Search

Crystals with mixed anions refer to inorganic salts containing at least two types of anions or anionic groups, and these anions can be Q 2− (Q = O, S, Se, Te) and X − (X = F, Cl, Br, I), and anionic groups include various B–O groups, (OH) − , (IO 3 ) − , (CO 3 ) 2− , (SiO 4 ) 4− , (NO 3 ) 3− and (PO 4 ) 3− . Recently, in view of the insufficiency and strong requirements of second-order nonlinear optical (NLO) crystals, especially ones in the deep ultraviolet (DUV) and middle and far-infrared (MFIR) regions, the study of NLO crystals have received intensive interest from researchers. For a NLO crystal candidate, desirable properties include large NLO coefficients, high laser-induced damage threshold values, phase matchabilities and wide transparent windows. The availability of the former two properties is especially problematic since the structural factor influences them in reverse order. To balance them, it is necessary to introduce different anions into the structure to induce them to function differently. Under the guidance of anionic group theory and the functional moiety concept, many NLO crystals with mixed anions have been obtained. However, to date, a systematic survey of this topic has not been carried out. In this review, recently reported NLO crystals with mixed anions are summarized, the contents of which are mainly focused on their crystal structures and NLO behaviors, together with the relationship between these two aspects. It is hoped that this work will provide a useful perspective on the most promising NLO candidates. [ABSTRACT FROM AUTHOR]

The exploration and development of second-order nonlinear optical (NLO) materials in the middle- and far infrared (MFIR) region are important and high profile topics in the fields of NLO, solid-state chemistry and laser. Common MFIR NLO materials are chalcogenides, halides, and iodates, which have a wide MFIR transparent range and large NLO coefficients. This review summarizes recent achievements on MFIR NLO materials, and specifically focuses on their crystal structures and NLO properties. Compared to known materials, the common choice for cations are alkali-metal Li, Na, K, Rb and Cs, the coin-metal Ag, and the alkali-earth metal Ba. Exploring mixed-anions materials could be one of the most promising solutions to obtaining NLO materials with both large second-harmonic generation (SHG) intensities and high laser induced damage thresholds (LIDTs). This review also summarizes functional moiety theory to elucidate the design of promising NLO materials. [ABSTRACT FROM AUTHOR]

Five isostructural quaternary rare-earth sulfide Mg RE 6 Si 2 S 14 ( RE = Y, Ce, Pr, Nd and Sm) have been successfully synthesized via high-temperature solid-state method. They crystallize in the hexagonal space group P 6 3 and belong to the MnLa 6 Si 2 S 14 structure type. Their 3-D structures are constructed by the connection between infinite 1-D [( RE 6 S 6 ) 6+ ] ∞ tubular and (SiS 4 ) 4– tetrahedron, and Mg 2+ ions occupy the octahedral interspaces in the [( RE 6 S 6 ) 6+ ] ∞ tubular. The lanthanide contraction phenomenon among these compounds is also discussed. Electronic structure calculation indicates that MgY 6 Si 2 S 14 has an indirect optical energy gap of 2.26 eV, and its optical absorption is mainly ascribed to the charge transition from S-3p to Y-4d states. [ABSTRACT FROM AUTHOR]

Three new ternary rare-earth zirconium chalcogenides, Ce 2 ZrSe 5 ( 1 ), Pr 2 ZrSe 5 ( 2 ) and Nd 2 ZrSe 5 ( 3 ), have been synthesized by a facile solid-state route with boron as the reducing reagent. They crystallize in the space group Pnma of the orthorhombic system, belonging to the U 3 Se 5 structure type. Their 3-D structures are constructed by parallel polyanionic {[ZrSe 5 ] 6– } n chains and LnSe 8 bicapped trigonal prisms. The magnetic susceptibilities' data indicate their antiferromagnetic-like behavior without magnetic order down to 2 K. The structural relationships among several similar structures are discussed, together with the lanthanide contraction in the Ln 2 ZrSe 5 system. [ABSTRACT FROM AUTHOR]

Abstract: Two new coordination polymers, {[Zn3L2.5(μ 3-OH)(H2O)3]·4H2O} n (1) and [Zn2L1.5(μ 3-OH)(4,4′-bpy)0.5] n (2) (H2L=2,5-bis(4-methylbenzoyl)terephthalic acid, 4,4′-bpy=4,4′-bipyridine), have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, TG, PXRD and single crystal X-ray diffraction. Complex 1 possesses a 2D double-layer configuration with 48·62 network constructed with trinuclear zinc(II) clusters and L2− ligands, which extends into a 3D architecture via O–H···O interactions between coordinated water molecules and lattice water molecules. Complex 2 is a uninodal 8-connected 3D framework with a 424·64 network based on tetranuclear zinc(II) clusters as nodes. Moreover, the luminescent properties of complexes 1 and 2 were also investigated. [Copyright &y& Elsevier]

Abstract: A new 3D sandwich-type MOF named [Zn3(bptc)1.5(H2O)4]·C2H5OH·2H2O (1) (H4bptc=biphenyl-2,5,2'',5''-tetracarboxylic acid) was obtained by solvothermal reaction, which represents a rare trinodal (3, 4, 10)-connected topology network. Moreover, the thermal stability, UV–vis absorption spectra and photoluminescent properties of 1 have been investigated as well. [Copyright &y& Elsevier]

Abstract: A new supramolecular complex [Hg6Sb4](InBr6)Br (1) has been prepared by the solid-state reaction of HgBr 2 with elemental In and Sb at 450°C. The crystal structure of 1 features a three-dimensional [Hg6Sb4]4+ framework with cavities of two different sizes occupied by different kinds of guest anions. The bigger cavities are filled with the octahedral InBr6 3− ions, while the smaller cavities trap Br− ions. The optical properties were investigated in terms of the diffuse reflectance and infrared spectra. The electronic band structure along with density of states (DOS) calculated by DFT method indicates that the present compound is semiconductor, and the optical absorption is mainly originated from the charge transitions from Sb-5p and Br-4p to In-5s and Hg-6s states. [Copyright &y& Elsevier]

Abstract CuGa x In 1- x Se 2 (x = 0.54, CGISe) has been obtained by a high temperature solid-state method. It crystallizes in the typical chalcopyrite structure. CGISe exhibits a second-harmonic generation intensity about 0.5 times that of AgGaS 2 in the particle size range 75–100 μ m. It's band structure, density of state, and optical properties are studied by theoretical calculations. The nonlinear optical properties of CGISe and several related chalcopyrite-type chalcogenides are discussed based on optical property and dipole moment calculations. Graphical abstract Experimental and theoretical NLO studies of CuGa 0.54 In 0.46 Se 2. Image Highlights • Single-crystal structure of CuGa 0.54 In 0.46 Se 2 is firstly studied. • The NLO property of CuGa 0.54 In 0.46 Se 2 is experimentally investigated. • Theoretical calculations are performed to explain the NLO property. [ABSTRACT FROM AUTHOR]

Three ternary rare-earth zirconium sulfides, Y 2 ZrS 5 ( 1 ), Ce 2 ZrS 5 ( 2 ) and Pr 2 ZrS 5 ( 3 ), have been synthesized by high-temperature solid-state reactions. They crystallize in the space group Pnma of the orthorhombic system, belonging to the Y 2 HfS 5 structure type. There are two types of building units in their structures, RE S 8 bicapped trigonal prisms and ZrS 7 monocapped trigonal prisms. Their structures feature polyanionic {[ZrS 5 ] 6− } n chains and cubane-like {[ RE 4 Zr 2 S 6 ] 8+ } n double chains along the b direction, and RE atoms occupying the polyhedral interspaces between the former chains. The lanthanide contraction phenomenon in the series of RE 2 ZrS 5 ( RE = La–Nd, Sm and Gd) is discussed. The electronic band structure and density of states calculations using Material Studio indicate that the direct optical energy gap of 1 is 1.39 eV and the optical absorption is mainly ascribed to the charge transition from S-3p to Y-4d and Zr-4d states. [ABSTRACT FROM AUTHOR]

[Display omitted] • The current research status of WO 3 hydrate-based photocatalysts were overviewed. • The relationship between synthesis strategies and crystal structure and coordination water content were summarized. • The feasibility strategies for improving the photocatalytic performance of WO 3 hydrate-based have been outlined. • The application status of photocatalysts in clean energy production and environmental purification were summarized. Photocatalysis is an attractive "green" solution to the energy crisis and environmental pollution; however, its practical application is still thwarted by low efficiency. As the core link of this technology, the continuous development of new photocatalysts is the main idea to improve efficiency. In the past few decades, a large number of semiconductor materials with photocatalytic activity have been synthesized successively, including transition metal oxides, nitrides, sulfides, carbon based materials, and metal organic frameworks. Considering various factors such as catalytic activity, production cost, and environmental safety, metal oxides are the most promising carriers of photocatalytic materials for development among them, such as titanium dioxide (TiO 2). Recently, tungsten trioxide (WO 3) based photocatalyst, especially tungsten trioxide hydrates (WO 3 · n H 2 O, n = 0.33, 0.5, 1 and 2), has become a new favorite among scholars. Not only due to its wider light response range and higher photocatalytic activity compared to TiO 2 , but also because the rich hydroxyl groups give it more flexible surface structure regulation possibilities. At present, there are over 200 literatures on WO 3 · n H 2 O-based photocatalysts have published; yet, no review article concluding such materials. To promote the development and provide a reference for colleagues, we present a systematic review of the applications and research progress of WO 3 · n H 2 O-based photocatalysts in the past decade. Starting from structural analysis, this work summarizes the preparation methods and modification strategies. Subsequently, it explores the application status in energy conversion and environmental pollution control, and finally a critical assessment and outlook of technical challenges and research opportunities for future was proposed. [ABSTRACT FROM AUTHOR]

• CoCrFeMoNi alloys were prepared by vacuum arc-melting from pure elements. • The validity of new PHACOMP method for high-entropy alloys are verified. • New PHACOMP method can be used to evaluate thermal stability of high-entropy alloy. • The designed CoCrFeMoNi high-entropy alloys show competitive corrosion resistance with commercial alloy. [Display omitted] Various methods can be used to predict the phase composition of conventional alloys. However, it is relatively difficult to predict high-entropy alloys (HEAs) owing to their complexity. There remain many challenges in designing HEAs with desirable properties. In this study, two strategies were applied to design corrosion-resistant non-equal-molar CoCrFeMoNi HEAs with a single phase. The two strategies were prediction for valence electron concentration dependent structural behavior to evaluate the matrix of HEAs, and average d -orbital energy level ( M ̅ d) that was initially used to predict precipitation in superalloys under different temperatures. The validity of these two approaches was determined by thermal stability. The corrosion behaviors of the designed HEAs were investigated by polarization tests. In conclusion, the phase compositions of CoCrFeMoNi HEAs were predicted using a combination of the two approaches. The corrosion resistance was also competitive compared to that of Hastelloy C276. This research can provide a reference for the future development of corrosion-resistant HEAs with a single phase. [ABSTRACT FROM AUTHOR]

The first inorganic metal phosphite iodide, CsSn 2 (HPO 3) 2 I, was successfully synthesized. It represents the first phosphite tin halide and features a [Sn(HPO 3)] ꝏ layer framework structure built by the SnO 3 pyramid and HPO 3 2− groups. Attractively, it shows the most giant experimental birefringence (Δn = 0.200@0.546 μm) among reported inorganic metal phosphite birefringent crystals. This work proves that the reasonable utilization of metal cations with lone pair electrons is an effective strategy for developing excellent birefringent materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: In our investigation of rare earth sulfides in the AE-RE-Sn-S (AE=alkaline-earth, RE=rare earth) system, three isostructural quaternary sulfides have been obtained. These compounds adopt the Eu5Zr3S12 structure type and crystallize in the P-62m space group (no. 189); the crystal data are as follows: Sr2Y2.67Sn3S12, a =11.600(7)Å, c =3.948(3)Å, Z =1; Ca3La2Sn3S12, a =11.5997(6)Å, c =3.9407(4)Å, Z =1; Ca3Er2Sn3S12, a =11.448(3)Å, c =3.8780(11)Å, Z =1. Single-crystal analysis indicated that the crystal structures consist of three types of building block: RES7, AES6, and SnS6 units. The structure of Sr2Y2.67Sn3S12 is characterized by the trimer-chains along the c direction, which are connected into a 3-dimensional framework by the Sn atoms via S(1), S(2), and S(3), with Sr atoms filling in the channels along the c direction. The optical band gap of 1.45eV for Ca3La2Sn3S12 was deduced from the diffuse reflectance spectrum. [Copyright &y& Elsevier]

The Von Hippel-Lindau (VHL) E3 ubiquitin ligase, which mediates its substrate hypoxia-inducible factor 1α (HIF-1α) for ubiquitination and subsequent degradation, is an attractive drug target in various diseases, such as anemia, inflammation, neurodegeneration and cancer. Proteolysis targeting chimeras (PROTACs) containing a VHL ligand that can hijack the E3 ligase activity to degrade the target protein has also been studied in academic and in industry areas recently. Herein, by developing and optimizing the Bayesian Model, we report ensemble-based virtual screening as an effective strategy to discover potential VHL inhibitors from Specs database. The virtual screening protocol was developed, ten representative molecules were obtained and five compounds were selected for subsequent binding mode analysis to be potent VHL inhibitors. • The Bayesian Models were created on representative structure or the ensembles of crystal structures and MD snapshots. • Pharmacophore modeling, molecular docking, MD simulations and Bayesian Model were applied. • An ensemble-based virtual screening strategy was developed to identify the potential VHL inhibitors. [ABSTRACT FROM AUTHOR]

The effect of low temperature on tensile properties of a AlCoCrFeNi 2.1 eutectic high entropy alloy (EHEA) was investigated in the present work. Transmission electron microscopy (TEM) showed that the initial as-cast microstructure consisted of B2 (ordered body centered cubic structure) and L1 2 (ordered face centered cubic structure) phases. Upon tensile testing at temperatures ranging from room temperature (RT) to −196 °C (77 K), the L1 2 phase became disordered, changing to a simple FCC (face centered cubic) crystal structure whereas the B2 phase maintained an ordered structure. An increase over 300 MPa was observed in the ultimate tensile strength ( σ UTS ) of the −196 °C tensile tested sample compared to the room temperature tensile tested sample, while keeping almost similar amount of total elongation. TEM results indicated an increase in the dislocation activity in the FCC phase as well as B2 phase in the −196 °C tensile tested sample compared to the sample deformed at room temperature. [ABSTRACT FROM AUTHOR]

Given the collaborative effect between different anions, compounds containing two types of anions can have improved physical performance compared with some aspects of those containing only one type of anion. To date, many such compounds have been investigated. This review focuses on metal chalcogenide halides, namely, M–Q–X (M = metal element; Q = S, Se, Te; X = F, Cl, Br, I) compounds. Although they have similar atomic radii, chalcogen atoms have much smaller electronegativities than those of its neighboring halogen atoms, which results in their different bonding styles. The inclusion of X − into chalcogenides can move their optical band gaps to higher values and their coordination polyhedra can become more distorted, albeit with little density change. These structural effects make metal chalcogenide halides a good choice to fine-tune the structures and physical properties of chalcogenides or halides. Several hundreds of metal chalcogenide halides already have been discovered. They demonstrate rich structures and versatile physical properties, enabling their diverse applications in the fields of solid-state electrolytes, second-order non-linear optics and thermoelectricity. Considering their flourishing development, this paper provides an overview of recent achievements in the structural chemistry and physical properties of metal chalcogenide halides. [ABSTRACT FROM AUTHOR]

A systematic and comprehensive review about Ag-based chalcogenides and derivations with IR NLO properties are summarized and discussed in detail. They possess rich structures, wide IR transparencies, large SHG responses, and suitable birefringences for phase-matchability, suggesting their potentials for high-performance IR NLO materials. [Display omitted] • The first comprehensive review about Ag-based IR NLO chalcogenides and derivations. • Ag-based chalcogenides and derivations possess rich structures, wide IR transparencies, large SHG responses, and suitable birefringences. • The chemical composition-structure-NLO performance are summarized and discussed in detail. • The research directions and development prospects for this topic are proposed. Infrared (IR) nonlinear optical (NLO) crystals with outstanding properties are crucial for extending the laser wavelengths through frequency conversion technology and have been employed in many fields such as civil industry, medicine, and military affairs. Among the studied IR NLO crystals, Ag-based chalcogenides are one of the most favorable candidates, not only owing to their compositional or structural relationship with the benchmark IR NLO materials AgGaS 2 and AgGaSe 2 , but also due to their diverse structures, large NLO intensities, wide IR transparent regions, and suitable birefringences for phase matching. So far, many Ag-based chalcogenides and derivatives (AChDs) with prominent NLO properties have been reported; however, a systematic summary of them is absent, which is significantly needed to facilitate the ever-increasing research on IR NLO materials. Herein, we summarized AChDs by classifying the investigated materials into three groups, based on their chemical composition and expounding the chemical composition-NCS structure-NLO performance relationship. In this review, the following features of AChDs with IR NLO properties were summarized. (1) Quaternary Ag-based chalcogenides were much more abundant compared to the ternary ones. (2) Although Ag possessed various coordination modes (linear or V-shaped, triangular, and tetrahedral), AgQ 4 tetrahedra were much more common than the AgQ 2 and AgQ 3 (Q = S, Se) units. (3) The cations of AChDs tended to construct one type of conventional IR NLO structural unit, namely, MQ 4 tetrahedra (M = Zn, Cd, Hg, Ga, In, Si, Ge, Sn, P; Q = S, Se), making great contributions to the microscopic NLO responses. Finally, the exploration directions and development prospects of AChDs as promising IR NLO candidates were discussed from the deduced structure–property relationship. [ABSTRACT FROM AUTHOR]

• Noncentrosymmetric (KBa 0.5) In 2 Se 4 and (K 0.58 Ba 0.71) (Ga 0.89 In 1.11)Se 4 derived from centrosymmetric BaIn 2 Se 4. • Their structural chemistry with related compounds is discussed. • Their nonlinear optical behaviors are studied. • Theoretical calculations on their electronic structure and optical properties are performed. Two new noncentrosymmetric multinary selenides, (KBa 0.5)In 2 Se 4 (1) and (K 0.58 Ba 0.71)(Ga 0.89 In 1.11)Se 4 (2), have been synthesized using a high-temperature flux method at 1123 K. They crystallize in the tetragonal noncentrosymmetric space group I 4 cm with cell parameters: a = 8.0277(2), c = 6.7654(3) Å, V = 435.99(3) Å3 for 1 ; a = 8.0296(4), c = 6.5403(9) Å, V = 421.68(7) Å3 for 2 vs the orthorhombic centrosymmetric space group Fddd for BaIn 2 Se 4. Their one-dimensional structures are constructed by [(MSe 2)–] n (M = Ga, In) chains composed of MSe 4 tetrahedra via sharing edges, and K+/Ba2+ cation occupying the interchain cavities. They both show moderate second-harmonic generation responses about 0.5 × AgGaS 2 @2.1 μ m. UV-vis-NIR diffuse reflectance spectroscopy measurement shows that the optical band gaps of 1 and 2 are about 2.60 and 2.34 eV, respectively. Theoretical calculations are also carried out to analyze their electronic structures and optical properties. [ABSTRACT FROM AUTHOR]

• A new chalcohalide K 2 Ba 3 Ge 3 S 9 Cl 2 was obtained by a solid-state reaction. • K 2 Ba 3 Ge 3 S 9 Cl 2 exhibits the largest band gap (3.69 eV) among all Ba-based chalcohalides. • K 2 Ba 3 Ge 3 S 9 Cl 2 has a remarkable high LIDT of 339.3 MW/cm2, which is 28.8 times that of AgGaS 2. • The experimental results are well verified by theoretical calculations. [Display omitted] A new noncentrosymmetric chalcohalide K 2 Ba 3 Ge 3 S 9 Cl 2 was synthesized. Its structural framework is established by [Ge 3 S 9 ]6– rings formed by three corner-sharing [GeS 4 ]4– tetrahedra. It exhibits a widest band gap of 3.69 eV among all Ba-based chalcohalides, and a high LIDT ~28.8 × AgGaS 2 (339.3 MW/cm2). Chalcohalides are attractive infrared (IR) nonlinear optical (NLO) materials because they can take advantages of the large second-harmonic generation (SHG) responses of chalcogenides and high laser-induced damage thresholds (LIDTs) of halides simultaneously, which are two correlated while contradictory indicators of the NLO performance. Here, a new chalcohalide, K 2 Ba 3 Ge 3 S 9 Cl 2 , was synthesized by a high temperature solid-state reaction, and it crystallizes in the polar noncentrosymmetric space group P 6 3. The fundamental structural unit [Ge 3 S 9 ]6– rings formed by three corner-sharing [GeS 4 ]4– tetrahedra construct the framework, which further connects with {[KS 3 Cl]6–} ∞ chains to build up the structure with Ba and K/Ba cations occupying the cavities. It exhibits a widest band gap of 3.69 eV among all Ba-based chalcohalides, and a high LIDT around 28.8 times that of AgGaS 2. It exhibits a SHG intensity around 0.34 times that of AGS. These experimental results are verified by theoretical calculations on its electronic structure and optical properties. [ABSTRACT FROM AUTHOR]

Abstract: Hydrothermal reaction of Cd(NO3)2, Co(NO3)2, Na(3-cba) and NaN3 yielded a 3D heterometallic coordination polymer, [Cd(μ5-3-tzba)(μ2-3-cba)(μ3-OH)Co(H2O)] n ·2nH2O 1 (3-H2tzba=3-(5H-tetrazol)benzoic acid and 3-Hcba=3-cyanobenzoic acid), which was characterized by single-crystal X-ray diffraction. The in situ [2+3] cycloaddition reaction of nitrile and azide in presence of Cd(II) salt afforded tetrazolate-based 3-tzba2− ligand. In 1, metal-oxo chains [Cd(μ3-OH)Co] n are linked by 3-tzba2− in an unprecedented μ5-κN1:κN2:κN3:κN4:κO1,O2 coordination mode to form 2D layers, which are further pillared by 3-cba− to generate a 3D open framework encapsulating 1D chiral channels. Variable-temperature magnetic studies show that 1 exhibits antiferromagnetic interactions between Co(II) ions bridged by μ3-OH group. [Copyright &y& Elsevier]

Abstract: Hydrothermal reaction of 1H-tetrazolate-5-ethyl acetate (Htzea), MCl2 (M=Zn, Cd) and NaOH at different reaction temperatures produced three new coordination polymers: 2-D layered polymer [Zn(tza)(H2O)2] n 1, and 1-D chained supramolecular isomers 2 and 3 formulated as [Cd(tza)(H2O)2] n (H2tza=1H-tetrazolate-5-acetic acid), respectively. In these obtained polymers, tza2− ligand adopts variable coordination modes: μ 3-κN3:κO1:κO2,N1 and μ 3-κN1:κN3:κO2 for 1, and μ 3-κN2:κN1,O2:κO1,O2 for 2 and 3. The effects of reaction temperature and metal centers on the final polymeric frameworks have been discussed. Polymers 1–3 exhibit blue photoluminescence mainly arising from intraligand transitions of tetrazolate rings in tza2− ligand. [Copyright &y& Elsevier]