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Four new alkali metal aluminum/gallium iodates, namely A2M(IO3)4(H0.5IO3)2 (A = K, Rb and M = Al, Ga), have been successfully synthesized via a hydrothermal reaction and structurally characterized through single-crystal X-ray diffraction analysis. These compounds are isostructural and crystallize in the P1¯ space group (no. 2) with one formula unit in each unit cell. The rare half-protonated H0.5IO3 building units were identified, and their structure feature isolated [M(IO3)4(H0.5IO3)2]2− anions, which are separated by alkali metal cations. The optical diffuse reflectance spectroscopy measurements associated with the Tauc analysis showed direct energy gaps, which are in good agreement with the theoretical calculation prediction. Moreover, this study also indicates that the electronic properties of these compounds are mainly determined by the IO3 and H0.5IO3 anionic units, and the alkali metal cations show a remarkable effect on their energy gap values, whereas the impacts of the group 13 elements aluminum and gallium are insignificant. [ABSTRACT FROM AUTHOR]

Two new alkali boroselenites RbSe3B2O9(OH) and CsSe3B2O9(OH) have been synthesized by traditional solid-state reactions. Single-crystal X-ray diffraction study indicated that they are isostructural and adopt a new type of structure, which crystallizes in the noncentrosymmetric space group P212121. Optical diffuse reflectance spectrum studies emphasized that both are indirect optical transitions with values of 3.79 and 4.17 eV for RbSe3B2O9(OH) and CsSe3B2O9(OH), respectively. Optical analysis revealed a broad transparency window in the 0.3–8.5 μm region for both compounds. In addition, RbSe3B2O9(OH) featured a relatively weak second-harmonic-generation response, and for CsSe3B2O9(OH), the response is 0.8-times that of KH2PO4. Theoretical calculations of band structure, density of state, and linear and nonlinear optical properties were also performed to get insight into the relationships between electronic structures and their optical properties. [ABSTRACT FROM AUTHOR]

Correction for ‘Infrared nonlinear optical properties of lithium-containing diamond-like semiconductors Li2ZnGeSe4 and Li2ZnSnSe4’ by Jian-Han Zhang et al., Dalton Trans., 2015, 44, 11212–11222. [ABSTRACT FROM AUTHOR]

Two new lithium-containing diamond-like semiconductors, Li2ZnGeSe4 and Li2ZnSnSe4, have been prepared by high-temperature, solid-state synthesis. Single crystal X-ray diffraction reveals that both compounds adopt the wurtz–kesterite structure type, crystallizing in the noncentrosymmetric space group Pn. X-ray powder diffraction coupled with Rietveld refinement indicates the high degree of phase purity in which the materials are prepared. Both compounds display optical bandgaps around 1.8 eV, wide optical transparency windows from 0.7 to 25 μm and type-I phase matched second harmonic generation starting at 2500 nm and persisting deeper into the infrared. Using the Kurtz powder method, the second-order nonlinear optical coefficient, χ(2), was estimated to be 19 and 23 pm V−1 for Li2ZnGeSe4 and Li2ZnSnSe4, respectively. Using a 1064 nm incident laser beam with a pulse width (τ) of 30 ps both compounds exhibit a laser damage threshold of 0.3 GW cm−2, which is higher than that of the AgGaSe2 reference material measured under identical conditions. Differential thermal analysis shows that the title compounds are stable up to 684 and 736 °C, respectively. These properties collectively demonstrate that Li2ZnGeSe4 and Li2ZnSnSe4 have great potential for applications in tunable laser systems, especially in the infrared and even up to the terahertz regime. Electronic structure calculations using a plane-wave pseudopotential method within density functional theory provide insight regarding the nature of the bandgap and bonding. [ABSTRACT FROM AUTHOR]

A series of new lanthanide borogermanates, namely, Ln2GeB2O8(Ln = Nd, Sm–Tb), have been synthesized by high temperature solid state reactions in platinum crucibles. They are isostructural and feature a layered [GeB2O8]6−architecture built of 1D chains of corner-sharing BO4-tetrahedra that are further bridged by GeO4-tetrahedra. The lanthanide(iii) ions are located at the interlayer space and are seven-coordinated. Results of magnetic measurements indicate Sm(iii), Eu(iii) and Gd(iii) compounds display an antiferromagnetic interaction between Ln(iii) centers whereas the Tb(iii) compound exhibits a ferromagnetic interaction between Tb3+ions. Luminescent studies indicate that Eu2GeB2O8and Tb2GeB2O8emit strong red and green light, respectively. [ABSTRACT FROM AUTHOR]

Galactaric acid (GA), an attractive biomass-based platform compound produced from galacturonic acid (GalA), has gained considerable attention in industry due to its application as a precursor for various polymers. Currently, GA is oxidized from galactose using nitric acid or GalA using bromine but its low selectivity and yield limit its industrial-scale production and application. The present study first sought to produce GA without any by-product from the monomeric compound of GalA obtained from pectin hydrolysis in an eco-friendly manner using Gluconobacter oxydans (G. oxydans) as the research object. In this regard, a wholly biological method was designed by combining enzymatic hydrolysis, electrodialysis, and resting-cell catalysis with pectin as a raw material to enhance its production. After a series of pectin degradation experiments, including degradation scheme screening and enzyme dosage and substrate concentration optimization, a pectin degradation rate of 96.9% was finally achieved. Furthermore, the resting-cell catalytic efficiency of the enzymatic hydrolysate purified by electrodialysis was consistent with that of the simulated solution, which was 20.7% higher than that of the untreated enzymatic hydrolysate. Additionally, the experiment confirmed that pH significantly influenced the catalytic and oxidative efficiency of resting-cell catalysis. Finally, 2520 mg L-1 of GA was stably produced by resting-cell catalysis in the broth at pH 4.0 for 72 h, suggesting it to be a promising green approach for industrial bio-production of GA. [ABSTRACT FROM AUTHOR]

Eight ion-pair compounds, [1-APy]I3 (1), [o-FBz-1-APy]I3 (2), [o-ClBz-1-APy]I3 (3), [o-BrBz-1-APy]I3 (4), [m-FBz-1-APy]I3 (5), [m-ClBz-1-APy]I3 (6), [m-BrBz-1-APy]I3 (7) and [m-IBz-1-APy]I3 (8), were synthesized and characterized structurally. The melting point of 1, 2 and 5–8 is below 90 °C and hence these compounds can be used as ionic liquids. A common characteristic of the crystal structures of 1–8 is that the inorganic components form a linear I3− anion and the non-planar Schiff base cations surround the anion to form molecular stacks. There exist H⋯I hydrogen bond contacts between the cations and I3− anion in the eight compounds, and H⋯H interactions are the main force between the cations. The melting point of crystal 1 is the lowest with 64 °C among the eight compounds. 3 and 4 show higher Tm, ΔHfus and ΔSfus values. The substituent group of the Schiff base cation in the meta-position can also decrease the melting point of the compounds. In addition, Hirshfeld surface analysis was used to understand the intricacies of interactions occurring in the eight compounds, and the relationship between the melting point and the weak interaction was discussed. [ABSTRACT FROM AUTHOR]

Two novel alkaline-earth zincophosphites, namely CaZn(HPO3)2 and Ba2Zn(HPO3)3, were successfully synthesized under hydrothermal conditions. CaZn(HPO3)2 exhibits a three-dimensional (3D) anionic framework with a 6-connected uni-nodal pcu α-Po primitive cubic topology, constructed by unique Zn2O8 dimers and HPO3 pseudo-tetrahedra, while Ba2Zn(HPO3)3 displays one-dimensional (1D) [Zn(HPO3)3]4− anionic chains. It is worth mentioning that CaZn(HPO3)2 represents the first example of an alkaline-earth zincophosphite compound with a 3D framework structure. Our research also revealed the importance of both alkaline earth cation sizes and Zn/P ratios in anionic open-framework formation. The crystal structures of both compounds were further verified by energy dispersive spectroscopy, IR spectroscopy and Raman spectroscopy. Optical diffuse reflectance spectra, coupled with Tauc's fitting, revealed direct bandgaps with energy values of 4.33 and 4.48 eV for CaZn(HPO3)2 and Ba2Zn(HPO3)3, respectively, which differ from the prediction of theoretical calculations. Density of states calculations were conducted to reveal the origin of the bandgaps and bond interactions. Both compounds exhibited moderate birefringence values. This work may have implications for the design and synthesis of novel metal phosphites with desired properties. [ABSTRACT FROM AUTHOR]

A novel complex (C6H16N)3[Tb2(Hsal)3(NO3)6] (1) was synthesised and characterized using X-ray crystallography. The PXRD patterns indicate that complex 1 is stable after heating at 180 °C for half an hour. More interestingly, high luminescence quantum yields of 90%, 78%, and 53% and long lifetimes of 1.71, 1.72, and 1.71 ms were obtained at room temperature, 80 °C, and 180 °C, respectively. Thus, complex 1 is one of the rare examples of luminescent lanthanide complexes with both high luminescence efficiency and thermostability. [ABSTRACT FROM AUTHOR]

The new, quaternary diamond-like semiconductor (DLS) Cu4MnGe2S7 was prepared at high-temperature from a stoichiometric reaction of the elements under vacuum. Single crystal X-ray diffraction data were used to solve and refine the structure in the polar space group Cc. Cu4MnGe2S7 features [Ge2S7]6− units and adopts the Cu5Si2S7 structure type that can be considered a derivative of the hexagonal diamond structure. The DLS Cu2MnGeS4 with the wurtz-stannite structure was similarly prepared at a lower temperature. The achievement of relatively phase-pure samples, confirmed by X-ray powder diffraction data, was nontrival as differential thermal analysis shows an incongruent melting behaviour for both compounds at relatively high temperature. The dark red Cu2MnGeS4 and Cu4MnGe2S7 compounds exhibit direct optical bandgaps of 2.21 and 1.98 eV, respectively. The infrared (IR) spectra indicate potentially wide windows of optical transparency up to 25 μm for both materials. Using the Kurtz–Perry powder method, the second-order nonlinear optical susceptibility, χ(2), values for Cu2MnGeS4 and Cu4MnGe2S7 were estimated to be 16.9 ± 2.0 pm V−1 and 2.33 ± 0.86 pm V−1, respectively, by comparing with an optical-quality standard reference material, AgGaSe2 (AGSe). Cu2MnGeS4 was found to be phase matchable at λ = 3100 nm, whereas Cu4MnGe2S7 was determined to be non-phase matchable at λ = 1600 nm. The weak SHG response of Cu4MnGe2S7 precluded phase-matching studies at longer wavelengths. The laser-induced damage threshold (LIDT) for Cu2MnGeS4 was estimated to be ∼0.1 GW cm−2 at λ = 1064 nm (pulse width: τ = 30 ps), while the LIDT for Cu4MnGe2S7 could not be ascertained due to its weak response. The significant variance in NLO properties can be reasoned using the results from electronic structure calculations. [ABSTRACT FROM AUTHOR]

Six new phases in the alkali metal-NbV/TaV–SeIV/TeIV–O systems have been prepared by solid-state reactions at high-temperatures. Their structures were determined by single-crystal X-ray diffraction studies. AM3O6(QO3)2(A = K, Rb, M = Nb, Ta, Q = Te; A = K, M = Nb, Q = Se) are isomorphous and their structures feature a 3D network with 1D 4- and 6-MRs tunnels along the a-axis which is composed of 2D layers of corner-sharing MO6octahedra bridged by QO3groups. The alkali metal ions are located at the above 1D tunnels of 6-MRs. The structure of Cs3Nb9O18(TeO3)2(TeO4)2features a thick Nb–Te–O layer built of corner-sharing NbO6octahedra, TeO3and TeO4groups. The 2D layer of the NbO6octahedra with 1D tunnels of 6-MRs along the c-axis are formed by 1D chains of NbO6chains along the c-axis and linear Nb4O21tetramers by corner-sharing. The TeO3and TeO4groups are grafted on both sides of the niobium-oxide layer viaNb–O–Te or/and Te–O–Te bridges. The caesium(i) ions are located at the above 1D tunnels of 6-MRs. TGA, UV-vis and infrared spectral measurements as well as electronic structure calculations have also been performed. [ABSTRACT FROM AUTHOR]

Herein, unprecedented NLO-brominated tin hypophosphites, namely [Sn2(H2PO2)3]Br, were discovered via a facile surfactant-induced method, which displayed a moderate powder SHG intensity (3.0 × KDP) in type – I phase matching behavior. This complex has high chemical and thermal stability at room temperature. DFT calculations and SHG coefficient analyses revealed that the alignment of the SHG-active-units SnO3 trigonal pyramids and Br− anions in its structure mainly contribute to the macroscopical SHG behaviors. [ABSTRACT FROM AUTHOR]

Compounds with isolated anionic groups often exhibit special linear and nonlinear optical properties and possess potential applications such as birefringence, second harmonic generation and stimulated Raman scattering crystals. In this paper, two new alkali and alkaline earth mixed-metal borates, Li3KB4O8 and LiNa2Sr8B12O24F6Cl, with isolated (B12O24)12- anionic groups have been successfully synthesized by spontaneous crystallization. Their structures were determined by single crystal X-ray diffraction and they both crystallize in the same space group, R3. More interestingly, further structure comparison shows that the discovered anhydrous borates with the (B12O24)12- groups also crystallize in the same space group R3, which is related with the local symmetry of the (B12O24)12- groups. These structural features suggest that the crystal structures of the family of compounds depend more on their anionic groups. In addition, the property characterizations of the two new borates were investigated by TG-DSC, IR and UV-vis-NIR diffuse reflectance. [ABSTRACT FROM AUTHOR]

A colourless single crystal of Li3Cs2B5O10 with dimensions of 20 × 15 × 4 mm3 has been grown. It was obtained from the stoichiometric melt using the top-seeded solution growth method in air. The infrared spectroscopy data, density and hardness of the Li3Cs2B5O10 crystal were measured. The measured density is in agreement with the calculated one and the hardness is about 4 Mohs. The GII value is larger than the BSI value, indicating that the lattice-induced strain is stronger than the electronic strain. Using the structural parameters of the single crystal Li3Cs2B5O10, we present a first-principles study of its electronic structure. The calculated band structures and the density of states of Li3Cs2B5O10 suggest that its indirect energy gap is 5.16 eV. The linear optical properties are examined based on the dielectric function. Our calculated bond lengths show a reasonable agreement with the experimental data. [ABSTRACT FROM AUTHOR]