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Two Co(II)-based coordination compounds, namely {[Co(apc)2]·H2O}n (1) and [Co(apc)2(H2O)2] (2), have been successfully prepared via reaction of a multifunctional ligand 2-aminopyrimidine-5-carboxylic acid (Hapc) with Co(NO3)2·6H2O based on different reaction environments. Both compounds were studied via elemental analysis (EA), single crystal X-ray diffraction analysis (SC-XRD), thermogravimetric analysis (TG), powder X-ray diffraction (PXRD) and infrared spectroscopy (IR). Fluorescence spectroscopy was employed to analyze the fluorescence properties of the ligand and the two compounds. The results revealed that the two compounds exhibited green and blue fluorescence, surpassing the original ligand in terms of properties. Based on the distinct fluorescence colors of the two compounds, there is potential to create multicolored fluorescent materials by adjusting their material ratios. This prospect could further extend their applications in the field of fluorescent materials. [ABSTRACT FROM AUTHOR]

A comparative spectral analysis was performed to investigate the impact of the host lattice on crystal phase, crystallinity, thermal properties, Raman shift, optical bandgap, surface behavior, and luminescent properties of the as-prepared La2O3:Eu, Gd2O3:Eu, and Y2O3:Eu nanoparticle(NPs). X-ray diffraction pattern (XRD) outcome shows the influence of the host matrix in identical formulae but the different crystal phases with an average size 15, 12, and 18 nm, respectively. X-ray photoelectron spectroscopy (XPS), transmission electron microscopy, and dynamic light scattering methods were exploited to determine the size, valence states, and size distribution of the samples. UV/visible spectra were measured in an aqueous solution to quantify the colloidal stability and optical characteristics of the samples. Energy bandgap values were calculated from the absorption spectra for the three different metal oxides. The laser-excited Raman spectra show abundant Raman active peaks because of the presence of the dopant ions. Based on the lattice constants of each metal oxide sample, the existence of a very prominent peak in the region of 320–420 cm−1 defines in all three Raman spectra. As the unit cell parameters rise, the frequency of this peak declines in intensity, making the structure less robust. Hexagonal phase La2O3:Eu NPs exhibited strong multiple emission transitions in the visible region, whereas cubic phase Gd2O3:Eu and Y2O3:Eu NPs illustrated most strong red emission transition located at 611 nm which correspond to the 5D0 → 7F2 under excitation from the same 325-nm wavelength. The proposed results are highly applicable in the development of photonic base applications and quantify the doping concentrations in the host lattices. [ABSTRACT FROM AUTHOR]

Coordination polymers have been a hot research topic in the field of biomedicine for their interesting bioactivities. To study the effects of metal ions on the bioactivity of the resulting coordination polymers, in this study, two novel coordination polymers, [Zn4(L)4(bix)4]·n(DMF)·4n(H2O) (1) and [Cd(L)(bix)(H2O)2]n·2n(H2O) (2) (H2L = 5-(1-oxoisoindolin-2-yl)isophthalic acid, bix = 5-(1-oxoisoindolin-2-yl)isophthalic acid, DMF = N,N′-dimethylformide), have been synthesized by the reactions of H2L, bix and Zn(II) or Cd(II) salts under the solvothermal condition and further characterized via the single crystal X-ray diffraction, powder X-ray diffraction, elemental analysis and thermogravimetric analyses. The CIE chromaticity diagram indicated that complexes 1 and 2 are excellent blue luminescent materials. Their therapeutic effect with synergistic curcumin on post-stroke depression was explored in the present work. First of all, the analysis of enzyme-linked immunosorbent assay was exploited for testing the 5-hydroxytryptamine (5-HT) content exists in brain. Next, the serotonin transporter relative expression was also analyzed with the detection of real-time reverse transcription-polymerase chain reaction (RT-PCR). The experimental results show that the CP 1 could be a better candidate for synergistic curcumin for treating post-stroke depression by increasing 5-HT content and relative expression of serotonin transporter than CP 2. [ABSTRACT FROM AUTHOR]

Transparent polylactic acid (PLA) fibers with Lumogen Red 305 (LR305) were prepared by melt spinning. The crystallization and melting behavior, absorbance spectra, emission spectra, mechanical properties, and the concentrator effect for a real solar cell of the PLA/LR305 fibers were characterized by differential scanning calorimetry (DSC), UV–Vis–NIR spectrophotometer, FL spectrophotometer, yarn tensile tester, and a digital multimeter (Victor VC980+), respectively. The results showed that the hot drawing improves the mechanical properties of the fibers while maintaining the optical properties. When the concentration of LR305 was 0.05 wt%, the breaking strength of the stretched fiber 22@217 (22% crystallinity, 217 diameters) and the as-formed fiber 3@205 (3% crystallinity, 205 diameters) were 69.3 and 182.7 MPa, respectively. Meanwhile, the absorbance intensity and luminescence intensity of 22@217 decreased only 6 and 11% compared with 3@205. When triple-drafted PLA/LR305 fibers with a concentration of 0.25 wt% were combined with the solar cell, the solar cell output current changed from 0 to 2.8 μA. [ABSTRACT FROM AUTHOR]

Lanthanides (Ln3+) doped luminescent materials play critical roles in lighting and display techniques. While increasing experimental and theoretical research have been carried out on aluminate-based phosphors for white light-emitting diodes (WLEDs) over the past decades, most investigation was mainly focused on their luminescent properties; therefore, the local structure of the light emission center remains unclear. Especially, doping-induced local composition and structure modification around the luminescent centers have yet to be unveiled. In this study, we use advanced electron microscopy techniques including electron diffraction (ED), high-resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), in combination with energy dispersive X-ray spectroscopy (EDX) and electron energy loss spectroscopy (EELS), to reveal atomically resolved crystalline and chemical structure of Ce3+ doped CaYAlO4. The microscopic results prove substantial microstructural and compositional inhomogeneities in Ce3+ doped CaYAlO4, especially the appearance of Ce dopant clustering and Ce3+/Ce4+ valence variation. Our research provides a new understanding the structure of Ln3+ doped luminescent materials and will facilitate the materials design for next-generation WLEDs luminescent materials. [ABSTRACT FROM AUTHOR]

Two coordination polymers, {[Cd3(2,4-pda)4(H2O)2][(CH3)2NH2]2}n·2n(DMF) (1) and [Mn3(2,4-pda)3(H2O)4]n (2), where 2,4-H2pda is pyridine-2,4-dicarboxylic acid, have been synthesized under solvothermal conditions and structurally characterized by single crystal X-ray diffraction. The solid state structure of both compounds is characterized by trinuclear metal entities, which expands to a 2D layer and 1D coordination polymer, respectively, thanks to the bridging behavior of 2,4-pda ligands. The luminescent performance of complex 1 and the magnetic activity of complex 2 were investigated. Their application towards the lung cancer was evaluated and the related mechanism was explored as well. Firstly, the levels of the apoptotic lung cancer cells, after treatment with compounds 1 and 2, were determined by using the Annexin V-FITC kit. Compound 1 significantly increased the levels of apoptotic lung cancer cells, more efficiently than 2. In addition, the relative expression of reactive oxygen species (ROS) related genes in the lung cancer cells were investigated with the real time reverse transcription-polymerase chain reaction (RT-PCR) assay. The levels of ROS significantly increased after treatment with compound 1 in comparison with 2. [ABSTRACT FROM AUTHOR]

The solvothermal reactions via the self-assemble approach produced two new metal–organic compounds, i.e., [Zn(4-cptpy)(HCOO)(H2O)]n·(DMF)n (1) and [Cd3(btc)2(4-cptpyH)(DMF)(H2O)3]n (2) (DMF is N,Nʹ-dimethylformamide, H3btc is benzene-1,3,5-tricarboxylic acid, and 4-Hcptpy is 4-[2,6-bis(pyridine-4-yl)pyridine-4-yl]benzoic acid). Furthermore, the compounds' luminescent performances have also been studied. Their application values against postoperative infectious endophthalmitis (PIE) were assessed and the related mechanism was explored at the same time. First of all, the activation levels of nuclear factor kappa-B (NF-κb) signaling pathway was measured with real time reverse transcription-polymerase chain reaction (RT-PCR) assay. In addition to this, the enzyme linked immunosorbent assay (ELISA) detection kit was further conducted and the and the content of inflammatory cytokines released after the cataract surgery was determined. The cytotoxicity of the compounds was also detected with CCK-8 assay. [ABSTRACT FROM AUTHOR]

The spectroscopic properties of lanthanide ions stem from absorption and emission radiation in the solar spectrum range, which promotes numerous applications in areas such as white light emission, bio-imaging, biological markers, and photovoltaic cells, among others. To intensify these properties, several matrixes have been studied, particularly the yttrium vanadate matrix due to its structural, mechanic, and physicochemical properties. The non-hydrolytic sol–gel process is a versatile way to prepare inorganic oxides doped with lanthanide ions. In this work, we describe the synthesis of yttrium vanadate matrixes doped with Eu3+, Er3+, and/or Yb3+ ions (containing 1% lanthanide ions with respect to Y3+ (molar ratio)) by the non-hydrolytic sol–gel, annealed at 800 °C for 4 h, and their characterization by X-ray diffraction and photoluminescence spectroscopy. The X-ray diffraction patterns display the peaks corresponding to the yttrium vanadate tetragonal phase. Laser excitation at 980 nm elicits Er3+ emission bands in the green and red regions and Eu3+ emission at 620 nm. Laser excitation at 322 nm; i.e., the charge transfer band, provides emission in the same regions, as well as infrared emission. This system is a promising candidate for applications in solar cells, optical amplifiers, and biomarkers because it can be excited at different wavelengths. [ABSTRACT FROM AUTHOR]

By employing a mixed-ligand strategy, we synthesized two new coordination polymers (CPs) featuring Co(II): {Co(H2L)(bib)]·2H2O}n (1) and {Co(L)(bib)2]·2H2O}n (2), where H4L represents 5-(3,5-dicarboxybenzyloxy) isophthalic acid, and bib denotes 1,4-bis(1-imidazolyl)benzene. These CPs were obtained through the reaction of H4L, a flexible carboxylic acid ligand, with Co(NO3)2·6H2O in various solvent mixtures, along with the N-donor co-ligand bib. Complexes 1 and 2 are formed through distinct coordination modes, resulting in their distinct structural features and excellent fluorescent properties. Based on ligand-centered fluorescence emission and the blue shift (CP 1) along with red shift (CP 2) characteristics, both complexes show promise for applications in fields such as blue fluorescence sensing materials and luminescent materials. After successfully synthesizing two CPs, CP 1 was chosen as the carrier for loading temozolomide (TMZ). Subsequently, leveraging the unique advantages of hydrogels, we developed a novel metal gel formulation loaded with TMZ. The inhibitory effect of this formulation on the growth of glioblastoma was evaluated. Our results demonstrate a significant suppression of glioblastoma cell proliferation by this system, providing an effective avenue for glioblastoma treatment. [ABSTRACT FROM AUTHOR]

A series of known Pb(II) metal–organic frameworks (MOFs) have been synthesized from the reaction of PbX2 (X = Cl, NO3 and OAc) with bpy (where bpy = 4,4-bipyridine) using three synthetic methods, namely solvothermal, mechanochemical and liquid-assisted grinding (LAG). The synthesized compounds were characterized with powder X-ray diffraction (PXRD) patterns and matched with calculated X-ray diffraction patterns of reported crystal structures of Pb(II)-based MOFs. Interestingly, most of the compounds can be easily prepared by solvent-free methods either mechanochemically or by LAG methods. Finally, the successfully synthesized MOFs were subjected to photoluminescence study. Solid-state photoluminescence of the selected MOFs has been studied by suspending the MOFs particles in various solvents. Although they are not soluble in the solvents used, the MOFs show a fair amount of solvent-dependent emission quenching that roughly correlate with solvent polarity. With further exploration and investigations, the observed solvatochromic emission behavior of these compounds may find importance in solvent sensing applications. [ABSTRACT FROM AUTHOR]

By using the π-electron-rich organic ligand biphenyl-3,4′,5-tricarboxylic acid (H3BPT), the three-dimensional coordination polymer [Zn4(μ4-H2O)Cl2(BPT)2](DMF)2 was successfully prepared by the reaction of H3BPT and Zn(NO3)2·6H2O in the presence of HCl as the pH modulator under solvothermal conditions. The sensing as well as fluorescence properties of the coordination polymer were studied in detail, showing the selective quenching response that was highly efficient for the Fe3+ ion. In the activity research section, we firstly evaluate the promotion effects of the compound on the efficacy of cisplatin against HO-8910/DDP cancer cells with CCK-8 assay, as well as the IC50 calculation. Next, to explore the relative mechanism, the reverse transcription polymerase chain reaction was performed and the mdr1 and mdr3 genes relative expression was measured. The results obtained through molecular docking and pose scoring software exhibited a possible binding mode of the compound binding to Bcl2, which might provide potential regulation mechanisms for the compound. [ABSTRACT FROM AUTHOR]

The binuclear iron(III) complex of the formula {[Fe(5,5′-dmbpy)2(OH2)]2(µ-O)}(NO3)4 was prepared from the reaction of Fe(NO3)3·9H2O with 5,5′-dimethyl-2,2′-bipyridine. The complex was characterized by FT-IR, UV–Vis, TGA, 1HNMR spectroscopy, elemental analysis, and luminescence measurements. Its structure was investigated using the single-crystal diffraction method. Crystal structure analysis showed that two crystallographically distinct oxygen-bridged Fe(III) cations are each coordinated by two bidentate ligands and one water molecule, resulting in a distorted coordination octahedron formed by four nitrogen atoms and two oxygen atoms. Several types of hydrogen bonds stabilize the crystal packing. In vitro biological screening of the free ligand, the complex and its metal salt against diverse microorganisms was done using the micro-dilution (tube) broth method. The antibacterial effects were also examined in vitro against standard bacterial strains, the Gram-positive Staphylococcus aureus, S. aureus ATCC 25923, and the Gram-negative Escherichia coli; E. coli ATCC 25922. Using these strains, the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and inhibition zones (IZ) were obtained for the complex, its ligand (5,5′-dmbipy) and its metal salt with Fe(NO3)3.9H2O. [ABSTRACT FROM AUTHOR]

Luminescent porous materials have shown various applications such as electronic devices, gas adsorption, energy materials and photocatalysis. Consequently, we designed and prepared a new type borondipyrromethene (BODIPY) based porous organic polymer (POP) by using Sonogashira coupling reaction. This POP-1 exhibits high thermal stability with moderate surface area. In addition, POP-1 is highly emissive in a solid state. Due to enrichment of different kinds of heteroatoms in the skeleton of the porous polymer, POP-1 selectively captures carbon dioxide (CO2) with relative high adsorption selectivity of CO2/N2. [ABSTRACT FROM AUTHOR]

Two lanthanide complexes [La(3,4-DMBA)3]n (1) and [Tb(3,4-DMBA)3(DIPY)2]2 (2) (where 3,4-DMBA = 3,4-dimethylbenzoate, DIPY = 2,2′-bipyridine) have been synthesized and then characterized. The single crystals of complexes 1 and 2 were obtained. Complex 1 adopts a distorted monocapped square antiprismatic molecular geometry, while complex 2 forms a distorted square antiprism. Complex 1 is stitched together by edge sharing through carboxylate ligands to form 1D chains along the b axis. The structure of complex 2 consists of 1D chains along the c axis by two kinds of π···π stacking interactions. Two complexes were characterized by elemental analysis, powder X-ray diffraction and IR spectra. The complex 2 shows typical green luminescence in the solid state. Thermal decomposition mechanisms of complexes were discussed by TG–DTG techniques. In the temperature range from 257.15 to 413.15 K, the molar heat capacities of the complexes were measured by DSC. The smoothed heat capacities and thermodynamic functions of complexes were calculated on the basis of fitted polynomial and thermodynamic equations. [ABSTRACT FROM AUTHOR]

A novel tetranuclear cluster-based polymer {[Cu(L)(NO)(DMF)]·(CHCl)} ( 1, HL = (1Z,2E,N′E)-N′,2-bis(2-hydroxybenzylidene)hydrazinecarbohydrazonic acid) was synthesized through diffusion method. The structure of 1 was characterized by elemental analysis, IR, and single crystal X-ray diffraction. 1 is tetranuclear copper cluster which further constructed 1-D chain through double Cu-O bonds. Luminescent and magnetic properties of 1 have been studied. Hirshfeld surfaces analysis revealed that complex 1 was supported mainly by H···H, O···H and H···Cl intermolecular interactions. [ABSTRACT FROM AUTHOR]

The installation of photovoltaic panels in dusty areas affects their efficiency by the accumulation of dust on glazing surfaces. The cleaning of the dusty panels allows recovering the maximum efficiency. However, it increases the cost of operating and maintenance for photovoltaic installations, a compromise between the reduction in the annual cleaning cost and the improvement solar energy production is obtained with implementation of a dust sensor. By this study, for a first time a dust sensor is developed by using luminescent glazing material with embedded photocells on borders. The dust deposited on sensor is detected from photogenerated current from the photocell integrated on the edges of a luminescent glass plate of 10 × 10 cm area. The optical and electrical characterization revealed that the generated photocurrent from the sensor output increases of 9 µA when dusts accumulation shading is widen by 10%. This new principal for dust sensors could be applied to monitor photovoltaic power plant installations for maximizing energy production from solar renewable source in dusty environment as like Saharan regions. In order to start the cleaning cycle of the photovoltaic modules, the signal generated by the dust sensor is amplified by a Darlington analog circuit which assures the relay control for operating of a direct current pump. [ABSTRACT FROM AUTHOR]

Blue luminescent carbon dots (CDs) were synthesized by the hydrothermal method. Blue-shifts of the maximum emission wavelength from 480 to 443 nm were observed when the concentration of CD solution decreased. The photoluminescence (PL) spectra of CDs at low concentration showed an excitation-independent behaviour, which is very different from the previous reports. Two different emitting mechanisms might work: the intrinsic luminescence from sp-carbon networks can be responsible for the shorter wavelength part of emission (excitation-independent) at low concentration and the high polarity of nanosized clusters led to the excitation-dependent behaviour of the longer wavelength part at high concentration of CD solution. The photophysical property and concentration-dependent behaviour of the CDs offered new insights into CDs from the viewpoints of both experiments and mechanisms, which will promote diverse potential applications of CDs in the near future. [ABSTRACT FROM AUTHOR]

We have successfully demonstrated the structural and luminescent properties from the crushed roots of Saccharum munja plant through controlled calcination and propose it for optical applications. Samples are characterized by energy dispersive x-ray spectroscopy, x-ray diffraction (XRD), Fourier transform infra-red spectroscopy, ultraviolet (UV)-visible spectroscopy and photoluminescence study. Energy dispersive x-ray spectroscopy study confirms that sample has the europium and yttrium elements. XRD study shows that the crystallinity of the samples is improving with the increase of the calcination temperature of the samples. It also reflects that sample contains europium and compound is YSiO-Eu. Photoluminescence study shows that sample exhibits excellent luminescent properties at higher calcination temperature and confirms the europium content in it. Results suggest a cheap, easy to extract and environment-friendly alternative phosphor source to fulfill the demand of europium for various optical applications. [ABSTRACT FROM AUTHOR]

Mononuclear [Zn(FcCOO)(DTBbpy)]ClO4.(HO) ( 1) and dinuclear [Cd(FcCOO)(DTBbpy)]ClO·(HO) ( 2), [Pb(FcCOO)(DTBbpy)(HO)]·ClO ( 3) (FcCOO = ferrocenecarboxylate, DTBbpy = 4,4′-di- tert-butyl-bipyridyl) metal complexes have been synthesized and characterized by single crystal X-ray diffraction. It reveals that the Zn(II), Cd(II) and Pb(II) metal complexes have different coordination geometries [Zn and Pb = distorted octahedral, Cd = distorted pentagonal bipyramidal]. The compound 3 shows the hemidirected mode of coordination in the geometrical system due to the inert pair effect of the lone pair of an electron on Pb(II) metal atom. The molecules are further forms 2D & 3D framework structure via intermolecular hydrogen bonding. All the three compounds exhibit strong fluorescence emission bands in the liquid state at ambient temperature, of which the emission maxima show red-shifted and the solution-state electrochemistry of compounds 1- 3 in CHCN has been investigated. [ABSTRACT FROM AUTHOR]

A new Schiff-base, HL luminescent chemosensor of 1-amino pyrene and 8-hydroxy quinoline-2-carboxaldehyde was synthesized which demonstrates selective fluorimetric detection of Fe in aqueous medium with detection limit of 2.52 × 10 M. The receptor shows selective 'turn-on' response towards Fe over other metal ions. This gradual 'turn-on' fluorescence response for Fe may be induced via CHEF (chelation-enhanced fluorescence) through close proximity of pyrene rings. The stoichiometry and binding property of HL with Fe was examined by emission studies. In presence of Fe, HL also exhibits reversible change in emission pattern with EDTA and thus offers an interesting property of molecular 'INHIBIT' logic gate with Fe and EDTA as chemical inputs. [ABSTRACT FROM AUTHOR]

The reaction of 1,4-bis((2 H-benzo[ d]imidazol-2-yl)methyl) naphthalene and pyridinium 1,1,2,3,3-pentacyanopropenide (PCP) with Zn(II) salts yielded two-dimensional (2D) chain coordination polymer ([Zn (CHN)][CN]). The 2D structure was synthesized via solvothermal synthesis; and structurally characterized by elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. The X-ray single crystal revealed that [Zn(CHN)][CN] is comprised of the [Zn(CHN)] cationic chains and PCP anion [CN]. As a result of the porous nature of the cationic 2D network, the PCP-anions are located at the rhombic windows that balance the charge of 2D structure. The luminescent and thermal properties were also investigated. The fluorescence emission of the coordination polymer was investigated in the presence of hydrocarbon molecules such as (anthracene, toluene, and benzene). [ABSTRACT FROM AUTHOR]

Cadmium selenide quantum dots (CdSe QDs) were synthesized in aqueous phase by the freezing temperature injection technique using different capping agents ( viz. thioglycolic acid, 1-thioglycerol, L-cysteine). Absorption spectra of CdSe QDs exhibited a blue shift as compared to its bulk counterpart, which is an indication of quantum confinement effect. The photoluminescence spectra of CdSe QDs confirmed that the particles are poly-dispersed and possess enhanced luminescent property, depending upon the chemical nature of capping agents. The QDs have been characterized by Fourier-transform infrared spectroscopy, atomic absorption spectroscopy and transmission electron microscopy. Further, antimicrobial activity of as-prepared QDs has also been investigated using the disk diffusion method. [ABSTRACT FROM AUTHOR]

Luminescent polystyrene microspheres were easily fabricated from poly (styrene-co-methacrylic acid) and aqueous RE(III) chloride solution (RE=Eu, Tb) in the presence of 2,2′-bipyridine as second ligand. The negative charges of carboxyl groups on the surface of microspheres coordinated with rare earth ions at first, such as complexes covalently linked to 2,2′-bipyridine, resulting in strong photoluminescence. Various methods, including transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and fluorescence spectrophotometer, were used to characterize the resultant polystyrene composite microspheres. This work highlights the idea that it is facile to synthesis luminescent microspheres by surface-modified method directly. [ABSTRACT FROM AUTHOR]

Hybrid nanosilicas constitute a broad study field. They find application as catalysts, pigments, drug delivery systems, and biomaterials, among others, and it is possible to obtain them via the sol-gel methodology. Lanthanide ions present special properties like light emission. Their incorporation into a silica matrix can enhance their luminescent properties, which enables their application as luminescent markers. This work reports on (i) the preparation of luminescent spherical hybrid silica nanoparticles by the hydrolytic sol-gel methodology, (ii) doping of the resulting matrix with the europium(III) ion or its complex with 1,10-phenanthroline, and (iii) characterization of the final powders by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, and europium(III) ion photoluminescence. The synthesized materials consisted of hybrid, amorphous, polydispersed nonspherical silicas with average size of 180 nm. Photoluminescence confirmed incorporation of the europium(III) ion and its complex into the silica matrix-the ligand-metal charge transfer band emerged in the excitation spectra. The emission spectra presented the bands corresponding to the transition of the excited state D level to F (J = 0, 1, 2, 3 and 4). The main emission occurred in the red region; the lifetime was long. These characteristics indicated that the prepared nanospherical hybrid silicas could act as luminescent markers. [ABSTRACT FROM AUTHOR]

In this paper, the temperature-sensitive luminescent particles with core-shell structure were synthesized by grafting poly (N-isopropylacrylamide) (PNIPAM) to the exterior surface of lanthanide-polyoxometalates (Ln-POM). The Ln-POM/PNIPAM nanoparticles were characterized by FT-IR, UV-vis spectra, thermogravimetric analysis, transmission electron microscopy, scanning electron microscope, dynamic light scattering and luminescence spectra. The results showed that the smart nanoparticles were spherical and had fine core-shell structure. The luminescent spectra showed that the luminescence properties of smart Ln-POM/PNIPAM nanoparticles were changeable in response to temperature stimuli. The luminescent nanoparticles have potential applications in luminescent probes and labels for biomedicine. [ABSTRACT FROM AUTHOR]

Selective recognition of adenosine 5′-triphosphate (ATP) is of great significance owing to its indispensable functions to organisms. Also, it is a challenging task because other nucleosides triphosphate hold the same triphosphate group and structurally planar bases as ATP. It is known that metal-organic frameworks (MOFs) are a new type of sensing material. In this work, highly selective recognition of ATP against other nucleosides triphosphate is successfully achieved with a luminescent MOF of [Zn(BDC)(HO)] (BDC = 1,4-benzenedicarboxylate). [Zn(BDC)(HO)] dispersed in water shows a remarkable redshift of the emission wavelength upon addition of ATP, while cytidine 5′-triphosphate (CTP), uridine 5′-triphosphate (UTP), and guanosine 5′-triphosphate (GTP), as well as some inorganic anions such as PO or PO can't induce such spectral change as ATP. H NMR, P NMR and Raman spectra indicate that both π-π stacking interactions and the coordination of Zn(II) with adenine and the phosphate group are involved in the interaction of [Zn(BDC)(HO)] with ATP. In addition, the experimental results showed that the redshift extent of the emission wavelength of [Zn(BDC)(HO)] has the linear relationship with the concentration of ATP in the range of 0.3-1.8 mmol/L. Based on this, the detection of ATP content in the sample of ATP injection was made with satisfactory results. This system pioneers the application of MOFs in the recognition of nucleotides, and testifies that the participation of base in the recognition process can improve the selectivity against the other nucleotides. [ABSTRACT FROM AUTHOR]

Two lanthanide complexes were encapsulated into silica matrix (aminopropyltriethoxysilane, APTS) via a mild sol-gel technique, resulting in two luminescent xerogels. Subsequently two novel luminescent polymeric hydrogels were successfully fabricated by incorporating these two lanthanide xerogels into the poly(acrylamide) matrix. The europium-ion-containing hydrogel can be sensitized by visible light (408 nm). More interestingly, the emissions of the Ln(III)-containing hydrogel can be switched 'on-and-off' reversibly by a change of the pH value. The resulting color change can easily be observed by naked eyes. These luminescent hydrogels exhibited high stabilities in comparison with xerogels in aqueous media. [ABSTRACT FROM AUTHOR]

In this study, the co-precipitation method has been developed for the synthesized FeO nanoparticles which are encapsulated with SiO/C/TiO via the facile and further functionalized by the deposition of YO:Eu phosphors. Transmission electron microscopy images revealed that the nanocomposites show a spherical morphology with size distribution around 100-250 nm, and the thickness of the coupling agents was 3-4 nm. The X-ray diffraction patterns showed that a cubic spinel structure of FeO core and a tetragonal phase of YO:Eu shell was obtained. The multifunctional nanocomposites showed ferrimagnetic behavior, the negligible coercivity Hc and remanence Mr at room temperature and showed unique europium fluorescence properties with strong red emission peak from the electric-dipole transition D → F of Eu ions at 611 nm. Therefore, the multifunctional nanocomposites are expected to develop many potential applications in biomedical fields and magnetic photocatalyst. [ABSTRACT FROM AUTHOR]

In this paper, a novel luminescent hydrogel was successfully prepared by incorporating Tb-HSA (HSA = Human Serum Albumin) complex into cellulose host. The green luminescence intensities of Tb(III) exhibited on- off changes in terms of pH variation. At the same time, europium activated phosphor (GdVO:Eu) was immobilized into the cellulose hydrogels through two approaches. The photophysical properties of luminescent gels with the temperature variation were investigated by fluorescence. The new group of soft materials will display task-specific usages in sensing fields. [ABSTRACT FROM AUTHOR]

A new class of terbium hybrids within the silica framework has been synthesized using modified silylated derivatives of aromatic acids. These organic-inorganic materials have very homogenous spherical shapes (diameter around 60 nm) and exhibit characteristic green emissions in DMSO/HO (1:1). Significantly, they present highly selective and rapid (1-2 s) emission quenching effects with respect to tryptophan compared to other essential amino acids for human. In addition, enhanced thermal stabilities can be achieved in these hybrid materials. [ABSTRACT FROM AUTHOR]

Lu3+/Yb3+ and Lu3+/Er3+ co-doped Sb2Se3 nanomaterials were synthesized by co-reduction method in hydrothermal condition. Powder X-ray diffraction patterns indicate that the LnxLnx'Sb2-2xSe3 Ln: Lu3+/Yb3+ and Lu3+/Er3+ crystals (x = 0.00 - 0.04) are isostructural with Sb2Se3. The cell parameters were increased for compounds upon increasing the dopant content (x). Scanning electron microscopy and transmission electron microscopy images show that co-doping of Lu3+/Yb3+ ions in the lattice of Sb2Se3 produces nanorods, while that in Lu3+/Er3+ produces nanoparticles, respectively. The electrical conductivity of co-doped Sb2Se3 is higher than that of the pure Sb2Se3 and increases with temperature. By increasing the concentration of Ln3+ions, the absorption spectrum of Sb2Se3 shows red shifts and some intensity changes. In addition to the characteristic red emission peaks of Sb2Se3, emission spectra of co-doped materials show other emission bands originating from f-f transitions of the Yb3+ ions. [ABSTRACT FROM AUTHOR]

Coordinating properties of uridine 5′-monophosphate (UMP) towards trivalent La, Pr, Nd, Sm, Eu and Gd ions in presence of cationic and anionic micelles have been investigated by potentiometric pH-titration and spectroscopic methods. Stability constants of the 2:1 complexes have been determined and the change in free energy, enthalpy and entropy associated with the complexation are also calculated. Nd(III) complexes isolated from aqueous and aqueous-micellar media do not show any significant structural difference. Formation of Ln(III) complexes in all cases completes below pH 7.5 showing that UMP best interacts with Ln ions at the physiological pH range 7.3-7.5. The nucleobase is not involved in the complexation and the metal ion coordination of UMP is through the phosphate moiety only. Coordinating tendency of UMP with lanthanides, Nd(III) ion in particular, at different pH is also discussed. Luminescent properties of Eu(III) complex and its decay lifetime are also presented. This information may prove helpful regarding the use of lanthanides as biological probes for calcium/magnesium ions. [ABSTRACT FROM AUTHOR]

Cellulose hydrogels are biodegradable materials that can be applied as accommodating hosts for various species. Here we report the preparation of novel thin films based on luminescent cellulose hydrogels. The spectroscopic behavior of these soft materials and their sensing effects are investigated. Interestingly, we found that these films only give selective signal changes in the presence of Cu in water in comparison with Na, K, Ag, Mn, Co, Ca, Cd, Hg, Pd, Mg, Ni, Fe, and Fe. High visible-light transmittance and good flexibility for these films can be observed. More importantly, the thermal stability of rare-earth complexes could be significantly enhanced in aqueous solution as result of the protection by hydrogel matrix. [ABSTRACT FROM AUTHOR]

A novel terbium 2-hydroxymethyl-benzoimidazole-6-carboxylic acid complex has been designed and unique emission changes to fluoride anions in comparison with HSO, AcO, Cl, Br, and I were observed. Then, the complex was encapsulated into an inorganic matrix. The novel hybrid material, with strong green emission was successfully synthesized as an anions receptor in water. More importantly, this hybrid material not only gave luminescence response to F, but also to HSO. Spectroscopic studies demonstrated that the recognition process for fluoride ions can be mainly ascribed to its hydrogen bonding interactions with hydrogen bond donor units (NH and OH). In case of hydrogen sulfate, the sensing effects can be probably attributed to its acidity instead of hydrogen bonding interactions. [ABSTRACT FROM AUTHOR]

A novel terbium 2-methyl-benzoimidazole-5-carboxylic acid complex was prepared and incorporated into silica matrix (tetraethoxysilane) using a mild sol-gel technique. We then successfully fabricated a terbium luminescent xerogel, which maintained intense green emission even in pure water. The emission was rapidly (~1 s) quenched by ClO (detection limit 10 M) but not NO, CHCOO, F, Cl, Br, I, CO, and OH. The selectivity appears to be due to the high vibrational energy of ClO as well as its strong oxidation capability. [ABSTRACT FROM AUTHOR]

Terbium silica hybrid material with imidazole ring that can be emissive in water has been designed and showed host-guest interactions with specific ions (cations and anions). In detail, we studied the sensing abilities of this material by addition of the anions HPO, HSO, F, Cl, Br and I to water suspension of the derived powders. Only dihydrogen phosphate resulted in the quenching of the lanthanide luminescence (detection limit 10 M). The same way was found in Cu ions which also gave rise to luminescence quenching (detection limit 10 M). More interestingly, luminescent sol-gel films were successfully prepared by the same materials and exhibited emission responses to HPO and Cu. For the sake of improving its mechanical property, the robust and flexible inorganic/PMMA hybrid material with sensing capability was also developed for future use. [ABSTRACT FROM AUTHOR]

5-Amino-1,10-phenanthroline (Aphen)-functionalized monodisperse luminescent iron oxide nanoparticles were prepared using a one-pot synthetic procedure via a thermal decomposition process. Amine functional groups of Aphen as a luminescent source afforded highly stabilized magnetic nanoparticles in polar solvents, resulting in a well-dispersed solution. Transmission electron microscopy (TEM) showed that the size distribution and particle morphology of the iron oxide nanoparticles was improved after anchoring with Aphen. The functionalization of iron oxide nanoparticles with Aphen was examined by UV-vis absorbance and photoluminescence spectroscopy. The Aphen-anchored iron oxide nanoparticles exhibited excellent luminescence properties with an estimated luminescence quantum yield of 0.00354 at room temperature. In addition, these Aphen-anchored iron oxide nanoparticles were characterized by vibrating sample magnetometry (VSM) to reveal the magnetic properties. The Aphenanchored iron oxide nanoparticles exhibited both luminescence and magnetic properties. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

This article reports the synthesis and characterization of a quantum-confined luminescent dot with size 2-3 nm using well-defined m-octa(bromophenyl) silsesquioxane ( m-OBPS) as core. The highly regioselective bromination of octaphenylsilsesquioxane (OPS), which is an electron-deficient nanometer-sized molecule, has been synthesized using combined catalyst of iodine and zinc chloride at room temperature in dichloromethane solvent. Based on m-OBPS, a hybrid luminescent dot with well-defined structure was synthesized. UV absorption and PL spectra of this light-emitting dot remain same in dilute solution, condensed state, and solid solution. Furthermore, time-resolved PL study indicates that the exciton decay time of the light-emitting dot remains similar regardless in dilute solution, condensed state, or blended with other polymers, suggesting that the charge carriers are well confined within the individual light-emitting dot due to the unique star-like structure and shielding alkyl chain layer. The light-emitting nano-particles can be considered as isolated chromophores as both inter- and intra- molecular aggregation are prohibited. [ABSTRACT FROM AUTHOR]

Luminescent polynorbornene (PNB)/quantum dot (CdSe@ZnS; QD) composite nanorods and nanotubes were successfully prepared using anodic aluminum oxide (AAO) membranes of various pore sizes as templates. To protect QDs with high quantum yield from quenching during the phosphoric acid treatment used to remove the AAO templates, chemically stable and optically clear norbornene-maleic anhydride copolymers (P(NB- r-MA)) were employed as a capping agent for QDs. The amine-terminated QDs reacted with maleic anhydride moieties in P(NB- r-MA) to form PNB-grafted QDs. The chemical- and photo-stability of QDs encapsulated with PNB copolymers were investigated by photoluminescence (PL) spectroscopy. By varying the pore size of the AAO templates from 40 to 380 nm, PNB/QD composite nanorods or nanotubes were obtained with a good dispersion of QDs in the PNB matrix. [ABSTRACT FROM AUTHOR]

The high sensitivity of silole- and silafluorene-containing polymers for detecting organic nitro, nitrate, and nitramine explosives cannot be solely attributed to favorable analyte–polymer hydrophobic interactions and amplified fluorescence quenching due to delocalization along the polymer chain. The Lewis acidity of silicon in conjugated poly(silafluorene-vinylene)s is shown to be important. This was established by examining the 29Si NMR chemical shifts (Δ) for the model trimer fragment of the polymer CH3–silafluorene–( trans-C2H2)–silafluorene–( trans-C2H2)–silafluorene–CH3. The peripheral and central silicon resonances are up-field from a TMS reference at −9.50 and −18.9 ppm, respectively. Both resonances shift down-field in the presence of donor analytes and the observed shifts (0 to 1 ppm) correlate with the basicity of a variety of added Lewis bases, including TNT. The most basic analyte studied was acetonitrile and an association constant ( Ka) of 0.12 M−1 was calculated its binding to the peripheral silicon centers using the Scatchard method. Spin-lattice relaxation times ( T1) of 5.86(3) and 4.83(4) s were measured for the methyl protons of acetonitrile in benzene- d6 at 20 °C in the absence and presence of the silafluorene trimer, respectively. The significant change in T1 values further supports a binding event between acetonitrile and the silafluorene trimer. These studies as well as significant changes and shifts observed in the characteristic UV–Vis absorption of the silafluorene group support an important role for the Lewis acid character of Si in polymer sensors that incorporate strained silacycles. The nitro groups of high explosives may act as weak Lewis-base donors to silacycles. This provides a donor–acceptor interaction that may be crucial for orienting the explosive analyte in the polymer film to provide an efficient pathway for inner-sphere electron transfer during the electron-transfer quenching process. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The luminescent heteroleptic Cd(II) complex bis (μ-1,2-benzenedithiolato)-1 kS, 1:2 k2 S′ 2 kS, 1:2 k2 S′-bis[(1,10-phenanthroline- k2 N1, N1′)cadmium], [Cd2(C6H4S2)2(C12H8N2)2], containing benzenedithiolate (bdt) and 1,10-phenanthroline (phen) has been synthesized and found to have the dinuclear formulation [Cd(bdt)(phen)]2. The complex crystallizes in the space group P21/ n with a = 10.3400(4), b = 11.5110(4), c = 13.6230(5) Å, and β = 106.828(2)°. The dinuclear complex has crystallographically imposed centrosymmetry with one S atom of the bdt ligand bridging the Cd atoms in an asymmetric fashion (Cd–S = 2.5743(5) and 2.6817(5) Å) while the second S atom is bound in a terminal mode (Cd–S = 2.4955(5) Å). The mean interplanar spacing between the phen ligand and the phenyl ring of the bdt ligand is 3.291 Å while that between the phen ligands of adjacent molecules is 3.363 Å, suggesting the presence of both intra- and intermolecular π-stacking. The complex is emissive in the solid state at room temperature (λem = 569 nm) with a luminecsent lifetime of 369 ns. The unstructured emission is believed to be a ligand-to-ligand π–π* charge transfer transition. [ABSTRACT FROM AUTHOR]