Cr1.45Tl1.87Mo15Se19, a monoclinic variant of the hexagonal In3Mo15Se19 type

The monoclinic compound Cr_1.45Tl_1.87Mo₁₅Se₁₉ (chromium thallium pentadecamolybdenum nonadecaselenide) represents a variant of the hexagonal In₃Mo₁₅Se₁₉ structure type. Its crystal structure consists of an equal mixture of Mo₆Se₈Se₆ and Mo₉Se₁₁Se₆ cluster units. The Mo and Se atoms of the median plane of the Mo₉Se₁₁Se₆ unit, as well as three Cr ions, lie on sites with m symmetry (Wyckoff site 2e). The fourth Cr ion is in a 2b Wyckoff position with site symmetry.     

ChemInform Abstract: Sc0.43(2)Rb2Mo15S19, a Partially Sc‐Filled Variant of Rb2Mo15S19.

Single crystals of the title compound are obtained from a mixture of Sc₂S₃, Rb₂MoS₄, MoS₂, and Mo (Mo crucible, 1773 K, 48 h).     

Synthesis, crystal structure, and electrical and magnetic properties of Ce3MoO7

Powder samples and single crystals of the ternary oxide Ce₃MoO₇ were obtained by solid state reaction. The structure was determined by single-crystal X-ray diffraction. Ce₃MoO₇ crystallizes in the orthorhombic space group P2₁2₁2₁ (no. 19) with unit-cell parameters a=7.5395(2) Å, b=7.6769(1) Å, c=10.9769(2) Å and Z=4. Full-matrix least-squares refinement on F² using 3903 independent reflections for 101 refinable parameters results in R₁=0.0281 and wR₂=0.0473. The structure consists of chains of corner-linked MoO₆ octahedra running parallel to the b-axis and separated from each other by seven- or eight-coordinate Ce-O polyhedra. The trend of the unit-cell parameters of the Ln₃MoO₇ series, plotted versus the R³⁺ ionic radius, shows a linear behavior, which strongly suggests a trivalent state for the Ce atoms. Magnetic susceptibility measurements confirm that the oxidation state of the Ce atoms is +3. Resistivity measurements on a single crystal show that the Ce₃MoO₇ compound is a semi-conductor with a band gap of about 2 eV.     

Solid-state NMR investigation on the interactions between a synthetic montmorillonite and two homopolypeptides

Interactions of two homopolypeptides (polylysine and polyglutamic acid) with a synthetic montmorillonite were studied by ¹H MAS, ¹H–²⁷Al HETCOR and ¹H–¹³C CP-MAS NMR experiments. ¹H–²⁷Al HETCOR with ¹H spin-diffusion NMR appears to be a powerful probe for the identification of the polypeptide fragments, which interact with the montmorillonite interlayer surfaces. In particular, selective interactions were observed between the polypeptide side-chains and the montmorillonite octahedral aluminum atoms. ¹H–¹³C CP-MAS NMR experiments were used to assess the dynamics of the two polypeptides through the measurement of the t_1/2 characteristic time of selected carbons. Results indicate that the local mobility of the side chains and their interaction with the montmorillonite layers depend on the nature of the adsorbed polypeptides.     

Real-Time Detection of Phenylacetaldehyde in Wine: Application of a Microwave Sensor Based on Molecularly Imprinted Silica

Molecularly imprinted sol–gel silica (MIS) coupled to a microwave sensor was designed and used to detect phenylacetaldehyde (PAA), a chemical tracer of wine oxidation. The developed method is fast, cheap and could replace the classical chromatographic methods, which require a tedious sample preparation and are expensive. To reach our objective, five MIS and their control non-imprinted silica (NIS) were synthesized and their extraction capacity toward PAA was studied in hydro alcoholic medium. The selected polymers, based on this first step, were subjected to a selectivity study in the presence of PAA and three other competing molecules. The best polymer was integrated in a microwave sensor and was used to assess PAA in red wine. The developed sensor was able to detect PAA at the µg·L⁻¹ level, which is below the off-flavour threshold.