Transition metal complexes with the thiosemicarbazide-based ligands. Part 12. Synthesis,structure and template reaction of ammine [2,4-pentane-dione S-methylisothiosemicarbazonato(2-)] nickel(II) dihydrate

Summary Ni(NO₃)₂·6H₂O reacts with 2,4-pentanedione S-methylisothiosemicarbazonehydrogen iodide (H₂L·HI) in aqueous solution; addition of ammonia then yields [NiL(NH₃)]·2H₂O, the crystal structure of which has been determined. In the square-planar [NiL(NH₃)]·2H₂O complex, the ligand, 2,4-pentanedione S-methylisothio-semicarbazone occupies three coordination sites with the bonds to the central atoms involving the terminal nitrogen atoms of the isothiosemicarbazide fragment [Ni–N(3) 1.831 Å and Ni–N(2) 1.842 Å] and the oxygen of the 2,4-pentanedione moiety [Ni–O 1.844 Å]. The template reaction of [NiL(NH₃)]·2H₂O with 2,4-pentanedione and triethyl orthoformate, HC(OEt)₃, gave, by heating the complexes, NiL¹ (1) (L¹ = dianion of the quadridentate NNNN macrocyclic ligand 2,10-bis(methylthio)-5,7,12,14-tetramethyl-1,3,4,8,9,11 -hexaazacyclotetradeca-2,4,6,9,12,-14-hexaene) and NiL² (2) (L² = dianion of the quadridentate ONNO ligand 3-acetyl-6-thiomethyl-9-methyl-5,7,8-tri-azadodeca-3,6,9-triene-2,11-dione) presents described.     

A theoretical study of the microhydration processes of iodine nitrogen oxides

This work reports for the first time the structures and the thermodynamics of the microhydrates of iodine nitrogen oxides (INO_x). Monohydrates and dihydrates were investigated for five different INO_x species (INO, INO₂, cis-IONO, trans-IONO, and IONO₂). The structures of the water complexes were characterized at the ωB97XD/aug-cc-pVTZ level of theory. Coupled-cluster calculations were performed with the ANO-RCC-VQZP basis sets. Standard reaction enthalpy and standard Gibbs free reaction energy (Δ_rG^°_{298 K}) were computed for all aggregates. The variation of Δ_rG^°[T] as a function of temperature reveals that only IONO₂ will be hydrated at tropospheric temperatures (T < 270 K). Its dihydration reaction remains a favored process in the same conditions. All INO_x species will not be hydrated in gas phase in the containment building of a pressurized water reactor for which temperatures are greater than 400 K.     

Selective Monoacylation of Ferrocene with Bulky Acylating Agents over Mesoporous Sieve AlKIT‐5

Ferrocene acylation with bulky acylating agents (1‐adamantoyl, benzoyl, 2‐chlorobenzoyl, and cinnamoyl chlorides; and benzoic anhydride) catalyzed by AlKIT‐5 mesoporous catalysts was investigated. AlKIT‐5 catalysts with varying ratios of Si/Al were synthesized using tetraethoxysilane and aluminum isopropoxide as the structural building blocks and Pluronic F127 as a template under acidic conditions and were characterized in detail by X‐ray powder diffraction, magic‐angle spinning (MAS) NMR spectroscopy, sorption of nitrogen, energy‐dispersive X‐ray spectroscopy (EDS), SEM, TEM, and FTIR with pyridine as a probe molecule. The catalytic activity of the prepared AlKIT‐5 catalysts in ferrocene acylation was shown to depend on the type of the acylating agent, thus likely reflecting the strength of interactions between the acyl source, the product, and the solid catalysts when the acylation reaction was carried out at 100 °C. In all reactions, the AlKIT‐5 catalysts afforded exclusively the monoacylated products (100 % selectivity) most likely due to deactivation of the second cyclopentadiene ring by attachment of the first acyl group, steric reasons, and some competitive interactions of the monoacylferrocenes with the catalysts. The prepared AlKIT‐5 catalysts could be regenerated without any significant loss of the ferrocene conversion.     

Correlation of acoustic and optical emission signals produced at 1064 and 532 nm laser-induced breakdown spectroscopy (LIBS) of glazed wall tiles

An acoustic signal was used for the internal standardization of laser-induced breakdown spectroscopy (LIBS) of a glazed wall tile. For the LIBS analyses, 1064 nm and 532 nm wavelengths of the Nd:YAG laser were utilized. The tile was depth profiled by a single-spot ablation from the glaze into the substrate. Some lines of major elements Si(I) 252.418, Si(I) 252.851, Al(I) 257.509, Cr(I) 295.368, Al(I) 309.271 nm and Ti(II) 334.904 nm were monitored. The decrease in the optical emissions during the ablation was successfully compensated for by normalization to the square power of the acoustic signal in the interval of 290–340 nm. This approach failed for the lines between 250–270 nm. The results were the same for both lasing wavelengths despite different irradiances. The acquired profiles are in good agreement with the reference X-ray fluorescence measurement.     

Mapping of lead,magnesium and copper accumulation in plant tissues by laser-induced breakdown spectroscopy and laser-ablation inductively coupled plasma mass spectrometry

Laser-Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) were utilized for mapping the accumulation of Pb, Mg and Cu with a resolution up to 200 μm in a up to cm × cm area of sunflower (Helianthus annuus L.) leaves. The results obtained by LIBS and LA-ICP-MS are compared with the outcomes from Atomic Absorption Spectrometry (AAS) and Thin-Layer Chromatography (TLC). It is shown that laser-ablation based analytical methods can substitute or supplement these techniques mainly in the cases when a fast multi-elemental mapping of a large sample area is needed.     

On discrete and continuous wirtinger inequalities

We shall present several generalizations of discrete Wirtinger's inequality, and establish their continuous analogs.     

From Double‐Four‐Ring Germanosilicates to New Zeolites: In Silico Investigation

To date, the majority of zeolites have been prepared by the solvothermal route using organic structure directing agents. Two new zeolites with structural codes PCR and OKO were recently prepared from UTL germanosilicate by removal of the double‐four ring (D4R) connecting the dense two‐dimensional layers [Nature Chem. 2013 , 5, 628]. The corresponding experimental protocol, Assembly–Disassembly–Organization–Reassembly (ADOR), is explored in this contribution with an in silico investigation. The structure and properties of hypothetical zeolites that could be obtained from zeolites with IWW, IWV, IWR, ITR, and ITH topologies using the ADOR protocol are reported based on a computational investigation. A total of 20 new structures are presented together with their characteristics.     

Al3Li4(BH4)13: A Complex Double‐Cation Borohydride with a New Structure

The new double‐cation Al–Li–borohydride is an attractive candidate material for hydrogen storage due to a very low hydrogen desorption temperature (～70 °C) combined with a high hydrogen density (17.2 wt %). It was synthesised by high‐energy ball milling of AlCl₃ and LiBH₄. The structure of the compound was determined from image‐plate synchrotron powder diffraction supported by DFT calculations. The material shows a unique 3D framework structure within the borohydrides (space group=P‐43n, a=11.3640(3) Å). The unexpected composition Al₃Li₄(BH₄)₁₃ can be rationalized on the basis of a complex cation [(BH₄)Li₄]³⁺ and a complex anion [Al(BH₄)₄]^?. The refinements from synchrotron powder diffraction of different samples revealed the presence of limited amounts of chloride ions replacing the borohydride on one site. In situ Raman spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TG) and thermal desorption measurements were used to study the decomposition pathway of the compound. Al–Li–borohydride decomposes at ～70 °C, forming LiBH₄. The high mass loss of about 20 % during the decomposition indicates the release of not only hydrogen but also diborane.