One-pot facile synthesis of highly photoluminescent graphene quantum dots with oxygen-rich groups

To achieve a new type of carbon-based quantum dots with unique photoluminescence PL a simple approach for fabrication of graphene quantum dots GQDs with oxygen-rich groups was developed via the hydrothermal reaction by using graphene oxides GOs as a precursor. Transmission electron microscope TEM and atomic force microscope AFM characterizations confirmed that the sizes and heights of GQDs were 5.02±0.92 nm and 0.6 nm respectively.A strong PL emission exhibited unique excitation wavelength dependent features.Also the carbene-like free zigzag edge sites were proposed to be the origin of the strong PL emission.The GQDs were demonstrated to be a superior probe for Fe3＋ detection in aqueous solution with a high sensitivity and feasibility due to the special coordinate interaction between Fe3＋and the phenolic hydroxyl group at GQDs.

Synthesis of Long Afterglow Photoluminescent Materials Sr_2MgSi_2O_7∶Eu^(2+), Dy^(3+) by Sol-Gel Method

Long afterglow photoluminescent materials Sr2MgSi2O7 doped with Eu2+, Dy3+ were prepared by sol-gel method. The synthesized samples were characterized by X-ray diffraction. The excitation spectrum, emission spectrum and long decay curve were measured and analyzed. XRD pattern indicates that phosphor is with Sr2MgSi2O7 crystal structure. The wide range of excitation wavelength indicates that luminescent material can be excited by light from ultraviolet ray to visible light. The main peak of emission spectrum is located at 466 nm. Sample excited by visible light can emit bright blue light, and the afterglow time lasts more than 8 h.

Synthesis,Structure and Photoluminescent Property of a Cd-organic Complex [Cd(L)_2(pbda)]_n

A new complex,[Cd（L）2（pbda）]n（1,L = 3-（2-pyridyl）-4-（p-methoxyphenyl）-5-（2-thienyl）-1,2,4-triazole,H2pbda = 1,4-benzenedicarboxylic acid）,has been hydrothermally prepared and characterized by single-crystal X-ray diffraction,IR spectroscopy,elemental analysis and PXRD.The complex crystallizes in monoclinic,space group P21/c with a = 8.2929（9）,b = 21.668（2）,c = 10.9940（11） ,β = 90.242（2）o,V = 1975.5（4） 3,Z = 2,C44H32N8O6S2Cd,Mr = 945.30,Dc = 1.589 g/cm3,μ = 0.721 mm-1,S = 1.097,F（000） = 960,the final R = 0.0590 and wR = 0.1045 for 3846 observed reflections（I 2σ（I））.In the title complex,the rigid bridging pbda2-ligands utilize oxygen atoms of carboxylate groups to coordinate with Cd（II） atoms to form one-dimensional chains which are further interlinked into a three-dimension framework via the intermolecular weak interactions.Photoluminescence study revealed that complex 1 exhibits strong fluorescent emission band in the solid state at room temperature.

Synthesis, Structure and Photoluminescent Property of a New 3D Cd(Ⅱ) Coordination Polymer with Terphenyl-2,2',4,4'-tetracarboxylic Acid and 1,10-Phenanthroline

A new 3D Cd（II） coordination polymer, [Cd2L（phen）（HzO）]n （1, HaL = terphenyl- 2,2＇,4,4＇-tetracarboxylic acid, phen = 1,10-phenanthroline）, has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, TGA and IR spectroscopy. Complex 1 crystallizes in the monoclinic system, space group P21/c with a = 8.196（2）, b = 18.348（5）, c = 19.036（5） A, β = 97.741（5）°, V= 2836.6（14） A3, Z = 4, Dc = 1.933 Mg.m-3, p = 1.565 mm1, F（000） = 1624, the final R = 0.0356 and wR = 0.0612 for 4990 observed reflections with 1 〉 2a（I）. Complex 1 has a 1D chain containing Cd4 structural units, which are linked by 2- and 2＇-carboxyl groups of L4- to result in a 3D framework. Additionally, the photoluminescent property of 1 was also studied in the solid state at room temperature.

Fluorescence Quenching of a Novel Eu(Ⅲ) Coordination Compound for the Detection of Trace Amounts of Water： Synthesis, Structure and Photoluminescent Property

A novel luminescent coordination compound Eu（TTA）3（DEDAF）（1, TTA = 1,1,1-trifluoro-3-（2-thenoyl）acetone, DEDAF = 9,9-diethyl-4,5-diazafluoren） has been synthesized and fully characterized by infrared spectrum, elemental analysis, UV-vis spectrum, etc. X-ray single-crystal diffraction analysis reveals that compound 1 shows a mononuclear structure with the europium atom in coordinating to one DAF and three TTA ligands. The mononuclear structure units are assembled into a 3-D polymer by hydrogen bonds and π-π interactions. Photoluminescent property of 1 was investigated in detail at room temperature. Complex 1 emits strong red luminescence. However, it could be quenched even by small amount of water. The fluorescence intensity at 614 nm decreases linearly with the water content increasing（vol% in acetonitrile） in the range of 0.025~0.2% under 278 nm excitation. Thermogravimetric analysis has also been studied, which demonstrates good thermal stability of 1.

Synthesis,structure and photoluminescent property of a novel potassic compound

A novel 3D coordination compound of K（H2TDA）（H20） （1） （H3TDA = 1H-1,2,3-triazole-4,5-dicarboxylic acid） has been prepared and characterized by IR spectroscopy, elemental analysis, ICP and single-crystal X-ray diffraction. Compound 1 displays strong fluorescent emission at room temperature.

Syntheses, Structures, and Photoluminescent Properties of Two 2D Coordination Polymers Based on 1,3-Di(2,4-dicarboxyphenyl) Benzene and 1,3-Di(4-pyridyl)propane

Two new 2D coordination polymers, [Zn（HL）（Hbpp）]n （1） mid [Cd（HL）（Hbpp）（H2O）]n （2） （H4L = 1,3-di（2,4-dicarboxyphenyl） benzene, bpp = 1,3-di（4-pyridyl）propane）, have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, TGA and 1R spectroscopy. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 13.1031（6）, b = 14.7315（7）, c = 15.0041（7） A, β = 91.202（1）°, V= 2895.6（2） A3, Dc = 1.532 g/cm3, Mr = 667.97, F（000） = 1376.0, μ = 0.909 mm-1, Z = 4, the final R = 0.0481 and wR = 0.1304 for 7027 observed reflections with 1 〉 2a（/）. Complex 2 also belongs to the monoclinic space group P2Jn, with a = 13.6326（4）, b = 14.6432（4）, c = 14.9395（5）A, β = 93.132（1）°, V= 2977.84（16） A3, D, = 1.613 g/cm3, ）14,. = 1445.98, F（000） = 733.0,/1 = 0.794 mm-1, Z = 2, the final R = 0.0283 and wR = 0.0784 for 7230 observed reflections with I 〉 2σ（I）. Both complexes 1 and 2 form 2D net structures, which are further linked to form 3D supramolecular net structures via intermolecular hydrogen bonds and aromatic π-π stacking interactions.

Synthesis, Crystal Structure and Photoluminescent Property of a Novel Disilver Complex with Pyrazinyl Oxime Ligand

A novel binuclear Ag（I） complex [Ag2（C6H6NaO）2（C6H7N3O）2]·2CH3CN （1） was synthesized by the evaporation reaction of silver nitrate and （E）-1-（pyrazin-2-yl）ethanone oxime （HL）. The complex was characterized by elemental analysis, IR spectrum and X-ray single-crystal diffraction analysis. It crystallizes in the monoclinic space group C2/c with a = 22.7089（3）, b = 11.5443（7）, c = 16.1468（4）/A, β = 127.7150（10）°, V= 3348.6（2） A^3, Dc = 1.675 g/cm^3, Mr = 844.42, Z = 4, F（000） = 1696.0,μ = 1.226 mm^-1, the final R =0.0250 and wR = 0.070. The coordination around the silver（I） atom is a distorted trigonal-bipyramidal geometry involving one protonated pyrazinyl oxime ligand （HL）, one deprotonated oxime ligand （L^-） and one CH3CN solvate molecule in the asymmetric unit of complex 1.

Structural Diversity and Photoluminescent Properties of Two Mn(Ⅱ) Sulfoterephthalate Complexes from Multi-pyridine N-containing Ligands

Solvothermal reaction of manganese（II） salt with monosodium 2-sulfoterephthalate（2-NaH2stp） and two multi-pyridine N-containing auxiliary ligands results in the formation of two new complexes formulated with [Mn2（Hstp）2（bpp）2（H2O）4]（1） and [Mn3（stp）2（tpy）3（H2O）]（H2O）5（2）（bpp = benz-2,3-pyrimidine-[2,3-f]-1,10-phenanthroline, tpy = 2,2＇：6＇,2＇＇-terpyridine）. X-ray diffraction structural analyses of two complexes reveal their structural diversity（0D and 1D） due to the difference of auxiliary ligands. 1 is a discrete structure, in which the Mn（Ⅱ） ion is hexa-coordinated with one stp, one bpp ligand and two water molecules. Complex 2 is a one-dimensional（1D） chain-like structure with three crystallographically independent Mn（Ⅱ） ions. The photoluminescent properties could be assigned to the π-π＊ transition of 2-sulfoterephthalate ligands.

Synthesis,Crystal Structure and Photoluminescent Property of a New Zn(Ⅱ)Complex Based on 3,4-Bis(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazole

The coordination polymer [Zn1.5（2,2？,4？？-tpt）（tpa）2]n （2,2？,4？？-tpt = 3,4-bis（2- pyridyl）-5-（4-pyridyl）-1,2,4-triazole, H2tpa = terephthalic acid） has been obtained by solution evaporation method and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. The title compound crystallizes in the triclinic system, space group P , with a = 10.331（3）, b = 10.596（1）, c = 14.966（3） ？, β = 99.029（0）o, V = 1448.86（6） ？3, Z = 2, Dc = 1.668 g/cm3, μ = 1.320 mm-1, F（000） = 740, R = 0.0359 and wR = 0.0841 with I 〉 2σ（I））. In this polymer, the asymmetric unit contains two crystallographically independent Zn（II） ions in different coordination environments. Zn（1） ion is five-coordinated, forming a distorted tetragonal pyramidal geometry, while the Zn（2） ion is six-coordinated to get a distorted octahedral geometry. Each Zn（II） ion is linked by 2,2？,4？？-tpt and H2tpa ligands, forming an infinite 2D structure. The existence of O（8）–H（8）？？？O（2） hydrogen bonding interactions leads the 2D chains to generate a 3D structure. In addition, 1 shows strong photoluminescent emissions in the solid state at room temperature, so it can be used as potential optical materials.

Photoluminescent properties of Ca_2Gd_8(SiO_4)_6O_2: Dy^(3+) phosphor films prepared by sol-gel process

There are growing interests on phosphor thin films owing to their potential application in high-resolution devices such as cathode ray tubes and flat panel display devices. The solution-based sol-gel method is one of the most important techniques for the synthesis of various functional coating films. Compounds with the apatite structure are very suitable host lattices for various luminescent ions. Ca2RE8（SiO4）6O2 （ RE=Y, Gd, La ） is a kind of ternary rare-earth-metal silicate with oxyapatite structure, which has been used as host material for the luminescence of various rare earth and mercury-like ions. In this article, Ca2Gd8（SiO4）6O2：Dy^3＋phosphor films were dip-coated on quartz glass substrates through the sol-gel process. X-ray diffraction （XRD）, atomic force microscopy （AFM）, photoluminescence （PL） spectra, as well as lifetimes were used to characterize the resulting films. AFM study revealed that the phosphor films consisted of homogeneous particles. The Dy^3＋ showed its characteristic emission in crystalline phosphor films, i.e., ^4F9/2-^6H15/2 and ^4F9/2-^6H13/2.

Synthesis,Structure and Photoluminescent Property of a New 2D Zn(Ⅱ) Coordination Polymer Constructed by Biphenyl-3,3',5,5'-tetracarboxylate

A new 2D Zn（II） coordination polymer,[Zn（btc）0.5（phen）]n（1,H4btc = biphenyl-3,3＇,5,5＇-tetracarboxylic acid,phen = 1,10-phenanthroline）,has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis,elemental analysis and IR spectro-scopy.Complex 1 crystallizes in the triclinic system,space group P1 with a = 7.6878（6）,b = 10.3453（8）,c = 10.9589（9） ,α = 113.3540（10）,β = 90.5460（10）,γ = 90.4280（10）°,V = 800.09（11） 3,Z = 2,Dc = 1.696 Mg.m-3,μ = 1.566 mm-1,F（000） = 414,the final R = 0.0359 and wR = 0.0778 for 2441 observed reflections with I 2σ（I）.Complex 1 has a 2D layered network containing dinuclear Zn（II） structural units.The 2D layers are further linked by the phen molecules through π-π stacking interactions into a 3D supramolecular framework.The photoluminescent property of 1 was also studied in the solid state at room temperature.

Two Zn(Ⅱ)/Cd(Ⅱ)Metal-organic Frameworks Constructed from 1,3,5-Benzenetricarboxylic Acid and 1,4-Bis(1-imidazolyl)benzene:Syntheses,Structures and Photoluminescent Properties

Two new d;metal-based metal-organic frameworks,{[Zn;（btc）;（bib）;（H;O）;]·2H;O};（1）and{[Cd;（btc）;（bib）;（H;O）;]·6H;O};（2）(btc=1,3,5-benzenetricarboxylate anion,bib=1,4-bis（1-imidazolyl）benzene)have been prepared under hydrothermal conditions by the reactions of d;metal oxides of ZnO and CdO with the aromatic polycarboxylic H;btc and the N-heterocyclic bib.The two products were characterized by single-crystal X-ray diffraction analysis,elemental analysis,thermogravimetric analysis（TGA）,and IR spectroscopy.Complexes 1 and 2 crystallize in monoclinic C2/c and triclinic P 1 space groups,respectively.1 shows a 3D framework,and the potential large voids of the 3D network lead to a 3-fold interpenetrating architecture.2 displays a 2D framework,and the adjacent 2D layers expand into a 3D supramulecular network via rich hydrogen bonds.Moreover,the luminescent properties of the two complexes are investigated in solid state.

Structures and Photoluminescent Properties of Two Complexes Based on Dipyrido[3,2-a：2？,3？-c]phenazine and 2,4＇-Biphenyldicarboxylic Acid

ABSTRAC Two new complexes [Cd（2,4＇-bpdc）（DPPZ）]2n·n H2O（1） and [Zn（2,4＇-Hbpdc）2（DPPZ）]· H2O（DPPZ = dipyrido[3,2-a：2＇,3＇-c]phenazine, 2,4＇-H2bpdc = 2,4＇-biphenyldicarboxylic acid） have been hydrothermally synthesized. The structure of complex 1 was determined by single-crystal X-ray diffraction diffraction and further characterized by elemental analysis, IR spectrum, powder X-ray diffraction（XRD） and single-crystal X-ray diffraction. Complex 1 has 1D chains, which are further connected by π-π stacking interactions of neighbouring chains, generating a steady 3D supramolecular structure. Complex 2 shows the isolated mononuclear units, which are further extended to a 2D supramolecular layered structure through π-π stacking interactions and hydrogen bonds. Furthermore, complexes 1 and 2 exhibit green photoluminescent properties at room temperature.

Novel four-hydrogen-bond assembled oligoamide dimer with pyrazoline moieties and its photoluminescent properties

In this paper, the synthesis and characterization of a triarylpyrazoline modified four-H-bonded molecular duplex are described. Its molecular structure has been confirmed by ^1H NMR and ESI-MS. The duplex emits strong pure blue light peaking at 448 and 452 nm under UV photoexcitation in solution and solid state, respectively, and its relative photoluminescence quantum efficiency in solution is determined as 0.778 using quinine sulfate as reference. In concentration of 〉40 mmol/L, the duplex can gelate DMSO, and the organogel formed shows good pure blue photoluminescence too. This novel duplex, for its well-defined structure and efficient photoluminescence property, is a prospective candidate for pure blue electroluminescent emitter.

Organic Carboxylate Ligand Tuned Topological Variations in Three Zn(Ⅱ)Coordination Polymers:Syntheses,Crystal Structures and Photoluminescent Properties

Three new Zn（Ⅱ） coordination polymers, namely [Zn2（suc）2（bib）2]n·nH2 O（1）, [Zn（glu）（bib）]n·4 nH2 O（2）, and [Zn（adp）（bib）]n（3）（bib = 1,4-bis（N-imidazolyl）butane, H2 suc = succinic acid, H2 glu = glutaric acid, H2 adp = adipic acid） have been hydrothermally synthesized and structurally characterized. Compound 1 features a 3D framework with 4-connected hxg-d topological network, compound 2 is comprised of 2D 44-sql-type sheets, and the adjacent 2D sheets are further packed into a 3D supramolecular architecture via intermolecular hydrogenbonding interactions, and compound 3 is a 3D framework with 4-fold interpenetrating dia topology. The structural comparison of these three compounds demonstrates that the topological variations can be well controlled by employing aliphatic dicarboxylate ligands with different spacer lengths. Moreover, the thermal stabilities and photoluminescent properties of them were also studied in detail.

A Photoluminescent Bimetallic Zinc-pyridinedicarboxylate:Diverse Supramolecular Motifs from Distinct Hydrogen Bonds

A cyclic bimetallic metal-organic complex [Zn（C）（H-fmpdc）（H2O）]2·2H2O （fmpdc = 4-（furan-2-yl）-2,6-dimethylpyridine-3,5-dicarboxylate） was synthesized and characterized by single-crystal X-ray analysis. The compound crystallizes in orthorhombic, space group Pbca with a = 12.905（2）, b = 14.774（3）, c = 16.833（3）A, V= 3029.4（10）A^3 Z = 4, Dc = 1.644 g/cm^3, F（000） = 1616, R = 0.0347 and wR = 0.0956 （I 〉 2σ（I））. There exist diverse supramolecular motifs （1-D, 2-D and 3-D） from distinct hydrogen bonds in the crystal structure of the title compound. The furanyl group has obvious contribution to the red-shift in the photoluminescent spectrum of the H2fmpdc ligand. The title compound 1 shows strong photoluminescence with emission maximum at 2 = 402 nm （λex.max = 367 nm）.

Comparative Study on Photoluminescent Properties of CaGdAlO_4∶Eu^(3+) Phosphors Synthesized with Three Methods

CaGdAlO4 ： Eu^3＋ powder phosphors were prepared using citrate sol-gel （CSG）, haft-dry and half-wet （HDW） and solid state （SS） methods, respectively. X-ray diffraction results confirm the formation of CaGdAlO4：Eu^3＋ at 900 % （CSG）, 1200℃ （HDW） and 1400℃ （SS）, respectively. Field emission scan electron microscopy （FE-SEM） images show that the CaGdAlO4：Eu^3＋ powder prepared by the CSG and HDW method has an elliptical shape and that prepared under the SS method has a flaky shape. Upon excitation with 280 nm UV light, all the CaGdAlO4： Eu^3＋ powders show bright red emission on account of the 4f-4f transitions of the Eu^3＋ ions. Moreover, the size of the phosphor particles and the emission intensity increase with the increase of calcined temperature. At the same calcination temperature of 1400 ℃, the ^5D0→^7F2 emission intensity of the sample prepared by HDW method is the highest. Stark components of the ^5D0→^7FJ emission transitions, both at room temperature and at a low temperature, reveal that the Eu^3＋ ions occupy only one site with non-centrosymmetry in the crystals.

Polyol-Mediated Synthesis and Photoluminescent Properties of LaPO_4∶Eu ^( 3+) Nanoparticles

Eu^3＋-doped LaPO4 nanoparticles were prepared by polyol method and characterized by X-ray diffraction （XRD）, field emission scanning electron microscopy （FE-SEM）, thermogravimetry-differential thermal analysis （TG-DTA）, Uv-vis diffuse reflectance spectra （DRS）, photoluminescence （PL） spectra and lifetime measurement. The results of XRD indicate that the as-prepared nanoparticles are crystallized well at 160 ℃ and assigned to the monoclinic monazite-structure of LaPO4 phase. The obtained LaPO4：Eu^3＋ nanoparticles are spherical with narrow size distribution and the average size of 25 nm.

Synthesis, Crystal Structure and Photoluminescent Property of a Novel Silver(I) Compound {[Ag(bpp)]_2(Hphth)(NO_3)·(H_2O)_2}_n

Self-assembly of Ag（I） nitrate, 1,3-bis（4-pyridyl）propane （bpp） and phthalic acid monopotassium salt （KHphth） in CH3OH-H2O solution produced the title complex, {[Ag（bpp）]2（Hphth）（NO3）-（H2O）2}n, which was characterized by single-crystal X-ray diffraction, elemental analysis, IR spectrum, and photoluminescent spectrum. Single-crystal X-ray analysis revealed that the complex crystallizes in a monoclinic system, space group P2dc, with a = 15.4174（5）, b = 8.6398（2）, c = 25.2466（8）A, β = 91.072（1）^o, V = 3362.34（17）A3, Z = 4, C34H37N5O9Ag2, Mr = 875.43, De = 1.729 g/cm^3, u = 1.228 mm^-1, F（000） = 1768, the final R = 0.0749 and wR = 0.1580 for 5754 reflections with I 〉 2o（I）. The Ag atom is coordinated by two N atoms from two bpp molecules in an approximately linear geometry. The Ag（I） ions are linked by the bpp molecules to form one-dimensional zigzag chains propagating along the c axis. The Hphth- and nitrate counter-ions are bridged by solvent water molecules through hydrogen bonds to generate a one-dimensional chain extending along the b axis. Electrostatic interactions between cations and anions, extensive hydrogen bonds and re-re interactions are responsible for the three-dimensional supramolecular structure. In the solid state, the compound exhibits blue photoluminescence with the maximum at 436 nm upon excitation at 344 nm.