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The 18-π electron ring in the phthalocyanines and porphyrins largely controls their chemical and spectroscopic properties. It is the aim of this microsymposium to explore the formation and reactivities and the spectroscopic and theoretical properties of the ring-oxidized and ring-reduced phthalocyanines and porphyrins, essentially the π cation and π anion radical species. Redox chemistry of the ring, through ring oxidation and reduction to the radical species, offers powerful, new synthetic capabilities in which photochemical as well as electrochemical techniques may be used to effect highly localized reactions. The chemistry of these radical species can be moderated by control of the redox states of the central metal, the addition of electron-withdrawing or electron-donating peripheral substituents, and by the extent of intermolecular association applying both solvent polarity and peripheral substitution.

Zr:Nd:LiNbO₃ crystals codoped with 0.1 mol% of Nd₂O₃ and three concentrations of ZrO₂ (0, 2 and 4 mol%) were grown by the Czochralski method from the congruent melt. The X-ray diffraction (XRD) patterns, UV–visible absorption and infrared (IR) spectra were measured to analyze the crystal composition and defect structure. The blue and green upconversion emissions of Nd³⁺ ions under 598 nm excitation were observed. The intensity of upconversion emissions was increased by the introduction of 2 mol% zirconium ion (Zr⁴⁺) and decreased by the introduction of 4 mol% Zr⁴⁺ ions. The luminescence decay measurement indicated that the ⁴G_7/2 state of Nd³⁺ ion was mainly populated by excited state absorption process. It was proposed that Nd:LiNbO₃ crystals doped with approximately 2 mol% Zr⁴⁺ ions could be applied as laser materials at 522/535 nm.

Novel red light-emitting ${\mathrm{\text{Li}}}_2{\mathrm{\text{MgSiO}}}_4\mathrm{\text{:}}x{\mathrm{\text{Eu}}}^{3+}$ ($x=0.005$–$0.05$) phosphors were prepared by solid state reaction. The crystal phase structure and powder morphology were measured by X-ray powder diffraction (XRD) and scanning electron microscope (SEM), respectively. The photoluminescence (PL) properties were investigated. The excitation spectrum shows a wide coverage in the UV-Vis region, and the ${}^5{\mathrm{\text{D}}}_0{\to }^7{\mathrm{\text{F}}}_2$ transition with the maximum peak of 613 nm governs the emission spectrum. The lifetime of ${\mathrm{\text{Li}}}_2{\mathrm{\text{MgSiO}}}_4\mathrm{\text{:}}x{\mathrm{\text{Eu}}}^{3+}$ ($x=0.005$–$0.05$) phosphor is temperature-independent as well as the ${\mathrm{\text{Eu}}}^{3+}$ doping content because of the existence of defect. In ${\mathrm{\text{Li}}}_2{\mathrm{\text{MgSiO}}}_4$ lattice, the Eu${}^{3+}$ ions substitute for the ${\mathrm{\text{Li}}}^{+}$ ions, and the charge compensation mechanism could be ascribed to the dipole complex (${{\mathrm{\text{Eu}}}_{\mathrm{\text{Li}}}}^{\cdot \cdot }-2{{\mathrm{\text{V}}}_{\mathrm{\text{Li}}}}^{\prime }$) combined by ${\mathrm{\text{Li}}}^{+}$ vacancy (${{\mathrm{\text{V}}}_{\mathrm{\text{Li}}}}^{\prime }$) and positive charge (${{\mathrm{\text{Eu}}}_{\mathrm{\text{Li}}}}^{\cdot \cdot }$).

The electrochemistry of homoleptic bis(naphthalocyaninato) double-decker complexes for the whole series of tervalent rare earths M(TBNc)₂ (M = Y, La…Lu except Ce and Pm; H₂TBNc = 3(4),12(13),21(22),30(31)-tetra(tert-butyl)naphthalocyanine) has been systematically studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Up to three quasi-reversible one-electron oxidations and four quasi-reversible one-electron reductions have been revealed for these double-deckers.The half-wave potentials of all oxidations and the first reduction for double-decker complexes are dependent on the size of the metal center. The difference between the redox potentials of the first and second reductions for M^III(TBNc)₂, which represents the potential difference between the first oxidation and first reduction of [M^III(TBNc)₂]⁻, lies in the range 1.09-0.95 V and gradually diminishes along with the lanthanide contraction, indicating increased π-π interaction in the double-deckers in the same order. Comparison of electrochemical characteristics between M(TBNc)₂ and M(TBPc)₂ (H₂TBPc = 2(3),9(10),16(17),24(25)-tetra(tert-butyl)-phthalocyanine) reveals that extension of the ligand conjugated system upon going from phthalocyanine to naphthalocyanine attenuates the ring-to-ring separation effect on the redox potentials of the double-deckers of the whole series of tervalent lanthanides.

A series of novel bis[3,4,12,13,21,22,30,31-octa(dodecylthio)-2,3-naphthalocyaninato] rare earth(III) complexes M[Nc(SC₁₂H₂₅)₈]₂(M = Nd, Eu, Gd, Tb, Y, Ho, Er) have been prepared by tetramerization of 2,3-bis(dodecylthio)-6,7-dicyanonaphthalene with M(acac)₃·nH₂O in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing n-octanol. These sandwich double-decker complexes were characterized by elemental analysis and various spectroscopic methods including UV-vis, near IR, IR, and mass spectroscopies. Their liquid crystal behavior was studied by polarized optical microscope (POM), differential scanning calorimeter (DSC), and X-ray diffraction. These alkylthio-substituted bis(2,3-naphthalocyaninato) rare earth complexes yield a hexagonal columnar liquid crystal whose stable temperature range is between 42 and 243°C. The stable temperature domain of the mesophase shows a trend to be dependent on the central rare earth ionic size. In contrast, the molecular packing of these complexes as revealed by X-ray diffraction was found to be almost independent of the ionic size of the central rare earth.

A series of tris[2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato] rare earth(III) complexes M₂[Pc(OC₈H₁₇)₈]₃ [M = Eu, Gd, Y, Lu] has been prepared by the reaction of corresponding bis[2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato] rare earth complexes with M(acac)₃·nH₂O in refluxing 1,2,4-trichlorobenzene. These liquid crystalline sandwich, triple-decker complexes were characterized by elemental analysis and various spectroscopic methods including ¹H NMR, UV-vis, IR and mass spectroscopies. Their liquid crystal phase transition behavior was studied by Polarized Optical Microscope, Differential Scanning Calorimeter and X-ray diffraction. The complexes, with octyloxy attached as side chains, showed rectangular columnar liquid crystal phases in a liquid crystal temperature range between 83 and 305°C. In addition to the rare earth contraction, both the transition temperature and the wide temperature range of the mesophase show a slight but obvious trend to decrease, respectively, in the same order. In contrast, the molecular packing of these complexes as revealed by X-ray diffraction was found to be almost independent of the ionic size of the central rare earth.

Phosphate glasses doped with Dy${}^{3+}$ ions and containing silver nanoparticles (SNPs) were synthesized in the present work. We report photoluminescence characterization by absorption and emission spectra. The effect of Ag concentration on the thermoluminescence (TL) glow curves was studied. The scanning electron microscopy (SEM) shows the formation of SNP. Absorption spectra of the samples show the influence of the SNP in the bands 350nm at 425nm associated with the Dy${}^{3+}$, in the same spectra we can see the bands 750, 800, 875, 1098, 1278nm and 1675nm belonging to the Dy${}^{3+}$. Emission spectra show two prominent bands at 480nm and 574nm and one faint band at 665nm corresponding to ⁴F${}_{9∕2}{\to }^6$H${}_{15∕2}$, ⁴F${}_{9∕2}{\to }^6$H${}_{13∕2}$ and ⁴F${}_{9∕2}{\to }^6$H${}_{11∕2}$ transitions, respectively. All bands under 364nm pumping, and the fluorescence in the 550nm and 590nm spectral range enhanced four times. The Commission Internationale de 1’Eclairage (CIE) color coordinates were evaluated from the emission spectra to simulate white light emission from the phosphate glasses. The photostability of the samples was also studied in the UVA (315–403nm) and UVB (280–315nm) ranges. TL due to ultraviolet radiation (UVR) was studied; the glow curves show significant dependence of the TL intensity with the increment of SNPs in the samples. These results show the phosphate glasses doped with Dy${}^{3+}$ and containing SNP as a potential candidate have to be used in solid-state illumination and retrospective dosimetry.

The confrontation between China and the United States in the international economic and trade field has been gradually evolving into a much wider one between China and the Western world at large. In the escalating technological confrontation between China and the United States, Beijing has chosen export controls on gallium and germanium as a means of retaliation against U.S. export controls on advanced chips to China. However, whether it is oil, gas, gallium, germanium, or rare earths, export controls on these natural resources can only have a visible effect in the short term and may not achieve the political objectives intended by the sanctioners. With continued advances in resource extraction technology, the ongoing exploration of alternative resources, and the increasingly important role played by the price adjustment mechanisms, the export control on natural resources may not produce a sanctionary effect of stranglehold in the long run. After the Group of Seven (G-7) Hiroshima Summit, the confrontation landscape between China and the West has been further established, and the geopolitics in the world has entered a new era in which global economic growth faces greater uncertainty. Only multilateralism and global cooperation can promote the long-term prosperity of the world economy.

The spinel ferrite Li_0.2Zn_0.6La_yFe_2.2-yO₄; 0.01 ≤ y ≤ 0.1 were prepared by the usual ceramic sintering technique. XRD confirmed the formation of the samples in single phase spinel structure for all the samples. The lattice parameters decreased with increasing the La-content. The d c resistivity was measured as a function of temperature. The obtained results indicate the semiconductor like behavior, where more than straight lines indicating the presence of different conductions mechanism exist. The density of states near Fremi level as a function of La-content and discussed based on the variable range hoping model. The dielectric constant and dielectric loss were measured as a function of temprature and frequency. The dispersion peak at low frequency (10 kHz) was splitted by increasing La-content up to the suggested absorber splitting.