Unprecedented transformation of [I−·I3−] to [I42−] polyiodides in the solid state: structures, phase transitions and characterization of dipyrazolium iodide triiodide

Autor:	Ryszard Jakubas, Piotr Zieliński, Anna Piecha-Bisiorek, M. Węcławik, Przemysław Szklarz, Wojciech Medycki, Rafał Janicki
Rok vydání:	2015
Předmět:	chemistry.chemical_classification Phase transition Iodide Dielectric Inorganic Chemistry Crystallography chemistry.chemical_compound Nuclear magnetic resonance Differential scanning calorimetry chemistry Phase (matter) Proton NMR Triiodide Spectroscopy
Zdroj:	Dalton Transactions. 44:18447-18458
ISSN:	1477-9234 1477-9226
Popis:	Dipyrazolium iodide triiodide, [C3N2H5(+)]2[I(-)·I3(-)], has been synthesized and studied by means of X-ray diffraction, differential scanning calorimetry, dielectric measurements, and UV-Vis spectroscopy. Two reversible, solid-solid phase transitions (Imma (I) ↔ (II) ↔Pbam (III)) at 254 K and 182/188 K respectively have been revealed. The anionic network experiences spectacular changes associated with a huge rebuilding of the inorganic network from [I(-)·I3(-)] to [I4(2-)]. The low frequency dielectric relaxation process occurs in phase II with the activation energy of ca. 34 kJ mol(-1). The molecular motion of the pyrazolium cations in [C3N2H5(+)]2[I(-)·I3(-)] has been studied by means of proton magnetic resonance studies ((1)H NMR). The ferroelastic properties of all phases have been confirmed by polarizing microscopy observations. The molecular mechanism of the phase transitions in the compound is proposed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e9562209b62a69249317552ea4a49413 https://doi.org/10.1039/c5dt02265g Zobrazit plný text záznamu