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Abstract: Sodium complexes of aminotroponiminate (ATI) ligands have been reacted with a range of neutral donor ligands. Upon addition of crown ethers, they undergo an unusual ligand‐induced disproportionation reaction with formation of [Na(ATI)2]− sodiate complex anions. The same structural motif has also been found in the first well‐defined mixed‐metal ATI complexes, which have been accessed starting from monometallic sodium and potassium species. The mixed‐metal compounds confirm the possibility of ATIs to act as ditopic ligands. Using the polymerization of ϵ‐caprolactone as a model system, structure‐reactivity‐relationships in sodium and mixed‐metal ATI compounds have been studied by comparing the reactivity of [Na(ATI)] and [Na(ATI)2]− structural motifs. These studies revealed trends in the catalyst activity depending on the nuclearity of the complex and the substitution pattern at the ATI ligand. Exceptionally high activities were obtained for dinuclear sodium sodiates of type [Na(crown)2][Na(ATI)2], making them the most active alkali metal initiators for this reaction. The organometallic and polymeric compounds presented in this work have been characterized by techniques including (VT‐)NMR spectroscopy, single‐crystal X‐ray diffraction, gel permeation chromatography, mass spectrometry, and DFT calculations. [ABSTRACT FROM AUTHOR]

A mixed decamethyltitanocene(III) isonitrile alkynyl complex ( 7) was synthesized by the sequential introduction of the isonitrile and alkynyl ligands. Direct synthesis results in the formation of the diamagnetic decamethyltitanocene bis(isonitrile) ( 2) and bis(alkynyl) ( 3) complexes. Compound 7 undergoes disproportionation at room temperature to give 2 and 3. All complexes were fully characterized by IR, NMR, and EPR spectroscopy, and mass spectrometry. Molecular structures for complexes 2 and 7 are reported. The stability and reactivity of these complexes are rationalized by DFT computations. [ABSTRACT FROM AUTHOR]

Single crystals of NbF4, niobium(IV) tetrafluoride, were synthesized by disproportionation of Nb2F5 at 1273 K in a sealed niobium tube, extracted and studied by single-crystal X-ray diffraction. Previous reports on the crystal structure of NbF4 were based on X-ray powder diffraction data and the observed isotypicity to SnF4 [Gortsema & Didchenko (1965). Inorg. Chem. 4, 182-186; Schäfer et al. (1965). J. Less Common Met. 9, 95-104]. The data obtained from a single-crystal X-ray diffraction study meant the atomic coordinates could now be refined as well as their anisotropic displacement parameters, leading to a significant improvement of the structural model of NbF4. In the structure, the Nb atom is octahedron-like surrounded by six F atoms of which four are bridging to other NbF6 octahedra, leading to a layer structure extending parallel to the ab plane. [ABSTRACT FROM AUTHOR]

As-cast Nd–Fe–B strips without an annealing treatment were treated by an appropriate hydrogenation–disproportionation–desorption–recombination (HDDR) process, and highly textured HDDR strip powders with uniform Nd-rich grain boundary layers can be obtained. The HDDR powders with a particle size of 50~\mu \textm show a Br of 1.13 T and a iHc of 10.5 kOe. The crystal texture in the HDDR powders may come from the memory for the own crystallographic orientation and the casting texture of Nd2Fe14B columnar grains in the as-cast strips. The highly textured HDDR powders with uniform Nd-rich grain boundary layers can be used to prepare the fine-grained sintered magnets by a conventional jet-milling technique and sintering process. [ABSTRACT FROM AUTHOR]

In this work, we present the synthesis and characterization of two new mononuclear complexes with the ligand 1,3-bis[(2-aminoethyl)amino]-2-propanol (HL), [Co(L)(H2O)](ClO4)2 (1), [Ni(HL)](ClO4)2 (2), as well as the known complex [Cu(HL)](ClO4)2 (3) for comparison. Their abilities to catalyze the dismutation of H2O2 and the oxidation of cyclohexane were investigated. The complexes were characterized by X-ray diffraction, elemental analysis, electronic and infrared spectroscopy, cyclic voltammetry, electrospray ionization mass spectrometry (ESI-MS) and conductivity measurements. The X-ray structures showed that the nickel (2) and copper (3) complexes are tetracoordinated, with the metal ion bound to the nitrogen atoms of the ligand. On the other hand, the cobalt complex (1) is hexacoordinated, possessing additional bonds to the alkoxo group of the ligand and to a water molecule. Neither of the complexes was able to catalyze the oxidation of cyclohexane, but all of them exhibited catalase-like activity, following Michaelis-Menten kinetics, which suggest resemblance with the catalase natural enzymes. The catalytic activity followed the order: [Ni(HL)](ClO4)2 (2) > [Cu(HL)](ClO4)2 (3) > [Co(L)(H2O)](ClO4)2 (1). As far as we know, this is the first description of a nickel complex presenting a significant catalase-like activity. [ABSTRACT FROM AUTHOR]

The behavior of An(V) (An = Np, Pu, and Am) in aqueous solutions of dipicolinic acid (in particular, the resistance to disproportionation) was studied. Taking these data into account, procedures were developed for preparing crystalline An(V) dipicolinates. Crystals of Li[AnO(DPA)]· nHO ( n = 4 and 6) of X-ray quality were prepared from aqueous solutions with pH 2-3. The trends in variation of the bond lengths in the complex compounds of An(V) and An(VI) with dipicolinic acid, caused by actinide contraction, were analyzed. [ABSTRACT FROM AUTHOR]

The oxidation of the earlier synthesized [4,6-di- tert-butyl- N-(2,6-diisopropylphenyl)- o-amidophenolato]methylgallium( iii) ( 1a) and [4,6-di- tert-butyl- N-(2,6-diisopropylphenyl)- o-amidophenolato]iodogallium( iii) ( 1b) by different reagents, such as mercury( ii) salts, molecular iodine, and tetramethylthiuram disulfide, was studied. The oxidation of the starting diamagnetic compounds gives pentacoordinated gallium( iii) bis- o-iminosemiquinolates 4-7 as the major products, which are generated as a result of the further disproportionation of intermediate monoradical tetracoordinated metal complexes. [ABSTRACT FROM AUTHOR]

Thermal stability of the \Nd12.5{\Fe}80.6{\B}6.4{\Ga}0.3{\Nb}0.2 hydrogenation, disproportionation, desorption and recombination (HDDR)-treated powder was studied, and it was correlated to the residual hydrogen in the powder. Presence of the residual hydrogen in the HDDR-treated powder was investigated by X-ray diffraction (XRD), thermopiezic analyser (TPA) and hydrogen analysis. The HDDR-treated material contained a significant amount of hydrogen, and it influenced the thermal stability of the material. Coercivity of the HDDR-treated powder was markedly reduced by heating above 600 ^\circ\C, and it was related to the residual hydrogen. The residual hydrogen existed in the form of \Nd2{\Fe}14{\BH}x hydride, and it was disproportionated into \alpha \-\Fe, \Fe2{\B} and \NdH2 phases at an elevated temperature. The coercivity reduction was attributed to the magnetically soft \alpha-Fe and \Fe2{\B} phases formed by the disproportionation. [ABSTRACT FROM PUBLISHER]

The paper determines the phase composition of the ground KS37 alloy after conventional and solid hydrogenation and disproportionation (SmCo being the main phase and SmCo the impurity phase) at a hydrogen pressure of 0.1-0.4 MPa and at temperatures up to 950°C for 5 h. It is established that products resulting from grinding of the SmCo phase interact with hydrogen to 560°C to form SmCo and unidentified phases. The SmCo phase disproportionates in the temperature range 560-650°C and pressure range 0.1-0.4 MPa for 2 h. Recombination at 650-950°C leads to the SmCo, SmCo, and SmCo phases. The SmCo content of the recombined alloy is the highest at 950°C. It is shown that grinding in hydrogen prior to hydrogenation, disproportionation, desorption, and recombination accelerates the disproportionation reaction owing to the formation of defects during grinding. The high-temperature recombination of the SmCo phase in hydrogen is confirmed. [ABSTRACT FROM AUTHOR]

A series of tridentate pincer ligands, each possessing two sulfur and one nitrogen donor (SNS), based on bis-imidazolyl or bis-triazolyl salts were metallated with CuCl2to give new tridentate SNS pincer copper(I) complexes [(SNS)Cu]+. These orange complexes exhibit a three-coordinate pseudo-trigonal-planar geometry in copper. During the formation of these copper(I) complexes, disproportionation is observed as the copper(II) salt precursor is converted into the Cu(I) [(SNS)Cu]+cation and the [CuCl4]2–counteranion. The [(SNS)Cu]+complexes were characterized with single crystal X-ray diffraction, electrospray mass spectrometry, EPR spectroscopy, attenuated total reflectance infrared spectroscopy, UV–Vis spectroscopy, cyclic voltammetry, and elemental analysis. The EPR spectra are consistent with anisotropic Cu(II) signals with four hyperfine splittings in the lower-field region (g||) andgvalues consistent with the presence of the tetrachlorocuprate. Various electronic transitions are apparent in the UV–Vis spectra of the complexes and originate in the copper-containing cations and anions. Density functional calculations support the nature of the SNS binding, allowing assignment of a number of features present in the UV–Vis and IR spectra and cyclic voltammograms of these complexes. [ABSTRACT FROM AUTHOR]

Changes in the structure and phase composition of silicon monoxide in the disproportionation reaction at high temperatures with the formation of a nanocrystalline silicon phase are studied. On itsseparation from the silicon oxides, the nanosilicon powder is subjected to X-ray diffraction analysis and examined by the small-angle X-ray scattering technique. It is found that, under the optimal heat-treatment conditions of silicon monoxide, the powder obtained contains nanosilicon particles with sizes of 17-20 nm and a volume fraction of 40%. [ABSTRACT FROM AUTHOR]

The compositional dependence of the negative thermal expansion (NTE) property of Bi1-xLnxNiO3 (Ln = La, Nd, Eu, Dy) was investigated. All x = 0.05 samples showed large NTE over αL = -70 ppm/K (αL: coefficient of linear thermal expansion) due to intermetallic charge transfer between Bi5+ and Ni2+. The temperature range of NTE shifted upward with decreasing ionic radius of Ln3+. Partial ordering of Bi/Ln is suggested to be the origin of this shift and the suppression of the broadening of the transition. [ABSTRACT FROM AUTHOR]

This study deals with the behavior of molybdenum–vanadium (Mo/V) mixed oxides catalysts in both disproportionation and selective oxidation of toluene. Samples containing different Mo/V ratios were prepared by a modified method using tetradecyltrimethylammonium bromide and acetic acid. The catalysts were characterized using several techniques: nitrogen adsorption–desorption isotherms, X-Ray diffraction (XRD), ammonia temperature-programmed desorption (TPD-NH3), temperature-programmed reduction by hydrogen (H2-TPR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier-transform infrared-spectroscopy (FTIR) and ultraviolet-visible spectroscopies (UV–VIS). The XRD results evidenced the presence of orthorhombic α-MoO3 and V2O5 phases, as well as monoclinic β-MoO3 and V2MoO8 phases, their abundance depending on the Mo to V ratio, while the TPD-NH3 emphasized that, the total amount of the acid sites diminished with the increase of the Mo loading. The TPR investigations indicated that the samples with higher Mo/V ratio possess a higher reducibility. The main findings of this study led to the conclusion that the presence of strong acid sites afforded a high conversion in toluene disproportionation (Mo/V = 1), while a higher reducibility is a prerequisite to accomplishing high conversion in toluene oxidation (Mo/V = 2). The catalyst with Mo/V = 1 acquires the best yield to xylenes from the toluene disproportionation reaction, while the catalyst with Mo/V = 0.33 presents the highest yield to benzaldehyde. [ABSTRACT FROM AUTHOR]