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Photoluminescent Properties (photoluminescent + property)
Selected AbstractsTetranuclear (Phosphane)(thiolato)gold(I) Complexes: Synthesis, Characterization and Photoluminescent Properties,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2007Eduardo J. Fernández Abstract The reactions of the tetraphosphane donor ligand (Ph2PCH2)2NCH2CH2N(CH2PPh2)2 with the gold precursors [AuCl(tht)] or [Au(C6F5)(tht)] (tht = tetrahydrothiophene) leads to complexes [Au4R4{(Ph2PCH2)2NCH2CH2N(CH2PPh2)2}] [R = Cl (1) or C6F5 (2)]. Further substitution of the chlorine atoms in 1 by the corresponding 4-substituted benzenethiolates gives rise to the tetranuclear (phosphane)(thiolato)gold(I) complexes [Au4(S-C6H4 -X)4{(Ph2PCH2)2NCH2CH2N(CH2PPh2)2}] [X = F (3), MeO (4), Me (5) and NO2 (6)]. Complexes 2 and 4 were characterized by X-ray diffraction studies showing Au···Au interactions in the case of complex 4. Complexes 3,6 display intense emissions in the solid state at 77 K with lifetimes in the microsecond range. The observed phosphorescent emissions are attributed to metal-to-ligand charge-transfer transitions. Nevertheless, the influence in the emission energies of gold,gold interactions or the contribution of the substituent in the 4-position of the benzenethiolate ring to the excited state cannot be neglected. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis, Crystal Structure, and Photoluminescent Properties of a Tetracarbonyl(naphthyridylcarbamoyl)rhenium(I) Complex and a Highly Emissive Tetracarbonyl(naphthyridylamido)rhenium(I) ComplexEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2003Jing-Lin Zuo Abstract The reactions of Re(CO)5X (X = Cl, Br) with 7-amino-2,4-dimethyl-1,8-naphthyridine (H2L1) and 7-[2-(6-chloropyridyl)amino]-2,4-dimethyl-1,8-naphthyridine (HL2) in the presence of tBuOK afforded the ,1 -naphthyridylcarbamoyl complex [Re(CO)4(HL1CO)] (1) and the naphthyridylamido complex [Re(CO)4(L2)] (2), respectively. The structures of HL2, 1·CHCl3, 1·HL3·2CH2Cl2 [HL3 = (7-chloronaphthyridyl)(5,7-dimethylnaphthyridyl)amine], and 2 have been determined by X-ray crystallography. Complex 1 displays a weak emission at 453 nm in an EtOH/MeOH (1:4, v/v) glassy solution at 77 K; complex 2 exhibits an intense (quantum yield: 0.22 in CH2Cl2) and long-lived emission (46 ,s in CH2Cl2), with a solvent-sensitive ,max, in degassed solutions at room temperature. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2003) [source] Photoluminescent Properties of SrTiO3:Pr, Al Nanophosphors Synthesized by Microemulsion,Microwave HeatingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2007Qi Pang A novel approach for the preparation of SrTiO3:Pr, Al nanophosphors by microemulsion,microwave heating is reported in this paper. In comparison with the conventional solid-state sintering processes, this novel method provides a limited small space in a micelle for the formation of nanosized precursors and requires a very short heating time, thus reducing the energy consumption. As a result, small-sized particles with a narrow size distribution and high purity were produced. Transmission electron microscopy characterizations indicated that the synthesized particles were almost spherical with an averaging diameter of ,24 nm and agglomerates slightly. The X-ray diffraction analysis revealed the perovskite cubic structure of SrTiO3:Pr3+ nanoparticles. The luminescent of SrTiO3:Pr, Al phosphors were investigated by photoluminescence. Under 350 nm excitation, SrTiO3:Pr, Al showed a strong red emission, peaking at around 615 nm. The photoluminescence excitation intensity was enhanced by the addition of Al3+ ions. [source] Synthesis and Photoluminescent Properties of Ce3+ Doped Terbium Aluminum Garnet Phosphors.CHEMINFORM, Issue 24 2007C. C. Chiang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] A Facile Synthesis and Photoluminescent Properties of Redispersible CeF3, CeF3:Tb3+, and CeF3:Tb3+/LaF3 (Core/Shell) Nanoparticles.CHEMINFORM, Issue 27 2006Z. L. Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthesis, Crystal Structure and Photoluminescent Properties of Two Novel Two-dimensional Coordination Networks Assembled by Lanthanide Salts and Carboxylate Ligand,CHINESE JOURNAL OF CHEMISTRY, Issue 1 2009Yajuan LI Abstract Two novel two-dimensional (2D) lanthanide(III) coordination polymers [Ln(PDC)(OH)(H2O)2]n (Ln=Eu (1) and Tb (2), H2PDC=pyridine-3,4-dicarboxylic acid) have been synthesized under hydrothermal conditions, and characterized by elemental analysis, IR, TGA and single-crystal X-ray diffraction. Both compounds show the same 2D layer containing 1D Ln,O,Ln chains, and the layers are further connected through hydrogen-bonding as well as ,-, stacking interactions into a three-dimensional supramolecular network. Furthermore, both compounds exhibit intense fluorescent emission bands in the solid state at room temperature. [source] Photoluminescent Fibers: Anisotropic Self-Assembly of Photoluminescent Oligo(p -Phenylenevinylene) Derivatives in Liquid Crystals: An Effective Strategy for the Macroscopic Alignment of , -Gels (Adv. Mater.ADVANCED MATERIALS, Issue 40 200940/2009) Takashi Kato, Ayyappanpillai Ajayaghosh, and co-workers report on p. 4029 that aligned photoluminescent ,-conjugated fibers are formed through anisotropic self-assembly of oligo(p -phenylenevinylene) gelators in smectic and nematic liquid crystals. The aligned fibers exhibit polarized photoluminescent properties. These self-assembled liquid-crystalline composites may be applicable to new types of electro-optical and photonic materials. [source] Solution, thermal and optical properties of novel poly(pyridinium salt)s derived from conjugated pyridine diamines,JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2010Alexi K. Nedeltchev Abstract Several novel poly(pyridinium salt)s with heterocyclic pyridine moieties in their backbones with tosylate and triflimide counterions were prepared by either ring-transmutation polymerization reaction of phenylated-bis(pyrylium tosylate) with isomeric pyridine diamines of 4-phenyl-2,6-bis(4-aminophenyl)pyridine in dimethyl sulfoxide (DMSO) for 48 h at 130,140 °C or by metathesis reaction of the respective tosylate polymers with lithium triflimide in DMSO at about 60 °C. Their chemical structures were characterized by FTIR, 1H, 13C NMR spectroscopy, and elemental analysis. Their number-average molecular weights (Mn) were in the range of 8,000,51,000 and their polydispersities in the range of 1.18,2.13 as determined by gel permeation chromatography. They had excellent thermal stabilities of 340,458 °C and high glass transition temperatures >200 °C. As they showed good solubilities in common organic solvents, their solution properties were also characterized for their lyotropic liquid-crystalline properties with polarizing optical microscopy (POM) studies. Their photoluminescent properties were examined by using a spectrofluorometer in both solution and solid states. Their quantum yields were rather low, which were in the range of 1.3,2.0%. Additionally, hand-drawn fibers from the melts were examined to determine their morphologies with a number of microscopic techniques including POM, scanning electron microscopy, and transmission electron microscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [source] Nanocomposites of silver nanoparticle and dinonylnaphthalene disulfonic acid-doped thermoreversible polyaniline gelPOLYMER ENGINEERING & SCIENCE, Issue 3 2010Ashesh Garai Silver/polyaniline-dinonylnaphthalene disulfonic acid (PANI-DNNDSA) gel nanocomposites are prepared from the reduction of silver salt by polyaniline in formic acid medium. Scanning electron micrographs (SEM) indicate the presence of three-dimensional fibrillar network structure and the silver nanoparticles remain dispersed within the PANI-DNNDSA fibrillar network. Differential scanning calorimetric (DSC) study shows reversible first-order phase transition characterizing the composite to behave as a thermoreversible gel. Transmission electron micrographs (TEM) show a decrease of nanoparticle size with increasing AgNO3 concentration. Wide angle X-ray scattering (WAXS) patterns show lamellar structure in the gel as well as in the gel metal nanocomposites (GMNCs) and the two melting peaks in the DSC patterns correspond to the melting of monolayer and bilayer crystals produced from the interdigitation of DNNDSA tails anchored from PANI chains within the PANI lamella. The above melting points are greater in the GMNCs than that of pure gel indicating the formation of complex melting thermogram with crystallites produced from the anchored surfactants tails at the surface of Ag nanoparticles. The GMNCs show a higher thermal stability than that of pure PANI-DNNDSA gel. PANI-DNNDSA gel has an emission peak at 354 nm but fluorescence quenching occurs in the GMNCs and the emission peak becomes red shifted. Also in the UV,vis spectra the , band-polaron band transition peak shows a red shift and the DC conductivity increases with increasing Ag nanoparticle concentration in the GMNCs. The current (I),voltage (V) characteristic curves indicate Ohmic nature of conductivity of the gel and the current at the same voltage increases appreciably with increasing Ag nanoparticle concentration. These GMNCs are easily processible due to its thermoreversible nature. So, an easily processible, thermally stable and highly conducting DNNDSA-doped PANI-Ag gel nanocomposite with interesting photoluminescent property has been successfully developed suitable for optoelectronic applications. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source] | |||||||||||||