Presence Of Transition Metals Research Articles

Selective Hydroboration of C-C Single Bonds without Transition-metal Catalysis.

Selective hydroboration of C-C single bonds presents a fundamental challenge in the chemical industry. Previously, only catalytic systems utilizing precious metals Ir and Rh, in conjunction with N- and P- ligands, could achieve this, ensuring bond cleavage and selectivity. In sharp contrast, we discovered an unprecedented and general transition-metal-free system for the hydroboration of C-C single bonds. This methodology is transition-metal and ligand-free and surpasses the transition-metal systems regarding chemo- and regioselectivities, substrate versatility, or yields. In addition, our system tolerates various functional groups such as Ar-X (X = halides), heterocyclic rings, ketones, esters, amides, nitro, nitriles, and C=C double bonds, which are typically susceptible to hydroboration in the presence of transition metals. As a result, a diverse range of γ-boronated amines with varied structures and functions has been readily obtained. Experimental mechanistic studies, density functional theory (DFT), and intrinsic bond orbital (IBO) calculations unveiled a hydroborane-promoted C-C bond cleavage and hydride-shift reaction pathway. The carbonyl group of the amide suppresses dehydrogenation between the free N-H and hydroborane. The lone pair on the nitrogen of the amide facilitates the cleavage of C-C bonds in cyclopropanes.

Molecular-strain induced phosphinidene reactivity of a phosphanorcaradiene

Phosphanorcaradienes are an appealing class of phosphorus compounds that can serve as synthons of transient phosphinidenes. However, the synthesis of such species is a formidable task owing to their intrinsic high reactivity. Herein we report straightforward synthesis, characterization and reactivity studies of a phosphanorcaradiene, in which one of the benzene rings in the flanking fluorenyl substituents is intramolecularly dearomatized through attachment to the phosphorus atom. It is facilely obtained by the reduction of phosphorus(III) dichloride precursor with potassium graphite. Despite being thermally robust, it acts as a synthetic equivalent of a transient phosphinidene. It reacts with trimethylphosphine and isonitrile to yield phosphanylidene-phosphorane and 1-phospha-3-azaallene, respectively. When it is treated with one and two molar equivalents of azide, iminophosphane and bis(imino)phosphane are isolated, respectively. Moreover, it is capable of activating ethylene and alkyne to afford [1 + 2] cycloaddition products, as well as oxidative cleavage of Si–H and N–H bonds to yield secondary phosphines. All the reactions proceed smoothly at room temperature without the presence of transition metals. The driving force for these reactions is most likely the high ring-constraint of the three-membered PC2 ring and recovery of the aromaticity of the benzene ring.

First-principles investigations and Monte Carlo simulation of Ti and Cr-doped w-ZnO and (Ti,Cr) co-doped w-ZnO based magnetic semiconductors: Materials for spintronic applications

This research paper investigates the electronic structure and magnetic properties of Ti-doped ZnO (Zn1−xTixO), Cr-doped ZnO (Zn1−xCrxO) and (Ti,Cr)-codoped ZnO (Zn1−xTix2Crx2O) systems with x = 0.08 and 0.12 dopant concentrations using density functional theory (DFT) combined with Monte Carlo simulation (MCS). Ab-initio calculations were based on spin-polarized density functional theory (SDFT) and were carried out within the framework of the GGA+U formalism. The study focuses on the impact of transition metal doping (TM = Ti, Cr) on the structural, electronic, and magnetic properties of the systems. The geometric analysis reveals that lattice parameters and bond lengths between atoms are influenced by the concentration of transition metal (TM) doping. The formation energies of all models indicate their energetic stability, making them suitable for synthesis in the laboratory. The results reveal that Ti-doped ZnO (ZTO), Cr-doped ZnO (ZCO), and (Ti,Cr)-codoped ZnO (ZTCO) systems exhibit a half-metallic behavior, with the Fermi level passing through localized impurity states. These systems behave as n-type semiconductors, with the Fermi level shifting into the conduction band. The presence of transition metal (TM) impurities in ZnO material enhances its magnetic moment and Curie temperature. Additionally, Monte Carlo simulation demonstrates that ZCO exhibits a Curie temperature above room temperature, consistent with experimental studies. Moreover, the co-doping of (Ti,Cr) in ZnO allows for the adjustment of the Curie temperature. At low temperatures, the hysteresis loop becomes more significant. These findings indicate the potential suitability of ZTO, ZCO, and ZTCO systems for spintronic applications.

Conductive Covalent Organic Frameworks of Polymetallophthalocyanines as a Tunable Platform for Electrocatalysis.

Developing an electrocatalyst platform that can control the interplay among activity, selectivity, and stability at atomic precision remains a grand challenge. Here, we have synthesized highly crystalline polymetallophthalocyanines (pMPcs, M = Fe, Co, Ni, and Cu) through the annulation of tetracyanobenzene in the presence of transition metals. The conjugated, conductive, and stable backbones with precisely installed metal sites render pMPcs a unique platform in electrochemical catalysis, where tunability emerges from long-range interactions. The construction of pCoNiPc with a Co and Ni dual-site integrates the advantageous features of pCoPc and pNiPc in electrocatalytic CO2 reduction through electronic communication of the dual-site with an unprecedented long atomic separation of ≥14 chemical bonds. This integration provides excellent activity (current density, j = -16.0 and -100 mA cm-2 in H-type and flow cell, respectively), selectivity (CO Faraday efficiency, FECO = 94%), and stability (>10 h), making it one of the best-performing reticular materials.

Effects of redox active agents on cyanocobalamin stability in heated milk

SummaryReducing agents and oxidizing agents have been identified as contributors to vitamin B12 losses associated with food processing and/or storage. We evaluated the effects of redox active agents on cyanocobalamin stability in heat‐treated non‐fat milk and neutral pH buffers. The largest average cyanocobalamin losses occurred in the presence of an added thiol (glutathione, cysteine, dithiothreitol and the thiamine decomposition product 2‐methyl‐3‐furanthiol) or dithionite, whereas cyanocobalamin recoveries generally increased in the presence of an added oxidizing agent. Cyanocobalamin instability in the heat‐treated, non‐fat milk (~40% loss after 90 min at 100 °C) was attributed to a combination of heat, cystine/cysteine, oxygen and a low‐level presence of transition metals, a combination also found in many other foods for which B12 instability has been reported. The proposed cyanocobalamin decomposition pathway – complexation with heat‐exposed cysteine thiolate, cobalt reduction, hydrolysis of the complex, conversion to hydroxocobalamin and irreversible oxidation – follows the sequence described by others.

Exploration of effects by the ‘alum-glue solution’ on Xuan paper degradation using a 23 factorial design experiment

In the traditional Chinese conservation mounting process, it is well acknowledged that the alum-glue solution, composed of potassium aluminum sulfate [KAl(SO4)2·12H2O], gelatin, and water, is commonly used for paper sizing. In this study, its adverse effects when prepared in different ratios on the contemporary Xuan paper are explored, demonstrating certain negative influences on material properties and paper durability. We primarily characterized an extra-pure Xuan paper as a reference sample. Then, a 23 full factorial experiment was designed and performed to explore the effects of the three factors, i.e., KAl(SO4)2·12H2O (denoted as alum), animal glue or gelatin (denoted as glue), and water contents on rates of paper degradation [kΔ(1/DP)] and color changes (kΔL and kΔb). The results show that the unsized extra-pure Xuan paper sample has good stability due to appreciable alkaline reserve, weakly alkalinity, and no presence of transition metals. Fourier transform infrared (FTIR) spectra and scanning electron microscope (SEM) images demonstrate the presence of sizing. Given that the alum-glue solution has been widely used in paper conservation, the results in this study demonstrate the devastating role of KAl(SO4)2·12H2O and the protective effects of gelatin on durability of treated papers, verified by the DP-related data. Additionally, it was found that the presence of alum is mainly responsible for the lightness decrease of the treated papers, and animal glue plays a primary role in paper yellowing. The findings in this research can deepen our understanding of the rate of paper degradation and color changes for the Xuan paper treated with the alum-glue solution.

High-Temperature Co-Electrolysis and Degradation by Oxidized Trace Contaminants in Feed Gases

The transformation of our energy system will likely require the indirect electrification of the sectors heating, chemical industry and mobility by power-to-X processes, because not all processes can easily use electrical power directly. The high-temperature co-electrolysis using solid-oxide cells (SOCs) can produce syngas compositions desired by the downstream power-to-X process without the need of a reverse water-gas shift reactor and is therefore particularly well suited to produce synthesis gas as feedstock for various power-to-fuel and power-to-chemicals processes. Besides, a coupling of heat-producing downstream processes would increase system efficiency significantly.1 Besides the intrinsic degradation processes of the cells (e.g. nickel migration) and stacks (e.g. contact deterioration) any additional processes triggered by impurities in the feed gases are of relevance for any technical applications. Under certain circumstances, impurities can be introduced by Balance of Plant (BoP) components like the steam generators or preheaters that can release silicon species.2 Also, the feed gases themselves may contain harmful substances. This poisoning effect must be taken into account, because economically gases of lower qualities are preferred as purification steps increase the costs of the syngas. Depending on the exact source of carbon dioxide (CO2) the supplier uses, it contains different secondary components, of which sulfur species are of particular concern. In contrast to fuel-cell mode operation, in electrolysis mode operation hydrogen sulfide (H2S) is not the most likely candidate, but sulfur dioxide (SO2). The reasons for this is that CO2 may be obtained from combustion processes and that hydrogen sulfide is not stable in the atmosphere but has a short half-life time.Therefore, understanding the influence of SO2 contained in the supplied carbon dioxide on the performance of the co-electrolysis is of great importance. There is substantial knowledge about the impact of H2S in feed gases in fuel-cell mode, but the impact of sulfur dioxide in electrolysis mode is not as well investigated. Skafte et al. reported a severe effect in CO2 electrolysis with as low as 20 ppb H2S.3 In the context of this application, the relevant sulfur species present in the feed gases will be SO2. It should be noted, that the heterogenous reduction of SO2 with hydrogen or carbon monoxide is catalyzed by oxides with oxygen vacancies and mobility like CeO2 or YSZ and facilitated by the presence of transition metals.4 Intermediary steps and products beside H2S can include significant amounts of elemental S and COS and the formation of sulfided nickel seems likely. The formation of these products depends on the exact reaction conditions, e.g. temperature, H2/SO2 ratio, steam content, which makes the situation more complex as in fuel-cell mode with hydrogen as fuel. Jeanmonod et al. came to the conclusion, that even concentrations of SO2 as low as 0.5 ppm caused irreversible degradation in Ni/YSZ electrodes in co-electrolysis mode.5 This contribution will report about investigations performed on the degradation caused by sulfur dioxide and silicon species in sub-ppm concentrations in SOCs with Ni/YSZ and Ni/GDC fuel electrodes operated in co-electrolysis mode, using stacks in the Jülich F10 and F20 design. These targeted their impact, potential recovery, possible damage mechanisms and safe thresholds of sulfur dioxide in carbon dioxide. For this the authors performed long-term stationary operation, monitoring of poisoning experiments by electrochemical impedance spectrocopy and post-test analysis of cells, including SEM/EDX and chemical trace analyses. Acknowledgement The authors would like to thank their colleagues at Forschungszentrum Jülich GmbH for their great support and the Helmholtz Society as well as the the German Federal Ministry of Education and Research for financing these activities as part of the Kopernikus P2X-2 project (03SFK2Z0-2). References (1) Peters, R.; Wegener, N.; Samsun, R. C.; Schorn, F.; Riese, J.; Grünewald, M.; Stolten, D. A Techno-Economic Assessment of Fischer–Tropsch Fuels Based on Syngas from Co-Electrolysis. Processes 2022, 10 (4), 699. https://doi.org/10.3390/pr10040699.(2) Schäfer, D.; Queda, L.; Nischwitz, V.; Fang, Q.; Blum, L. Origin of Steam Contaminants and Degradation of Solid-Oxide Electrolysis Stacks. Processes 2022, 10 (3), 598. https://doi.org/10.3390/pr10030598.(3) Skafte, T. L.; Blennow, P.; Hjelm, J.; Graves, C. Carbon Deposition and Sulfur Poisoning during CO2 Electrolysis in Nickel-Based Solid Oxide Cell Electrodes. Journal of Power Sources 2018, 373, 54–60. https://doi.org/10.1016/j.jpowsour.2017.10.097.(4) Liu, W.; Sarofim, A. F.; Flytzani-Stephanopoulos, M. Reduction of Sulfur Dioxide by Carbon Monoxide to Elemental Sulfur over Composite Oxide Catalysts. Applied Catalysis B: Environmental 1994, 4 (2–3), 167–186. https://doi.org/10.1016/0926-3373(94)00019-0.(5) Jeanmonod, G.; Diethelm, S.; Van Herle, J. The Effect of SO 2 on the Ni-YSZ Electrode of a Solid Oxide Electrolyzer Cell Operated in Co-Electrolysis. J. Phys. Energy 2020, 2 (3), 034002. https://doi.org/10.1088/2515-7655/ab8b55.

Selective hydrogenation of eggshell/clamshell to methane with the assistance of the alkaline earth and transition metals at room temperature

Producing clean fuel using shell wastes (eggshell and clamshell) can eliminate food waste and alleviate the energy shortage. Mechanochemical hydrogenation of eggshell/clamshell was investigated at room temperature. The results show that the alkaline earth metals can effectively assist the hydrogenation of shell wastes to CH4. The calcium metal has a better effect, and the methane yield for the calcium-assisted hydrogenation of clamshell and eggshell reaches 45.04% and 33.30% with 100% CH4 selectivity. At the same time, the calcium-assisted methanation of shell wastes in the presence of transition metals (Fe, Co, Ni, Ru) was investigated. By doping Ru, the methane yield of clamshell and eggshell was improved to 52.62% and 54.76%, respectively. The milling time, rotating speed, hydrogen pressure, and the species of the doped transition metals influence the calcium-assisted methanation of shell wastes. This study provides an alternative method to eliminate shell wastes and produce clean CH4 fuel at room temperature.

Spotlight on the Winners of the DCO‐SCF 2021 Awards – An Ever Valuable Collaboration with EurJOC

Spotlight on the Winners of the DCO‐SCF 2021 Awards – An Ever Valuable Collaboration with EurJOC

Magnetic nanoparticles modified with a copper(i) complex as a novel and efficient reusable catalyst for A3 coupling leading to C-N bond formation.

Propargylamines are an important and valuable family of nitrogen-containing compounds with many applications in the fields of medical, industrial, and chemical processes. One-pot multicomponent A3 coupling reactions of aldehydes, amines, and alkynes in the presence of transition metals as catalysts is an efficient strategy for preparing propargylamines. In this study, we fabricated a novel magnetically reusable copper nanocatalyst [Fe3O4-BIm-Pyrim-CuI] through the immobilization of the copper(i) complex on the surface of the magnetic nanoparticles modified with benzimidazole-pyrimidine ligand and evaluated its catalytic activity in the preparation of propargylamines through one-pot multicomponent A3 coupling reactions of aldehydes, amines, and alkynes. Under this catalytic system, aryl substrates with both electron-donating and electron-withdrawing substituents also gave the desired products in excellent yields under standardized conditions. The Fe3O4-BIm-Pyrim-CuI catalyst was easily separated using an external magnet, and the recovered catalyst was reused in 8 cycles without significant loss of activity.

Aerobic-peroxide oxidation of naphthalene in the presence of transition metal on a nanocarbon carrier

The paper describes the results of aerobic-peroxide catalytic oxidation of naphthalene in the presence of iron-containing multi-walled carbon nanotubes Fe@MWCNT. The active nanocarbon substrate containing α-iron atoms and carbides realizes by the Fenton reaction active formation of active particles and intensive oxidation of the hydrocarbon under rather mild conditions. It was found that at the temperature range 333 - 353K, in the presence of hydrogen peroxide (30% aqueous solution) and Fe@MWCNT (Fe ≈3.7 wt. %), under intense air current, the reaction proceeds without destroying the cyclic structure of the molecule with predominant formation of phthalic anhydride and naphthol. Identification of the functional groups of the main target products was performed by the infrared (IR) spectroscopy. The results obtained can be proposed for further development of such studies and bringing them into compliance with the standards of the industrial process. Keywords: aerobic oxidation of hydrocarbons; oxidation of naphthalene; hydrogen peroxide; multi-walled carbon nanotubes; nanocarbon catalysis; Fenton system, oxygencontaining aromatic compounds.

Characterization of some Nigerian coal for effective power generation and industrial utility

Large numbers of trace elements occur in coals used for coal power plants combustion. In order to assess the environmental impact of the coal fuel cycle, coal and coal ash samples need to be analyzed for a number of toxic and radioactive elements. Six coal samples from Ridi-Awe and Lafia (Nasarawa State), Garin Maiganga (Gombe state) Nigeria coal deposit were collected. The samples were subjected to gross calorific value determination, X-ray diffraction spectrometry, X-ray fluorescence spectroscopy to determine it suitability for power generation and industrial utility. Base on the laboratory analysis and results, it is observed that the gross calorific values of Awe are 29.18MJ/kg, 30.79MJ/kg. Lafia are 26.10MJ/kg, 25.10MJ/kg and Maiganga are 25.50MJ/kg, 24.21MJ/kg respectively. The XRF results indicates the presence of transition metals and some trace element but void of elements such as Arsenic, tin and tungsten which makes it environmental and health hazard friendly. The proximate analysis revealed that the % ash content of Awe, Lafia, and Maiganga is 87, 62, 79. % moisture content of Awe, Lafia, and Maiganga is 8.7, 16.3, 8.3 and % volatile matter content of Awe, Lafia, and Maiganga coals is 4.3, 21.7 and 12.7 whereas % fixed carbon of Awe, Lafia, and Maiganga 78.3,55.8 and 71.1 respectively. However, in terms of coal rank, the Awe is bituminous high volatile C, whereas Lafia and Maiganga coal are Subbituminous A, hence the reactivity and maturity of the coal decrease in the order of Awe (A) ˂ Lafia (L) ˂ Maiganga (M). The result shows that the coal samples are void of nitrogen and dangerous radioactive elements.

Photocatalytic degradation of methyl orange in the presence of transition metals (Mn, Ni, Co) modified TiO2 coatings formed by plasma electrolytic oxidation

The effect of selected transition metals (Mn, Ni, Co) modified TiO2 coatings formed by plasma electrolytic oxidation of titanium on their surface morphology, phase and chemical composition, optical absorption, and photocatalytic degradation of methyl orange (MO) was investigated. Coatings were formed in an alkaline electrolyte with varying concentrations of MnO, NiO, or Co3O4 powders. The morphology, thickness and phase structure of all formed coatings are nearly identical and independent of the content of transition metal ions embedded in TiO2. The X-ray diffraction and X-ray photoelectron spectroscopy results indicated that anatase TiO2 coatings were loaded with MnO, NiO, or Co3O4 from electrolytes. When up to 2.0 g/L of MnO, NiO, or Co3O4 is added to the electrolyte, the photocatalytic activity (PA) of the forming coatings is higher than for pure TiO2. The coatings formed in electrolyte with the addition of 0.75 g/L MnO, 1.5 g/L NiO, or 2.0 g/L Co3O4 had the highest PA. Increased PA is associated with a decrease in photogenerated electron/hole recombination rate, according to UV–Vis diffuse reflectance spectroscopy and photoluminescence measurements.

Oxygen-Sensitive Metalloprotein Structure Determination by Cryo-Electron Microscopy.

Metalloproteins are involved in key cell processes such as photosynthesis, respiration, and oxygen transport. However, the presence of transition metals (notably iron as a component of [Fe-S] clusters) often makes these proteins sensitive to oxygen-induced degradation. Consequently, their study usually requires strict anaerobic conditions. Although X-ray crystallography has been the method of choice for solving macromolecular structures for many years, recently electron microscopy has also become an increasingly powerful structure-solving technique. We have used our previous experience with cryo-crystallography to develop a method to prepare cryo-EM grids in an anaerobic chamber and have applied it to solve the structures of apoferritin and the 3 [Fe4S4]-containing pyruvate ferredoxin oxidoreductase (PFOR) at 2.40 Å and 2.90 Å resolution, respectively. The maps are of similar quality to the ones obtained under air, thereby validating our method as an improvement in the structural investigation of oxygen-sensitive metalloproteins by cryo-EM.

Bitumen and asphaltene derived nanoporous carbon and nickel oxide/carbon composites for supercapacitor electrodes

Asphaltenes from bitumen are abundant resource to be transformed into carbon as promising supercapacitor electrodes, while there is a lack of understanding the impact from different fractions of bitumen and asphaltenes, as well as the presence of transition metals. Here, nanoporous carbon was synthesized from bitumen, hexane-insoluble asphaltenes and N,N-dimethylformamide (DMF)-fractionated asphaltenes by using Mg(OH)2 nanoplates as the template with in-situ KOH activation, and used as an supercapacitor electrode material. All of the carbon exhibited large surface area (1500–2200 m2 g−1) with a distribution of micro and mesopores except for that derived from the DMF-soluble asphaltenes. The pyrolysis of asphaltenes resulted in the formation of nickel oxide/carbon composite (NiO/C), which demonstrated high capacitance of 380 F g−1 at 1 A g−1 discharge current resulting from the pseudocapacitance of NiO and the electrochemical double layer capacitance of the carbon. The NiO/C composite obtained from the DMF-insoluble portion had low NiO content which led to lower capacitance. Meanwhile, the specific capacitance of NiO/C composite from the DMF-soluble part was lower than the unfractionated asphaltene due to the higher NiO content resulting in lower conductivity. Therefore asphaltenes derived from nickel-rich crude bitumen is suitable for the synthesis of nanoporous NiO/C composite material with high capacitance.

A new view on Redox processes in aquatic systems

In the present paper, the redox processes in the aquatic environment were studied, by conducting fundamental research and the mechanisms of chemical reactions with the participation of natural oxidizing agents in the presence of transition metals. It is a synthesis of scientific results including a new vision regarding the chemical reactions with one or two electrons transfer, which explains how the free radicals and complex compounds with partial charge transfer are formed. This view includes an explanation for the phenomenon of aggressive free radical generation that “kills” biota, rather than destroying pollutants, and why the intermediate particles resulting from chemical and biochemical processes act much softer.

Copper Supported on Mesoporous Structured Catalysts for NO Reduction

Nitrogen oxides (NOx) are one of the pollutants of greatest concern in terms of atmospheric contamination and, consequently, human health. The main objective of this work, is the synthesis of structured carbon catalysts, introducing on their surface metals and nitrogen groups, catalytically active in NO reduction. Structured catalysts represent an attractive alternative to powder catalysts because they have better thermal stability and lower pressure drop. The catalysts were synthesized by coating a melamine foam using precursor solutions of carbon xerogels with and without nitrogen (using melamine and urea as precursors), and impregnated with transition metals (Fe, Ni and Cu). The introduction of nitrogen and metals modified the textural properties of the materials. Samples synthesized with melamine presented the highest amount of nitrogen, while the highest content of copper, found to be the most active transition metal for NO reduction, was found in structured catalysts impregnated with urea. The presence of transition metals in catalysts is essential for the reduction of NO to N2 and the introduction of nitrogenous precursors makes this evident. The synthesis and application of carbon-supported structured catalysts containing transition metals for NO reduction is demonstrated in this work for the first time, as well as the study of the factors influencing their performance.

Development of catalysts for the synthesis of higher hydrocarbons from carbon dioxide

The paper is devoted to the development of a catalyst for the synthesis of the higher hydrocarbons from carbon dioxide and hydrogen. The conversion of greenhouse gas CO2 into value-added chemicals contributes not only to sol-ving environmental problems, but also to obtaining valuable fuel. Catalysts that are active in the hydrogenation reaction of CO are also active in the process of CO2 hydrogenation. The most active catalysts in the hydrogenation of carbon dioxide are based on transition metals, in the presence of which mainly methane and a small amount of carbon monoxide are formed. Investigation of the kinetics of hydrocarbons synthesis by hydrogenation of carbon dioxide in the presence of transition metals allowed establishing the mechanism of the process and no perspective of such catalytic systems for hydrocarbons synthesis via intermediate formation of carbon monoxide. It is established that the optimal method of synthesis of higher hydrocarbons is the indirect path, through the intermediate formation of methanol with its further dehydration. The synthesis of methanol from gas mixtures of H2, CO, and CO2 with different composition in the presence of industrial catalysts takes place along the same macroscopic route, by reducing CO2, and is accompanied by a reverse water-gas shift reaction. Therefore, gas mixtures of different composition can be used as raw material for methanol production. Based on our own and literature data, the general peculiarities of the carbon dioxide hydrogenation reaction were obtained, which allowed developing a complex multifunctional catalyst for the synthesis of higher hydrocarbons from carbon dioxide and hydrogen. The proposed catalyst combines the properties of ones for the synthesis of oxygenates from carbon dioxide, and catalysts for the processes of hydrocarbons synthesis from me-thanol and other alcohols. The synthesis of higher hydrocarbons with a predominant content of branched hydrocarbons on the developed bifunctional catalyst was carried out and the optimal conditions for the process were determined.

Transition metal complexes of the PPO/POP ligand: variable coordination chemistry and photo-luminescence properties.

In the current work the tautomeric equilibrium between tetraphenyldiphosphoxane (Ph2P-O-PPh2, POP) and tetraphenyldiphosphine monoxide (Ph2P-P(O)Ph2, PPO) in the absence and presence of transition metal precursors is investigated. Whereas with hard transition metal ions, such as Fe(II) and Y(III), PPO-type complexes, such as [FeCl2(PPO)2] (1) and [YCl3(THF)2(PPO)] (2), are formed, softer transition metals ions tend to form so-called coordination stabilised tautomers of the POP ligand form, such as [Cu2(MeCN)3(μ2-POP)2](PF6)2 (3), [Au2Cl2(μ2-POP)] (4), and [Au2(μ2-POP)2](OTf)2 (5). The photo-optical properties of the PPO- and POP-type transition metal complexes are investigated experimentally using photo-luminescence spectroscopy, whereby the presence of metallophillic interactions was found to play a crucial role. The dinuclear copper complex [Cu2(MeCN)3(μ2-POP)2](PF6)2 (3) shows a very interesting thermochromic behavior and intense photo-luminescence with remarkable phosphoresence lifetimes at 77 K, which can probably be attributed to short intramolecular Cu-Cu distances.

Effects of Selected Metal Chlorides on the Micellization Parameters of Cetrimonium Bromide at Different Temperatures

The pre-modification of surfactant counterions using transition metal salts provides a means to activate the interface using corresponding properties of metal ions. In this work, a cationic surfactant cetyltrimethylammonium bromide (CTAB) was modified by pre-mixing metal chlorides (FeCl3, CuCl2 and ZnCl2) and CTAB in 1:1 molar ratio using methanol as solvent. As a result, FeCl3, CuCl2 and ZnCl2 were added as [FeCl3Br]-1, [CuCl2Br]-1 and [ZnCl2Br]-1 respectively acting as counter anions (CAs) instead of bromide anion. Hence CTAB was called CTAF, CTAC and CTAZ in order of added CAs i.e., [FeCl3Br]-1, [CuCl2Br]-1 and [ZnCl2Br]-1 respectively. The effect of these metal chlorides on the micellar behaviour of CTAB was investigated using conductivities of their different solutions. Furthermore, the critical micelle concentration (CMC) as well as the degree of counterion binding were considered at 25.0, 30.0, 35.0, 40.0 and 45.0 and#176;C 0.1 and#176;C. The analysis of results revealed that incorporation of metal cations reduces the CMC values in the order CTAF CTAZ CTAC CTAB. Change in entropy (S), enthalpy (H) and free energy (G) were calculated to understand the thermodynamics of micellization under the circumstances. The aim of this study is to improve the understanding regarding the presence of transition metals in micellization process as well as the possibility of their interactions with Bromide counterions and possibility of the formation of complex counter-anions.