Study of the Mechanism of Thermal Chemical Processes in the Crystals of YAF Tripeptides by Means of Mass Spectrometry and Solid State NMR

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• 作者：Ewelina Drabik ; Agata Jeziorna ; Urszula Bienias ; Katarzyna Trzeciak-Karlikowska ; Tomasz Pawlak ; Piotr Paluch ; Marek J. Potrzebowski
• 刊名：Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：October 31, 2013
• 年：2013
• 卷：117
• 期：43
• 页码：13481-13489
• 全文大小：470K
• 年卷期：v.117,no.43(October 31, 2013)
• ISSN：1520-5207

文摘

Thermal reactions in two Tyr-Ala-Phe (YAF) tripeptide crystals with different molecular packing (monoclinic and hexagonal), distinct stereochemistry of central amino acid (D or L alanine) and specific arrangement of molecules in the crystal lattice (head-to-tail) were investigated. Samples were heated up to 180 掳C, while the melting point for YAF crystals is above the 220 掳C. Below the melting temperature, in both cases the chemical reactions leading to formation of cyclic dipeptides (YA diketopiperazine) and leaving of phenylalanine were observed. Two possible mechanisms of chemical reaction in the crystal lattice assuming intra- and/or intermolecular pathways were considered. ¹³C and ¹⁵N enriched YAF samples were employed to study of mechanism of solid state reactivity using mass spectrometry and advanced solid state NMR techniques (2D DARR (Dipolar Assisted Rotational Resonance) and 2D Double CP (Cross-Polarization) correlations).