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In this work a new donor of nitric oxide (NO) with antibacterial properties, namely nitrosyl iron complex of [Fe(C6H5C-SNH2)2(NO)2][Fe(C6H5C-SNH2)(S2O3)(NO)2] composition (complex I), has been synthesized and studied. Complex I was produced by the reduction of the aqueous solution of [Fe2(S2O3)2(NO)2]2− dianion by the thiosulfate, with the further treatment of the mixture by the acidified alcohol solution of thiobenzamide. Based on the structural study of I (X-ray analysis, quantum chemical calculations by NBO and QTAIM methods in the frame of DFT), the data were obtained on the presence of the NO...NO interactions, which stabilize the DNIC dimer in the solid phase. The conformation properties, electronic structure and free energies of complex I hydration were studied using B3LYP functional and the set of 6–31 + G(d,p) basis functions. The effect of an aquatic surrounding was taken into account in the frame of a polarized continuous model (PCM). The NO-donating activity of complex I was studied by the amperometry method using an "amiNO-700" sensor electrode of the "inNO Nitric Oxide Measuring System". The antibacterial activity of I was studied on gram-negative (Escherichia coli) and gram-positive (Micrococcus luteus) bacteria. Cytotoxicity was studied using Vero cells. Complex I was found to exhibit antibacterial activity comparable to that of antibiotics, and moderate toxicity to Vero cells. [ABSTRACT FROM AUTHOR]

The cationic complexes of Mn(III) with the 5-Hal-sal2323 (Hal = Cl, Br) ligands and a paramagnetic doubly charged counterion [ReCl6]2− have been synthesized: [Mn(5-Cl-sal2323)]2[ReCl6] (1) and [Mn(5-Br-sal2323)]2[ReCl6] (2). Their crystal structures and magnetic properties have been studied. These isostructural two-component ionic compounds show a thermally induced spin transition at high temperature associated with the cationic subsystem and a field-induced slow magnetic relaxation of magnetization at cryogenic temperature, associated with the anionic subsystem. The compounds are the first examples of the coexistence of spin crossover and field-induced slow magnetic relaxation in the family of known [MnIII(sal2323)] cationic complexes with various counterions. [ABSTRACT FROM AUTHOR]

We report the comparison of the electrochemical performances of α-MnO2 and δ-MnO2 produced by hydrothermal treatment. The structure and morphology of these materials were analyzed by SEM, HRTEM, XRD, and XPS, while their electrochemical properties were tested in the 1 M Na2SO4 aqueous electrolyte by cyclic voltammetry, galvanostatic charge–discharge measurements, and electrochemical impedance spectroscopy. The specific capacitance of δ-MnO2 at 1 mV·s−1 was 4.8 times higher than that of α-MnO2 (211 vs. 44 F·g−1) because of the layered structure of δ-MnO2 that provided better availability of the electrode surface for electrolyte ions during charge–discharge cycles and pseudocapacitance behavior attributed to faradaic redox reactions. Moreover, δ-MnO2 revealed high electrochemical stability (more than 98% of the initial capacitance after 5000 charge/discharge cycles) confirming its good performance as an electrode material for pseudocapacitors. The contributions of surface and diffusion capacitances were analyzed by the differentiation method. [ABSTRACT FROM AUTHOR]

Electrical resistivity measurements of a dual layered organic conductor (ET)4ZnBr4(1,2-C6H4Cl2) above room temperature show abrupt changes in resistivity at 320 K. Single-crystal X-ray diffraction studies in the 100–350 K range show polymorphic transformation at Tp ∼320 K, indicating that the crystals belong to the tetragonal system (high-temperature phase, HT-phase) above Tp and to the triclinic system (low-temperature phase, LT-phase) below Tp with abrupt phase transition from the HT-phase to the LT-phase. During the sequential heating of the crystal, anharmonic effects are detected in the 260–315 K range: i) an increase in growth of rate of parameter a and rate of the mean-square atomic displacements of the [ZnBr4]2− anions; ii) an increase in the amplitudes of thermal vibrations of ET and solvent molecules. The structure near the phase transition at 315 K reveals splitting of the positions of ethylene groups of ET, demonstrating for the first time that for the (ET)4MBr4(1,2-C6H4Cl2) family disordering of the ET occurs in the LT-phase when approaching Tp. The final rearrangement of the structure from the triclinic LT-phase to the tetragonal HT-phase occurs above 315 K. [ABSTRACT FROM AUTHOR]

Tunability of optoelectronic properties of lead halide perovskites achieved through halide mixing can potentially enable their multiple applications, for example, in tandem solar cells and light‐emitting diodes. However, mixed halide perovskites are unstable under illumination due to their segregation to Br‐rich and I‐rich phases, which negatively affects the performance and the operational stability of devices. Research efforts over the past years provided a substantial understanding of the factors influencing light‐induced halide phase segregation. While several mechanisms have been proposed, none of them could account for all available experimental data; and hence the origin of the effect is still under active debate. Herein, the photodegradation of CsPbI2Br and Cs1.2PbI2Br1.2 is thoroughly investigated using a set of complementary techniques. In situ atomic force microscopy provides a visualization of the real‐time halide phase segregation dynamics demonstrating that iodoplumbate is selectively expelled from the mixed halide perovskite grains and nucleates as a separate I‐rich phase at the grain boundaries. A mechanism based on the reversible Pb2+/Pb0 and I−/I3− redox (photo)chemistry is proposed, which explains the experimental findings and other previously reported results. Furthermore, it sheds new insights on the underlying mechanisms of multiple phenomena related to light‐ or electric field‐induced degradation of various lead halide perovskites. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid halide perovskites exhibit a wide range of unique optoelectronic properties that can be applied to a variety of semiconducting photoelectronic devices. There is also a growing interest in using perovskites as sensor materials for detecting various gas-phase analytes. In the present work, we report the design and investigation of a gas sensor based on formamidinium lead chloride (FAPbCl3), which demonstrated a strong and highly selective response towards ammonia. These observations were confirmed by our calculations to be due to a "lock-and-key" mechanism of the ammonia molecule filling the chlorine-vacancy defect, which effectively healed the carrier trap created by such a defect. A good reversibility and operational stability of the devices at room temperature was also observed, suggesting that complex lead halides are highly promising families of materials for gas sensor and electronic nose applications. [ABSTRACT FROM AUTHOR]

The coalescence of two Fe8N as well as the structure of the Fe16N2 cluster were studied using density functional theory with the generalized gradient approximation and a basis set of triple-zeta quality. It was found that the coalescence may proceed without an energy barrier and that the geometrical structures of the resulting clusters depend strongly on the mutual orientations of the initial moieties. The dissociation of N2 is energetically favorable on Fe16, and the nitrogen atoms share the same Fe atom in the lowest energy state of the Fe16N2 species. The attachment of two nitrogen atoms leads to a decrease in the total spin magnetic moment of the ground-state Fe16 host by 6 μB due to the peculiarities of chemical bonding in the magnetic clusters. In order to gain insight into the dependence of properties on charge and to estimate the bonding energies of both N atoms, we performed optimizations of Fe16N and the singly charged ions of both Fe16N2 and Fe16N. It was found that the electronic properties of the Fe16N2 cluster, such as electron affinity and ionization energy, do not appreciably depend on the attachment of nitrogen atoms but that the average binding energy per atom changes significantly. The lowering in total energy due to the attachment of two N atoms was found to be nearly independent of charge. The IR and Raman spectra were simulated for Fe16N2 and its ions, and it was found that the positions of the most intense peaks in the IR spectra strongly depend on charge and therefore present fingerprints of the charged states. The chemical bonding in the ground-state Fe16N20,±1 species was described in terms of the localized molecular orbitals. [ABSTRACT FROM AUTHOR]

A layered organic conductor -(ET)4CdI4(PhCl) has been synthesized and characterized (ET is bis(ethylenedithio)tetrathia-fulvalene). It belongs to the family of dual-layered conductors -(ET)4MBr4(C6H6−nXn) and for the first time includes the iodine-containing anion [CdI4]2−. It exhibits metallic conductivity within the plane of organic ET molecules down to 206 K, and semiconductor properties in the perpendicular direction. The temperature dependence of in-plane resistivity for the compound shows changes in the conductive properties at 199 K and below 164 K. Structural phase transitions have been revealed at these temperatures. Crystal structures determined at 220, 185, and 100 K are attributed to tetragonal, monoclinic, and triclinic crystal systems, respectively. As a result of the structural phase transition at 199 K, equivalent ET layers become nonequivalent, the dihedral angles between ET molecules of neighboring stacks change, and ordering of terminal ethylene groups of ET molecules occurs in a half of radical cation layers. At 100 K, the difference between neighboring radical cation layers increases as compared with the monoclinic phase and the ordering of terminal ethylene groups in all ET molecules has been found. The solvent molecule PhCl remains disordered in all these structures. [ABSTRACT FROM AUTHOR]