An exceptional series of phase transitions in hydrophobic amino acids with linear side chains

0465896 - FZÚ 2017 RIV GB eng J - Journal Article
Görbitz, C.H. - Karen, P. - Dušek, Michal - Petříček, Václav
An exceptional series of phase transitions in hydrophobic amino acids with linear side chains.
IUCrJ. Roč. 3, Sep (2016), s. 341-353. ISSN 2052-2525. E-ISSN 2052-2525
R&D Projects: GA MŠMT LO1603
EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510
Institutional support: RVO:68378271
Keywords : amino acids * disorder * hydrogen bonding * modulated phases * phase transitions * side-chain stacking * polymorphism * molecular crystals
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 5.793, year: 2016

The solid-state phase transitions and intermediate structures of S-2-aminobutanoic acid (l-2-aminobutyric acid), S-2-aminopentanoic acid (l-norvaline), S-2-aminohexanoic acid (l-norleucine) and l-methionine between 100 and 470 K, identified by differential scanning calorimetry, have been characterized in a comprehensive single-crystal X-ray diffraction investigation. Unlike other enantiomeric amino acids investigated until now, this group featuring linear side chains displays up to five distinct phases. The multiple transitions between them involve a number of different processes: alteration of t he hydrogen-bond pattern, sliding of molecular bilayers, concerted side-chain rearrangements and abrupt as well as gradual modifications of the side-chain disorder. Ordering of l-norleucine upon cooling even proceeds via an incommensurately modulated structure.
Permanent Link: http://hdl.handle.net/11104/0265104