Stable Electronic Configuration Research Articles

Design of Thermally Activated Delayed Fluorescence Materials: Transition from Carbonyl to Amide‐Based Acceptor

AbstractBenzophenone skeletons containing a carbonyl unit (O=C) have been widely used as electron acceptors in the thermally activated delayed fluorescence (TADF) materials. Herein, we present a novel molecular design concept for TADF materials by transitioning from a carbonyl to an amide (O=C−N) skeleton as the acceptor. The amide unit, compared to its carbonyl counterpart, offers a more stable electronic configuration. Leveraging this insight, we have developed a series of high‐performance TADF molecules based on benzoyl carbazole and carbazoline acceptors. These molecules exhibit exceptionally small singlet‐triplet energy gaps and pronounced aggregation‐enhanced emission properties, achieving photoluminescence quantum yields in neat films as high as 99 %. Consequently, these materials serve as efficient emitters in non‐doped organic light‐eimtting diodes (OLEDs), reaching a maximum quantum efficiency (EQEmax) of up to 26.0 %, significantly higher than the 17.0 % obtained with benzophenone acceptor‐based TADF molecules. Additionally, they have been used as TADF hosts in narrowband red fluorescent OLEDs, setting a record‐high EQEmax of 22.4 %.

Design of Thermally Activated Delayed Fluorescence Materials: Transition from Carbonyl to Amide-Based Acceptor.

Benzophenone skeletons containing a carbonyl unit (O=C) have been widely used as electron acceptors in the thermally activated delayed fluorescence (TADF) materials. Herein, we present a novel molecular design concept for TADF materials by transitioning from a carbonyl to an amide (O=C-N) skeleton as the acceptor. The amide unit, compared to its carbonyl counterpart, offers a more stable electronic configuration. Leveraging this insight, we have developed a series of high-performance TADF molecules based on benzoyl carbazole and carbazoline acceptors. These molecules exhibit exceptionally small singlet-triplet energy gaps and pronounced aggregation-enhanced emission properties, achieving photoluminescence quantum yields in neat films as high as 99 %. Consequently, these materials serve as efficient emitters in non-doped organic light-eimtting diodes (OLEDs), reaching a maximum quantum efficiency (EQEmax) of up to 26.0 %, significantly higher than the 17.0 % obtained with benzophenone acceptor-based TADF molecules. Additionally, they have been used as TADF hosts in narrowband red fluorescent OLEDs, setting a record-high EQEmax of 22.4 %.

Organotin (IV) complexes: Synthesis, characterization, DFT, and molecular docking studies unveiling their potential biomedical uses

This study investigates organotin (IV) complexes derived from the recently synthesized quinazoline Schiff base ligand (L). The research involves synthesizing and characterizing these complexes, including elemental analysis, UV–visible, FT‐IR, mass spectra, and conductometric measurements. Advanced studies such as density functional theory (DFT) are employed to gain insights into the stable electronic configuration. Specifically, the study explores the proposed geometry, revealing a distorted octahedral structure for the complexes. The findings contribute as critical molecular characteristics of these newly synthesized complexes, paving the way for potential applications in diverse fields, including medicinal chemistry. Through an investigation into the antimicrobial properties, the efficacy of the synthesized compounds was assessed against a diverse range of bacterial and fungal strains. Remarkably, the complexes demonstrated significant antimicrobial activities, showing potential applications in combating various microbial infections. In an extended exploration of their medical utility, the compounds were examined for their antibiotic properties against Helicobacter pylori. The Schiff base and its metal complexes emerged as promising antibiotics with notable efficacy against H. pylori, suggesting their potential in addressing infections associated with this bacterium. Furthermore, the antitumor potential of the synthesized complexes was investigated, focusing on their impact on MCF‐7 (Breast carcinoma) cells. The organotin (IV) Schiff base complexes in this research showed remarkable efficacy, evidenced by their notably low IC50 values (9, 10, 11 μg/mL) in comparison with cisplatin. In addition to their potent antitumor effects, these complexes exhibited reduced cytotoxicity toward normal cells (VERO cells) compared with cisplatin. The investigation extends to molecular docking, where this approach aims to elucidate their interactions with specific protein structures, including (2JFZ, 1SC7, and 6W41). The primary objective is to clarify the potential properties of these compounds, focusing on their antibiotic efficacy, anti‐H. pylori activity, antitumor potential, and anti‐COVID‐19 properties.

Selectivity regulation of CO2 photoreduction via the electron configuration of active sites on single-atom photocatalysts

The major challenge in the photocatalytic reduction of CO2 is to achieve high conversion efficiency while maintaining selectivity for a single product. Photocatalysts containing single-metal Cu2+ with 3d9 and Zn2+ with 3d10 on g-C3N4 were prepared using a high-energy ball mill. Single-atom Zn inner electron configuration is stable (3d10) and the peripheral empty orbitals act as electron traps to trap photo-generated electrons and improve the efficiency of charge separation; Zn is an active site to enhance the adsorption and activation of CO2. The stable electron configuration can reduce the energy required for the overall reaction and increase the activity while changing the reaction pathway to form CO. As a result, the 0.5 mol% Zn/g-C3N4 (Zn-CN-0.5) photocatalyst achieves ∼100 % selectivity for the photocatalytic reduction of CO2 to CO at a rate of ∼21.1 μmol·g−1·h−1. In contrast, the 0.5 mol% Cu/g-C3N4 (Cu-CN-0.5) photocatalyst with an unstable electronic structure does not exhibit high selectivity.

In-situ synthesis of 2D Z-scheme MnTiO3/g-C3N4 heterostructure for efficient electrocatalytic hydrogen production

BackgroundZ-scheme semiconductor heterostructure promotes the practical separation of electron-hole pairs and enhances the carrier separation efficiency, which has broad application prospects in efficient electrocatalytic hydrogen production (HER). However, it remains a significant challenge to construct high-quality directly Z-scheme heterostructure effectively. MethodsIn this work, the construction of stable and controllable two-dimensional (2D) Z-scheme MnTiO3/C3N4 (MTO/CN) heterostructure via In-situ growth strategy is obtained. This strategy relies mainly on the cooperation of ligand covalent bonds arising from the controlled growth of precursors and the tendency of metal ions to acquire stable electronic configurations. Significant findingsBenefiting from the unique electronic structure of heterostructure, the excellent performance of HER based on the MTO/CN heterostructure is systematically investigated. It reveals that the overpotential of the MTO/CN heterostructure is only 357 mV at 10 mA cm2, which is 2.02 times lower compared to the pure g-C3N4. At the same time, the ESCA results show that the value of Cdl of the heterostructure is 42.79 mF cm−2, which is 6.26 times higher compared to the pure g-C3N4. Furthermore, this strategy provides new insight and theoretical guidance for the design of the Z-scheme semiconductor heterostructure.

Computational exploration of Cu(II)-en chelate-catalyzed hydrolysis of O-isopropyl methylphosphonofluoridate

In contrast to un-catalyzed hydrolysis of organophosphorus (OP) compounds, metal ions or/and their complexes with chelating ligands show catalytic effects in several ways depending upon the nature of the metal, ligand, substrate, and medium. It is known that Cu(II)-en chelate containing copper complexes accelerate the hydrolysis of OP compounds. However, the mechanism for this rate enhancement in the Cu(II)-en chelate catalytic hydrolysis reaction of sarin remains unexplored. We have examined possible mechanisms involving a Cu(II)-en with hydroxide nucleophile for the reaction pathway of the hydrolysis of O-isopropyl methylphosphonofluoridate (sarin) computationally. The density functional (B3LYP) employed in this study has reproduced the experimental Gibb’s free energy of activation value 15.5 kcal/mol for alkaline hydrolysis of sarin. Earlier proposal of push–pull mechanism for metal ion chelate-catalyzed hydrolysis of OP compounds has been found to be unfavorable in the present study. The role of water molecules in catalyzing the hydrolysis of sarin with Cu(II)-en chelate is crucial. The catalytic process involving Cu(II)-en chelate with one water molecule is the more plausible pathway to achieve the hydrolysis of sarin with Cu(II)-en chelate complexes. The most popular B3LYP method was used for optimization of given geometries. Except LANL2DZ for Cu atom, all the atoms are described using the 6–31 + G(d) basis set. The stability test has been performed for the wave functions as we are dealing with the open-shell molecules in order to ensure stable electronic configuration form, and the stable wavefunction is used as the initial configuration for the subsequent optimization. Harmonic frequency calculations and thermodynamic corrections were performed at the same level of theory. PCM method has been used for solvation effects. In order to ensure that each saddle point is linked to a minimum, IRC calculations were performed in forward and reverse directions to ensure the eigenvectors associated with the unique negative eigenvalues of the Hessian matrix. All energies discussed are solvated Gibbs free energies corrected to 298.15 K for the relative stability of the chemical structure. All calculations were performed using the Gaussian 09 code.

Van der Waals nanomesh electronics on arbitrary surfaces

Chemical bonds, including covalent and ionic bonds, endow semiconductors with stable electronic configurations but also impose constraints on their synthesis and lattice-mismatched heteroepitaxy. Here, the unique multi-scale van der Waals (vdWs) interactions are explored in one-dimensional tellurium (Te) systems to overcome these restrictions, enabled by the vdWs bonds between Te atomic chains and the spontaneous misfit relaxation at quasi-vdWs interfaces. Wafer-scale Te vdWs nanomeshes composed of self-welding Te nanowires are laterally vapor grown on arbitrary surfaces at a low temperature of 100 °C, bringing greater integration freedoms for enhanced device functionality and broad applicability. The prepared Te vdWs nanomeshes can be patterned at the microscale and exhibit high field-effect hole mobility of 145 cm2/Vs, ultrafast photoresponse below 3 μs in paper-based infrared photodetectors, as well as controllable electronic structure in mixed-dimensional heterojunctions. All these device metrics of Te vdWs nanomesh electronics are promising to meet emerging technological demands.

Co and Ni single sites on the (111)n surface of γ-Al2O3 – a periodic boundary DFT study

Coordination of Co and Ni single-atom on the most active tri-coordinated Al/Metal single-site (111)n surface of γ-Al2O3 leads to stable electron configuration of d7 for Co and d8 for Ni on the surface of γ-Al2O3.

Insights into the aftereffects phenomenon in solids based on DFT and time-differential perturbed γ−γ angular correlation studies in 111In (→ 111Cd) -doped tin oxides

Recently, a model based on a combined ab initio/time-differential perturbed $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ angular correlation (TDPAC) study in the $^{111}\mathrm{In}(\ensuremath{\rightarrow}^{111}\mathrm{Cd})$-doped ${\mathrm{SnO}}_{2}$ semiconductor was proposed to enlighten the origin of the dynamic hyperfine interactions (HFIs) observed in oxides after the electron-capture (EC) decay of the probe nucleus of the $^{111}\mathrm{In}$ parent. It was demonstrated that both the EC as well as the acceptor level introduced by the Cd impurity can contribute to the variation of the electric-field gradient (EFG) at the Cd site (responsible for this phenomenon) due to charge fluctuations of the electronic holes created [Darriba et al., J. Phys. Chem. C 122, 17423 (2018)]. To disentangle both effects, we performed here TDPAC reversible experiments in $^{111}\mathrm{In}(\ensuremath{\rightarrow}^{111}\mathrm{Cd})$-doped SnO in the temperature range 20--900 K and a complete electronic structure density functional theory study of the Cd-doped SnO system as a function of the charge state $(q)$ of the impurity. The isovalent $^{111}\mathrm{Cd}$ probe impurity in this isocationic oxide was selected to demonstrate that the acceptor character of the probe is not a necessary condition to observe this electronic phenomenon when the EC is already present. A majority fraction of probes sensed a time-dependent HFI (HFI1) for all temperatures, and the unexpected minority always sensed a static interaction (HFI2). Comparing results from these experiments, the ab initio calculations of the EFG tensor and defect formation energies, HFI1 and HFI2, were assigned to $^{111}\mathrm{Cd}$ probes localized at substitutional Sn sites free of defects [with the valence band (VB) completely filled, $q=0$] and with an electronic hole trapped $(q=1+)$, respectively. In addition, we show that the systems with charge state between these values have very similar formation energies at the top of the VB and different predicted EFGs, giving support from first principles to the existence of random fluctuations between different EFGs, necessary in the construction of the on-off perturbation factor used. We demonstrate that all the probes fill their electronic holes before the TDPAC time window except the outermost one, giving a quantification of the number of electronic holes involved in the production of the dynamic effect, only one in SnO. The probes related to HFI2 reach their stable electronic configuration $(q=1+)$ before the emission of the first \ensuremath{\gamma} ray $({\ensuremath{\gamma}}_{1})$ of the \ensuremath{\gamma}-\ensuremath{\gamma} cascade, while those related to HFI1 fill the last hole after the emission of ${\ensuremath{\gamma}}_{1}$, producing the dynamic interaction. Enlighted by these results and reviewing TDPAC experiments from the literature using probes with different nuclear decay characteristics, we concluded that, in the absence of EC decay of the probe nucleus of the parent, any probe impurity introducing acceptor or donor states (in semiconductors and insulators) whose ionization changes the EFG should observe a time-dependent HFI provided the lifetime of the nuclear levels that feed the ${\ensuremath{\gamma}}_{1}$ level and this level itself is shorter than the lifetime of the recovery process (i.e., the lifetime of the electronic holes or the ionized donor electrons).

Low-Dimensional Metal–Organic Frameworks with High Activity and Selectivity toward Electrocatalytic Chlorine Evolution Reactions

Chlorine gas plays a paramount role in modern industrial chemistry and is one of the most basic chemicals produced by the electrolysis of brine solution. In the past decades, the dimensionally stable anode (DSA) made of RuO2 is the benchmark catalyst for the chlorine evolution reaction (CER) with high activity. However, the drawbacks of the DSA, such as high cost and inferior selectivity, demand the development of low-cost and efficient electrocatalysts for CER. Herein, three low-dimensional Fe/Co/Ni-dithiolene metal–organic frameworks (MOFs) were systematically investigated using the density functional theory. Our calculation results predict that Ni-based dithiolene MOF can efficiently catalyze the CER with a low thermodynamic overpotential of 0.049 V via the Cl* intermediate. The electronic resonance structure of [Ni2+(L•–)(L2–)]− in the Ni-based dithiolene MOF leads to the electron transfer first from S atoms in ligands to Ni cations to achieve a stable electronic configuration, which leads to the most desirable Ni–Cl interaction strength for CER. Moreover, the selectivity to Cl2 generation is due to its high thermodynamic overpotential of oxygen evolution reaction. Our findings may, therefore, accelerate CER catalyst discoveries beyond DSAs with the optimized electronic structures.

Direct conversion of N2 and O2: status, challenge and perspective.

As key components of air, nitrogen (N2) and oxygen (O2) are the vital constituents of lives. Synthesis of NO2, and C-N-O organics direct from N2 and O2, rather than from an intermediate NH3 (known as the Haber-Bosch process), is tantalizing. However, the extremely strong N≡N triple bond (945kJmol-1) and the nonpolar stable electron configuration of dinitrogen lead to its conversion being extensively energy demanding. The further selective synthesis of high-value C-N-O organics directly from N2, O2 and C-containing molecules is attractive yet greatly challenging from both scientific and engineering perspectives. Enormous efforts have been dedicated to the direct conversion of N2 and O2 via traditional and novel techniques, including thermochemical, plasma, electrochemical, ultrasonic and photochemical conversion. In this review, we aim to provide a thorough comprehension of the status and challenge of the direct conversion of N2, O2 and C-containing molecules (particularly N2 and O2). Moreover, we will propose some future perspectives to stimulate more inspiration from the scientific community to tackle the scientific and engineering challenges.

The Difficulties of X Grade High School Students in Palangka Raya City Academic Year of 2018/2019 in Understanding Chemical Bond Concept using Two-Tier Multiple Choice

The concept of chemical bonds is one of the concepts that students are less familiar with, so there is a need for a diagnostic test to determine students' difficulty. This study aims to describe students' difficulties in understanding the concept of chemical bonds using two-tier multiple-choice which includes the following sub: (1) stable electron configuration, (2) valence electrons, (3) ionic bonds, (4) covalent bonds, and (5) metal bonds. The subjects of this study were students of class X MIA from SMA Negeri 1 Palangka Raya, SMA Negeri 3 Palangka Raya, and SMA Negeri 4 Palangka Raya with a total number of research subjects being 335 students. Students' difficulties in understanding the concept of chemical bonds were expressed using the Tes Kemampuan Ikatan Kimia (TKIK) form two-tier multiple choice of 15 questions and interviews to confirm the students' difficulty. The test results of TKIK showed a reliability of 0.68, an item discrimination power of 0.5, and an item difficulty level of 0.41. The results showed that the difficulty of the students in understanding the concept of chemical bonds with the percentage of the most difficult to easy difficulties was in order to determine the covalent bonds of 58.7%, determined the ionic bond at 55.4%, determined the metal bond at 54.3%, determined the stable electron configuration of 35.8%, and determine the valence electrons at 35.1%.

NUMERICAL CALCULATION OF THE CHARGE STATE AND ELECTROSTATIC POTENTIAL OF A BINARY NANOCLUSTER STRUCTURE WITH SI2ZNS CELLS IN A CUBIC LATTICE OF CRYSTALLINE SILICON WITH A DIAMOND STRUCTURE

Numerical calculation of electronic and atomic structures of complex systems of crystalline and transitional nano- and micro-sizes by using quantum physical methods will make it possible to forecast new properties of crystalline silicon with various concentrations of clusters of impurity atoms, structural arrangement at lattice sites and types of clusters. The quantum-chemical method was used to calculate the required characteristics of the cell, i.e. the charge state and electrostatic potential for the base matrix of Si (silicon) and silicon with an impurity cluster consisting of 3 tetrahedral cells type- Si2ZnS in the base lattice of Si. Calculation of the electrostatic potential of the base lattice of Si, and silicon with an impurity cluster of Si2ZnS in the Si lattice revealed a noticeable change in the potential intensity at the cell sites. In the cluster, charge transfer occurs from S (sulfur) atoms to Zn (zinc) atoms. Zn atoms at sites acquire a negative charge while S atoms acquire a positive charge. In fact, the numerical calculation confirms the hypothesis that instead of completing its structure to the most stable electronic configuration ... s2p6, in certain cases the chalcogen atom can also donate some of its electrons to form a quasi-stable configuration ... sp3.

ANALISIS KESALAHAN MAHASISWA DALAM MENYELESAIKAN SOAL IKATAN KIMIA

Chemical bonding is an important topic in chemistry. The chemistry students have to expert on the topic. Due to the importance of chemical bonding topic, qualitative descriptive research was conducted to analyze the students' errors in solving the chemical bond problems. The participants were 38 students of the third semester of Chemistry Education Department in one of the universities in Aceh, Indonesia. The result showed that the percentage of the students’ errors in solving the chemical bonds problems was high with an average of 69.08%, it means that the students’ ability in understanding chemical bond concepts is still low. This research concludes two things. First, the types of errors in solving chemical bonds problems are the students’ error in understanding the basic concepts of chemical bonds, lack of understanding of the concept how an element has a stable electron configuration, the mechanism of the difference in the forming of ion bonds and covalent bonds, the influence of geometric figures, the resultant molecular dipole moments, the number of electronegativity to molecular pollutants, the writing of a Lewis structure for molecules and polyatomic ions, the determining of the formal contents of each atom of a Lewis molecular structure, and the drawing of the Lewis structure. Second, the causes of students’ errors have forgotten the materials and also pre-requisite materials and inaccurate in reading and solving the problems. These results need to be considered in the learning process in order to improve students’ ability in solving chemical bond problems.

The Use of Silane-Aniline as Coupling Agent between Titanium (IV) Oxide Core and Polyaniline Emeraldine Salt Shell

Stable electronic configuration between the interface of an n-type oxide semiconductor core and a p-type polymer shell is necessary in order to guarantee a consistent functioning core-shell structure. This research aims to use silane-aniline to link between an n-type Titanium (IV) oxide (TiO2) core and p-type polyaniline emeraldine salt (PANI-ES) shell. Core-shell structure was created by functionalizing TiO2 powders with silane aniline molecules using simple soaking technique and then polymerizing the attached aniline molecules using an oxidative technique. Infrared spectroscopy reveals the presence of Si-O bonds signifying the presence of linkage between the inorganic core and polymeric shell. Polymerization of the attached aniline molecules may have led to coupling of aromatic rings to form long polymeric structures which caused widening and shifting of aromatic rings’ IR peak to lower wavenumber. In conclusion, silane-aniline was successfully utilized to connect the n-type TiO2 core and p-type PANI-ES shell.

Lithium ion storage in 1D and 2D redox active metal-organic frameworks

The lithium ion storage properties of a series of metal-organic frameworks (MOFs) with formula {[M(L)(H2O)2]H2O}n and [M(CA)(Pyz)]n (where L refers to the tetraoxolene ligands: CA = chloranilate and DHBQ = dihydroxybenzoquinone; Pyz = pyrazine; M = Fe and Mn) and exhibiting a 1D and 2D structure, respectively, have been studied. The 1D MOFs ({[M(L)(H2O)2]H2O}n) show higher reversible capacity values for lithium ion insertion with respect to 2D structures containing two organic ligands (M(CA)(Pyz)]n). The gravimetric capacity for the 1D Fe-CA MOF is 75 mAh/g at 2.16 mA/g (∼ 1 lithium atom per formula unit) higher than for the Mn complexes which is 65 mAh/g at 2.12 mA/g, though isostructural. Lithium ion insertion in the 1D Mn-CA chains takes place at 2.4 V vs. Li+/Li which is ∼700 mV higher than what is recorded for the Fe analogue. This result is most probably due to much more stable d5 electronic configuration of Mn2+ than d6 of Fe2+ in its isostructural Fe-based framework analogue of the final reduced phases. The 1D Fe-DHBQ capacity is higher than its manganese analogue 75 mAh/g at 2.5 mA/g (0.8 lithiums) against 40 mAh/g. In general, the high voltages of reaction in these 1D MOFs suggest that they involve the participation of the ligand on the redox processes along with the reduction of the transition metal if any. In fact, the potential of ion insertion changed depending on the metal. This fact along with the absence of evidence of conversion reaction by x-ray diffraction of cycled electrodes suggests that the charge delocalization may be all along the metal-ligand molecular framework participating as a whole hybrid unit in the lithium storage.

Atomic-scale identification of influencing factors of sodium dendrite growth on different current collectors

In the process of Na ion plating on SWCNTs and Cu/Al current collector surfaces, SWCNTs exhibit the highest electron transfer ability and the most stable electron configuration, inducing the instability of the Na dimer, but favour the presence of evenly distributed Na adatoms.

ДО ПИТАННЯ ТЕОРІЇ ПРОЦЕСУ БОРУВАННЯ ЗАЛІЗО-ВУГЛЕЦЕВИХ СПЛАВІВ В МАГНІТНОМУ ПОЛІ

The article offers an analysis of the results of the processes of formation of iron borides from the point of view of quantum theory. The object of study is the phase composition, physicomechanical and electrophysical properties of boride, borosilicidal and aluminum-boride coatings on iron and steel. The research method is x-ray and metallographic analysis. Based on the analysis of the results of the formation of iron borides on boron diffusion from the point of view of quantum theory, it was found that a significant increase in the physicomechanical properties of partially microhardness and wear resistance occurs by establishing stable electronic configurations of chemical compounds. So, when creating FeB compounds, boron atoms (2s22p1) form sp3 configurations due to electrons of iron atoms (3d64s2), which have the donor property to form stable d5 configurations. Experimental studies of the properties of chemical compounds that form during diffusion saturation confirm a correlation with their electronic structure, and iron atoms tend to form a strong covalent bond with boron atoms. KEY WORDS: BORING, BOROSILICATION, ATOMS, ENERGY LEVELS, QUANTUM NUMBERS, ELECTRON CONFIGURATION.

Superoxide dismutase mimic activity of spinel ferrite $${\hbox {MFe}}_{2} {\hbox {O}}_{4}$$ MFe 2 O 4 ( $$\hbox {M} = \hbox {Mn}$$ M = Mn , Co and Cu) nanoparticles

In the present study, superoxide dismutase (SOD) mimic activity of ferrite nanoparticles (NPs), having a formula \({\hbox {MFe}}_{2} {\hbox {O}}_{4}\) (\(\hbox {M} = \hbox {Mn}\), Co and Cu) was investigated. Spinel ferrite NPs were synthesized by employing sol–gel methodology and characterized using scanning electron microscopy, X-ray diffraction, BET analysis and Fourier transform infrared spectroscopy techniques. BET analysis revealed that the surface area of ferrite NPs ranged from \(0.43{-}23.49 \, {\hbox {m}}^{2} \, {\hbox {g}}^{-1}\). Enzyme mimic activity was compared using SOD as a model enzyme. \({\hbox {CuFe}}_{2} {\hbox {O}}_{4}\, \hbox {NPs}\) exhibited a maximum activity followed by \({\hbox {CoFe}}_{2} {\hbox {O}}_{4}\) and \({\hbox {MnFe}}_{2} {\hbox {O}}_{4}\, \hbox {NPs}\). The results were correlated with a facile interconversion of the oxidation state leading to a stable electronic configuration in \({\hbox {CuFe}}_{2} {\hbox {O}}_{4}\, \hbox {NPs}\). Optimum pH and contact time was 1 and 3 min respectively. Kinetic studies were performed under optimum conditions and data were analysed using the Michaelis Menten equation. The values of \(V_{\mathrm{max}} \, (0.77 \, {\hbox {s}}^{-1})\) and \(K_{\mathrm{m}}\) (4.20 mM) proved \({\hbox {CuFe}}_{2} {\hbox {O}}_{4}\, \hbox {NPs}\) as potential SOD mimic for a wide range of applications.

On the question of the applicability of G.V. Samsonov’s activated sintering concept in studying the processes of powder material deformation

Some Yu.G. Dorofeev’s memoirs about joint work and meetings with outstanding materials science expert G.V. Samsonov are given. Meetings in Yugoslavia were of particular importance where G.V. Samsonov and M.M. Ristićtogether with other worldfamous scientists created the International Institute for the Science of Sintering. In the last years of his life, G.V. Samsonov proposed the concept of sintering activation by additives that act as electron acceptors and additionally contribute to the ionic bond in the matrix material. The paper considers the possibility of using this concept in the development of activating additives that reduce the activation energy of the plastic deformation of iron-based powder materials. Sintering activation when forming stable electronic configurations can be accomplished by: 1) accelerating the grain-boundary heterodiffusion of the matrix material in the presence of phase segregations containing an activating microadditive (W–Ni system); 2) intensifying shrinkage durng the plastic flow of matrix material particles facilitated by diffusion porosity formed in the additive particles as a result of predominant additive atom diffusion into base metal particles (Fe–Ni, Fe–Co, Fe–Mn systems); 3) increasing the self-diffusion coefficient of base metal atoms due to the expanded area of a less close-packed crystal lattice (αphase) upon activating additive dissolution (Fe–Mo system). The article reviews the information available on the prospects for using manganese and chromium as compaction activating additives. The compaction activation energy of iron-based powder materials can be reduced by introducing manganese additives. At the same time, the use of diffusion saturation technology is promising. The question of using chromium as an activator does not have an unambiguous answer and suggests the need for further study.