Polymorphism, phase transitions, and thermal stability of L-Pyroglutamic acid

Kód výsledku v IS VaVaI

RIV/68378271:_____/10:00438343 - isvavai.cz

Výsledek na webu

http://dx.doi.org/10.1021/cg100260f

DOI - Digital Object Identifier

10.1021/cg100260f

Jazyk výsledku

angličtina

Název v původním jazyce

Polymorphism, phase transitions, and thermal stability of L-Pyroglutamic acid

Popis výsledku v původním jazyce

L-Pyroglutamic acid undergoes a phase transition, alpha-->beta, at similar to 68 degrees C on heating, which is reversible with hysteresis depending on the cooling rate, before melting at similar to 162 degrees C. On cooling, a further reversible transition, alpha-->alpha', which shows martensitic characteristics, occurs at similar to -140 degrees C. The structural changes at the transitions were studied by variable temperature X-ray powder diffraction and Raman spectroscopy and compared with reports ofsingle crystal structure determinations. Differences in Raman spectra were attributed to differences in intermolecular N-H center dot center dot center dot O interactions in the three enantiotropic polymorphs. By optical microscopy, crystals frequentlyjumped around the microscope slide on passing through the alpha/beta transition; this is attributed to discontinuous changes in the unit cell dimensions leading to a spring effect in the crystals.

Název v anglickém jazyce

Polymorphism, phase transitions, and thermal stability of L-Pyroglutamic acid

Popis výsledku anglicky

L-Pyroglutamic acid undergoes a phase transition, alpha-->beta, at similar to 68 degrees C on heating, which is reversible with hysteresis depending on the cooling rate, before melting at similar to 162 degrees C. On cooling, a further reversible transition, alpha-->alpha', which shows martensitic characteristics, occurs at similar to -140 degrees C. The structural changes at the transitions were studied by variable temperature X-ray powder diffraction and Raman spectroscopy and compared with reports ofsingle crystal structure determinations. Differences in Raman spectra were attributed to differences in intermolecular N-H center dot center dot center dot O interactions in the three enantiotropic polymorphs. By optical microscopy, crystals frequentlyjumped around the microscope slide on passing through the alpha/beta transition; this is attributed to discontinuous changes in the unit cell dimensions leading to a spring effect in the crystals.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

BM - Fyzika pevných látek a magnetismus

OECD FORD obor

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Projekt

—

Návaznosti

Z - Vyzkumny zamer (s odkazem do CEZ)

Rok uplatnění

2010

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Crystal Growth & Design

ISSN

1528-7483

e-ISSN

—

Svazek periodika

10

Číslo periodika v rámci svazku

7

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

8

Strana od-do

3141-3148

Kód UT WoS článku

000279422700045

EID výsledku v databázi Scopus

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