Motivated by the task to replace toxic lead halide perovskites with lead-free environmentally benign light-harvesting materials for photovoltaics, we have synthesized two new hybrid bromometallates, (AH2)4[Sb2Br10(SbBr6)2(Br)2] (1) and (AH2)2[(BiBr6)(SbBr6)]·2H2O (2), where A = 1,5-dimethyl-3,7-diazabicyclo[3.3.1]nonane. Their crystal structures show combinations of Sb3+/Sb5+ (1) or Bi3+/Sb5+ (2) centers each surrounded by six Br- anions forming distorted (Sb3+ or Bi3+) or almost regular (Sb5+) octahedra. These octahedra are arranged in the crystal structure in a perfectly ordered way owing to weak Br⋯Br interactions within the inorganic anionic part and to hydrogen bonds linking inorganic anions and organic cations. The electronic structures of both compounds are alike in that they have M3+/Br- states (M = Sb or Bi) dominating the top of the valence band and acceptor in-gap states formed by the Sb5+/Br- interactions. Such an electronic structure leads to the reduced band gap of 1.27 (1) and 1.58 eV (2), favorable for creating light-harvesting materials for photovoltaics. We support our data by powder and single-crystal X-ray diffraction study, 121Sb Mossbauer spectroscopy, and optical spectroscopy. We infer that tailoring the band gap is a very important step on the way to lead-free light-harvesting materials for photovoltaic applications.

Low-dimensional metal halides emerge as materials for optoelectronics beyond perovskite photovoltaic applications. In a search for physical grounds of optical halometallate properties differences, we have investigated two homologous dications of cyclic aliphatic amines that are homopiperazine (Hpipe, C5H12N2, 1,4-diazocycloheptan) and piperazine (Pipe, C4H10N2, 1,4-diazocyclohexan) as structure-directing agents. Mixing of solutions of respective cations and PbI2 in concentrated hydroiodic acid results in obtaining new compound (HpipeH2){PbI5} (I)& sdot;H2O (1) and (PipeH2){PbI5}(I)& sdot;H2O (2), the latter being described in the literature. 1 and 2 demonstrate analogous yet non-isomorphous crystal structures, they share an identical anionic substructure, composed by a zigzag chain-like cis-{PbI5}3- 1D-anion and an isolated I- ion, as well as the same packing of all structural fragments. This rare situation among low-dimensional hybrid metal halide structures provides a unique platform for disentangling the effects of closely related cations on the supramolecular organization, more importantly, on the geometry of the halometallate anion without packing nuances, and, consequently, on optical properties, especially luminescence. A minor distinction in the cation's size and topology leads to dissimilar hydrogen bond systems and, most critically, distortion degrees of the iodoplumbate anion. Both compounds exhibit dual-band photoluminescence consisting of violet free exciton (FE) and yellow/orange (1/2) self-trapped exciton (STE) emission. The greater distortion of halometallate anion in 1 results in a larger Huang-Rhys factor, which governs the characteristics of the STE band and influences the thermal quenching efficiency. Vibrational spectra and thermal stability are also analyzed and correlated with structural features in this paper.

A new tricationic organic supramolecular tecton has been designed and synthesized. Contrary to known mono- and dicationic species, this new molecule, being a "three-way connector", allows assembling infinite supramolecular sheets and nets upon interaction with appropriate inorganic counterpart complex anions. In this work, triprotonated 6-amino-5,7-dimethyl-1,3-diazaadamantane, comprising two secondary and one primary nitrogen atoms, is used as a trication to form hybrid compounds with iodometallate anions by forming five hydrogen bonds at a time. It is shown that the bulky cation works simultaneously as a spacer and a connector, such that the positions of inorganic [MI6]3- anions (M = Sb or Bi) in the crystal structures are defined by five hydrogen bonds and are well-separated from each other. The latter is considered as a prerequisite for the hybrid compounds to exhibit optical properties originating from the undisturbed electronic structure of individual inorganic anions.

In pursuit of identifying less toxic hybrid compounds suitable for optoelectronic applications, we synthesized a novel homopiperazinium bromoantimonate(iii), (C5H14N2)3{Sb2Br9}2. It readily crystallized from an aqueous hydrobromic acid solution and was found to be stable both in air and upon heating up to 175 degrees C. The crystal structure of the new bromoantimonate(iii) consisted of {Sb2Br9}3- zigzag chains, which were composed of strongly trigonally distorted SbBr63- octahedral anions and C5H14N22+ dications. Weak interactions, including (N)H & ctdot;Br hydrogen bonds and Br & ctdot;Br van der Waals contacts, facilitated the assembly of the structural moieties into a three-dimensional (3D) supramolecular framework. The photoluminescence (PL) spectrum of (C5H14N2)3{Sb2Br9}2 displayed two broad bands in visible and near-infrared regions, which were scarcely detectable at room temperature but gained intensity upon cooling. Red emission at 645 nm, typically observed in zero-dimensional halometallates, was attributed to antimony 5s2 lone-pair-driven luminescence that corresponded to the emission from the self-trapped exciton (STE) state. The title compound also exhibited an atypical PL band at 880 nm, which has been discussed along with the optical properties and Raman spectrum of (C5H14N2)3{Sb2Br9}2.

External reinforcement of concrete structures using CPRF sheet is used both to prevent the development of unwanted deformations and to restore structures that have been damaged during operation. One of the processes leading to the failure of the structure, there may be detachment of the composite layer from the concrete surface. Organizing continuous monitoring of the deformation state of such structures is an urgent task. One of the promising methods for monitoring the integrity of concrete structures is the acoustic emission (AE) method. Its use is attractive due to the fact that it makes it possible to record the occurrence and development of defects over time, as well as to determine the places where they arise. This paper presents the results of an experimental study that allows us to evaluate the possibilities of using the AE method to monitor the deformation interaction of a composite sheet with the surface of a reinforced concrete beam subjected to a bending load. The AE data recorded during testing of an ordinary reinforced concrete beam were compared with the results obtained for a beam with external reinforcement with CFRP sheet. Features of AE signals have been identified, which can be considered signs of the occurrence and development of detachments of the composite sheet from the concrete base. The possibility of using this approach in organizing systems for continuous monitoring of changes in the deformation state of building structures reinforced with composite materials has been demonstrated.

Two new hybrid iodoantimonates( iii ), (3-C 5 H 12 NO) 4 [Sb 4 I 16 ] · 2 H 2 O ( 1 , 3-C 5 H 12 NO + is 3-hydroxypiperidinium) and (4-C 5 H 12 NO) 4 [Sb 4 I 16 ] · 3 H 2 O ( 2 , 4-C 5 H 12 NO + is 4- hydroxypiperidinium), were synthesized. Their crystal structures were established. The anionic substructures of the new compounds are composed of the same tetranuclear complex anions [Sb 4 I 16 ] 4− . The differences in the structure of 3-hydroxypiperidine and 4-hydroxypiperidine are responsible for the differences in the supramolecular organization of the cationic substructures and in the packing of the structural units. The comparative analysis of hydrogen bonding systems in the structures of compounds 1 and 2 was carried out. The band gap width for compound 1 was estimated at 2.38 eV according to the direct band gap model and at 2.28 eV in terms of the indirect band gap model.

The paper describes a novel high-performance catalyst that was developed for partial oxidation of methane (POM) and dry reforming of methane (DRM) into synthesis gas. The catalyst is based on samarium cobaltite dispersed in a samarium oxide matrix. Unlike its known counterparts based on samarium cobaltate, the novel catalyst is resistant to carbonization and contains active sites that exhibit higher syngas productivity.

Syngas is crucial raw for the production of hydrogen-rich gas for green energy and for various petrochemical processes. Herein, we report the Syngas production via partial oxidation of methane (POM) on new SmCoO3-derived catalysts produced from simple in-dividual precursor. Precursor modified by supercritical antisolvent precipitation (SAS) involving supercritical CO2 yields SmCoO3 with finer grains, and the catalytic activity of respective Co/Sm2O3 composite formed in situ during POM is considerably enchanced. This catalyst does not undergo coking, and provides CO and H2 yields of 75-88% for 55 h at 900 degrees C, thereby being the most efficient POM catalysts derived from non-substituted LnCoO3. Thus, the prospects of exploiting SAS modification of the precursor for SmCoO3 to enhance the catalytic activity of the daughter Co/Sm2O3 composites are demonstrated for the first time. Given the overall simplicity in production, studied Co/Sm2O3 composites can also be convenient systems for further development of POM catalysts.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

In searching for a tool for optimizing the band gap of a hybrid compound capable of serving as a light-harvesting material in lead-free photovoltaics, we synthesized a new polyiodoantimonate (HpipeH2)2[Sb2I10](I2) and analyzed its crystal and electronic structure by application of X-ray crystal structure analysis, Raman and diffuse reflectance spectroscopies, and quantum chemical calculations. It was demonstrated that I2 molecules link Sb2I10 edge-sharing octahedra into zig-zag chains, whereas the organic cations link inorganic anionic chains into a 3D structure featuring a complex pattern of covalent bonds and non-covalent interactions. Overall, these features provide the background for forming the electronic structure with a narrow band gap of 1.41 eV, therefore being a versatile tool for optimizing the band gap of a potential light-harvesting hybrid compound.

New organic-inorganic hybrid halometallates of the general formula (HpipeH 2 )-[M 2 X 10 ] · 2H 2 O, where M = Sb, Bi; X = Br, I; Hpipe is homopiperazine (C 5 N 2 H 12 ), were synthesized. The crystal structures of three new compounds, α-(HpipeH 2 ) 2 [Sb 2 I 10 ] · 2H 2 O (1) , β-(HpipeH 2 ) 2 [Sb 2 I 10 )]-2H 2 O (2) , and (HpipeH 2 ) 2 [Bi 2 Br 10 ] · 2H 2 O (3) , were determined and analyzed in comparison with the previously synthesized analog (HpipeH 2 ) 2 [Bi 2 I 10 ] · 2H 2 O (4). All four compounds have similar crystal structures, in which inorganic dioctahedral [M 2 X 10 ] 4− anions alternate with organic (HpipeH 2 ) 2+ cations and water molecules to form 3D systems based on (N)H⋯X, (N)H⋯O, and (O)H⋯X hydrogen bonds. In all structures, the (HpipeH 2 ) 2+ cation serves the same template function, forming three (N)H⋯X hydrogen bonds with halogen atoms of the inorganic anion and one (N)H⋯O bond with a water molecule. In going from Sb to Bi and from I to Br, the band gap width increases and reaches 2.89 eV for compound 3 .

A new approach to preparing a series of Co/Sm2O3 catalysts for hydrogen production by the dry reforming of methane has been developed. The catalyst precursors were synthesized with a simple method, including the evaporation of aqueous solutions of cobalt and samarium nitrates, followed by a short-term calcination of the resulting material. The as-prepared and spent catalysts were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, temperature-programmed reduction, and thermogravimetric analysis. The content of cobalt in the synthesized materials affects their phase composition and carbonization resistance in the dry reforming of the methane reaction. It has been shown that preheating in N2 atmosphere produces catalysts that provide a stable yield of hydrogen and CO of 94–98% for at least 50 h at 900 °C. These yields are among the highest currently available for the dry reforming of methane catalysts made from Co-Sm complex oxides. It has been established that the decrease in the amount of cobalt in the catalyst and its preheating to an operating temperature of 900 °C in a nitrogen flow help to prevent the carbonization of the catalyst and the sintering of metal particles.

The amantadinium iodoacetatobismuthate(III) [C10H15NH3·(CH3)2CO]2[BiI3.67(CH3COO)1.33] is a new hybrid halometallate with iodide ions partially replaced by oxygen-containing acetates to form stronger interaction between the anionic and cationic substructures. The title compound as well-shaped orange-red crystals was synthesized by a facile reaction in acetone solution in the presence of glacial acetic acid. The crystal structure of the compound consists of the infinite anionic chains [BiI3.67(CH3COO)1.33]2– and the countercations [C10H15NH3·(CH3)2CO]+; according to the optical absorption data, the test compound is a semiconductor with a band gap of 2.06 eV.

The dry reforming of methane to syngas (DRM) is of increasing significance concerning, first, the production of raw materials for commercial organic/petrochemical syntheses and for hydrogen energetic, and, second, the utilization of two most harmful greenhouse gases. Herein, new SmCoO3-based DRM catalysts derived from heterometallic precursors and operated without preliminary reduction are reported. For the first time, the effect of supercritical fluids-assisted modification of the SmCoO3-derived catalysts combined with the re-oxidation of spent catalysts to SmCoO3 onto its long-term performance was studied. In particular, the modification of heterometallic precursors by supercritical antisolvent precipitation (SAS) considerably decreases coke formation upon the exploitation of the derived SmCoO3 sample. Moreover, the re-oxidation of the corresponding spent catalysts followed by pre-heating under N2 affords catalysts that stably provide syngas yields of 88-95% for at least 41 h at 900 °C. The achieved yields are among the highest ones currently reported for DRM catalysts derived from both LnMO3 perovskites and related oxides. The origins of such good performance are discussed. Given the simplicity and availability of all the applied methods and chemicals, this result opens prospects for exploiting SAS in the design of efficient DRM catalysts.

Two new compounds, trichloro[O-bis(2-hydroxyethyl)ammonium] manganese(ii), {Mn[(HOCH2CH2)2NH2]Cl3}n (1), and N-(2-hydroxyethyl)-N-methylammonium aquatrichloromanganate(II), [CH3NH2CH2CH2OH][Mn(H2O)Cl3] (2), were synthesized. The crystal structures of the new compounds were determined by single-crystal X-ray diffraction. Both structures contain similar chains composed of (MnOCl5) octahedra. In the structure of 1, the manganese atom is coordinated by the OH group of the cation; in the structure of 2, the manganese atom is coordinated by a water molecule. There are different hydrogen bond systems in the structure of 1 due to disorder of OH groups of the cation. The melting points and enthalpies of the synthesized compounds evaluated by DSC are 162 °C and 17.3 kJ mol−1 for compound 1 and 30 °C and 16.9 kJ mol−1 for compound 2, respectively. Compound 1 is a chain coordination polymer, while compound 2 is an ionic liquid with a polynuclear anion.

High-performance catalysts for partial oxidation (POM) and dry reforming of methane (DRM) into synthesis gas with a yield of more than 90% have been developed. The GC, XRD, SEM, TGA, and TEM methods of analysis demonstrate that the catalysts generated from presynthesized SmCoO3 and PrNi0.5Co0.5O3 materials exhibited high catalytic performance in DRM and contained nanoparticles of cobalt and nickel metals and samarium or praseodymium oxides. Due to the method employed in this study for SmCoO3 the catalyst prepared from this precursor showed higher syngas selectivity, both in DRM and POM, than catalysts with similar compositions prepared by a citrate method. It was also demonstrated that the PrNi0.5Co0.5O3 catalyst prereduced in hydrogen was more efficient in POM than the sample reduced in the reagent flow.

The reaction of homopiperazine, C5N2H12, with BiBr3 in strong hydrobromic acid affords a new organic-inorganic hybrid (C5N2H14)2[BiBr6]Br·H2O. It crystallizes in the orthorhombic space group, Pbca, with unit cell dimensions of a = 15.0775 (2), b = 15.7569 (2), and c = 20.7881 (4) Å, and eight formula units per unit cell. The crystal structure features slightly distorted octahedral BiBr63− and monoatomic Br− anions in the inorganic substructure and C5N2H142+ dications and adjacent water molecules in the organic substructure. Various weak interactions that include (N)H···Br, (N)H···O, and (O)H···Br hydrogen bonds ensure the assembling of the structural moieties into a 3D supramolecular structure. (C5N2H14)2[BiBr6]Br·H2O shows two emission bands in the photoluminescence spectrum, a rather narrow deep-blue PL at 432 nm, and a broadband red PL centered at 650 nm. Their nature and relations to the crystal structure are discussed in this paper.

A new method was developed to prepare nanoscale Ni/La2O3 composites—efficient catalysts of the partial oxidation of methane (POM) into syngas. The catalysts are formed in situ during POM from LaNiO3 obtained by the thermal decomposition of heterometallic La–Ni nitrate complexes. The catalysts ensure an almost 100

A new organic-inorganic hybrid [{p-(CH3)2NH—C6H4—NH3}2Cl][BiI6] was synthesized and its crystal structure was established. The hybrid consists of an inorganic anion [BiI6]3− and an organic cation [{p-(CH3)2NH-C6H4-NH3}2Cl]3+. The [BiI6]3− anions are linked via non-covalent I...I interactions between axial atoms of neighboring anions to form chains running along the c axis of the tetragonal unit cell. In the cationic part, the Cl− anion is involved in four (N)H…Cl hydrogen bonds with hydrogen atoms of the p-(CH3)2NH—C6H4—NH32+ cation, forming a two-dimensional substructure. Alternating covalent and I...I halogen bonds in the anionic substructure and cation—anion hydrogen bonds provide the formation of a three-dimensional supramolecular structure with a band gap of 1.93 eV.

Metal-containing ionic liquids composed of the 2,8-dioxo-5-azoniaspiro[4.5]decane (MorphOx) and 2-oxo-5-azoniaspiro[4.4]nonane (PyrOx) spiro cations and tetrachlorometallate anions MCl42-(M = Mn, Ni, Co) were synthesized and studied by X-ray diffraction (CIF file CCDC nos. 2033482 (Morph-Ox(2)CoCl(4)), 2033483 (PyrOx(2)CoCl(4)), 2033484 (PyrOx(2)MnCl(4)), and 2033485 (PyrOx(2)NiCl(4))). The compounds PyrOx(2)MCl(4) are isostructural. The phase transition temperatures of the compounds were determined by differential scanning calorimetry.