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Crystalline materials AHg4Ga5S12 (A = Rb, Cs) with diamond-like anionic frameworks constructed by the aligned arrangement of tetrahedral units exhibit moderate second-order nonlinear optical (NLO) responses and high laser-induced damage thresholds.

Two novel quaternary nonlinear optical phosphides AIn3Si4P9 (A = Ca, Sr) with a unique double-helix structure are reported for the first time, resulting in a high laser-induced damage threshold, ∼7 times that of benchmark AgGaS2.

The moisture instability and toxicity of lead have hindered the development of lead organometal halide perovskites (Pb-OHPs). Similar to Pb-OHPs, OHPs based on Pb-free elements, including Group VA ...

Incorporating different alkali elements into a diamond-like anionic framework affords the first polar quaternary sulfide with mixed ordered alkali cations, CsLiGa6S10, which acquires a high-performance nonlinear optical material.

The unique type of molecular architectures with a remarkable initiation ability and enhanced stability is proposed. The relationship between the structure and sensitivity of Cu(N3)2-based primary explosive is revealed.

AIn4S6Cl (A = Rb and Cs) and Pb5Sn3Q10Cl2 (Q = S and Se) were obtained by the halide salt flux method. They feature mixed-anionic structure units with cations coordinated by aliovalent anions and exhibit significant photocurrent responses.

CsCuS4 was obtained by halide salt flux method, in which polysulfide anion S42− is relatively rare in Cu chalcogenides. It is multifunctional and exhibits significant photocurrent, humidity-sensitive, and proton-conductive properties.

Two new quaternary nonlinear optical crystals AAg3Ga8Se14 (A = Rb, Cs), exhibited phase-matching second-harmonic generation responses (0.6 and 0.7 times that of AgGaS2) and LIDT (2.1 and 1.5 times that of AgGaS2).

We found two Zn(ii) compounds with similar metalloviologen structures that, upon being exposed to light at room temperature in air, generated Zn(i) species.

A high contrast of ∼67 times, exceeding those of all known photoswitching bulk quadratic nonlinear-optical materials, has been realized in a photochromic semiconductor, by the strategy of increasing electron-transfer efficiency and self-absorption.

Photoresponse ranges of commercially prevailing photoelectric semiconductors, typically Si and InGaAs, are far from fully covering the whole solar spectrum (∼295-2500 nm), resulting in insufficient solar energy conversion or narrow wave bands for photoelectric detection. Recent studies have shown that infinite π-aggregation of viologen radicals can provide semiconductors with a photoelectric response range covering the solar spectrum. However, controlled assembly of an infinite π-aggregate is still a great challenge in material design. Through directional self-assembly of electron-transfer photoactive polycyclic ligands, two crystalline inorganic-organic hybrid photochromic viologen-based bismuth halide semiconductors, ((Me)3pytpy)[BiCl6]·2H2O [1; (Me)3pytpy = N,N',N″-trimethyl-2,4,6-tris(4-pyridyl)pyridine] and ((Me)3pytpy)[Bi2Cl9]·H2O (2), have been synthesized. They represent the first series of pytpy-based photochromic compounds. After photoinduced coloration, the conductivities of both 1 and 2 increased. The radical products have electron absorption bands in the range of 200-1600 nm, exceeding that of Si. Both the conductivity and the photocurrent intensity of 2 are stronger than those of 1, due to better planarity, tighter π-stacking, and higher degrees of overlap of ((Me)3pytpy)3+ cations. This study not only provides a new design idea for synthesizing radical-based multispectral photoelectric semiconductors but also enriches the family of electron-transfer photochromic compounds.

Luminescent multidentate naphthalene-sulfonic moieties and non-toxic barium ions worked synergistically to fabricate scintillating barium-based metal–organic frameworks into latent applications of X-ray dosage detection with their merited intrinsic energy resolution.

Detection of oxygen though color change is highly desirable for rapid qualitative analysis like the case of pH test papers. This work demonstrates

Conductive covalent organic frameworks (c-COFs) have been widely used in electrochemical energy storage because of their highly adjustable porosity and modifiable skeletons. Additionally, the fast carrier migration and ion catalysis requirements of micro-electrochemical energy storages (MEESs) are perfectly matched with c-COFs. Therefore, c-COFs show great potential and unlimited prospects in MEESs. However, the main organic component blocks electron conduction, and the internal active sites are difficult to fully utilize, which limits the application of c-COFs. In order to overcome these obstacles, a great deal of research has been conducted on conductivity enhancement. This review first focuses on the exploration of c-COFs in the field of electrical conductivity. Then, the mechanism and explanation of the effect of synthesis on electrical conductivity enhancement are discussed, which emphasizes the range and suitability of c-COFs in MEESs. Finally, the excellent performance characteristics of c-COFs are demonstrated from the MEES perspective, with key points and potential challenges addressed. This review also predicts the direction of development of c-COFs in the future.

Due to their highly changeable porosity and adaptable skeletons, covalent organic frameworks (COFs) have been frequently used in supercapacitors. Additionally, COFs are a wonderful match for supercapacitors’ requirements for quick carrier migration and ion catalysis. COFs exhibit significant potential and limitless opportunities in electrochemical storage supercapacitors. The applicability of COFs has, nonetheless, been limited because the primary organic component prevents electron conduction and the interior active sites are challenging to fully utilize. The conductivity enhancement of COFs has been the subject of extensive research to solve these challenges. This review begins by outlining the features of COFs in the context of their use in supercapacitors and their methods of synthesis. The application of previously published COF materials in supercapacitors were evaluated including electrode materials and solid-state devices. Finally, essential aspects and potential problems are discussed as the exceptional performance characteristics of COFs are illustrated from a supercapacitor standpoint. This review also forecasts the future of COF-based supercapacitor development.

Owing to the structural diversity and potential applications in optoelectronic devices, inorganic-organic hybrid materials have attracted great attentions in recent years. They have potential applications in the fields of fluorescence, photoconductivity, ferroelectricity and solar cells. A new inorganic-organic hybrid, [H2(dmen)]PbCl4 (dmen = N,N-Dimethylethylenediamine), was solvothermally synthesized using [H2(dmen)]2+ as templates and balance cations. The inorganic structure is two-dimensional (2D) single layer perovskite. This compound exhibits typical semiconductive behavior, whose conductivity increases along with the raising of temperature. The compound also shows yellow light emission property, which indicates great potential application in light-emitting diodes.

IR NLO sulfides BaMnSnS4 and BaCdGeS4 exhibit significant SHG efficiencies (1.2 and 0.3AgGaS2) with phase-matching behavior and high laser-induced damage thresholds (10 and 13AgGaS2). Their strong SHG efficiencies mainly originate from SnS4 and GeS4 tetrahedra that are being modulated by highly distorted MnS4 and CdS4 tetrahedra.

Solid-state X-ray scintillators are widely applied in medical imaging and space exploration. However, it is still a great challenge to probe into the intrinsic nature of scintillating behaviour due to the ambiguous structure–function relationship. Herein, four structure-defined X-ray scintillating Pb(II)-based metal–organic frameworks (SMOFs) were successfully obtained under solvothermal conditions, [Pb(1,4-ndc)(DMF)]n (SMOF-1), [Pb(1,4-ndc)(DMA)]n (SMOF-2), [Pb2(2,6-ndc)2(H2O)]n·nDMF (SMOF-3) and [Pb4(2,6-ndc)3Cl2]n (SMOF-4), where 1,4-H2ndc = 1,4-naphthalene dicarboxylate, 2,6-H2ndc = 2,6-naphthalene dicarboxylate, DMF = N,N-dimethylformamide, and DMA = N,N-dimethylacetamide. SMOFs 1–4 show scintillating signals under X-rays triggered by a highly purified tungsten target. Compared with SMOFs 1–3, SMOF-4 exhibits excellent scintillating performance owing to its solvent-free and denser structure, which favours more efficient conversion ability of X-rays to visible light. X-ray stimulated luminescence (XSL) spectra present multiple emission peaks, which is further confirmed by wavelength-dependent luminescence spectra under UV-Vis light, and density of state and DFT calculations. The synergistic effects of heavy metal Pb(II) centres as effective X-ray absorbers and organic ligands as luminescent motifs endow these Pb(II)-based MOFs with application prospects in X-ray detection.

Photochromic open-framework compounds are of potential application in detection/sensors. The issue of improving the detection limits has received much attention. We synthesized a new open-framework Zn compound, namely, compound 1 ([Zn(MQ)(IPA)Cl]·5H2O) (MQ = N-methyl-4,4'-bipyridinium, IPA = m-phthalic acid), which showed a 1D channel structure by a cationic-π interaction. It is noteworthy that this compound is an effective detector for aniline though luminescence emission, which exhibited unprecedented detection limits in photochromic open-framework compounds.

A Ce–Bi@CeBiOx/C with core–shell structure has been synthesized by pyrolysis of cerium doped bismuth-based metal–organic frameworks. This novel catalyst exhibits excellent performance for electrochemical CO2 reduction to formate with a maximum faradaic efficiency of 96% and a maximum partial current density of 15.2 mA cm−2, which could be attributed to the synergistic effects of electronic structure modification of Bi as well as the enrichment of oxygen vacancies on catalyst surfaces.

The synergy of unusual X-aggregation induced luminescent chromophores and heavy Pb(II) ions has facilitated excellent X-ray scintillation of two structurally similar Pb-SMOFs, which are heat-resistant due to solvent-free lattices. Owing to their higher Pb(II) contents, Pb-SMOFs with larger X-ray absorption coefficients are more sensitive for X-ray dosage detection than powdered CsPbBr3.

Single-crystal (SC) layered oxides as cathodes for Li-ion batteries have demonstrated better cycle stability than their polycrystalline (PC) counterparts due to the restrained intergranular cracking formation. However, there are rare reports on comparisons between single-crystal LiMn2O4 (SC-LMO) and polycrystalline LiMn2O4 (PC-LMO) spinel cathodes for Li-ion storage. In this work, the Li-ion storage properties of spinel LiMn2O4 single-crystalline and polycrystalline with similar particle sizes were investigated in a wide voltage window of 2–4.8 V vs. Li/Li+. The SC-LMO cathode exhibited a specific discharge capacity of 178 mA·h·g−1, which was a bit larger than that of the PC-LMO cathode. This is mainly because the SC-LMO cathode showed much higher specific capacity in the 3 V region (Li-ion storage at octahedral sites with cubic to tetragonal phase transition) than the PC-LMO cathode. However, unlike layered-oxide cathodes, the PC-LMO cathode displayed better cycle stability than the SC-LMO cathode. Our studies for the first time demonstrate that the phase transition-induced Mn(II) ion dissolution in the 3 V region rather than cracking formation is the limiting factor for the cycle performance of spinel LiMn2O4 in the wide voltage window.

The R2R3-MYB is a large gene family involved in various plant functions, including carotenoid biosynthesis. However, this gene family lacks a comprehensive analysis in wolfberry (Lycium barbarum L.) and other Solanaceae species. The recent sequencing of the wolfberry genome provides an opportunity for investigating the organization and evolutionary characteristics of R2R3-MYB genes in wolfberry and other Solanaceae species. A total of 610 R2R3-MYB genes were identified in five Solanaceae species, including 137 in wolfberry. The LbaR2R3-MYB genes were grouped into 31 subgroups based on phylogenetic analysis, conserved gene structures, and motif composition. Five groups only of Solanaceae R2R3-MYB genes were functionally divergent during evolution. Dispersed and whole duplication events are critical for expanding the R2R3-MYB gene family. There were 287 orthologous gene pairs between wolfberry and the other four selected Solanaceae species. RNA-seq analysis identified the expression level of LbaR2R3-MYB differential gene expression (DEGs) and carotenoid biosynthesis genes (CBGs) in fruit development stages. The highly expressed LbaR2R3-MYB genes are co-expressed with CBGs during fruit development. A quantitative Real-Time (qRT)-PCR verified seven selected candidate genes. Thus, Lba11g0183 and Lba02g01219 are candidate genes regulating carotenoid biosynthesis in wolfberry. This study elucidates the evolution and function of R2R3-MYB genes in wolfberry and the four Solanaceae species.

The assembly of a carboxylate substituted anthracene derivative with barium(II) salt yielded a 3D luminescent metal-organic framework [Ba2(adda)2(H2adda)(H2O)2]n 1 (H2adda = (2E,2′E)-3,3′-(anthracene-9,10-diyl) diacrylic acid), which was structurally characterized by elemental analysis, powdered and single-crystal X-ray diffraction. Compound 1 exhibits a “turn on” luminescence response toward 4-nitrobenzoic acid (4-NBA) different from most nitroaromatic compounds displaying a “turn-off” luminescence stimulus. Increasing luminescence intensities with addition of 4-NBA in 1 dispersed in DMF are attributed to the dissociation of H2adda, evidenced by 1H NMR. Compound 1 is effective as a potential 4-NBA detector by establishing the relationship between the luminescence intensity of 1 and the molar concentration of 4-NBA.

Crystals with mixed anions refer to inorganic salts containing at least two types of anions or anionic groups, and these anions can be Q2− (Q = O, S, Se, Te) and X− (X = F, Cl, Br, I), and anionic groups include various B–O groups, (OH)−, (IO3)−, (CO3)2−, (SiO4)4−, (NO3)3− and (PO4)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.

The appearance of the nitrogen-rich energetic MOFs provides another opportunity for the new-generation of high energetic explosives. In this work, an insensitive energetic nitrogen-rich ligand, 3-amino-1, 2, 4-triazole (Hatz) was imported into the system of transition-metal azides via the coordination polymerization strategy in the hope to prepare mixed-ligand nitrogen-rich high energetic MOF materials with low sensitivity and finally a solvent-free 3D energetic compacted metal-organic framework (MOF), Cd3(atz)4(N3)2 (1) was successfully isolated under hydrothermal conditions. Compound 1 was characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis (EA), different scanning calorimetry (DSC), and thermogravimetry analysis (TGA). Topological analysis shows that the 3D framework of 1 can be abstracted into a ten-connected topological network. The volatile azido ion can be viewed as a counter anion to be stabilized in a 3D framework as the connection of Cd(II) ions with two independent atz− ligands still remains a 3D framework. Compound 1 has a high calculated density (ρ) of 2.517 g cm−3. The standard molar enthalpy of formation (ΔfHo) of 1 was calculated to be 1330.10 kJ mol−1, which is higher than those of most of the previously 3D energetic MOFs. Sensitivity tests demonstrate that 1 is insensitive to external mechanical stimuli. TGA demonstrates that 1 has an excellent thermostability which can be stable up to 372 °C. Compound 1 can be served as a high-energy-density material with a favorable level of safety due to its excellent energetic performances, low sensitivities and excellent thermostability.

Two new infrared (IR) nonlinear optical (NLO) sulfides, Na2Ga2GeS6 and Na2Ga2SnS6, were obtained by mixing different typical NLO-active motifs GaS4 and GeS4/SnS4 in the alkali metal-containing system. The IR NLO sulfides present laser-induced damage thresholds that are 18.1 and 17.9 times that of the reference AgGaS2 (AGS) and second-harmonic generation efficiencies that are 0.8 and 1.1 times that of AGS. These properties originate from the GaS4, GeS4, and SnS4 tetrahedral blocks in the structures of the sulfides. Both compounds also exhibit a broad transparency range and type-I phase-matching behavior, which support their high potential in high-power laser applications. This work sheds new light on the development of promising mid-IR NLO materials by combining different NLO-active motifs.

Self-assembly reaction of Pb(NO3)2 with thiophene-2, 5-dicarboxylic acid (H2TDC) led to an acentric three-dimensional (3D) metal-organic framework under solvothermal conditions, namely, Pb(TDC) (1). The 3D framework of 1 is a pillared-layer structure with the I2O1 type which is composed of a 2D inorganic Pb–O–Pb substructural layer and two independent μ6-TDC2- anions pillars. This 3D framework shows a six-connected pcu topological net according to the topological analysis. Compound 1 crystallizes in an acentric space group and displays potential ferroelectric property which could be due to the swing of the thiophene rings. The remnant polarization (Pr), coercive field (Ec) and saturation spontaneous polarization (Ps) of 1 are ca. 0.034 μC cm−2, 15.7 kV cm−1 and 0.0997 μC cm−2, respectively. Among the H2TDC-based MOFs, the present compound is the first example which shows ferroelectric property. In addition, 1 also exhibits photoluminescent property which can be attributed to ligand-to-metal charge transfer.

Two new coordination polymers {[Zn(L)(DMA)]2*H2O }n (1) and {[Cd(L)(H2O)3]*DMA*H2O}n (2) (H2L = 5-[(pyren-9-ylmethyl)-amino]-isophthalic acid, DMA = N,N-dimethylacetamide) were successfully synthesized from the reaction of H2L and zinc (II) or cadmium (II) nitrate in mixed solvents. Single-crystal X-ray diffraction analyses show that polymers 1 and 2 feature 1D chain structures. Due to the existence of pi...pi stacking interactions in the crystal structure, 1 exhibits mechanoresponsive luminescence, with the fluorescence color changing from weak yellow to noticeable greenish yellow after external mechanical stimulus applied. Meanwhile, 1 displays grinding size-dependent fluorescent emissions with different grinding degree.

The photocatalytic selective oxidation of biomass derivate compound 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran is an environmentally friendly and energy-saving process. Nb2O5 was prepared and applied in the oxidation of HMF under visible light, although its bandgap energy is higher than 3.2 eV. The reaction process follows a special mechanism over a Nb2O5 catalyst different from the normal oxide semiconductor. The effect of calcination temperature, incident wavelength, and reaction time on photocatalytic performance was investigated. Nb2O5-800 exhibits the best performance in the presence of O2 with benzotrifluoride as a solvent under visible light irradiation.

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.

Vapor-responsive magnetic materials are highly promising for applications as chemical switches or sensors. Compared with porous materials, nonporous species benefit in overcoming the intrinsic conflict between magnetic exchange and porosity but usually suffer from the powdering of single crystals, which hinders the understanding of the structural nature of vapor response and magnetic switch. Single-crystal-to-single-crystal (SCSC) transformation of nonporous compounds through the desorption/absorption of gaseous HCl is unprecedented. Reported here is a discrete nonporous copper(II) complex, (H3O)[K(15-crown-5)2][CuCl4], that exhibits reversible SCSC transformation and magnetic change by the chemisorption/desorption of HCl and H2O. Significant changes in the coordination number (4 ↔ 3), space group (P1 ↔ P21/c), color (green ↔ red), and magnetic behavior (antiferromagnetic ↔ paramagnetic) were found during the SCSC transformation.

Quaternary metal thiophosphates containing second-order Jahn–Teller distorted d10 Ag+ and lone-pair cations, Ag3Bi(PS4)2 (1), Ag7Sn(PS4)3 (2), and Ag7Pb(PS4)3 (3), were obtained by solid-state synthesis. The structural frameworks of 2 and 3 feature an infinite 1-D interchiral double helix ∞1(Ag3P2S11), which is rare in inorganic compounds. Compound 3 undergoes a significant first-order structural phase transition from monoclinic to hexagonal at ∼204 °C. This can be ascribed to the significant mismatch in the expansion coefficients between Pb–S (Ag–S) and P–S bonds evaluated by bond valence theory. The three compounds are Ag+ ionic conductors, and Ag+ ion migration pathways are proposed by calculating maps of low bond valence mismatch. Moreover, the optical properties of the three compounds were studied, and electronic structure calculations were performed. The combination of second-order Jahn–Teller distorted d10 cation and lone-pair cation provides a new strategy to explore new metal thiophosphates with ...

Two new phases in the Ag–Cd–P–S system containing two second-order Jahn–Teller (SOJT) distorted d10 cations (Cd2+ and Ag+), namely, Ag2Cd(P2S6) (1) and AgCd3(PS4)S2 (2), are obtained via medium-temperature solid-state synthesis. Compound 1 exhibits a two-dimensional layered structure and undergoes a first-order structural phase transition at approximately 280 °C. This outcome can be ascribed to the significant mismatch in the expansion coefficients between Cd–S (Ag–S) and P–P (P–S) bonds evaluated through bond valence theory. The three-dimensional non-centrosymmetric (NCS) framework of 2 is constructed by two types of tetrahedral layers consisting of corner-shared CdS4, AgS4, and PS4 tetrahedra. Compound 2 exhibits second harmonic generation (SHG) intensity of 0.45 times that of commercial AgGaS2 (AGS) at a laser irradiation of 1.85 μm and an optical band gap of 2.56 eV, and no intrinsic vibrational absorption of chemical bonds is observed in the range of 2.5–18.2 μm. Both phase transition in 1 and SHG pr...

Microstructural analyses based on aberration-corrected scanning transmission electron microscopy (STEM) observations demonstrate that low-dimensional CsxBi4Te6 materials, known to be a novel thermoelectric and superconducting system, contain notable structural channels that go directly along the b axis, which can be partially filled by atom clusters depending on the thermal treatment process. We successfully prepared two series of CsxBi4Te6 single-crystalline samples using two different sintering processes. The CsxBi4Te6 samples prepared using an air-quenching method show superconductivity at approximately 4 K, while the CsxBi4Te6 with the same nominal compositions prepared by slowly cooling are nonsuperconductors. Moreover, atomic structural investigations of typical samples reveal that the structural channels are often empty in superconducting materials; thus, we can represent the superconducting phase as Cs1–yBi4Te6 with considering the point defects in the Cs layers. In addition, the channels in the n...

A new inorganic − organic hybrid compound [Zn2(MAA)4(bipy)4]n (1, MAA = Methacrylate, bipy = 4,4′-bipyridine) with photochromic properties has been synthesized by diffusion method. Upon irradiation, compound 1 turned from colorless to pale purple and new absorption peaks appeared at 380 nm and 548 nm. The luminescence emission of 1 can be modulated through photoinduced electron transfer process, and the luminescence intensity of the colored sample at 476 nm decreased 1.4 times after irradiation. In this study, MAA is first induced into metalloviologen-based hybrid material for photochromism and photomodulated luminescence applications and compound 1 has enriched the family of photoresponsive materials.

Herein, we presented an in-situ hydrothermally synthesized photoluminescent zinc(II) coordination polymer (Zn–CP), namely [Zn2(tzeba)2(bpy)]n1, in which H2tzeba = 3-(1-tetrazol-ethyl)benzoic acid, bpy = 4,4′-bipyridine. Compound 1 exhibits ligand-centered photoluminescence (PL) and displays interesting dual emissions based on the excitation of different chromophores from the mixed organic ligands. The PL colors of 1 could be tuned from blue-to-cyan-to-green directly by varying the excitation wavelengths. The PL mechanism has been investigated by the density of states (DOS) and density functional theory (DFT) calculations.

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.

A flexible metal-organic framework (FMOF) with functionalized pores was hydrothermally synthesized to improve CO2 affinity and selectivity. The obtained FMOF exhibits a reversible shrinking and swelling framework transformation, which is triggered by the adsorption of CO2 rather than by the adsorption of N2 and CH4. At ambient temperature and an atmospheric pressure, this FMOF shows not only a high CO2 uptake (98 cm(3) g(-1), 19.3 wt %) but also a good calculated adsorption selectivity for CO2 over both CH4 and N2 (CO2/CH4 50:50 v/v: 28.6:1, CO2/N2 15:85 v/v: 210.4:1 calculated by ideal adsorbed solution theory), indicating potential applications in the purification of natural gas and industrial flue gas.

By UV–Vis spectroscopy, ESR study, X-ray photoelectron spectroscopy and theoretical calculation, a newly synthesized tetrazole-viologen based zinc(II) coordination compound, [ZnCl2(3-TzV)(H2O)] (3-TzV = N-(3-tetrazylbenzyl)-4,4′-bipyridinium), was found to exhibit electron-transfer photochromism. In addition to the commonly observed decrease in fluorescence intensity, the fluorescence color changes from green to blue during the coloration, and this change is reversible by altering UV–Vis irradiation and heating for at least seven cycles. The unprecedented photoswitching of fluorescence color for viologen-based photochromic compounds offers a good candidate for multicolor emitting display.

High-performance catalysts are the key factor for CO2 activation and conversion. In this paper, we systematically investigate the whole composition evolution process of Cu/SiO2 catalysts for CO2 hydrogenation. The precursor gradually evolved from amorphous Cu species to copper phyllosilicate, then to CuO with the increase of calcination temperature from ambient temperature to 700 °C. With the evolution of the precursor, the corresponding species after reduction were gradually evolved from Cu0 to Cu+, then to Cu0 again. The ratios of Cu+/(Cu+ + Cu0) are positively correlated with the catalytic activities. The Cu+ species derived from copper phyllosilicate were demonstrated to be crucial in achieving high-performance Cu/SiO2 catalysts for CO2 hydrogenation. The composition evolution has been demonstrated to be an efficient strategy to synthesize high-performance catalysts. This strategy of composition evolution can be applied to the synthesis of other high-performance Cu-based heterogeneous catalysts.

In this work, we report a new mechanoresponsive luminescent Cd(ii) coordination polymer that exhibits a sensitivity to mechanical stimulation. The luminescence colour changed gradually from weak yellowish-green to bright cyan in response to different grinding sizes, thereby showing interesting mechanochromic properties, namely a grinding-enhanced luminescence and good crystalline maintenance ability.

Using a hydrothermal reaction of SmCl3•6H2O, ZnBr2 and TPPS, a crystalline metalloporphyrinic compound (MPC), [SmZn(TPPS)H3O][Formula: see text]•2[Formula: see text]H2O (1), was synthesized. The crystal structure of the MPC exhibits a condensed and robust 3-D porous open framework. We studied the adsorption and desorption isotherms for N2, H2 and CO2 conducted at 77 K and 273 K. They show different isotherms such as Type I, II and III isotherm behaviors. We found that low temperature is propitious for the title complex to adsorb more H2, but less N2. Compound 1 showed remarkably high selectivity for CO2–N2 separation, and good thermal stability. The temperature dependent magnetic susceptibility shows an antiferromagnetic-like behavior for 1.

Solvothermal reaction of CdCl2·2.5H2O and 1-tetrazole-4-imidazole-benzene (Htzib) yielded a new cadmium(II) coordination polymer [Cd2Cl2(tzib)2]n·nH2O (1), which has been characterized by single-crystal X-ray diffraction analysis. In 1, metal center Cd(II) ions are linked by μ2-Cl and tzib– with μ3-κ3N1:N2:N6 and μ4-κ4N1:N3:N4:N6 coordination modes into a novel 3D structure. Due to the lattice water molecules filled in the closed cages of 1, they cannot easily escape from the 3D framework. Because of this structural feature, polymer 1 displays relative high thermal stability up to ~400 °C. Moreover, luminescent properties and theoretical calculations of 1 are also discussed. Interestingly, tunable ultraviolet-to-visible emissions for 1 are observed.