Luminescence spectroscopy framework

The synthesis, structural characterization and luminescence spectroscopy studies of AV-5 and AV-9 (Aveiro microporous solids no. 5 and 9), the first examples of microporous framework cerium(III) and europium(III) silicates (Na4K2X2Sii6O3gT0H2O, X = Eu, Ce) are reported. Both materials display interesting photoluminescence properties and present potential for applications in optoelectronics. This work illustrates the possibility of combining in a given framework silicate microporosity and optical activity. 

This volume of the Handbook on the Physics and Chemistry of Rare Earths adds five new chapters to the science of rare earths, compiled by researchers renowned in their respective fields. Volume 34 opens with an overview of ternary intermetallic systems containing rare earths, transition metals and indium (Chapter 218) followed by an assessment of up-to-date understanding of the interplay between order, magnetism and superconductivity of intermetallic compounds formed by rare earth and actinide metals (Chapter 219). Switching from metals to complex compounds of rare earths, Chapter 220 is dedicated to molecular stmctural studies using circularly polarized luminescence spectroscopy of lanthanide systems, while Chapter 221 examines rare-earth metal-organic frameworks, also known as coordination polymers, which are expected to have many practical applications in the future. A review discussing remarkable catalytic activity of rare earths in site-selective hydrolysis of deoxyribonucleic acid (DNA) and ribonucleic acid, or RNA (Chapter 222) completes this book. 

The crystallization of zeolites from alkaline aluminosilicate gels was studied by luminescence and Raman spectroscopy. Trace amounts of Fe3+ ions substituted for Al3+in the tetrahedral aluminosilicate gel framework exhibit characteristic phosphorescence spectra, which have been used to follow the buildup of the zeolite framework. Phosphorescence spectra of exchanged Eui+ cations and Raman spectra of (CH N+ cations present in the solid phase of the gel indicate that no zeolitic cages exist in this phase during the induction period. Raman spectra of the liquid phase of the gel system show only the presence of Si02-(0H)2 and Al(OH)a anions. Our results demonstrate that crystallization of zeolites occurs within the solid phase of the gel, which is believed to consist of amorphous tetrahedral alumino-... 

As multidentate ligands, s-tetrazines successfiilly find application in coordination chemistry. Their derivatives are useful building blocks for metal-organic frameworks (MOFs). Thus, the first example of an MOF with the novel 3,3 -(l,2,4,5-tetrazine-3,6-diyl)dibenzoic spacer 57 was reported and its luminescence and adsorption properties were studied (13IC546). Complexation of Sm(III) with 2,6-bis(4-npropyl-2,3,5,6-tetrazine-l-yl)pyridine 58 as an analog of BTP was studied using time-resolved laser fluorescence spectroscopy (13DT12139). 

In the preparation of zeolite-entrapped CdS, considerable attention has been paid to the ncd/nj ratio. A marked non-stoichiometry of zeolite-hosted metal sulfide particles has been found for CdS nanoparticles by X-ray photoelectron spectroscopy [345]. After sulfidation of a zeolite X sample that is partially ion-exchanged with Cd ions, the binding energies of Cd 3ds/2 electrons decrease by about 0.3 - 0.5 eV in dependence on the diameter of the CdS nanoparticles formed. The shift originates from the replacement of ionic interactions between the Cd + ions and the zeolitic framework oxygen by more covalent (Cd -S ) bonds. However, due to the larger effective masses of the electrons and holes in CdS (m, eff = 0.42 nie, mn, eff = 0.18 m ) [339], the absorption of CdS clusters in the pores of zeohtes is less affected by the zeoUte framework than that of PbS clusters. However, the effect of the zeolite framework on the excited-state relaxation processes, i. e., the luminescence behavior of the CdS clusters, can be very large. 

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