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A sensitive detection method combined with an effective on-line concentration may improve the analytical performance of a paper-based analytical device (PAD), and its merits of low cost and portability in POCT are fully demonstrated. Here, a sensitive PAD system with chemiluminescence (CL) detection and electrokinetic preconcentration was introduced, and the performance was demonstrated by the detection of hemin. A commercially available low cost and miniaturized optical detection module was used for the CL detection. Firstly, hemin was stacked on a simple paper fluidic channel based on field amplified stacking (FAS), and then a CL reagent (luminol–H2O2) was loaded on the stacked band to initiate the CL reaction. The photons were directly detected using the detection module. With optimization of the background electrolyte (BGE), voltage and CL reagent, a limit of detection (LOD) of 0.58 nM for hemin was obtained with a linear range of 1–1000 nM (R2 = 0.995). With FAS, the signal intensity was about 13-fold enhanced. This PAD also exhibited satisfactory selectivity over possible interfering components at a 104 times higher concentration. The applicability of the PAD was demonstrated by the detection of hemin from iron supplements and human serum samples. With total manual operation, recovery rates of 84.8–115.6% were obtained with an RSD of less than 14.3%. With the introduction of the optical detection model, and together with FAS, both the LOD and dynamic range of this PAD were effectively improved. [ABSTRACT FROM AUTHOR]

Radical-cation salts of formula β?-(BEDT-TTF)4[(H3O)Fe(C2O4)3]·guest have produced a large number of superconductors and provided a route to introduce magnetism and chirality into the same multifunctional material. A relationship has been found in these salts between the length of the b axis and the superconducting Tc. Increasing the b axis length by introducing larger guest molecules, such as benzonitrile and nitrobenzene, gives the highest superconducting Tcs in this family of salts. Smaller guests such as pyridine show no superconducting transition, whilst asymmetrical guests which are larger than nitrobenzene have given a different bilayered structure. Other potential guest molecules have been limited by their ability to be used as the solvent in which the crystals are grown via electrocrystallisation. This paper reports a method which introduces guest molecules into the crystal which are a solid or liquid additive within the crystal-growing solvent 1,2,4-trichlorobenzene:ethanol. We present the crystal structures of five new BEDT-TTF radical-cation salts with tris(oxalato)ferrate anions using guest molecules toluene, phenol, benzaldehyde, 4-bromobenzaldehyde, and kojic acid. [ABSTRACT FROM AUTHOR]

We previously reported that Zr substitution improves the chemical stability of Ba3Y4O9 and nominally 20 mol% Zr-substituted Ba3Y4O9 is an oxide-ion conductor at intermediate temperatures (500–700 °C). However, the influence of Zr substitution on the structural properties of Ba3Y4O9 was poorly understood. This paper aims to comprehensively understand the crystal structure of Ba3Y4O9 with Zr substitution by powder X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) measurements, and first-principles calculations. From the results, firstly we found that the hexagonal unit cell of Ba3Y4O9 reported in the database should be revised as doubled along the c-axis in terms of the periodicity of oxide-ion positions. The revised unit cell of Ba3Y4O9 consists of 18 layers of BaO3 and 24 layers of Y which periodically stack along the c-axis. In this work, we focused on the cationic lattice and noticed that the periodical stacking of Ba and Y layers comprises a similar sequence to that in the body-centered cubic (BCC) structure. There are two regions in the Ba3Y4O9 structure: one is a hetero-stacking region of Ba and Y layers (Ba–Y–Ba–Y–Ba) and the other is a homo-stacking region (Ba–Y–Y–Ba). It is noteworthy that the former region is similar to a cubic perovskite. In Zr-substituted Ba3Y4O9, Zr ions preferentially substitute for Y ions in the hetero-stacking region, and therefore the local environment of Zr ions in Ba3Y4O9 is quite similar to that in BaZrO3. Besides, the Zr substitution for Y in Ba3Y4O9 increases the fraction of the cubic-perovskite-like region in the stacking sequences. The structural change in the long-range order strongly affects the other material properties such as chemical stability and the ionic-conduction mechanism. Our adopted description of perovskite-related compounds based on the stacking sequence of the BCC structure should help in understanding the complex structure and developing new perovskite-related materials. [ABSTRACT FROM AUTHOR]

Viologen is capable of generating radicals in response to an applied stimulus, giving it an abundance of stimuli responsive properties. However, the radical state of viologen is often unstable, which hinders further studies on the radical properties of viologen. In this paper, the salicylhydrazide group was chosen as a donor group to bond with mono-substituted bipyridyl groups to obtain three novel D–A type viologen compounds. The compounds were harvested and characterized by X-ray single crystal diffraction, optical spectroscopy, EPR and DFT calculation, etc. The results show that compounds 1–3 adopt certain free radical states at room temperature under ambient light, which may be attributed to the electron-donating properties of the salicylhydrazide group and the degree of system conjugation. In addition, compound 1 has a hydrochromic property and compounds 2 and 3 have photocurrent effects under UV radiation. [ABSTRACT FROM AUTHOR]

In this paper, a new high-pressure (HP) polymorph of the otherwise known oxyfluoride K2MoO2F4 is presented. The crystal structure was determined by use of single-crystal X-ray diffractometry and its features are described in detail herein. HP-K2MoO2F4 crystallizes in the monoclinic space group C2/m (no. 12) with the cell parameters a = 13.8579(5), b = 5.8109(2), c = 6.9442(3) Å, β = 90.36(1)°, V = 559.18(4) Å3, and Z = 4 at T = 301(2) K. Bond valence (BV) and charge distribution (CHARDI) calculations were carried out to support the assignment of oxygen and fluorine to the various anion positions and Madelung part of lattice energy (MAPLE) calculations were used to validate the structure model. Infrared spectroscopy provided further information on the structure and water content of the inseparable side phase. [ABSTRACT FROM AUTHOR]

In this paper, we present the synthesis and characterization of a Cl-bearing member of the phosphate family of compounds with a tetragonal crystal structure and similar topology in the basic projection. The title compound was obtained under hydrothermal conditions and its crystal structure was determined by single crystal low temperature X-ray diffraction. The structure of NaCo7.38(PO4)4Cl4 is formed with CoO4Cl2 octahedra sharing faces and assembled into eight-component ring clusters with a very short Co–Co distance of 3.014 Å. These clusters are linked in a three-periodic network via vertex-bridge contacts of adjacent octahedra and PO4 tetrahedra. Na atoms occupy the open channels of the framework. The structure is discussed as a derivative of cubic sulphohalite, Na6(SO4)2ClF, with the symmetry lowering from the widespread Fm3¯m space group of sulphohalite to the tetragonal acentric space group I4¯2m in our case; these space groups are symmetrically related by subordination "group → subgroup". Theoretical calculations of possible pathways of Na migration through the framework showed that although the structure contains a sufficient number of voids for sodium ions, their migration is limited by the size of the channels. However, the obtained results indicated that the migration of Li+ ions is very likely through a two-periodic network parallel to the ab plane, which means that Li-containing structural varieties of NaCo7.38(PO4)4Cl4 with possible formulae Li5Co2+Co3+3(PO4)4Cl4 or Li4Co3+4(PO4)4Cl4 can possess ionic conductivity. The angle of intracluster Co–O–Co bonds of 105.4° allows us to assume that there is an antiferromagnetic exchange interaction between the Co atoms, and we assume that the intercluster exchange interactions between Co2+/3+ ions through the intermediate PO4 groups are also probable. [ABSTRACT FROM AUTHOR]

This paper reports three new crystallographically characterized europium complexes with composition as follows: [Eu(fod)3(L1)] (1), [Eu(fod)3(L2)] (2) and [Eu(fod)3(L3)] (3) {L1 = benzimidazole (bzi), L2 = 4,7-diphenyl-1,10-phenanthroline (bath), L3 = 2-(2-pyridyl) benzimidazole (py-im) and fod = anion of 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione (Hfod)}. The single crystal (SC) XRD analysis shows that complex 1 is seven-coordinated while complexes 2 and 3 are eight-coordinated with the geometrical structures of a mono-capped octahedron and a trigonal dodecahedron, respectively. The NMR spectra of the complexes validate the SC-XRD results in solution. The complexes are stable in solution as no dissociation of any ligand was observed in the NMR spectra of the complexes. The photophysical properties of the complexes in solution, solid state, and PMMA thin films were studied. The hypersensitive transition 5D0 → 7F2 dominates the emission spectra in all phases, showing the highly asymmetric environment around the Eu(III) ion. The bath ligand is found to be the best sensitizer of the Eu ion and hence complex 2 shows the strongest luminescence properties with the highest absolute quantum yield among the three complexes. The CIE coordinate analysis shows that pure red-luminescence is emitted by the Eu complexes in the solid state since the coordinates found in this phase are closer to the standard NTSC 1987 values. The optical band gaps were determined for the complexes and the observed values suggest that the complexes can have possible applications in the field of semiconductor materials. [ABSTRACT FROM AUTHOR]

Exploring the functionalities of materials requires a profound understanding of the crystal structure. In this paper, room temperature crystal structures of a new solid solution (1 − x)Ba(Cu1/3Nb2/3)O3-(x)PbTiO3 have been investigated in the entire compositional span and different crystallographic phases and phase coexistence regions have been discovered. The confirmation of the symmetry of these crystal structures has been done with the help of Rietveld analysis of the high-resolution XRD data. Despite both the end components, Ba(Cu1/3Nb2/3)O3 and PbTiO3, having tetragonal (P4mm) symmetry, new cubic and monoclinic phases have been discovered for the intermediate compositions with multiple phase boundaries. The composition region 0.05 ≤ x ≤ 0.55 exhibits a cubic crystal structure and increasing PbTiO3 concentration to 0.62 results in a unique coexistence of two tetragonal phases with different tetragonalities. This transformation is mediated by coexisting cubic and tetragonal phases, for 0.59 and 0.60. The crystal structure of the solid solution later transforms into coexisting monoclinic and tetragonal phases for a wider compositional span i.e., 0.65 ≤ x ≤ 0.85. This composition region is very fascinating, as two phenomenologically different monoclinic structures have been observed in it. Finally, a tetragonal phase at x = 1 is achieved through the mediation of two coexisting tetragonal phases, for the region 0.85 < x ≤ 0.975. The evolution of different crystallographic structures and the coexisting phases are critically comprehended using the variations in the lattice parameters and unit cell volume. The presence of multiple phase boundaries spread across a wide range of compositions makes this solid solution very intriguing and a viable choice for exploring different properties with compositional tuning. [ABSTRACT FROM AUTHOR]

Four novel indole thiosemicarbazone derivatives, 1-(indole-2-methylene)-4-substituted-thiosemicarbazides, were synthesized via a one-step reaction by introducing substituents with different conjugacy (methyl, ethyl, cyclohexyl, phenyl). Different from the traditional Schiff-base photochromic compounds, these compounds in this work present dual response signals to UV light, and they exhibit not only reversible solid-state photochromic behavior but also aggregation-induced emission (AIE) characteristics. Furthermore, the structure–activity relationships were revealed by experimental studies, and their photochromism and fluorescence emission were enhanced efficiently with the increase of the conjugation. Furthermore, based on the single crystal structure, FT-IR spectra and theoretical calculations, the proposed photochromic mechanism originates from the intermolecular proton transfer between the thio–keto and thio–enol configurations, and the AIE property is closely related to the restriction of intramolecular rotation. Furthermore, the picture of anti-counterfeiting suggests that the dual responses of these compounds are extremely suitable for multiple encryptions. This work enriches the AIE system and provides a reference for constructing excellent multi-photoresponsive materials. [ABSTRACT FROM AUTHOR]

The Cr3+-doped near-infrared (NIR) phosphors have been extensively investigated owing to their promising applications in biomedicine, food safety detection, and night vision surveillance. However, achieving broadband (FWHM > 160 nm) NIR emission is still challenging. In this paper, novel Y2Mg2Ga2−xSi2O12:xCr3+ (YMGS:xCr3+, x = 0.005–0.08) phosphors were prepared by a high-temperature solid-state reaction. The crystal structure, photoluminescence properties of the phosphor, and the device performance of a pc-LED were researched in detail. When excited at 440 nm, the YMGS:0.04Cr3+ phosphor exhibited broadband emission in the range of 650–1000 nm, peaking at 790 nm with a full width at half-maximum (FWHM) of up to 180 nm. The wide FWHM of YMGS:Cr3+ is conducive to its extensive application in NIR spectroscopic technology. In addition, the YMGS:0.04Cr3+ phosphor could maintain 70% of the initial emission intensity at 373 K. By combining the commercial blue chip with the YMGS:0.04Cr3+ phosphor, the resulting NIR pc-LED demonstrated a near-infrared output power of 14 mW with a photoelectric conversion efficiency of 5% at a drive current of 100 mA. This work provides a broadband emission NIR phosphor option for NIR pc-LED devices. [ABSTRACT FROM AUTHOR]

Transition metal-based two-dimensional nanomaterials with competing magnetic states are at the cutting edge of spintronic and low-power memory devices. In this paper, we present a Fe-rich NbFe1+xTe3 layered telluride (x ≈ 0.5), which shows an interplay of spin-glass and antiferromagnetic states below the Néel temperature of 179 K. The compound has a layered crystal structure, where the NbFeTe3 layers are terminated by the Te atoms and van der Waals gaps. Bulk single crystals grown by chemical vapor transport reactions possess the (1¯01) cleavage plane suitable for the exfoliation of two-dimensional nanomaterials. Combination of high-resolution transmission electron microscopy and powder X-ray diffraction reveals the zigzag ladders of Fe atoms inside the structural layers, as well as complementary zigzag chains of the partially occupied Fe positions in the interstitial region. Fe atoms carry large effective magnetic moment of 4.85(3)μB per atom in the paramagnetic state yielding intriguing magnetic properties of NbFe1+xTe3. They include frozen spin-glass state at low temperatures and spin-flop transition in high magnetic fields indicating promising flexibility of the magnetic system and its potential control by magnetic field or gate tuning in the spintronic devices and heterostructures. [ABSTRACT FROM AUTHOR]

A bibliographic and literature-based analysis of the impact of the Cambridge Structural Database (CSD) and the papers associated with crystal structures in the CSD has been undertaken. The analysis shows the broad impact of the CSD in the chemical sciences and also highlights how areas where the CSD has impact have changed over time. In addition, we note the changing nature of crystallography as a science, observing how crystal structures are now impactful. A brief illustration of some more unusual contributions to the CSD and publications using the CSD is also presented. [ABSTRACT FROM AUTHOR]

Copper sulfides have gained significant attention as alternative electrodes for rechargeable batteries. A simple and easily scalable synthetic pathway to access these materials is highly desirable. This paper describes the facile synthesis of metal-rich digenite Cu1.8S nanocrystals from a structurally characterized new single-source molecular precursor in various high boiling solvents of varied polarity. The as-prepared nanostructures were thoroughly characterized by PXRD, Raman spectroscopy, EDS, XPS, electron microscopy techniques and diffuse reflectance spectroscopy to understand the crystal structure, phase purity, elemental composition, morphology and band gap. It was found that the reaction solvent has a profound role on their crystallite size, morphology and band gap, however the crystal structure and phase purity remained unaffected. Pristine Cu1.8S nanostructures have been employed as an anode material in lithium-ion batteries (LIBs). The cell delivers a high initial charge capacity of ∼462 mA h g−1 and retains a capacity of 240 mA h g−1 even after 300 cycles at 0.1 A g−1. DFT calculations revealed that multi-size polyhedron layers in the direction perpendicular to the two Li movement channels aid in the sustainable uptake of Li atoms with controlled volume expansion. The structure-mediated flexibility of the metal-rich Cu1.8S lattice during lithiation permits high cyclability with reasonable retention of capacity. [ABSTRACT FROM AUTHOR]

Co-precipitation of Ni0.8Co0.1Mn0.1(OH)2 (NCM811) and Mg-doped (0.25 wt% and 0.5 wt%) NCM811 precursors is carried out from concentrated metal sulphate solutions. In this paper, the aim is to study the role of magnesium dopant in the co-precipitation step of NCM811, the cathode active material and further the Li-ion battery cell performance. Based on the results, magnesium was fully co-precipitated in the NCM811 precursors, as expected from thermodynamic calculations. The presence of magnesium in these precursors was also confirmed by several characterization methods and magnesium was evenly distributed in the sample. It was observed that tapped density decreased and surface area increased with an expected increase in Mg content. Surprisingly, Mg doping did not improve the cyclability of coin cells, due to the stable crystal structure of NCM811. However, a slight improvement in cyclability was seen in pouch cells after 1000 cycles. A washing effect was clearly seen in lattice parameters and washing also decreased the capacity retention after 62 cycles for all samples. [ABSTRACT FROM AUTHOR]

The 6p orbit coupling of bismuth ions and the magnetism of iron ions endow bismuth–iron compounds with magnetic, optical and electrical properties. In this paper, non-rare-earth bismuth–iron crystals, KBa8Fe12(Bi6−xFex)O38 (x = 0.2, 1.1, 2.0, 2.9, and 3.8), with a large magnetocaloric effect were prepared by a hydrothermal method. The structure–function relationship is discussed. With the increase of the Fe content, the lattice parameters and unit cell volume decrease, while the magnetization intensity shows an increase on the whole and a fluctuation at the same time. The increase of the Fe content can improve the magnetocaloric effect. Importantly, the maximum magnetic entropy change (ΔSM) of KBa8Fe12(Bi4.9Fe1.1)O38 is as high as 1.54 J kg−1 K−1 at the low temperature of 2 K. [ABSTRACT FROM AUTHOR]

A systematic investigation of the system manganese(II) salt–H2SBA–auxiliary ligand–solvent successfully led to the isolation of six new multidimensional coordination polymers: [Mn5(2-pic)2(DMA)4(SBA)4]·4DMA (1), [Mn3(pyzc)2(DMF)(H2O)(SBA)2]·DMF·H2O (2), [Mn5(pyzc)2(DMA)4(SBA)4]·4DMA (3), [Mn5(mpyzc)2(DMA)4(SBA)4]·4DMA (4), [Mn2(phen)2(H2O)(SBA)2]·2DMA (5) and [Mn3(phen)2(SBA)3]·5DMF (6), where SBA = 4,4′-sulfonyldibenzoate 2-pic = 2-picolinate, pyzc = 2-pyrazinecarboxylate acid, mpyzc = 5-methyl-2-pyrazinecarboxylate and phen = 1,10-phenanthroline. The selected use of N-containing ligands to block the coordination sites of manganese enabled us to understand their influence in controlling the nuclearity and the dimensionality of the extended manganese carboxylate coordination networks. Single crystal X-ray crystallography established that the structures of all the solids were built of homometallic clusters varying from monomeric to pentameric manganese(II) carboxylate units. While the solids 1, 3 and 4 are isostructural, possessing a 2D coordination network containing pentanuclear SBUs of the composition {Mn5N2O3}, the 2D solids 2 and 5 are respectively built from binuclear {Mn2N4O7} and trinuclear {Mn3N2O14} SBUs. The solid 6 is the lone example of a 3D coordination network in this system. Dielectric measurements showed comparable dielectric behavior for the isostructural solids 1, 3 and 4 with ε′ ∼ 17 at room temperature. Relatively lower values observed for 2 and 5 (ε′ ∼ 14) were due to a combined effect of strong manganese carboxylate interaction and the presence of ordered polar guest molecules. Significantly higher values for 6 (∼21) could be attributed to disordered guest molecules. All the six solids exhibited antiferromagnetic behavior at lower temperatures. This paper also discusses the growth of the solids in terms of supramolecular aggregation of manganese carboxylate complex species with or without an auxiliary ligand, proposing a mechanistic pathway to trace the chemical events from molecules to the final solid. [ABSTRACT FROM AUTHOR]

The majority of the fabrication procedures of lanthanide-doped materials involve thermal treatment that often results in crystallite regrowth, stabilizing the specific crystal structure and resulting in luminescence enhancement. The efficiency and intensity of up-conversion luminescence are closely related to the structure and synthesis process of the materials. Herein, well-crystallized and pure tetragonal NaY(MoO4)2 microcrystals with a uniform octahedral shape have been successfully synthesized via an environmentally friendly hydrothermal method, followed by annealing treatment. The phases, structures, morphologies, and compositions of the synthesized products annealed at 500–1000 °C remain unchanged, indicating high thermal stability. Furthermore, the NaY(MoO4)2:Yb3+/Er3+ microcrystals exhibit strong green emission when irradiated using infrared (980 nm) or ultraviolet (378 nm) wavelengths. Upon 980 nm excitation, up to 37-fold luminescence enhancement is achieved when the samples are annealed at about 700 °C. Interestingly, the high colour purity of the strong green emission is not only independent of the dopant concentration and heat treatment temperature, but it is also independent of the excitation conditions, including power and wavelength, and this makes it particularly suitable as a green safety signal light and luminescent security ink in paintings. As-prepared safety inks with NaY(MoO4)2:Yb3+/Er3+ microcrystals were used for visual fingerprint recognition printed on A4 paper with three-level fingerprint security features, significantly increasing the difficulty of illegal imitation and enhancing the levels of anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Saponification, resulting from pigment–binder interactions, is one of the most endangering phenomena affecting the appearance and stability of painted works of art. The crystallization of metal carboxylates (soaps) in paint layers is recently assumed as the most critical point for the development of undesirable changes induced by saponification, however, the factors triggering it are not fully understood. The red pigment cinnabar (HgS) has been suspected of contributing to saponification, however, the paucity of reliable reference structural data limited the experimental research of its effect at the molecular level. Within this study we synthesized mercury(II) carboxylates of the formula Hg(C16)x(C18)2−x (x = 0.0; 0.2; 0.5; 0.8; 1.0; 1.2; 1.5; 1.8; 2.0) where C16 and C18 are hexadecanoate (palmitate) and octadecanoate (stearate), respectively, and characterize them by combination of X-ray powder diffraction (XRPD) and 13C and 199Hg solid state NMR (ssNMR). For a more detailed interpretation of their structural and thermal behavior, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used. The crystal structure of the studied mercury carboxylates was described on the basis of complementary ssNMR and XRPD measurements, Rietveld refinement and DFT calculations. All the subjected compounds crystallize in a monoclinic lattice of the C2/c symmetry. Mercury atoms are arranged in a slightly distorted square antiprismatic geometry and are monodentatically bonded to carboxylate anions. The structural disorder at the aliphatic end of the stearic acid chains was detected in the mixed carboxylates. Within the paper, the structural (dis)similarity with the corresponding lead carboxylates is discussed. The synthesized and characterized mercury carboxylates were applied to describe neo-formed mercury soaps in a model experiment simulating an egg-based paint system. [ABSTRACT FROM AUTHOR]

We synthesized a perovskite-type RbNbO3 at 1173 K and 4 GPa from non-perovskite RbNbO3 and investigated its crystal structure and properties towards ferroelectric material design. Single-crystal X-ray diffraction analysis revealed an orthorhombic cell in the perovskite-type structure (space group Amm2, no. 38) with a = 3.9937(2) Å, b = 5.8217(3) Å, and c = 5.8647(2) Å. This non-centrosymmetric space group is the same as the ferroelectric BaTiO3 and KNbO3 but with enhanced distortion. Structural transition from orthorhombic to two successive tetragonal phases (Tetra1 at 493 K, Tetra2 at 573 K) was observed, maintaining the perovskite framework before reverting to the triclinic ambient phase at 693 K, with no structural changes between 4 and 300 K. The first transition is similar to that of KNbO3, whereas the second to Tetra2, marked by c-axis elongation and a significant cp/ap ratio jump (from 1.07 to 1.43), is unique. This distortion suggests a transition similar to that of PbVO3, where an octahedron's oxygen separates along the c-axis, forming a pyramid. Ab initio calculations simulating negative pressure like thermal expansion predicted this phase transition (cp/ap = 1.47 at −1.2 GPa), aligning with experimental findings. Thermal analysis revealed two endothermic peaks, with the second transition entailing a greater enthalpy change and volume alteration. Strong second harmonic generation signals were observed across Ortho, Tetra1, and Tetra2 phases, similar to BaTiO3 and KNbO3. Permittivity increased during the first transition, although the second transition's effects were limited by thermal expansion-induced bulk sample collapse. Perovskite-type RbNbO3 emerges as a promising ferroelectric material. [ABSTRACT FROM AUTHOR]

YGa3(BO3)4 single crystals were grown from a K2Mo3O10-based flux, and also RGa3(BO3)4 (R = Y, Pr–Yb) spontaneous crystals (RGB) were obtained by a high-temperature flux growth technique from a complex R2O3–Bi2O3–B2O3–Ga2O3 solvent. A number of gallium orthoborates, including new ones (PrGa3(BO3)4, TmGa3(BO3)4), were obtained under identical conditions, their stability was determined, and their morphological features were shown. The crystal structure was confirmed by powder X-ray diffraction and their unit cell parameters were calculated. The micromorphology of the crystals was examined by the SEM method. Differential thermal analysis measurements show that RGa3(BO3)4 (R = Y, Pr–Yb) is an incongruently melting compound with temperatures varying with the rare earth cation type. [ABSTRACT FROM AUTHOR]

An original approach for the determination of unit cell parameter temperature dependence using a conventional single-crystal X-ray diffractometer is proposed. The approach is based on the calibration of the goniometer equatorial circle segment using the position of several Kα1/Kα2 doublets from reference single crystals. It allows for the refinement of lattice parameters of single crystals with a relative error of less than 10−4. Its capabilities are demonstrated using an example of tetragonal single crystals. The space group, crystal structure, and composition of t-Ag0.8Li0.2InSe2 were determined using single-crystal X-ray diffraction analysis of three small (linear sizes ∼0.1 mm) fragments from a larger (linear sizes up to 10 mm) single-crystal grown using the Bridgman method. The dynamics of the crystal structure changes in the temperature range of 90–500 K were studied. The obvious anisotropy of t-Ag0.8Li0.2InSe2 thermal behavior was shown with an overall increase in the volume of the tetragonal unit cell by 0.51%—parameter a increased by 0.34, while parameter c decreased by 0.17%. The nonlinear dependence of the thermal expansion tensor elements on temperature was determined: α 11 × 106 = −4.28 + 0.08T − 1.95 × 10−4T2 and α 33 × 106 = −5.59 + 0.01T − 1.97 × 10−5T2. [ABSTRACT FROM AUTHOR]

For isotactic polybutene-1 (iPB-1), II-I transition is of great industrial importance; however, the traditional nucleation-controlled solid-solid II-I transition mechanism eventually encountered challenges and the roles of iPB-1 amorphous phase gained the interest of many researchers. With three nucleating agents, namely WBQ-88, TMB-5 and WBG-II, incorporated into iPB-1, the amorphous phase was tuned with a form II crystalline structure remaining fixed. Based on the observed Tm,II decrease and Tm,I increase during the II-I transition as well as the resulting final Tm,I synergistically tuned by nucleating agent incorporation and crystallization conditions, it is proposed that the entire II-I transition of iPB-1 involves a form II consumption process and a form I formation process. The same as-crystallized form II structures of iPB-1 containing various nucleating agents are involved in a fixed form II consumption process. The amount of iPB-1 chain segments in the amorphous phase, which have the ability to crystallize, as well as their actual ability to crystallize synergistically determine the initiation of form I crystallization. Consequently, the started form I crystallization triggers II-I transition by overcoming the energy barrier for form II crystal cells to be destroyed. Both the initiation and the subsequent form I crystallization process can be enhanced by nucleating agent incorporation or isothermal crystallization at different Tc values, comprehensively resulting in a fast II-I transition process with final form I crystalline structures determined. The results provide an understanding of the II-I transition mechanism and shed light on the development of techniques to accelerate the II-I transition for iPB-1 industrial applications. [ABSTRACT FROM AUTHOR]

A series of versatile phthalocyanine precursors, consisting of gem-dibromovinyl phthalonitrile derivatives, were synthesized and characterized by various spectroscopic techniques. The assigned structures were further supported by X-ray crystallographic techniques. The crystal structures showed primarily C-H...N, C-H...Br, C-Br...N and π...π interactions. The overall intermolecular interactions in the structures were quantified and fully described by Hirshfeld surface analysis. In addition, energy-frame calculations were used to analyse the three-dimensional topology of the crystal packing. The dispersion energy framework of all compounds was shown to be dominant over the electrostatic framework. [ABSTRACT FROM AUTHOR]

The development of new compounds in the domain of metal dinitridocarbonates is most efficiently performed via solid-state metathesis or simply by addition reactions. Our discovery of Pb7I6(CN2)4 is the result of a solid-state reaction of PbCN2 with PbI2 at 420 ℃. Its crystal structure was solved and refined from X-ray diffraction data based on a single crystal with the space group P63/mmc. The crystal structure is based on a network of lead tetrahedra, lead trigonal bipyramids and lead octahedra interconnected by [NCN]2- and iodide. Properties of the material were investigated by diffuse reflection measurement, photoluminescence measurements, and electronic band structure calculations demonstrating that this material is a semiconductor. [ABSTRACT FROM AUTHOR]

LiCa8[CrIVN3]2N2F (Pnnm (#58), a = 17.5230(13) Å, b = 7.3379(5) Å, c = 4.9433(4) Å) is an example of a multinary nitridochromate fluoride, that provides additional information on almost elusive tetravalent nitridochromates. Shorter Cr–N bond lengths compared to those in the previously reported nitridochromates(III), as well as diamagnetic behavior and vibrational spectroscopy data suggest Cr(IV), which is in good agreement with the charge balance and crystal structure refinement. According to band structure calculations, LiCa8[CrIVN3]2N2F is a semiconductor with a band gap of 1.1 eV. The compound features trigonal planar [CrN3]5− units of Cs symmetry, and lithium, calcium, nitrogen and fluorine atoms arranged in a fragment of the rock salt type structure. [ABSTRACT FROM AUTHOR]

The assembly of a metal–organic framework (MOF) containing bent phenanthroline linkers and iron trinuclear clusters remains rare. Herein, we report the synthesis and single crystal structure of a two-dimensional (2D) MOF, Fe-cage-MOF, assembled from 2,9-substituted phenanthroline based carboxylate linkers and pre-synthesized iron trinuclear clusters. The distinctive octahedral cages and ordered 1D channels endow the MOF with permanent porosity and potential for selective capture of the greenhouse gas sulfur hexafluoride. [ABSTRACT FROM AUTHOR]

A series of ten N^N chelating ligands based on a 2,2′-bipyridine (bpy) metal-binding domain and featuring sterically hindering substituents in the 6- and 6,6′-positions has been synthesized and characterized. The ligands have been incorporated into a family of 15 heteroleptic complexes of type [Cu(P^P)(N^N)][PF6] where P^P is the wide bite-angle bisphosphane ligand bis(2(diphenylphosphanyl)phenyl)ether (POP) or (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane) (xantphos). Substituents in several of the N^N ligands ligands possess phenyl rings remotely tethered to enable intra- and intermolecular π–π-interactions in the [Cu(P^P)(N^N)]+ cations. Single crystal X-ray structures of 12 complexes are reported. The effects of the functional groups in the bpy ligand on the photophysical properties of the complexes have been studied; solid-state emission maxima range from 518 to 567 nm. Values of the solid-state photoluminescence quantum yields (PLQYs) of the [Cu(P^P)(N^N)][PF6] compounds respond to the nature of the N^N ligand. In general, we observed that the [Cu(P^P)(N^N)]+ complexes containing 6,6′-disubstituted complexes with phenyl moieties connected via a CH2CH2 or CH2CH2CH2 spacer to the bpy domain have the highest values of PLQY. The most significant compounds are [Cu(POP)((2-PhEt)2bpy)][PF6] (PLQY = 67%) and [Cu(POP)((3-PhPr)2bpy)][PF6] (PLQY = 72%) where (2-PhEt)2bpy = 6,6′-bis(2-phenylethyl)-2,2′-bipyridine and (3-PhPr)2bpy = 6,6′-bis(3-phenylpropyl)-2,2′-bipyridine. These PLQY values are among the best performing previously reported families of [Cu(P^P)(N^N)][PF6] compounds. [ABSTRACT FROM AUTHOR]

A new sodium tellurate has been hydrothermally synthesized and comprehensively analysed using spectroscopic and thermogravimetric techniques, resulting in the determination of its composition as NaTeO3(OH). The analysis of synchrotron X-ray and neutron diffraction data indicates that NaTeO3(OH) has a crystal structure similar to that of the previously reported tellurate, KTeO3(OH), with the space group P21/a (No. 14). NaTeO3(OH) consists of zigzag one-dimensional chains built by edge-sharing TeO6 octahedra, running parallel to the c-axis and connected to sodium and hydrogen atoms. The hydrogen atoms covalently bond to the terminal oxygen atoms on the one-dimensional chain and also form hydrogen bonds with other terminal oxygen atoms on nearby chains. The structure has been confirmed by optimization using the pseudopotential method and performing Bond Valence Sum (BVS) analysis. Although Li+ ions in LiTeO3(OH) can be exchanged reversibly with H+ ions, no ion exchange behaviour is observed in NaTeO3(OH). The difference is attributed to the size of the alkali ions and their crystal structure. [ABSTRACT FROM AUTHOR]

Multi-band emission characteristics open up more possibilities for the application of phosphors in LEDs. In this work, a novel Bi3+-activated Sr3NaSbO6 phosphor is developed. The Bi3+ occupation, luminescence properties and application in LEDs of the phosphor are investigated and discussed. There are Sr and Na sites in the crystal structure for Bi3+ substitution, corresponding to two different luminescence centers, which can be excited by commercial UV chips. By changing the excitation wavelength, Bi3+ in the two lattice sites can be excited separately, and a switchable multi-band emission can be obtained accordingly. The blue emission peaks at 450 nm, and the other emission has an ultra-wide full-width at half-maximum of 206 nm, which can cover a wider visible spectrum. All the results show that the phosphor has application prospects in LEDs. [ABSTRACT FROM AUTHOR]

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) are considered as next-generation of NIR light sources for spectroscopy. However, it is still a challenge to develop an inexpensive broadband NIR phosphor with relatively long-wavelength (λem > 800 nm) emission. In this work, an octahedral Al3+-containing pyrophosphate Al0.5Ta0.5P2O7 with a cubic structure was chosen as a host for Cr3+. Synthesizing this material indicates that this phosphor exhibits a broadband NIR emission peaking at 850 nm with a full width at half maximum (FWHM) of 155 nm under 465 nm excitation. The crystal structure, morphology, local structure, and photoluminescence properties of this material were investigated in detail. The results revealed a full understanding of this new material. A NIR pc-LED device fabricated by using this material combined with a 450 nm LED chip generates a NIR output power of 10.7 mW and a NIR photoelectric conversion efficiency of 3.4% under a 100 mA driving current, which shows the possibility of this material to be utilized in NIR pc-LED applications. Moreover, this material exhibits a linear relationship between emission intensity, decay time and temperature in a wide temperature range, implying that excellent multi-model temperature sensing applications can be expected. [ABSTRACT FROM AUTHOR]

In this work, we report the structural and magnetic characterization of two new B-site rock-salt ordered double perovskites ALaCoTeO6 (A = K+ and Na+) with mixed A-site cations. KLaCoTeO6 crystallizes in the space group P4/nmm with a long-range ordering degree of 84.8% for the A-site K+/La3+ cations, whereas NaLaCoTeO6 adopts an unexpected triclinically distorted I1¯-structure with Na/La3+ disordering, validated by combined Rietveld refinements against high-resolution neutron diffraction data and Cu Kα1 X-ray powder diffraction data. Magnetic susceptibility at low temperatures shows clear antiferromagnetic (AFM) transitions for both compounds. KLaCoTeO6 exhibits the highest AFM transition temperature of 20 K amongst all the Co/Te-ordered 3C-type A2CoTeO6 (A = Pb2+, Sr2+, and Ca2+) and ALaCoTeO6 double perovskites due to its larger Co2+–O–Te6+ bond angle and A-site cationic ordering-induced larger distortion of the Co2+-based face-centered cubic sublattice. Moreover, we found that the average radius of the A-site cations plays a decisive role in the AFM transition temperatures of all these ordered double perovskites, that is, a larger A-site cation always results in a higher AFM transition temperature. This provides a strategy to subtly manipulate the magnetic properties of ordered double perovskites. [ABSTRACT FROM AUTHOR]

This article describes the synthesis and crystal structure of ten new Tc(V) complexes with pyrazine containing homologous alkoxy ligands. We carried out an analysis of the Hirshfeld surfaces for the described compounds and found out that with increasing length of the hydrocarbon substituent from CH3 to C10H21 the percentage of H⋯H interactions in crystals increases from 28% to 59%. The purpose of this article was to show the pattern of increase in interplanar distances in crystals depending on the length of the hydrocarbon substituent, and also to study the thermochemical properties of Tc(V) complexes. The mechanism of thermolysis does not depend on the length of the hydrocarbon substituent and differs only in the temperature range of the reactions. The absorption bands of the obtained complexes in IR and UV-vis spectra do not depend on the length of the hydrocarbon substituent. Using a complex with a propyl substituent as an example, the UV-vis spectral data of the mother solution are presented. Based on DFT calculations of spectra and molecular models, an indirect identification of the reaction intermediate is provided. Using a complex with a methyl substituent as an example, data on MALDI spectrometry are presented. [ABSTRACT FROM AUTHOR]

The influence of the metal ratio on the geometric characteristics and crystal structures of heterometallic clusters with {Re6−xMoxQ8} cores was studied. For this purpose, nine new molecular cluster complexes of the type [Re6−xMoxS8L6] (x = 2, 3 or non-integer value between 2 and 3; L = pyridine, 4-ethylpyridine or 4-tert-butylpyridine) were synthesized. The compounds were obtained by one-step replacement of the cyanide apical ligands of [Re6−xMoxS8(CN)6]5−/4− cluster complexes with the corresponding organic compounds under solvothermal conditions. The crystal structures of all the obtained compounds were investigated by single-crystal X-ray diffraction analysis. Analysis of the crystal structures showed that clusters with the same apical ligands and different x values have similar geometries and form isostructural packings, demonstrating the formation of solid solutions. [ABSTRACT FROM AUTHOR]

The discovery of phosphors with highly efficient broadband near-infrared emission is urgent for constructing NIR sources for various applications. Herein, we synthesized a series of near-infrared emitting garnet-type (A3B2C3O12) Lu2−xCaAl3.99Cr0.01SiO12:xGd/La and Lu2CaAl3.99−yCr0.01SiO12:ySc/Ga phosphors and systematically investigated the effect of A/B-site substitution on the crystal structure and luminescence properties. Structural and optical analyses revealed that the A/B-site substitution weakened the crystal field strength, further enhancing the broadband emission of the allowed 4T2 → 4A2transition and diminishing the narrow-peak emission of the forbidden 2E → 4A2 transition. As expected, NIR phosphors, exemplified by Lu1.7CaAl3.99Cr0.01SiO12:0.3Gd and Lu2CaAl3.49Cr0.01SiO12:0.5Sc, showed outstanding thermal stabilities at 423 K (150 °C) registering values of 103.02% and 94.91%, with high quantum efficiencies of 80.48% and 85.01%, respectively. In addition, pc-LEDs with broadband NIR output and good optoelectronic properties have been realized, demonstrating the great potential of broadband NIR pc-LEDs for applications. This work not only provides a series of high-efficiency phosphors for NIR pc-LED applications, but also provides a systematic idea and an efficient method to improve the luminescence performance of garnet-type phosphors. [ABSTRACT FROM AUTHOR]

The goal of this study was to investigate how the electron-donating capability around the lower valent metal ion and the electron-accepting capability of the higher valent metal ion influence metal to metal charge transfer (MMCT) properties in mixed-valence complexes. A series of trinuclear ruthenium complexes represented as [Ru2(ap-4-Me)3(CH3COO)N≡CRuCpMex(dppe)][PF6] (CpMex = polymethylcyclopentadienyl, x = 0, 1, and 5; and dppe = 1, 2-bis(diphenylphosphino)ethane, ap-4-Me = 2-anilino-4-methylpyridine) and their one-electron oxidized products were synthesized and fully characterized. The UV–vis-NIR spectra confirmed that as the electron donor character of the CpMex(dppe)RuCN fragment enhanced or the electron-accepting capability of the higher valent diruthenium cluster increased, the RuII → Ru V2 or Ru VI2 Ru2 MMCT bands shifted to lower energies, which was supported by TDDFT calculations. [ABSTRACT FROM AUTHOR]

For a series of chiral para-alkylphenyl glycerol ethers—para-Alk–C6H4–OCH2CH(OH)CH2(OH) [Alk = Me (1), Et (2), n-Pr (3), n-Bu (4), iso-Pr (5), tert-Bu (6)]—we used information on their solubility in cyclohexane and thermochemical melting parameters to calculate the standard free energies of dissolution, , and melting, ΔG 0f. Our observations showed consistent patterns in these parameters within the homologous series. This analysis allowed us to compare the energy characteristics of the crystal structures, thus enabling the quantification of enantiophobic and enantiophilic effects. Furthermore, it facilitated the examination of trends in chiral discrimination as the molecular constitution changed sequentially. We identified distinct trends for enantiopure substances and corresponding racemic compounds within the series studied. In particular, the difference in crystal packing energies among the series members following these trends favours racemic molecular compounds by approximately 2.5 kJ mol−1. However, for (R)-3 and (R)-4, the realised crystal structures are more energetically favoured than expected, thus deviating from the established correlations. This anomaly allows homochiral crystal structure 3 to bridge the energy gap and crystallise from the racemic mixture as a thermodynamically more favourable conglomerate of enantiomeric crystals. In contrast, for racemic compound rac-5, the energy of its molecular packing is lower than expected from the correlations but insufficient to make conglomerate 5 thermodynamically more favourable. At the same time, the formation of racemic compound rac-6 was abnormally preferable in terms of energy. In addition, we presented the X-ray diffraction data for the homo- and heterochiral crystals of 5, thereby complementing the structural information available for the "chiral pool" class of glycerol derivatives. [ABSTRACT FROM AUTHOR]

Monodispersed and faceted Bi2Fe4O9 micro-cuboid crystals with a mullite-type structure have been successfully synthesized by a facile hydrothermal method. The single crystalline Bi2Fe4O9 micro-cuboids exhibited a length of 10–20 μm and a square cross-section with a side length of 1–2 μm. The preferential growth of the Bi2Fe4O9 micro-cuboid crystals has been determined to be along 〈001〉 with the dominant (110) and (−110) facets enclosed. These micro-cuboid crystals were probably formed by a dissolution–recrystallization mechanism, where a phase transition from irregular-shaped sillenite Bi25FeO40 agglomerates to perovskite BiFeO3 microspheres occurred and finally resulted in the micro-cuboid crystals. More interestingly, these micro-cuboids demonstrated a remarkable photo-Fenton catalytic degradation activity towards RhB under visible light irradiation (λ > 400 nm). 90.2% RhB decomposition at 120 min can be achieved and the corresponding apparent rate constant is 0.0175 min−1, 11.67 times and 3.65 times larger than that of Fenton-like oxidation and pure photocatalysis, respectively. The as-prepared Bi2Fe4O9 micro-cuboid crystals also showed intriguing morphology-dependent ferromagnetism at room temperature, possibly allowing the magnetic recollection and reuse of Bi2Fe4O9 samples as well as their magnetic-field-mediated photocatalytic performances. [ABSTRACT FROM AUTHOR]

Identifying and evaluating novel and extremely stable materials for catalysis is one of the major challenges that mankind faces today to rapidly reduce the dependence on fossil fuels. To contribute to achieving this goal, we have evaluated within the density-functional framework the properties of a new two-dimensional MXene structure, the asymmetric MXene YZrCOF monolayer. Phonon dispersion calculations at 0 K and 300 K indicate that the studied material is dynamically stable. The calculations also indicate that the material has a rigid crystal structure with a wide band gap, a strong potential difference, and a band-gap alignment that favors the production of both H2 and O2 molecules from water splitting. We also report the outcome of the strain effect on the electrical and photocatalytic characteristics of the studied material. We will demonstrate that even under a large strain, the YZrCOF monolayer is stable and useful for photocatalytic applications. [ABSTRACT FROM AUTHOR]

Five new alkylaluminum complexes with different pyridinyl-substituted imines or cyclohexyl-substituted imines were synthesized and characterized successfully. The aluminum complex [FlCHNCH(CH3)Py]AlMe2(Py = 2-pyridyl) (1) was obtained by reacting 9-[2-pyridyl-CH(CH3)-N＝CH]Fl (Fl = fluorenyl) (L1) and equimolar AlMe3. The reactions of 9-(2-pyridyl-N＝CH)Fl (L2) and 9-[2-N(CH3)2-cyclohexyl-N＝CH]Fl (L3) with equimolar AlMe3 or AlEt3 afforded other alkylaluminum complexes [FlCHNPy]AlMe2(Py = 2-pyridyl) (2), [FlCHNPy]AlEt2 (Py = 2-pyridyl) (3), [FlCHNCyN(CH3)2]AlMe2 (Cy = 2-cyclohexyl) (4) and [FlCHNCyN(CH3)2]AlEt2 (Cy = 2-cyclohexyl) (5). All these complexes (1–5) were characterized using NMR spectroscopy, elemental analysis, and X-ray crystal structure analysis. The catalytic properties of these new alkylaluminum complexes for the hydrophosphonylation of aldimines were examined. Complex 5 showed the best catalytic performance under mild reaction conditions with a low catalyst loading (1 mol%), and 20 different substituents of aldimines were isolated with more than 90% yields. [ABSTRACT FROM AUTHOR]

Marbofloxacin (MB) is a newly developed fluoroquinolone antibiotic used especially as a veterinary drug. It may be regarded as the improved version of enrofloxacin owing to its antibacterial activity, enhanced bioavailability, and pharmacokinetic–pharmacodynamic (PK–PD) properties. In this study, nine heavy rare-earth ions (Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) were selected in light of their potential antibacterial activity and satisfactory biosafety to afford the corresponding rare-earth metal complexes of MB: the MB–Ln series. Their chemical structures and coordination patterns were characterized using IR spectroscopy, HRMS, TGA, and X-ray single-crystal diffraction analysis. Our results confirmed that all the MB–Ln complexes yielded the coincident coordination modes with four MB ligands coordinating to the Ln(III) center. In vitro antibacterial screening on five typical bacteria strains revealed that the MB–Ln complexes exhibited antibacterial activities comparable with MB, as indicated by the MIC/MBC values, in which Escherichia coli and Salmonella typhi were the most sensitive ones to MB–Ln. Furthermore, the MB–Ln complexes were found to be much less toxic in vivo than MB, as suggested by the evaluated LD50 (50% lethal dose) values. All the MB–Ln series complexes fell in the LD50 range of 5000–15 000 mg kg−1, while the LD50 value of MB was only 1294 mg kg−1. Furthermore, MB–Lu, as the selected representative of MB–Ln, could effectively inhibit the activity of DNA gyrase, the same as MB, suggesting the primary antibacterial mechanism of the MB–Ln series. The results demonstrated the good prospects and potential of metal-based veterinary drugs with better drug performance. [ABSTRACT FROM AUTHOR]

Ideonella sakaiensis PETase (IsPETase) is a unique polyethylene terephthalate (PET) hydrolase that displays great potential for mitigating PET waste at moderate temperatures. Although IsPETase exhibits greater specific activity towards PET, rapid activity loss limits its commercial application. Herein, semi-saturation mutation was carried out to stabilize the most flexible region in IsPETase and a thermostable S92P/D157A variant with a Tm value of 70.8 °C (ΔTm = 24.1 °C) was constructed, which enabled a 109.3-fold increase in products released from amorphous PET depolymerization at 40 °C. The further depolymerization of untreated post-consumer PET obtained 17.34 mM products (95.0% TPA). The crystal structure indicated that the "wobbling" W156 residue in IsPETaseWT was fixed in the substrate-binding conformation in the S92P/D157A variant, which contributed to an increase in thermostability and could provide steady interaction with the substrate. Previous studies emphasized that the W156 residue exhibiting a "wobbling effect" is critical to substrate binding, while the different structure–function relationship of the S92P/D157A variant indicated that the wobbling of W156 may not be a pre-requisite for efficient PET biodegradation. Instead, engineering PET hydrolases for fixing the conserved W156 residue in the substrate-binding conformation was proposed. The S92P/D157A variant exhibited a preference for PET in the gauche conformation, which is consistent with its efficiency towards the degradation of low crystallinity PET, further cementing the importance of conformation selection and providing complementary evidence for the function of the fixed W156 residue in PET binding and catalytic processes. Collectively, our results could contribute to the understanding and engineering of more effective PET hydrolases, promoting the industrial application of the enzymatic PET recycling process. [ABSTRACT FROM AUTHOR]

Explaining the intensification of upconversion luminescence (UCL) from a single phase NIR-upconverting (UC) crystal due to non-lanthanide dopant insertion appears challenging in the absence of proper mechanistic investigation. In this paper, through extensive synchrotron based X-ray probing, we made an attempt to understand the variations in the structural attributes of UC crystals generated through non-lanthanide ion doping. The structures of the NaYF4/Yb3+/M3+ (M3+ = Er3+/Tm3+) UC crystals doped with different Li+ concentrations were primarily investigated using Rietveld refinement analysis from synchrotron X-ray diffraction (SXRD) and supported with absorption data (XAFS), where necessary. The structural investigation was also supported by TEM, HRTEM, XANES, FT-IR and Raman spectroscopy. Rietveld analysis revealed that all the generated Li+ doped NaYF4 crystals belong to the P6 space group. Most of the Li+ ions were found to be localized in octahedral voids and lattice positions, simultaneously, in the P6 crystal structures. The overall study showed that the change in the UCL intensity behavior with Li+ incorporation could not be predicted from the lattice parameters, morphology or the particle size variation. A detailed XAFS study rather suggested the possible existence of local lattice disorder, which was found to be reflected in terms of lattice strain obtained from Williamson--Hall analysis, irrespective of the activator ions. The remarkable coherence between the variation trends of UCL intensity and lattice strain indicated that the perturbation of the local symmetry field is in some way connected with the local disorder that may not always manifest through average structural attributes like lattice parameters. [ABSTRACT FROM AUTHOR]

Disordered crystals have garnered increasing attention as new laser materials because of their broad emission bandwidths. This paper reports a novel Yb-doped strontium yttrium phosphate (Yb:YSr3(PO4)3) crystal with a disordered structure, as well as its crystal growth, structure, spectral properties, and laser performance. The crystal structure (cubic, 4¯3m point group) was refined using the Rietveld method. The absorption cross-section and fluorescence lifetime were determined to be 1.31 × 10−20 cm2 at 976 nm and 1267 μs, respectively. The stimulated emission cross-section was 1.04 × 10−20 cm2 at 1013 nm, with an emission bandwidth of 55 nm. In addition, continuous-wave laser operation was realized using the Yb:YSr3(PO4)3 crystal with different output coupler transmissions, where the obtained maximum output power and slope efficiency were 1.3 W and 61%, respectively. A dual-wavelength regime with wavelengths centered at 1039 nm and 1047 nm (Δν = 2.2 THz) was achieved under certain conditions; thus, this crystal is expected to be employed for developing terahertz sources. In addition, the laser can operate at multiple wavelengths, ranging from 1023 to 1050 nm. The results indicate that the Yb:YSr3(PO4)3 crystal with a disordered structure may be a promising multi-wavelength laser crystal. [ABSTRACT FROM AUTHOR]

Sulfamethoxazole (SMZ) is a synthetic broad-spectrum antibiotic of biopharmaceutical classification system (BCS) class IV, with both low solubility and permeability, requiring probably higher drug doses in orally-administered formulations to promote an expected systemic absorption. To overcome such limitations and especially to increase its solubility, this study has a main purpose of the development of novel optimized crystalline forms of SMZ. Herein, two crystalline salts of SMZ (SMZBr and SMZNO3) have been synthesized from solution crystallization and characterized using X-ray (single and powder), spectroscopic (infrared, FT-IR) and thermal (DSC and TGA) techniques. Furthermore, a solubility study was performed in pure water and compared with the SMZCl salt and SMZ form I. It was observed that the SMZBr salt exhibits phase stability in water media and shows enhanced solubility compared to the SMZCl salt and SMZ form I. Additionally, a qualitative litmus paper test was employed to verify the volatiles released during the thermal drug degradation. [ABSTRACT FROM AUTHOR]

In recent years, the research and development of new white LEDs have attracted extensive attention. Whether the new LEDs have a higher color rendering index and can simulate natural sunlight without damaging human health is the issue of concern. Therefore, we introduce in detail the ultraviolet (UV) excited luminescence characteristics of Eu ions, Ce ions, and other ions in different host lattice (aluminate, silicate, phosphate, and borate) matrices. This paper summarizes the introduction and application of rare-earth ions as activation center phosphors and expounds on the application potential of cyan and blue phosphors in many fields such as display technology from the aspects of excitation and emission characteristics, lifetime, color purity, and thermal stability. Finally, we put forward our views on improving the thermal stability of phosphors and selecting crystals with suitable structures as the host for the preparation of phosphors. [ABSTRACT FROM AUTHOR]

Co-crystallization of the antibacterial agent proflavine (PF) with the inorganic salt ZnCl2 by mechanochemical and solution methods results in the formation of novel compounds ZnCl3(HPF) (1) and [HPF]2[ZnCl4]·H2O (2), both containing the proflavinium cation (HPF)+. Both compounds show a 50–125% enhanced antimicrobial activity with respect to a reference standard of AgNO3, and a 25–50% enhancement to the behaviour of the separate components against pathogen indicator strains of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. In terms of crystal structure, both compounds ZnCl3(HPF) and [HPF]2[ZnCl4]·H2O are characterized by extensive π-stacking interactions between the proflavine moieties. The same interaction is predominant in the previously unknown crystal structures of neutral proflavine (PF), as well as in that of its dihydrated monochloride salt, [HPF]Cl·2H2O, which are also described in this paper. [ABSTRACT FROM AUTHOR]

Four Ni4O4 cubanes with formula [Ni4(Cl2-L)4(μ3-OMe)4(MeOH)4] (1), [Ni4(Br2-L)4(μ3-OMe)4(MeOH)4] (2), [Ni4(I2-L)4(μ3-OMe)4(MeOH)4] (3) and [Ni4(BrCl-L)4(μ3-OMe)4(MeOH)4] (4) (Cl2-LH = 3,5-dichlorosalicylaldehyde, Br2-LH = 3,5-dibromosalicylaldehyde, I2-LH = 3,5-diiodosalicylaldehyde, BrCl-LH = 3-bromo-5-chlorosalicylaldehyde) were obtained by self-assembly from commercially available 3,5-halogen-substituted salicylaldehydes and NiCl2·6H2O in high yields at room temperature. The X-ray crystal structure analysis of 4 showed a cubane-type structural topology as each Ni(II) ion is six-coordinated in a distorted octahedral geometry defined by four oxygen atoms from the MeOH molecule (three as bridging methoxy-oxygens and one as terminal group) and two oxygen atoms from the 3-bromo-5-chlorosalicylaldehyde ligands. The cubane core is stabilized via an intramolecular O–H⋯O hydrogen bond, while in the crystal, complex molecules are linked into the zigzag chain to the a-axis via strong Br⋯Br interaction. Both SQUID and μSQUID measurements indicate the coexistence of ferromagnetic and antiferromagnetic interactions in two complexes. The fitting of the magnetic data yields different magnetic parameters for each complex, clearly highlighting the differences in the magnetic properties among these systems. DFT calculations have also been performed on compounds 1–4 to explain the exchange interaction mechanisms between the Ni(II) ions, supporting both the magnitude and sign of the coupling constants. [ABSTRACT FROM AUTHOR]

Despite extensive research on the photoluminescence properties of Bi3+ ions, the origins of their emission and excitation bands remain elusive. Herein, we present a comprehensive analysis of the photoluminescence properties of Bi3+-activated LuXnGaO4 (Xn = Mg, Zn), elucidating the underlying factors governing the intra-ionic and extra-ionic electronic transitions. By integrating crystal structure data and spectroscopic data analyses with semi-empirical formula calculations, the origins of excitation and emission states were elucidated. Moreover, the impact of alterations in chemical surroundings on the luminescence of Bi3+ was investigated. Both LuXnGaO4:Bi3+ phosphors exhibit three excitation peaks in the near ultraviolet region and display a broadband yellow emission. However, the luminous behavior of LuMgGaO4:Bi3+ and LuZnGaO4:Bi3+ differs due to variations in the band gap, bond length and neighboring atoms. It is anticipated that the investigation of Bi3+-activated gallates presents a promising avenue for advancing wide-band and long-wavelength emitting phosphors. [ABSTRACT FROM AUTHOR]

This research utilized a recently developed co-melting crystallization method to synthesize four distinct energetic coordination compounds (ECCs). The method involves the direct heating of organic ligands with inorganic salts, leading to the formation of the desired ECCs upon cooling and subsequent crystallization. This approach effectively bypasses various challenges associated with the conventional solvent-based ECC preparation process. In this study, the organic ligands employed were pyrazole and 4-chloropyrazole, while the inorganic salts included copper nitrate and copper perchlorate. A rigorous pre-experiment was meticulously designed to validate the feasibility of this method, followed by control experiments to underscore its advantages. Subsequently, comprehensive characterizations were conducted on the four ECCs, with a primary emphasis on their crystal structures and energetic properties. Notably, ECCs-3 and ECCs-4, among the synthesized ECCs, exhibit significant potential for applications in pyrotechnic materials and ignition agents. This work extends the practical applicability of the co-melting crystallization method we have developed, providing further substantiation of its advantages and potential. [ABSTRACT FROM AUTHOR]

The self-assembly of cluster-based halide framework materials has been a matter of great interest but with great challenges. Herein, by exploiting hexamethylenetetramine (Hmta) with Td symmetry as a structural modifier, we successfully constructed and systematically characterized an unusual three-dimensional (3D) hybrid bromoargentate, namely K[NH4][Ag4Br6(Hmta)] (1), bearing a diamond-type [Ag4Br6(Hmta)]n2n− anionic skeleton built up from adamantane-like units of inorganic [Ag4Br6] clusters and organic Hmta ligands. UV–Vis diffuse reflectance analysis showed that the optical bandgap of the title compound was 2.68 eV, indicating a visible-light-responsive semiconductive behavior. More importantly, upon alternate light illumination, the so-designed compound exhibited remarkable photoelectric switching properties, with photocurrent densities (0.38 and 1.10 μA cm−2 for visible and full-spectrum light, respectively) that compete well with and even exceed those of some high-performance metal halide counterparts. Further theoretical calculations, including band structure, density of states, and wave functions, revealed that compound 1 has a unique valence band and conduction band distribution, rendering it with small effective masses (especially the electrons), which may be responsible for its good photoelectricity. Furthermore, in this work, Hirshfeld surface analysis, thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS) studies were performed. [ABSTRACT FROM AUTHOR]