Microwave Assisted Synthesis of a New Triplet Iridium（Ⅲ） Pyrazine Complex

A new cyclometalated iridium（IlI） complex Ir（DPP）3 （DPP=2,3-diphenylpyrazine） was prepared by reaction of DPP with iridium trichloride hydrate under microwave irradiation. The structure of the complex was confirmed by elemental analysis, ^1H NMR, and mass spectroscopy. The UV-Vis absorption and photoluminescent properties of the complex were investigated. The complex shows strong ^1MLCT （singlet metal to ligand charge-transfer） and aMLCT （triplet metal to ligand charge-transfer） absorption at 382 and 504 nm, respectively. The complex also shows strong photoluminescence at 573 nm at room temperature. These results suggest the complex to be a promising phosphorescent material.

Selective synthesis and shape-dependent photoluminescence properties of (Y_(0.95)Eu_(0.05))_2O_3 submicron spheres and microplates

Red-emission （Y0.95Eu0.05）2O3 submicron spheres and microplates were selectively obtained via hydrothermal precursor synthesis （150 °C, 12 h） followed by calcination at 1000 °C. Characterizations of the products were carried out by combined means of XRD, FT-IR, FE-SEM and PL analysis. The precursors could be modulated from basic-carbonate submicron spheres to normal carbonate microplates by increasing the molar ratio of urea to Y＋Eu from 10 to 40-100. The resultant oxides largely retain their respective precursor morphologies at 1000 °C, but morphology confined crystal growth was observed for the microplates, yielding more enhanced exposure of the （400） facets. Both the （Y0.95Eu0.05）2O3 spheres and microplates exhibit nearly identical positions of the PL bands and similar asymmetry factors of luminescence [I（5D0→7F2）/I（5D0→7F1）, ～11] under 250 nm excitation, but the microplates show a significantly strong red emission at ～613 nm （ ～1.33 times that of the spheres） owing to their larger particle size and denser packing of primary phosphor crystallites.

Synthesis and optophysical properties of blue-emitting iridium (Ⅲ) complex bearing oxadiazole-based picolinic acid derivative

An iridium （Ⅲ） bis[（4,6-difluorophenyl）pyridinato-N, C^2][6-（6＇-（4＂-（ 5＂-phenyl- 1＂, 3＂, 4＂-oxadiazole-2＂-yl） phenoxy） hexyloxy picolinate） was synthesized and characterized by IH NMR and elementary analysis in order to study the effect of ancillary ligand of the oxadiazole-based picolinic acid derivative on optophysical properties of its iridium complex, and further to obtain an iridium complex with highly-efficient blue emission. The thermal stability, UV absorption and photoluminescent properties of this iridium complex were investigated. Compared with iridium （Ⅲ） bis[（4,6-difluorophenyl）pyridinato-N, C^2]（picolinate） reported as a highly-efficient blue electroluminescent material, this iridium complex bearing an oxadiazole-based picolinic acid derivative presents higher thermal stability, more intense UV absorption at 291 nm and similar photoluminescent spectrum peaked at 469 nm. This indicates that tuning ancillary ligand of picolinic acid with an oxadiazole unit can improve the optophysical properties of its iridium complex.

Optical Reskponse of Metal—Dielectric Composite Containing Interfacial Layers

A phenomenological approach to investigate the effect of interfacial layers on the absorption of metal-dielectric composite at elevated temperatures is put forward by making use of a model in which weakly nonlinear spherical metallic particles with linear concentric shells are randomly embedded in a linear host. Corresponding formulae in terms of the interfacial factor are derived in detail by incorporating Taylor expansion and Drude model. We take composite as numerical calculation. It is concluded that such absorption is dependent not only on the temperature, but also on the properties of interfacial layers. Many other interesting phenomena are shown.

Preparation and Properties of Eu^(3+) Rare Earth Complex and Fluorescent Fiber

A novel Eu^3＋ rare earth complex, composed of 4 - hydroxybenzolate acid and 1, 10 - phenanthroline ligands was synthesized. The apparent morphology, composition, thermal stability and fluorescent property of the rare earth complex were measured by TEM, Element analysis, IR, TG and Fluorescence spectrometer. The results indicated that this rare earth complex has sphere-like morphology and its diameter was about 100 nm. The complex has good thermal stability due to the strong coordination between the Eu^3＋ ions and the ligands. Based on the composition analysis, the complex structure formula was： Eu （HOC6 H4 COI）3 （phen） ·H2O Fluorescence spectra showed that the rare earth complex emission peaks were corresponding to the transition of ^5D0→7FJ（J=0,1,2,4）,. and the highest intensity fluorescence peak was at 617 nm. The luminescent fiber was prepared by blending melt-spinning with rare earth complex and polypropylene resin. It also has a good luminescent quality, which the strongest emission peak was at 619 nm. It could be considered suitable for industrial application.

Synthesis and emission analysis of novel rare earth complex Eu(TTA)_3(2NH_2-Phen)

The rare earth ternary complex of Eu 3+ with thenoyltrifluoroacetone,and 4,7-2NH2 phenanthroline was synthesized and well characterized by UV,fluorescent,IR spectrometry and X-ray diffractometry(XRD)as well as elemental analysis.The results show that the complex of Eu(III)emits strong red luminescence when excited by UV light,and Eu(TTA)3(2NH2-Phen)has the higher sensitized luminescent efficiency and longer lifetime than Eu(TTA)3(Phen).In device of ITO/PVK/Eu(TTA)3(2NH2-Phen)/Al,the spectra of Eu(TTA)3(2NH2-Phen)with different ratios for spin-cast film were monitored.The main emitting peak at 614 nm can be attributed to the transition of 5 D0→ 7 F2 of Eu 3+ and this process results in the enhancement of red emission from electroluminescence device.The effect and mechanism of the ligands on the luminescence properties of europium complex were discussed.The results show that the luminescence intensity of the title complexes greatly increases in comparison with that of their corresponding complexes,revealing that the second ligands form very good synergistic effect with the first ligands.The title complexes possess excellent thermal stability properties,and are hopefully developed into fine PL and EL red materials.

Synthesis and Crystal Structure of Novel Emitting Material 9,9-Bis(buthoxycarbonylethyl) fluorene

Synthesis of 9,9-bis（buthoxyearbonylethyl） fluorine（C27 H34 04, Mr= 422.54） with butyl acrylate as alkylation reagent and fluorene as starting material has been performed. The crystal structure was measured by using the X-ray diffraction method. The crystal belongs to monoclinic, space group P2 （1）/c with parameters as： a=l. 2912（1）nm, b=l. 0974（1）nm, c=1. 7468（1）nm, β=90. 252（2）, V=2. 4752（4）nm^3 , Z=4, Dcacl= 1. 134 g · cm^-3 ,λ=0. 071 073 nm, μ（MoKα） =0. 075mm^-1 , F（000） =912, R=0. 0651 and wR=0. 1475. X-ray analysis reveals that the three fused rings of the fluorene system are almost coplanar and the two ester groups are nearly perpendicular to the fused-ring system, weak CH O hydrogen-bonding connects the molecule into centrosymmetric dimmers

Synthesis and photocatalytic activity of ZnO-Au_(25) nanocomposites

ZnO-Au_(25) nanocomposites were synthesized by doping Au_(25) nanoclusters into the porous Zn O nanospheres. It was notable that the ultrasmall Au_(25) nanoclusters possessed uniform sizes and fine dispersibility on the porous ZnO supports. A considerable correlation between the loading of Au_(25) nanoclusters and the photocatalytic activity was found. Compared with the pure ZnO nanospheres, the ZnO-Au_(25) nanocomposites exhibited more efficient photocatalytic activity in terms of degradation of Rhodamine B(RhB) in an aqueous solution. In addition, the possible photocatalytic mechanisms are discussed in this work. This strategy may be helpful for preparing other novel hybrid nanocomposites with well-defined structures and superior performances.

Synthesis, characterization, and theoretical analysis of three new nonlinear optical materials K7MRE2B15O30（M= Ca and Ba, RE= La and Bi）

Three new complex borate compounds K7CaBi2B15O30, K7CaLa2B15 O30 and K7BaBi2B15O30 have been synthesized by the high-temperature solution method.K7CaLa2B15O30and K7CaBi2B15O30crystallize in the chiral trigonal space group R32, while K7BaBi2B15O30 crystallizes in the noncentrosymmetric orthorhombic polar space group Pca21. All of the title compounds have similar three-dimensional crystal structures, which are composed of isolated B5 O10 groups and LaO6 or BiO6 octahedra, and K^+, Ca^2+, and Ba^2+ cations fill into the cavities to keep charge balance. Based on our research, in the system of K7 MIIRE2 B15O30(MII= Ca, Sr,Ba, Zn, Cd, Pb, K/RE0.5;RE = Sc, Y, La, Gd, Lu, Bi),K7BaBi2B15O30 is unique and crystallizes in a different space group, which enriches the structural chemistry of borate.Detailed structural analyses indicate that the structural variation is due to the difference in size and coordination number of the alkaline-earth metal cations. Besides, UV-Vis-NIR spectroscopy analysis and the second-harmonic generation(SHG) measurement on the powder samples show that K7CaBi2B15O30 exhibits a UV cutoff edge(about 282 nm) and a moderate SHG response(about 0.6 × KDP). In addition,thermal analysis and infrared spectroscopy were also presented. To better understand the structure-property relationships of the title compounds, the first-principles calculations have been performed.

Photocatalysis with visible-light-active uranyl complexes

Atomic energy is an important part of current energy resources.Production of nuclear weapons and applications of nuclear fuels in nuclear power plants have accumulated numerous spent fuels containing238U compounds,which are critical nuclear materials.How to reduce the nuclear wastes and to make use of the spent uranium are key scientific issues of environmental and nuclear science.We have reviewed here the physiochemical properties and photocatalytic mechanisms of homogeneous and heterogeneous uranium-containing materials.The current research efforts demonstrate that spent fuels can become promising new photocatalytic materials.

Physio-and chemo-dual crosslinking toward thermoand photo-response of azobenzene-containing liquid crystalline polyester

Combining the stability of chemical crosslinking and the processability of physical crosslinking is a well-established strategy to design new materials with desirable stimuli–responsive properties. Herein, a series of azobenzenebased thermotropic liquid crystalline polyesters were synthesized by introducing mesogenic dial named 4,4＇-bis（6-hydroxyhexyloxy）azobenzene（BHHAB）, 2-phenylsuccinic acid（PSA）, and different contents of 1,2,3-propanetricarboxylic acid（PTA） as the chemical crosslinker. All these polyesters showed good thermal stability and smectic liquid crystalline phase. Wide-angel X-ray diffraction（WAXD） and the fluorescence emission spectra confirmed the existence of π–πstacking interactions as the physical crosslinking in the polymer chains, particularly at the lower content of PTA. However, when the PTA content increased, the chemical crosslinking changed the chain conformation, and thus the intensity of physical crosslinking slackened gradually. Combining the physical and chemical crosslinking, these polyesters showed the thermoplastic processability, thermal shape memory, heat-assisted healing and photoresponsive behaviors. Taking advantages of these features, these multiple stimuli–responsive polymers can bring more chances for smart materials such as soft actuator.

Amplified circularly polarized luminescence promoted by hierarchical selfassembly involving Pt···Pt interactions

The design and construction of highly effective circularly polarized luminescence(CPL)-active materials has aroused considerable attention due to their widespread applications in sensors,optical devices,and asymmetric synthesis.However,the exploration of novel CPL-active materials with high luminescence dissymmetry factor(glum)values is still a challenge.Herein,we describe a new approach for the preparation of supramolecular metallacycles with amplified CPL promoted by hierarchical self-assembly involving Pt···Pt interactions.Notably,the resultant metallacycles exhibited strong CPL signals with high glum values,while their corresponding precursors were CPL silent.The CPL amplification mechanism was comprehensively validated by ultravioletvisible absorption,emission spectroscopy,nuclear magnetic resonance spectroscopy,scanning electron microscopy,transmission electron microscopy,atomic force microscopy,coarse-grained molecular dynamics simulations,and timedependent density functional theory calculations.This work thus provides the first example of preparing highly effective CPL-active materials based on hierarchical self-assembly involving Pt···Pt interactions.

Heterometallic copper(Ⅱ) vanadates: synthesis, crystal structures and third-order nonlinear optical properties

Three polymeric heterometallic clusters with 1D, 2D, and 3D frameworks, constructed from a cyclic vanadate {V4O12}4- building block and three geometric constraint ligands, were synthesized by a one-pot self-assembly reaction. Z-scan experiments demonstrated that all the three cluster polymers have large hyperpolarizability y values. TD-DFT calculations afforded insight into the electronic transitions and spectral characterization of these novel NLO molecular materials.

Full-temperature covered switching material with triple optic-dielectric states in a lead-free hybrid perovskite

Optic-electric responsive materials have attracted much attention for their applications in temperaturesensing,actuators,and memory switches.However,it is a challenge to integrate various functions to form multifunctional responsive materials.As molecule-based hybrid materials usually consist of organic and inorganic components,the introduction of multiple functions can be achieved through structural construction.Thus far,even though fulltemperature cover is required for device applications,fulltemperature covered multi-switchable hybrid materials have rarely been successfully synthesized.Herein,the dynamic[(CH3)3NOH]+cation and luminous center Mn(II)were introduced to form a hybrid material[(CH3)3NOH][Mn Cl3],showing multiple temperature-responsive behaviors.Upon temperature change,it exhibits multi-state dielectric switching response and intensity or peak shift response of luminous in full-temperature range(low,room,and high temperatures).These responsive behaviors are triggered by the motion or reorientation of[(CH3)3NOH]+cations and inorganic framework.Overall,the switchable photoelectric material has potential applications in multiple encrypted storage and sensor devices.

Synthesis of a sulfur-graphene composite as an enhanced metal-free photocatalyst

A novel metal-free photocatalyst--sulfur/graphene （S/GR） composite--has been synthesized using a facile one-pot, two-step hydrothermal method with thiosulfate and graphene oxide （GO） as precursors. A green reductant--L-ascorbic add--was used to transform GO to GR under mild conditions. The photocatalyst powders were characterized by Fourier transform infrared spectroscop, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and energy dispersive spectroscopy. Experimental tests were conducted on the photocatalytic decomposition of methyl orange （MO） by different catalysts. Compared to pure oL-S, the as-prepared S/GR composite showed much enhanced photocatalytic activity for the degradation of MO under both UV and solar light. The presence of GR also greatly increased the hydrophilicity and adsorption capacity of the catalyst material. The results indicate that the incorporation of GR with a-S results in a synergistic effect for the S-based photocatalysts offering more effective environmental applications.

Ag4Hg（SeO3）2（SeO4）: a novel SHG material created in mixed valent selenium oxides by in situ synthesis

Explorations of new second harmonic generation materials in Ag^+-Hg^2+/Bi^3+-selenites systems afforded three new silver selenium oxides, namely, Ag4 Hg(SeO3)2(SeO4)(1), Ag2Bi2(SeO3)3(SeO4)(2) and Ag5 Bi(SeO3)4(3). They exhibit flexible crystal chemistry. Compounds 1 and 2 are mixed valence selenium oxides containing Se(IV) and Se(VI) cations simultaneously. Compounds 1 and 3 exhibit a 3 D open framework with 4-, 6-and 8-member polyhedral ring tunnels along a, b and c axes. Compound 1 crystallized in a polar space group and could display a subtle frequency doubling efficiency about 35% of the commercial KH2PO4(KDP). UV-vis-NIR spectra reveal that compounds 1–3 are wide-band semiconductors with the optical bandgaps of 3.11, 3.65, 3.58 e V respectively. Theoretical calculations disclose that compounds2 and 3 are indirect band gap structures and their bandgaps are determined by Ag, Bi, Se and O atoms together.