Hongsheng Shi

Synthesis, Crystal Structure, and Properties of a Dinuclear Cu(I) Cluster

Abstract A new dinuclear copper(I) cluster complex, [(o-Tol)3PCuI2CuP(o-Tol)3(DMF)] (1) ((o-Tol)3P = tris(2- methylphenyl)phosphine, DMF = N, N′-dimethylformamide), has been synthesized and the crystal structure was determined by a single-crystal X-ray diffraction study. The dinuclear copper(I) cluster molecule containing an asymmetric Cu2I2P2O core and the dinuclear clusters are fused together by a strong π–π stacking interaction to form asupramolecular one-dimensional (1D) chain. After having compared the relevant complexes composed of CuI and monodentate triarylphosphine ligands, the impact of the substituent of the triarylphosphine ligand to the subsequent complex structure has also been discussed.Except for a strong π–π* bond, the complex 1 also exhibits a weak metal-to-ligand charge transfer (MLCT) absorption bond in the 430–530-nm region and displays a weak green-yellow emission when irradiated by ultraviolet (UV) light. The thermogravimetric analysis demonstrates that its thermal stability is good, and the corresponding PXRD analysis has revealed that the final, organic-free decomposed product is CuI. GRAPHICAL ABSTRACT

A study on the structure, luminescence and thermo-stability of polycrystalline Gd2Si2O7:Ce and (Gd,La)2Si2O7:Ce

Gd2Si2O7:Ce (GPS:Ce) and (Gd,La)2Si2O7:Ce (La-GPS:Ce) phosphors with different crystal structures, tetragonal, orthorhombic and triclinic, were synthesized via a sol–gel technique. The prepared samples have been systematically investigated using room temperature (RT) XRD, high temperature (HT) XRD, HRTEM, selected area electron diffraction (SAED) and EDS elemental analysis. The results show that the phase transition occurred at 1350–1450 °C and the tetragonal phase was a low-temperature metastable phase and the orthorhombic and triclinic structures were stable at high temperatures. It was observed that the three structures display completely different luminescence efficiencies under both UV lamp and X-ray excitation, but the decay time was not strongly dependent on the crystal structure. The luminescence thermo-stability and activation energy were also measured and calculated. The results indicate that the thermo-stability was strongly dependent on the crystal structure and the GPS:Ce-1500 °C sample showed the best thermo-stability. The three materials have potential application as a novel type of scintillator.

Facile preparation of a three-coordinate copper(I) complex: Steric hindrance, supramolecular structure, optical property and TD-DFT study

GRAPHICAL ABSTRACT ABSTRACT The solution reaction of Cu(CH3CN)4(PF6) with a NN ligand 2-(2′-quinolyl)benzimidazole and a sterically bulky P ligand tris(2-methylphenyl)phosphine facilely yielded the three-coordinate copper(I) complex [Cu(2-QBI)(o-Tol3P)](PF6) (1). The complex has been characterized by single-crystal X-ray diffraction, Fourier Transform infrared spectroscopy and elemental analysis, UV–Vis (ultraviolet–visible) and photoluminescent spectroscopy studies. Time-dependent density functional theory has been used for calculating the electronic origin of the low-lying excited states, which were unexpectedly assigned mainly as a ligand-to-ligand or an intra-ligand charge transfer state instead of the metal-to-ligand charge transfer transition. Interestingly, 1 exhibits a concentration-dependent absorption in solution. This absorption behavior is interpreted as some excimers formation based on the study of supramolecular structure, spectroscopy and calculations.

Two-dimensional dysprosium(III) triiodate(V) dihydrate, Dy(IO3)3(H2O)·H2O

During our research into novel nonlinear optical materials using 1,10-phenanthroline as an appending ligand on lanthanide iodates, crystals of an infinite layered DyIII iodate compound, Dy(IO3)3(H2O)·H2O, were obtained under hydrothermal conditions. The DyIII cation has a dicapped trigonal prismatic coordination environment consisting of one water O atom and seven other O atoms from seven iodate anions. These iodate anions bridge the DyIII cations into a two-dimensional structure. Through O—H⋯O hydrogen bonds, all of these layers stack along [111], giving a supramolecular channel, with the solvent water molecules filling the voids.

Enhanced Transparency of Rough Surface Sapphire by Surface Vitrifaction Process

A novel, simple, and low-cost in situ surface vitrification method has been effectively developed to enhance the optical transparency of rough surface sapphire at UV-visible-IR regions. This method is to obtain a glass layer on the sapphire surface through vitrifaction process. The thickness, refractive index, components and transition temperature of the glass layer have been investigated and discussed respectively by XRD, DSC, SEM and EDS elemental analysis. The experimental results show that the vitrified sapphire has high transparency even after 1000 °C annealing at UV-visible-IR regions.

Growth and luminescence properties of Pr3+-doped LaCl3 single crystal

A transparent LaCl3:Pr3+ single crystal with a dimension of Φ 25×95mm was grown by vertical Bridgman method. The differential scanning calorimetry (DSC) shows that the melting point of LaCl3:Pr3+ crystal is about 841.5∘C. The powder X-ray diffraction (XRD) pattern proves the crystal structure of LaCl3:Pr3+ is hexagonal with space group P63/m. There is a dominant peak centered at 335nm and a weaker peak located at 400nm under X-ray excitation, while three peaks located at 335nm, 356nm and 400nm under ultra-violet. The peaks of 335nm and 356nm can be ascribed to the transition of 5d–4f of Pr3+, while the 400nm maybe related to LaCl3 host. Decay times were fitted to be about 14.5ns for 335nm, 14.6ns for 356nm and 1.3ns for 400nm. The experimental results show that the LaCl3:Pr3+ crystal will be a promising scintillator.

Poly[(μ5-5-carboxylatotetrahydrofuran-2,3,4-tricarboxylic acid)sodium]

The search for the novel metal-organic frameworks (MOFs) materials using tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THFTCA) as a versatile multi-carboxyl ligand, lead to the synthesis and the structure determination of the title compound, [Na(H3THFTCA)] or [Na(C8H7O9)]n, which was obtained by a solution reaction at room temperature. The ligand is mono-deprotonated, coordinating five sodium ions through one furan oxygen atom and six carboxyl oxygen atoms. The sodium ion exhibits a distorted pentagonal-bipyramidal NaO7 geometry consisting of seven O atoms derived from five surrounding ligands. Two adjacent pentagonal bipyramids share an O—O edge, forming a dinuclear sodium cluster. Finally, these clusters are effectively linked by the carboxyl groups of THFTCA ligands, forming a firm metal organic framework and O—H⋯O hydrogen bonds contribute to the crystal packing.