and their interconversion in the gas phase with the highest-level calculations up-to-date. We have identified a number of structurally distinct furanose and open-chain isomers and predicted αα and...

We performed large-scale second-order perturbation theory gas-phase calculations to study about five hundred structures of D-fructose, a biologically and industrially important ketohexose. The two lowest energy fructose structures identified are β-pyranoses possessing 2C5 chair, with ΔG(298K) of 6 kJ/mol, differing in orientation of the equatoriall...

We present an extensive computational study of a complex conformational isomerism of two gas phase pentoses of biological and potential astrobiological importance, d-ribose and 2-deoxy-d-ribose. Both cyclic (α- and β-pyranoses, α- and β-furanoses) and open-chain isomers have been probed using second order Møller-Plesset perturbation theory (MP2), M...