Search Results (35)

The structures of hexaammine solvated indium(III) and thallium(III) ions in liquid ammonia solution are determined by EXAFS. Both complexes have regular octahedral coordination geometry with mean In-N and Tl-N bond distances of 2.23(1) and 2.29(2) Å, respectively. Ammine solvated thallium(III) in liquid ammonia is characterized with ²⁰⁵Tl NMR measurements. Solvents such as liquid ammonia, N,N-dimethylthioformamide (DMTF), trialkyl and triphenyl phosphite and phosphine are strong electron pair donors and thereby able to form bonds with a large covalent contribution with strong electron pair acceptors. A survey of reported structures of ammine, DMTF, trialkyl and triphenyl phosphite and phosphine solvated metal ions in the solid state and solution is presented. The M-N and M-S bond distances in ammine and DMTF solvated metal ions are compared with the M-O bond distance in the corresponding metal ion hydrates, expected to form mainly electrostatic interactions with metal ions. The d¹⁰ metal ions have high ability to form bonds with a high degree of covalency with increasing ability down the group and with decreasing charge of the metal ion. The difference in M-N and M-O bond distances between ammine solvated and hydrated metal ions with the same coordination geometry decreases significantly with the increasing ability of the metal ion to form bonds with a large covalent contribution. This difference correlates well with the covalent bonding index, γ_M²*r. Full article

The utilization of platinum complexes in medicine continues to be a prevalent treatment modality for diverse tumour types. However, it should be noted that certain platinum complexes are characterized by a high degree of toxicity. In recent years, there has been a focus among scientists on synthesizing “non-classic” platinum complexes, such as those with a trans-configuration, Pt(IV) complexes, and mixed ammine/amine platinum complexes, with the aim of reducing the toxic side effects of certain platinum complexes, including cisplatin. For instance, newly synthesized platinum complexes with a trans-configuration exhibited substantial cytotoxic activity which was comparable to that of the corresponding cis-isomers and cisplatin. This finding challenged the prevailing cis-geometry paradigm and prompted a re-evaluation of the structural activity relationships (SARs) of antitumour platinum complexes. It is widely accepted that Pt(IV) complexes act as prodrugs and release the active Pt(II) species. This property renders them promising candidates as anticancer drugs. Furthermore, it has been established that mixed ammine/amine platinum complexes are less toxic than cisplatin. In addition, compared to cisplatin, they have been observed to have equivalent or greater cytotoxic activity. Full article

It is known that the effectiveness of drug treatment for depression, ammine deficit based, is largely unsatisfactory. In this review, we examine the proposal of a precision therapy has emerged and has received a strong push by the identification of the role of inflammation in depression. However, precision psychiatry risks being caught in the reductionist trap of searching for the molecular switch that resets the whole system and switches off the disease. This is an illusion since the human being is complex and depression is a systemic and variable disorder. In this study, we show the inadequacy of the reductionist paradigm, and, at the same time, illustrate the superiority of the systemic paradigm centered on psychoneuroendocrineimmunology (PNEI). According to the PNEI paradigm, depression is a disease of the whole human being, caused by different sources working together: psychological, biological, and behavioral. This means knowing the biological and psychological history of the subject, identifying relational and biological crisis factors, and building personalized treatments targeting those factors with the tools of medicine and psychology, which are not reducible to the combination of drugs and psychotherapy. Our proposal presents a paradigm shift that is both theoretical and practical, which enables clinicians to assess patients experiencing depression in a unified way and treat them in an integrated manner. Full article

Rayon is an extremely valuable cellulosic fiber in the global textile industry. Since cuprammonium rayon is more eco-friendly than other types of rayon fabrics, it was synthesized by regenerating α–cellulose isolated from wastepaper using a novel gaseous-ammoniation injection (GAI) process. This was achieved by preparing tetra–ammine copper hydroxide (cuoxam solution) via reacting copper sulfate and sodium hydroxide to produce copper hydroxide that was, finally, ammoniated by injecting the gas directly to the reaction vessel instead of using ammonium hydroxide applied by prior art. After that, the air-dried cellulose was chemically generated by dissolving it in a freshly prepared cuoxam solution and, subsequently, was regenerated by extruding it within a hardening bath constituted mainly from citric acid, producing the cuprammonium rayon (c. rayon). The properties of the fibrous, structural (XRD and mechanical), physical, and chemical features were investigated. It was found that the rayon was produced in a high yield (90.3%) with accepted properties. The fibrous properties of the rayon staple length, linear density, and fiber diameter were found to be 44 mm, 235 Tex, and 19.4 µm, respectively. In addition, the mechanical properties determined, namely tensile strength, elongation at break, modulus of elasticity, and breaking tenacity, were found to be 218.3 MPa, 14.3 GPa, 16.1%, and 27.53 cN/Tex, respectively. Based on this finding, and upon injecting the ammonia gas through the α–cellulose saturated and immersed in the Cu (OH)₂ to complete producing the cuoxam solvent, we find that theuse of an injection rate of 120 mL/minute to obtain the highest fibers’ tensile strength for the final product of the c. rayon is preferable. Utilization of higher rates will consume more amounts of the ammonia gas without gaining noticeable enhancement in the c. rayon’s mechanical quality. Accordingly, the GAI invention rendered the c. rayon favorable for use in making sustainable semisynthetic floss for either insulation purposes or spun threads for woven and nonwoven textile clothing. Full article

This work looks at the effects of a varying concentration, soak time, pH and temperature on the sorption of tetraammineplatinum(II) chloride (Pt-Ammine) in Nafion-117 films in the context of the electroless plating of ionic polymer–metal composites (IPMCs). Sorption is characterised by atomic absorption spectroscopy. A definitive screening design carried out determined all four factors to be significant for further analysis using response surface modelling. A duplicated central composite design (CCD) was utilised to characterise how the four factors affect the sorption amount and efficiency. Regression models for both responses were of poor fit. Nevertheless, key insights were obtained on the effects of the process parameters on sorption behaviour. The results indicate that above 0.5 g/L Pt-Ammine sorption, the platinisation of 10 × 50 mm IPMC samples through sodium borohydride reduction becomes redundant by the surface resistance metric. IPMCs with surface resistance values of approximately 2.5 Ω/square were obtained through only one round of chemical reduction. Varying surface morphologies and electrode thicknesses were analysed under a scanning electron microscope. The CCD parameter settings were validated. Recommended settings for optimised Pt-Ammine sorption in 10 × 50 mm Nafion-117 films were identified as follows: 1.0 g/L Pt-Ammine concentration, 24 h soak time, pH of 3 and temperature of 20 °C. Full article

Zinc is essential for animals, playing a vital role in enzyme systems and various biochemical reactions. It is crucial to ensure a sufficient intake of zinc through the diet to maintain efficient homeostasis. Only few studies on zinc effect in cow lactating diet evaluated the effects on milk and cheese quality, with conflicting findings. 24 cows of the Friesian breed were divided into two groups (CTR: control and TRT: treated group). Cows were selected for age, body weight, parity and phase of lactations (mid lactation, 140–160 days). CTR diet contained 38 mg/kg of Zn and TRT diet was supplied with 120 mg/kg of complete feed for 60 days. The objective of current investigation was to evaluate the impact of a dietary Zinc Oxide (ZnO) integration of lactating Friesian cows on chemical composition, zinc content, fatty acid and proteic profile, ammine content, pH, a_w, texture, and sensory profile of cheese and to improve the chemical-nutritional quality of milk and cheese. The results showed that ZnO supplementation reduced mesophilic aerobic bacteria and Presumptive Pseudomonas spp. growth, proteolysis, biogenic amines content, lipid oxidation, odour intensity and sour and increased hardness, gumminess, chewiness, elasticity of cheese. Biogenic amines are considered an important aspect of food safety. ZnO integration in cow diet could represent a promising strategy for improving the quality, the safety and shelf-life of caciotta cheese. Full article

[Carbonatotetraamminecobalt(III)] permanganate monohydrate was synthesized first in the metathesis reaction of [Co(NH₃)₄CO₃]NO₃ and NaMnO₄ in aqueous solution. Its thermal dehydration at 100 °C resulted in phase-pure [Co(NH₃)₄CO₃]MnO₄ (compound 1). Compounds 1 and 2 (i.e., the hydrated form) were studied with IR, far-IR, and low-temperature Raman spectroscopies, and their vibrational modes were assigned. The lattice parameters were determined by powder X-ray diffraction (PXRD) and single crystal X-ray diffraction (SXRD) methods for the triclinic and orthorhombic compounds 1 and 2, respectively. The detailed structure of compound 2 was determined, and the role of hydrogen bonds in the structural motifs was clarified. UV studies on compounds 1 and 2 showed the distortion of the octahedral geometry of the complex cation during dehydration because of the partial loss of the hydrogen bonds between the crystal water and the ligands of the complex cation. The thermal decomposition consists of a solid phase quasi-intramolecular redox reaction between the ammonia ligands and permanganate anions with the formation of ammonia oxidation products (H₂O, NO, N₂O, and CO₂). The solid phase reaction product is amorphous cobalt manganese oxide containing ammonium, carbonate (and nitrate) anions. The temperature-controlled thermal decomposition of compound 2 in toluene at 110 °C showed that one of the decomposition intermediates is ammonium nitrate. The decomposition intermediates are transformed into Co_1.5Mn_1.5O₄ spinel with MnCo₂O₄ structure upon further heating. Solid compound 2 gave the spinel at 500 °C both in an inert and air atmosphere, whereas the sample pre-treated in toluene at 110 °C without and with the removal of ammonium nitrate by aqueous washing, gave the spinel already at 300 and 400 °C, respectively. The molten NH₄NO₃ is a medium to start spinel crystallization, but its decomposition stops further crystal growth of the spinel phase. By this procedure, the particle size of the spinel product as low as ~4.0 nm could be achieved for the treatments at 300 and 400 °C, and it increased only to 5.7 nm at 500 °C. The nano-sized mixed cobalt manganese oxides are potential candidates as Fischer-Tropsch catalysts. Full article

This paper presents scientific investigations into the materiality and aging behavior of a copy of Dieter Roth’s multiple PO^EMETRIE (1968), mainly made of p-PVC components and minced meat, with the aim of informing conservation-restoration strategies. The main issues were represented by plasticizer migration, fat diffusion, and leakage, which led to the formation of a sticky surface layer. Replicas of p-PVC without minced meat were prepared and artificially thermally aged, while several techniques were used to investigate both the artwork and the replicas in terms of materials and degradation state. These include UV/Vis imaging, pH measurements, FTIR-ATR, and Py-GC/MS. In addition to showing that p-PVC-based materials composed of slightly different plasticizers were affected by similar degradation pathways (i.e., plasticizer migration, yellowing, etc.), this study reports that fat components were also shown to be unstable, resulting in migration/leakage in different directions, where their degradation amplified that of the p-PVC bags. This work represents a first study of plasticizer migration and fat diffusion in the art and conservation context. Also, an ammine-wax type of lubricant was identified in the most recent p-PVC formulations as the replicas selected for this study, thus providing an important source of information in different polymer-based research areas. Full article

Developing rapid and efficient analytical methods is of great importance for food safety Herein, we present a novel homogeneous electrochemical aptasensor for ultrasensitive quantitative determination of zearalenone (ZEN) based on a nanocomposite probe and silica nanochannel film. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and UV–Vis characterization techniques confirm that graphene oxide (GO) bears an aromatic conjugated structure, along with hydroxyl and carboxyl groups, facilitating the subsequent adsorption of cationic redox hexa-ammine-ruthenium (III) (Ru(NH₃)₆³⁺) and anionic ZEN aptamer, to form a Ru(NH3)63+–ZEN aptamer–GO nanocomposite probe in a homogeneous solution. Vertically-ordered mesoporous silica films (VMSF) bearing silanol groups can be simply grown on the solid indium tin oxide (ITO) electrode surface and enable the selective preconcentration of Ru(NH₃)₆³⁺, eventually leading to signal amplification. Since the detachment of Ru(NH₃)₆³⁺ from the GO surface by the recognized ZEN aptamer in the presence of ZEN, more free Ru(NH₃)₆³⁺ is released in solution and produces enhanced redox signals at the VMSF modified ITO electrode, allowing quantitative detection of ZEN. On the basis of the above sensing strategy, the proposed homogeneity, due to the assistance of graphene, as well as of the signal amplification and anti-fouling effects of VMSF, accurate analysis of ZEN can be realized in maize and Chinese chestnut samples. Full article

A series of thirty novel tetracarboxylatoplatinum(IV) complexes in trans-configuration featuring combinations of mixed ammine, methylamine, dimethylamine, and cyclopentylamine ligands as well as acetato/propanoato and trifluoropropanoato ligands was synthesised. The platinum(IV) complexes were characterised by one- and two-dimensional multinuclear NMR spectroscopy (¹H, ¹³C, ¹⁵N, ¹⁹F, ¹⁹⁵Pt), ESI-MS, elemental analysis, and X-ray diffraction. Additional parameters such as reduction behaviour and lipophilicity were measured via NMR spectroscopy and RP-HPLC, revealing slow reduction and a broad spectrum of log k_w values in line with the respective ligand combination. In order to determine structure–activity relationships, cytotoxic activity was evaluated via the MTT assay in three human cancer cell lines (CH1/PA-1, ovarian teratocarcinoma, SW480, colon adenocarcinoma, A549, non-small-cell lung carcinoma). The induction of apoptosis and necrosis was determined in SW480 cells via the flow-cytometric annexin V/PI assay. In general, a tendency of higher lipophilicity leading to higher cytotoxicity was noticed. In contrast, lipophilicity alone plays a subordinate role for the induction of apoptosis, which strongly depends on the combination of am(m)ine and trifluoropropanoato ligands. Full article

The maritime sector is among the most polluting industrial sectors in the world. To oppose this and following the global trend towards carbon neutrality, the International Maritime Organization (IMO) introduced the objective to reduce the CO₂ emission of vessels by the year 2030 of 40% and at the same time the European Union will introduce the maritime sector into the ETS system. Therefore, there is a need to reduce the emissions of the working vessels, and this can be accomplished through the Carbon Capture and Storage (CCS). There are many possible CCS technologies that can be applied to vessels: the one that has already been studied the most is the ammine scrubbing of the exhaust gasses. In parallel, other technologies have been proposed to reduce volume and energy needs, which are the Molten Carbonate Fuel Cells (MCFCs), membrane technologies, fixed bed absorption processes and limestone. The review shows how, depending on the used vessel type, the technology to be used may vary, and proposes some preferential options for different applications. The obtained results can be of relevant importance in the present context of energy transition promoting immediate retrofitting to respond to the urgent request for intervention. Full article

The mineral-like anthropogenic phase Zn(NH₃)₂Cl₂, with ammine (NH₃⁰) complexes from the burned dumps of the Chelyabinsk coal basin (South Urals, Russia), has been investigated using single-crystal and high-temperature powder X-ray diffraction, and Raman and infrared (IR) spectroscopy. The anthropogenic Zn(NH₃)₂Cl₂ is orthorhombic, Imma, a = 7.7399(6), b = 8.0551(5), c = 8.4767(8) Å, V = 528.49(7) ų, R₁ = 0.0388 at −73 °C. Its crystal structure is based upon isolated ZnN₂Cl₂ tetrahedra connected by hydrogen bonds (between NH₃ groups and Cl atoms) into a three-dimensional network. Upon heating, the Zn(NH₃)₂Cl₂ phase is stable up to about 150 °C, which is in good agreement with the data on the temperature of its formation. The crystal structure of Zn(NH₃)Cl₂ expands anisotropically with the strongest thermal expansion observed along the a axis. The thermal expansion of the structure is controlled by the changes in the hydrogen bonding system. The Raman and IR spectroscopic characteristics of this phase are close to those of the mineral ammineite, CuCl₂(NH₃)₂. The studied anthropogenic phase, formed in the unique conditions of burned coal dumps, is identical to the synthetic Zn(NH₃)₂Cl₂. Full article

The preparation of ammine complexes of transition metals having oxidizing anions such as permanganate and perrhenate ions is a great challenge due to possible reactions between ammonia and oxidizing anions during the synthesis of these materials. However, it has an important role in both the development of new oxidants in organic chemistry and especially in the preparation of mixed-metal oxide catalyst precursors and metal alloys for their controlled temperature decomposition reactions. Therefore, in this paper, synthetic procedures to prepare ammonia complexes of transition metal permanganate, pertechnetate, and perrhenate (the VIIB group tetraoxometallates) salts have been comprehensively reviewed. The available data about these compounds’ structures and spectroscopic properties, including the presence of hydrogen bonds that act as redox reaction centers during thermal decomposition, are given and evaluated in detail. The nature of the thermal decomposition products has also been summarized. The available information about the role of the ammine complexes of transition metal permanganate salts in organic oxidation reactions, such as the oxidation of benzyl alcohols and regeneration of oxo-compounds from oximes and phenylhydrazones, including the kinetics of these processes, has also been collected. Their physical and chemical properties, including the thermal decomposition characteristics of known diammine (Ag(I), Cd, Zn, Cu(II), Ni(II)), triammine (Ag(I)), and simple or mixed ligand tetraammine (Cu(II), Zn, Cd, Ni(II), Co(II), Pt(II), Pd(II), Co(III)), Ru(III), pentaammine (Co(III), Cr(III), Rh(III) and Ir(III)), and hexaammine (Ni(II), Co(III), Cr(III)) complexes of transition metals with tetraoxometallate(VII) anions (M = Mn, Tc and Re), have been summarized. The preparation and properties of some special mixed ligand/anion/cation-containing complexes, such as [Ru(NH₃)₄(NO)(H₂O)](ReO₄)₂, [Co(NH₃)₅(H₂O)](ReO₄)₂, [Co(NH₃)₅X](MnO₄)₂ (X = Cl, Br), [Co(NH₃)₆]Cl₂(MnO₄), [Co(NH₃)₅ReO₄]X₂ (X = Cl, NO₃, ClO₄, ReO₄), and K[Co(NH₃)₆]Cl₂(MnO₄)₂, are also included. Full article

[κ²-O,O′-Carbonatotetraamminecobalt(III)] iodide, or [Co(NH₃)₄CO₃]I, named in this paper as compound 1, was prepared and characterized comprehensively with spectroscopic (IR, Raman and UV) and single-crystal X-ray diffraction methods. Compound 1 was orthorhombic, and isomorphous with the analogous bromide. The four ammonia ligands and the carbonate anion were coordinated to the central cobalt cation in a distorted octahedral geometry. The carbonate ion formed a four-membered symmetric planar chelate ring. The complex cations were bound to each other by N-H···O hydrogen bonds and formed zigzag sheets via an extended 2D hydrogen bond network. The complex cations and iodide ions were arranged into ion pairs and each cation bound its iodide pair through three hydrogen bonds. The thermal decomposition started with the oxidation of the iodide ion by Co^III in the solid phase resulting in [Co(NH₃)₄CO₃] and I₂. This intermediate Co^II-complex in situ decomposed into Co₃O₄ and C-N bond containing intermediates. In inert atmosphere, CO or C-N bond containing compounds, and also, due to the in situ decomposition of CoCO₃ intermediate, Co₃O₄ was formed. The quasi-intramolecular solid-phase redox reaction of [Co(NH₃)₄CO₃] might have resulted in the formation of C-N bond containing compounds with substoichiometric release of ammonia and CO₂ from compound 1. The C-N bond containing intermediates reduced Co₃O₄ into CoO and Co, whereas in oxygen-containing atmosphere, the end-product was Co₃O₄, even at 200 °C, and the endothermic ligand loss reaction coincided with the consecutive exothermic oxidation processes. Full article

We synthesized and characterized (IR, Raman, UV, SXRD) hexaamminecobalt(III) dichloride permanganate, [Co(NH₃)₆]Cl₂(MnO₄) (compound 1) as the precursor of Co–Mn–spinel composites with atomic ratios of Co:Mn = 1:1 and 1:3. The 3D−hydrogen bond network includes N–HO–Mn and N–HCl interactions responsible for solid-phase redox reactions between the permanganate anions and ammonia ligands. The temperature-limited thermal decomposition of compound 1 under the temperature of boiling toluene (110 ${}^{\circ }$C) resulted in the formation of (NH₄)₄Co₂Mn₆O_12. which contains a todorokite-like manganese oxide network (Mn^II₄Mn^III₂O₁₂¹⁰⁻). The heat treatment products of compounds 1 and [Co(NH₃)₅Cl](MnO₄)₂ (2) synthesized previously at 500 ${}^{\circ }$C were a cubic and a tetragonal spinel with Co_1.5Mn_1.5O₄ and CoMn₂O₄ composition, respectively. The heating of the decomposition product of compounds 1 and 2 that formed under refluxing toluene (a mixture with an atomic ratio of Co:Mn = 1:1 and 1:2) and after aqueous leaching ((NH₄)₄Co₂Mn₆O₁₂, 1:3 Co:Mn atomic ratio in both cases) at 500 ${}^{\circ }$C resulted in tetragonal Co_0.75Mn_2.25O₄ spinels. The Co_1.5Mn_1.5O₄ prepared from compound 1 at 500 ${}^{\circ }$C during the solid-phase decomposition catalyzes the degradation of Congo red with UV light. The decomposition rate of the dye was found to be nine times faster than in the presence of the tetragonal CoMn₂O₄ spinel prepared in the solid-phase decomposition of compound 2. The todorokite-like intermediate prepared from compound 1 under N₂ at 115 ${}^{\circ }$C resulted in a 54 times faster degradation of Congo red, which is a great deal faster than the same todorokite-like phase that formed from compound 2 under N₂. Full article