Different dynamics of chiral and racemic L and DL serine crystals Evidenced by incoherent inelastic neutron and Raman scattering

Interest in chiral vs racemic amino acid forms stems from their different solid state properties associated to the packing arrangement that leads to starkly different physical behavior. Here we focus on the different dynamic properties of the chiral L form and racemic DL form crystals of serine, C3H7NO3 . Measuring incoherent inelastic neutron and Raman scattering over a wide temperature range we could asses a subtle dynamical transition in L serine near 150 K. The difference in the dynamic properties of the crystals of L and DL serine evidenced from our spectroscopic studies is in a good agreement with the different Cp T dependences and different structural strain of the two forms on cooling. Despite a higher bulk density, the molecular fragments in the crystals of L serine are more dynamic than in DL serine, and this manifests itself in the incoherent inelastic neutron and Raman spectra, as well as in a higher heat capacity, a higher thermal expansion coefficient, or in the NMR spectr

CCDC 710543: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures

Halogen···halogen contacts in triiodide salts of pyridinium-derived cations: Theoretical and spectroscopic studies

© 2020 Elsevier B.V. Triiodide salts of pyridinium-type cations CatI3 (cat = 1,2-MePy (1), 1,2,6-MePy (2) and 1,2,4,6-MePy (3) were prepared and characterized by X-ray diffractometry. In the cases of 1 and 2, formation of supramolecular anionic dimers {(I3)2}2- was observed in solid state (I⋯I = 3.685 and 3.912 Å, respectively), while in 3 triiodides remain isolated. The features of I⋯I contacts were studied by theoretical methods and Raman spectroscopy

Nitrogen and Oxygen Functionalization of Multi walled Carbon Nanotubes for Tuning the Bifunctional Oxygen Reduction Oxygen Evolution Performance of Supported FeCo Oxide Nanoparticles

The combination of nanostructured transition metal oxides and carbon materials is a promising approach to obtain inexpensive, highly efficient, and stable bifunctional electrocatalysts for the oxygen reduction ORR and the oxygen evolution OER reactions. We present a strategy for improving the bifunctional ORR OER activity of supported FeCoOx nanoparticles by tuning the properties of multi walled carbon nanotubes MWCNT via nitrogen doping during their synthesis in the presence of ammonia and subsequent oxidative functionalization. In depth structural characterization indicates that oxidative treatment provides fine control of the dispersion and localization of FeCoOx nanoparticles in MWCNT, while the optimal degree of nitrogen doping leads to increased bifunctional activity due to enhanced electrical conductivity as well as improved catalyst stability, in both OER and ORR conditions, for nanoparticles formed by two different synthesis routes. The findings reported can be strategically considered for the design of high performance reversible ORR OER electrocatalyst