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Ink-paper historical documents, which are an important part of cultural heritage, can be damaged by various materials on the outside and the inside of the paper. Cotton fiber sheets treated with iron gall ink and then treated with stabilization materials were studied. Nanosized Mg(OH)2 was used as a deacidification material and potassium bromide, tetrabutylammonium bromide, or propyl gallate as antioxidant materials were investigated as a stabilization system for iron gall ink-damaged paper. All samples were artificially aged in the air for 150 h at 65 °C in a UV/moisture chamber or 500 h at 90 °C. The pH and alkaline reserve (AR) measurements, monitoring of color change, and scanning electron microscopy analysis data confirm that the aging effect is more destructive to the iron gall inked paper. The experiment results show that using alkaline materials with antioxidants, such as nano-Mg(OH)2 and propyl gallate, positively affects color changes of ink-damaged paper. Treatment with a stabilization system such as nanosized Mg(OH)2, a binder hydroxypropyl cellulose (Klucel), and an antioxidant as propyl gallate is a suitable method for iron gall ink damaged paper stabilization and preservation, according to the study results. [ABSTRACT FROM AUTHOR]

Ionic complexes [(κ4−PP3)P(OCH2PPh2)3NiX]BF4 (2 (X=Cl) and 3 (X=Br)) were formed when P(OCH2PPh2)3 ligand (1) was reacted with mixtures of salts NiX2/Ni(BF4)2 (X=Cl or Br). Single crystal X‐ray characterizations performed on complexes 2 and 3 established that metal centers are in pseudo‐trigonal bipyramidal ligand geometries formed by the phosphorus centers from coordinated 1 and the halide ligand. Reactions of 1 with other nickel(II) salts (acetate, nitrate or tetrafluoroborate) proceeded in 2 : 1 (ligand‐salt) ratio yielding complex 4, [(κ3−PP2)((−O−P)(OCH2PPh2)2)(κ2−PP)(−O−P)(OCH2PPh2)(OCH2P(=O)Ph2)Ni]. The formation of this complex required hydrolysis of one of the P−O ester bonds in ligand P(OCH2PPh2)3 thus forming O‐anionic phosphite/diphosphine fragment [−O−P(OCH2PPh2)2]. One of such fragments is coordinated to the metal center as a tridentate (κ3−PP2) ligand, whereas the other is in bidentate (κ2−PP) coordination via phosphorus centers of the −O‐P‐OCH2PPh2 chelating pocket; the remaining ‐OCH2P(=O)Ph2 arm is P‐oxidized and uncoordinated. Nickel center in 4 is in distorted trigonal‐bipyramidal geometry, with O‐anionic‐phosphite groups coordinated at the axial positions, and the three ‐PPh2 groups located in the equatorial plane. Compounds 2–4 were characterized by multinuclear NMR spectroscopy, elemental analyses, electron absorption spectroscopy, cyclic voltammetry, and single crystal X‐ray crystallography. Their electronic structures were also investigated by DFT methods. [ABSTRACT FROM AUTHOR]

Calcium hydroxyapatite (Ca10(PO4)6(OH)2,CHAp) has unique characteristics and can be used as artificial material for the recovering of bones and teeth, for drug delivery systems, as adsorbent and catalyst. The specific chemical, structural and morphological properties of calcium hydroxyapatite are highly sensitive to the changes in chemical composition and processing conditions. Various kinds of transition metal and other cations can be readily accommodated into the apatite framework based on their large cation exchangeability. The traces of metal ions introduced in apatite structure can affect the lattice parameters, crystallinity, dissolution kinetics and other physical properties of apatite. The aim of this study was to find more economically accessible metal-substituted calcium hydroxyapatite–based catalyst. In this paper, the sol-gel and co-precipitation synthesis methods were used for the preparation of metal-substituted (M = Mg2+, Zn2+ and Na+) calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp) samples. The synthesized powders were characterized by powder X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and gas chromatography-mass spectrometry (GC-MS). The CHAp:M samples prepared by co-precipitation method were almost single-phase at different concentrations of substituents, while the sol-gel-derived CHAp:M specimens contained additional impurity phases. Metal-containing CHAp samples were tested as catalysts in a solvent-free synthesis of 2-adamantylidene(phenyl)amine. It was demonstrated that the zinc-containing CHAp improved the yield of Schiff base. [ABSTRACT FROM AUTHOR]

Magnesium-aluminium-bismuth-layered double hydroxides (LDH) intercalated with carbonate were studied in respect of maximal rate of substitution of Al by Bi for the first time. LDH with the nominal compositions of MgAlBi-CO ( x = 0 to 0.5) were prepared using both the conventional super saturation co-precipitation method and sol-gel processing via hydration of the mixed oxide powders in carbonate-containing solutions. The mixed oxides were obtained either by calcination of the LDH (prepared by co-precipitation) or by using a novel alkoxide-free sol-gel method. All the LDH products were characterised using the methods of X-ray diffraction, scanning electron microscopy and thermogravimetry. The observed values of the lattice parameters of LDH phases were compared with the calculated values. It has been found that, regardless of the preparation method used and the conditions (pH, temperature, time) applied, the maximum rate of substitution of aluminium by bismuth in LDH is about 20 mol.%. Graphical abstract: A schematic representation of LDH structure of a 3R polytype [4, 5] where the lattice parameter c and the basal spacing d relate to each other as c = 3 d. [ABSTRACT FROM AUTHOR]

An aqueous sol–gel method was used for the preparation of bulk Y3Al5–xFexO12 (yttrium aluminum–iron garnet, YAIG) with the composition of x = 0.0, 1.0, 2.0, 2.5, 3.0, 4.0, 5.0 and thin films with the composition of x = 0, 3.0, 4.0, 5.0. The dip-coating technique was used for the preparation of Y3Al5–xFexO12 films on a silicon (Si) substrate. The phase composition and surface morphology of both bulk and coatings were determined and compared. The synthesized powder samples were investigated by X-ray diffraction analysis, infrared spectroscopy, scanning electron microscopy, and Mössbauer spectroscopy. The data provide evidence that some sol–gel-derived powder specimens consist of magnetically ordered component, while others show paramagnetic behavior depending on the composition of the product. It was also shown that sol–gel processing route could be successfully used for the preparation of mixed-metal YAIG thin films. [ABSTRACT FROM AUTHOR]