Three copper(i) complexes have been obtained by the reaction of CuI with 3-picolylamine in acetonitrile solution and characterized by X-ray powder diffraction, both from synchrotron and laboratory radiation. Photophysical investigations in the solid state revealed highly efficient thermally-activated delayed fluorescence (TADF) with photoluminescence quantum yields (PLQYs) up to 18%. Notably, the complex [CuI(3pica)] displays a strong luminescence thermochromism due to the presence of both (X + M)LCT excited states and a lower-lying cluster-centered (CC) one, leading to multiple emission at room temperature; as a result, a white luminescence is achieved with a PLQY of 4.5%.
The copper iodide complexes are known for their large variety of coordination geometries. Such diversity, while making it difficult to predict the final structure, permits the preparation of a great number of copper iodide complexes based on the same ligand. The target of the research was that of thoroughly exploring the chemistry of CuI and the ligand diphenyl-2-pyridyl phosphine (PN) by varying the stoichiometric ratio and/or the aggregation state. Six different compounds have been identified: [Cu4I4(PN)2], [Cu4I4(PN)2·(CH2Cl2)0.5], [CuI(PN)0.5]∞, [CuI(PN)3] whose structures have been determined during this study, CuI(PN)2 which was characterized by powder diffraction and [Cu2I2(PN)3] which has been already reported. The preparation routes are also different: synthesis in solution yielded [Cu4I4(PN)2·(CH2Cl2)0.5] and [CuI(PN)3] while [CuI(PN)0.5]∞ and CuI(PN)2 were obtained only via solid state reactions. These two latter examples confirmed that mechanochemistry is a valid route to explore the landscape of the possible structures of CuI derivatives. Crystallization by traditional solution procedures failed to give the desired crystal, so structure determination of the new compounds was tackled in two ways: by attempting crystal growth via solvothermal synthesis and by resolving the structure from X-ray powder diffraction data with "direct space" methods. What is more the photophysical properties of the complexes that could be obtained as sufficiently pure powders have also been investigated and are reported herein.
Depending on the experimental conditions, the solid-state reactions of CuI with pyrazine (pyz) yield three distinct coordination polymers (CPs): a double chain polymer [Cu 2 I 2 (pyz)] n (yellow powder) and a single strand [CuI(pyz)] n (red powder) and its new isomeric compound [(CuI) 2 (pyz) 2 ] n (orange powder), which present dimers of CuI bridged by the pyrazine ligands. The conversions among the three CPs were studied: by heating to 110 °C, [CuI(pyz)] n or [(CuI) 2 (pyz) 2 ] n convert into [Cu 2 I 2 (pyz)] n , which reverts to the starting compounds upon kneading or grinding in the presence of pyrazine. The orange isomer [(CuI) 2 (pyz) 2 ] n is obtained only when the solid-state reaction is performed with neat grinding or by direct melting of the pyrazine; it is unstable in the presence of solvent or vapor, and it readily transforms into the red isomer. The structure of [(CuI) 2 (pyz) 2 ] n was determined by X-ray powder diffraction. [Cu 2 I 2 (pyz)] n reacts also with 4-cyanopyrazine to yield the mixed ligand compound [(CuI)(4CNpy) 2 py] n , which, when heated, decomposes into [Cu 2 I 2 (pyz)] n and [(CuI) 4 (4CN-py) 5 ] n.
The
crystal forms of the active pharmaceutical ingredient enzalutamide,
a drug used for the treatment of metastatic prostate cancer, have
been investigated by X-ray, thermogravimetric analysis, and differential
scanning calorimetry techniques. The single crystal structure of the
anhydrous form R1 (marketed by Astellas) has been determined and compared
with the powder diffraction data. Upon crystallization from MeOH and
formic acid, a new solvate form called R2 has been discovered and
characterized. The crystal structure of R2 contains voids that can
host other small molecules such as formic acid, methanol, or water.
Form R2 loses solvent at ca. 120–140 °C and recrystallizes
into the stable unsolvated form R1. In the case of isopropyl alcohol,
a solvate form R3 has also been obtained. R1 converts into R3 under
slurry conditions in isopropyl alcohol. The structure of R3 has been
determined from powder diffraction data. Importantly, while form R1
is easily contaminated with O-enzalutamide (the substitution
impurity of S-enzalutamide) by forming stable solid
solutions up to 50%, form R3 does not and can be used to easily purify
the raw S-enzalutamide.
Hybrid coordination polymers are interesting for their ability to converge the properties of both inorganic and organic system in one single compound and recently the attention has been focused on...
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