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The synthesis, excited-state dynamics, and biological application of luminescent lanthanide salen complexes (Ln = Lu, Gd, Eu, Yb, salen = N, N'-bis(salicylidene)ethylenediamine-based ligands) with sandwich structures are described. Among them, Lu(III) complexes show unusually strong ligand-centered fluorescence with quantum yields up to 62%, although the metal center is close to a chromophore ligand. The excited-state dynamic studies including ultrafast spectroscopy for Ln-salen complexes revealed that their excited states are solely dependent on the salen ligands and the ISC rates are slow (10 8 -10 9 s -1 ). Importantly, time-dependent density functional theory calculations attribute the low energy transfer efficiency to the weak spin-orbital coupling (SOC) between the singlet and triplet excited states. More importantly, Lu-salen has been applied as a molecular platform to construct fluorescence probes with organelle specificity in living cell imaging, which demonstrates the advantages of the sandwich structures as being capable of preventing intramolecular metal-ligand interactions and behaviors different from those of the previously reported Zn-salens. Most importantly, the preliminary study for in vivo imaging using a mouse model demonstrated the potential application of Ln coordination complexes in therapeutic and diagnostic bioimaging beyond living cells or in vitro.

A new chloride borate, Ba 1.31 Sr 3.69 (BO 3 ) 3 Cl, was obtained when exploring potential phosphor materials. It belongs to orthorhombic system, Pnma space group, with cell parameters of a = 6.965(1) Å, b = 16.546(3) Å, c = 9.557(1) Å and Z = 4. Ba 5- x Sr x (BO 3 ) 3 Cl ( x = 0, 0.5, …to 5) was synthesized and the cell volumes of the solid solutions were obtained by Rietveld refinement. Detailed structure description of Ba 1.31 Sr 3.69 (BO 3 ) 3 Cl was conducted and the structure comparison between Ba 1.31 Sr 3.69 (BO 3 ) 3 Cl and M 5 (BO 3 )X (M = Ba or Sr, X = Cl or F) was illustrated. In Ba 1.31 Sr 3.69 (BO 3 ) 3 Cl, there are hexagonal tunnels extending along a -axis, which is the main feature of apatite family compounds. The density functional theory calculation suggested that in Ba 1.31 Sr 3.69 (BO 3 ) 3 Cl space group Pnma is more energy favourable than C 222 1 . DSC-TG showed that Ba 1.31 Sr 3.69 (BO 3 ) 3 Cl is stable up to 950 °C and Raman and Infrared spectroscopy demonstrate the existence of planar (BO 3 ) 3- in the structure. [ABSTRACT FROM AUTHOR]

The high pressure behaviour of a cubic dense inorganic–organic framework [DABCOH22+][K(ClO4)3] (DABCOH22+ = diazabicyclo[2.2.2]octane-1,4-diium) has been systematically studied via synchrotron X-ray powder diffraction, over the range of 0–3.12 GPa. The framework [DABCOH22+][K(ClO4)3] shows a more rigid response, with a bulk modulus of 30(1) GPa and an axial compressibility of 7.6(4) × 10−3 GPa−1, compared with ZIF-8 and the dense hybrid solar cell perovskite CH3NH3PbI3. Density functional theory calculations reveal that the structural change in [DABCOH22+][K(ClO4)3] is attributed to the contraction of the KO12 polyhedra, which consequently results in the rotation of the perchlorate linkers and synergistic movement of the DABCOH22+ guest. Further extensive theoretical calculations of full elastic tensors give full mapping of the Young's moduli, shear moduli and Poisson's ratios of [DABCOH22+][K(ClO4)3], which are in the range of 31.6–36.6, 12.3–14.6 GPa and 0.2–0.32, respectively. The Young's and shear moduli of [DABCOH22+][K(ClO4)3] are larger than those of cubic MOF-5, ZIF-8 and CH3NH3PbI3. In addition, the narrow range of Poisson's ratios in [DABCOH22+][K(ClO4)3] indicates its very isotropic nature in response to biaxial stress. [ABSTRACT FROM AUTHOR]

Ammonia-borane (AB) is a promising chemical hydrogen-storage material However, the development of real-time, efficient, controllable, and safe methods for hydrogen release under mild conditions is a challenge in the large-scale use of hydrogen as a long-term solution for future energy security. A new class of low-cost catalytic system is presented that uses nanostructured Ni2P as catalyst, which exhibits excellent catalytic activity and high sustainability toward hydrolysis of ammonia-borane with the initial turnover frequency of 40.4mol(H2) mol(Ni2P) -1 min-1 under air atmosphere and at ambient temperature. This value is higher than those reported for noble-metal-free catalysts, and the obtained Arrhenius activation energy (Ea = 44.6 kJmol-1) for the hydrolysis reaction is comparable to Ru-based bimetallic catalysts. A clearly mechanistic analysis of the hydrolytic reaction of AB based on experimental results and a density functional theory calculation is presented. [ABSTRACT FROM AUTHOR]

Nonlinear optical (NLO) crystals are very important optoelectronic functional materials and their developments have significantly contributed to the progress of laser science and technology for decades. In order to explore new NLO crystals with superior performances, it is greatly desirable to understand the intrinsic relationship between the macroscopic optical properties and microscopic structural features in crystals. In this paper, the applications of density functional theory (DFT) method to the elucidation of the structure-property relationship and to the exploration on novel NLO materials in the ultraviolet and infrared spectrum regions are reviewed. The great success in the linear and NLO property predictions has been achieved using the first-principles computational simulations, and the mechanism understanding obtained by various analysis tools can give substantial guidance to the search and design of new NLO crystals. [ABSTRACT FROM AUTHOR]

We identify the microscopic structural origins determining the bandgaps in the deep-ultraviolet borates, and propose an efficient method for the prediction of their bandgaps. This method considers only the chemical bond lengths around oxygen atoms and achieves the very high precision with the relative error <5% typically. Its validity is verified by the first-principles studies, which reveal the strong dependence of bandgaps on the coordination environment around oxygen atoms. Our studies have great implications on the search and design of optoelectronic functional materials with large bandgap. [ABSTRACT FROM AUTHOR]

With the development of laser technology and related scientific fields, understanding of the structure–property relationships in nonlinear optical (NLO) crystals is becoming more and more important. In this article, first-principles studies based on density functional theory, and their applications to elucidate the microscopic origins of the linear and NLO properties in NLO crystals, are reviewed. The ab initio approaches have the ability to accurately predict the optical properties in NLO crystals, and the developed analysis tools are vital to investigating their intrinsic mechanism. This microscopic understanding has further guided molecular engineering design for NLO crystals with novel structures and properties. It is anticipated that first-principle material approaches will greatly improve the search efficiency and greatly help experiments to save resources in the exploration of new NLO crystals with good performance. [ABSTRACT FROM AUTHOR]

• Ag–Cu NAs effectively inhibited the E. coli and S. aureus growth. • In Ag–Cu NAs, the strong charge-transfer leads to an earlier dissolution of Ag+. • The Ag+ ion dissolution is correlated with the antibacterial activity of Ag–Cu NAs. Immiscible bimetallic Ag–Cu system has been synthesized by the pulsed plasma in liquid method with a graph of one pulse duration. Herein, by combining X-ray power diffraction, K-edge X-ray absorption near edge structure and high-resolution transmission electron microscopy, our results indicate that homogeneously alloyed Ag–Cu nanoparticles (Ag–Cu NAs) have the average diameter about 2.1 nm, composed by 48.5 at% Ag and 51.5 at% Cu with chemical analysis and the estimated lattice parameter was 3.873 Å. The antibacterial property of Ag–Cu NAs was detected against E. coli and S. aureus strains according to the colony formed abilities of bacteria on agar plates covered with the nanoparticles. With very short incubation period, Ag–Cu NAs completely inhibited the E. coli and S. aureus growth at an ultralow concentration. The mechanism of antibacterial property of Ag–Cu NAs was performed by the inductively coupled plasma-atomic emission spectrometry and the plane wave pseudopotential method implemented in the CASTEP package based on the density functional theory. The Ag+ dissolution is correlated with antibacterial activity for Ag–Cu NAs-assisted antibacterial treatment. These findings obtained revealed that our Ag–Cu NAs could be served as a containing material of numerous bacteria-free products in order to avoid their bacterial contamination. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new type of phosphomolybdate K2Bi(PO4)(MoO4) photocatalyst was successfully synthesized. [•] The products synthesized at 600°C were mainly composed of nano-cubes. [•] The indirect band gap of K2Bi(PO4)(MoO4) has been determined to be 2.93eV. [•] K2Bi(PO4)(MoO4) synthesized at 600°C exhibits the highest photocatalytic activity. [•] The electronic structure was calculated by density functional calculations. [ABSTRACT FROM AUTHOR]