Solid-state Fluorescence Properties Research Articles

固相法制备Ce,Cr∶YAG透明陶瓷及其荧光性能研究

固相法制备Ce,Cr∶YAG透明陶瓷及其荧光性能研究

Anion-dependent construction of a series of fluorescent coordination polymers based on 1D zinc∩4,4′-bis(imidazol-1-yl)-biphenyl substrates

In this work, the rod-like ligand 4,4′-bis(imidazol-1-yl)-biphenyl (bibp) has been utilized as a building block to carry out counterion effects on the structural diversities of coordination polymers. A series of new zinc complexes, [Zn(trans-bibp)Cl2]∞ (1), [Zn(trans-bibp)Br2]∞ (2), {[Zn(cis-bibp)(Ac)2]·(H2O)}∞ (3), [Zn(trans-bibp)SO4]∞ (4), {[Zn2(cis-bibp)2(ipa)2]·(H2O)}∞ (5, H2ipa=isophthalic acid) and {[Zn(trans-bibp)(cis-bibp)]·(ClO4)2(CHCl3)2(CH3OH)}∞ (6) have been successfully synthesized. Complexes 1 and 2 are iso-structural, which show a 1D W-type chain [Zn(trans-bibp)]∞. Complex 3 exhibits a 2D wave-like layer formed by the hydrogen bond among the 1D linear chain [Zn(cis-bibp)]∞. Complex 4 displays a 2D fish-bone lattice, which is generated from connecting the 1D W-type chain [Zn(trans-bibp)]∞ by the μ2-SO42-. Complex 5 presents an interesting 2D–3D 65·8 architecture, including two 1D chains [Zn(ipa)]∞ and [Zn(cis-bibp)]∞. Complex 6 demonstrates a 2D wave-like layer [Zn(trans-bibp)(cis-bibp)]∞. The structural diversities among 1–6 have been carefully discussed, and the role of counterion in the self-assembly of coordination polymer have also been well documented from the coordination affinity and bridging mode. Furthermore, the solid-state fluorescence properties of 1–6 at room temperature have been studied.

Contrasting Solid-State Fluorescence of Diynes with Small and Large Aryl Substituents: Crystal Packing Dependence and Stimuli-Responsive Fluorescence Switching.

There has been a significant current interest in solid state luminescence of organic molecules and their stimuli responsive fluorescence switching behavior. Although small organic derivatives with olefinic, acetylenic, phenylenevinylenic, phenyleneethynylenic spacers are widely documented as solid state emitters in the literature, the solid state photophysics of organic derivatives with "butadiyne" spacer still remains unexplored. We provide detailed investigation on the solid state fluorescence properties of a series of butadiynyl fluorophores. Replacement of a phenyl ring, which is at periphery of the butadiyne bridge, with a large moiety such as pyrenyl group furnishes contrasting emissions in the solid state. While the butadiyne bridged phenyl derivatives show a blue shift of emission maxima in the solid powder with respect to monomer spectra in solution state, the butadiyne bridged pyrenyl derivatives exhibit a red shift in the solid state. The blue shift of the emission maxima of the butadiyne bridged phenyl derivatives in the solid powder is attributed to allowed excitonic transition in aggregates with nearly parallel transition dipoles. On the other hand, formation of pyrenyl excimer accounts for the red shift of the butadiyne bridged pyrenyl derivatives in the solid powder. In addition to that, the solid state fluorescence of the pyrenyl analogues is reversibly switched between two aggregate forms through external heating and rubbing stimuli.

Assembly of sandwich-type 3-D supramolecular coordination polymers based on hexa-molybdenum chain and {PMo12O40} heteropolyanion

A {PMo12O40}-directed organic–inorganic hybrid compound H3O[Mo6(bpy)6O17][PMo12O40]·2H2O (1) (bpy=2,2′-bipyridine) has been hydrothermally synthesized and characterized by the elemental analysis, IR, XRD, TG analysis and single-crystal X-ray diffraction. In compound 1, Keggin heteropolyanions as templates induce the [MoO4(bpy)] complexes to form unusual wave-liked hexa-molybdenum unit's chains, which are further linked to form pure Mo-oxide-based host layers via supramolecular interaction. {PMo12} as guest units is grafted on the host layer to result in Keggin ions layers. The host cation layers and Keggin ions layers alternately array together to form unique sandwich-type supramolecular networks. In addition, the solid state fluorescent properties, and electro- and photo-catalytic behaviors of compound 1 have been studied.

A novel Zn6Co3 cluster-based heterometallic coordination polymer with PMG3 − linker formed via in situ decarboxylation from H4PMIDA

A novel Zn6Co3 cluster-based heterometallic coordination polymer, [Zn6Co3(PMG)6(H2O)4]·12H2O (1), has been hydrothermally synthesized, in which the PMG3− (N-(phosphonomethyl)glycinate) as a multifunctional ligand was firstly formed via in situ decarboxylation from original ligand N-(phosphonomethyl)imino-diacetic acid during the hydrothermal reaction. The complex was characterized by elemental analysis, FT-IR, powder X-ray diffraction, thermal analysis and single-crystal X-ray diffraction techniques. Its structure features a 2D framework constructed by [Zn6Co3(PMG)6(H2O)4] pinwheel-like heteronuclear clusters, which contains rings with two tropisms. Through extensive O–H⋯O hydrogen bondings, the adjacent 2D layered structure further extends into a 3D supramolecular network. Moreover, the solid-state fluorescence property of this complex has also been investigated at room temperature, which exhibits a good fluorescent emission.

A new linear bismuth coordination polymer based on 1,10-phenanthroline-2,9-dicarboxylic acid: ionothermal synthesis, crystal structure and fluorescence properties.

A new linear bismuth(III) coordination polymer, catena-poly[[chloridobismuth(III)]-μ3-1,10-phenanthroline-2,9-dicarboxylato-κ(6)O(2):O(2),N(1),N(10),O(9):O(9)], [Bi(C14H6N2O4)Cl]n, has been obtained by an ionothermal method and characterized by elemental analysis, energy-dispersive X-ray spectroscopy, IR spectroscopy, thermal stability studies and single-crystal X-ray diffraction. The structure is constructed by Bi(C14H6N2O4)Cl fragments in which each Bi(III) centre is seven-coordinated by one Cl atom, four O atoms and two N atoms. The coordination geometry of the Bi(III) cation is distorted pentagonal-bipyramidal (BiO4N2Cl), with one bridging carboxylate O atom and one Cl atom located in the axial positions. The Bi(C14H6N2O4)Cl fragments are further extended into a one-dimensional linear polymeric structure via subsequent but different centres of symmetry (bridging carboxylate O atoms). Neighbouring linear chains are assembled via weak C-H···O and C-H···Cl hydrogen bonds, forming a three-dimensional supramolecular architecture. Intermolecular π-π stacking interactions are observed, with centroid-to-centroid distances of 3.678 (4) Å, which further stabilize the structure. In addition, the solid-state fluorescence properties of the title coordination polymer were investigated.

Tuning the structures of three coordination polymers incorporating ZnII and 2,2′-dichloro-4,4′-azodibenzoic acid via selective auxiliary ligands

By tuning the auxiliary ligands in the assembling reaction, three ZnII coordination polymers of [Zn(Cl-adc) (phen) (H2O)](DMF) (1), [Zn(Cl-adc) (DMA)](DMA) (2), and [Zn(Cl-adc) (dip)](DMF)0.5 (3) (Cl–H2adc = 2,2′-dichloro-4,4′-azodibenzoic acid, phen = 1,10-phenanthroline, dip = 1,3-di(imidazole)propane) have been successfully synthesized and characterized by single-crystal X-ray diffraction study, elemental analysis, IR spectra, TGA analyses, solid-state fluorescent property, and powder X-ray diffraction (PXRD). Single crystal X-ray diffraction reveals that 1 and 2 displays a 1D polymeric chain and 2D sql layered net with the presence of chelated phen and terminal DMA ligands, respectively. By incorporating dip linker, 3 exhibits a 2D + 2D → 3D entangled network, with each 2D net portraying wavelike sql layered structure. Their structural divergences should be properly attributed to fact that, the structural topologies can be well regulated by using three auxiliary ligands incorparating different coordination function.

Synthesis and fluorescence properties of 4-diarylmethylene analogues of the green fluorescent protein chromophore

New green fluorescent protein (GFP) chromophore analogues, namely 4-(diarylmethylene)imidazolinones (DAINs), were readily synthesized under weakly acidic conditions using a novel condensation reaction between methyl imidate (or thioimidate) and ethyl N-(diarylmethylene)glycinate. DAINs showed notable fluorescence properties. Although they were nearly non-fluorescent in the solution, visible emissions were detected in most of their frozen solution states and crystalline powder states. Therefore, control of the molecular motions significantly affected emissions by DAINs. Comparison of the fluorescence properties of DAIN 5a with those of the corresponding GFP-chromophore analogues 8 revealed that 5a possessed superior solid-state fluorescence properties.

Synthesis, structure and properties of a new three-dimensional interpenetrated metal-organic framework with 3,3'-azodibenzoic acid (H2azdc) and 1,4-bis(1H-imidazol-1-yl)butane (bimb): {[Cd(azdc)(bimb)2]·H2O}n.

A new three-dimensional interpenetrated Cd(II)-organic framework based on 3,3'-azodibenzoic acid [3,3'-(diazenediyl)dibenzoic acid, H2azdc] and the auxiliary flexible ligand 1,4-bis(1H-imidazol-1-yl)butane (bimb), namely poly[[bis[μ2-1,4-bis(1H-imidazol-1-yl)butane-κ(2)N(3):N(3')][μ2-3,3'-(diazenediyl)dibenzoato-κ(2)O:O']cadmium(II)] monohydrate], {[Cd(C14H8N2O4)(C10H14N2)2]·H2O}n, (1), was obtained by a typical solution reaction in mixed solvents (water and N,N'-dimethylformamide). Each Cd(II) centre is six-coordinated by two O atoms of bis-monodentate bridging carboxylate groups from two azdc(2-) ligands and by four N atoms from four bimb ligands, forming an octahedral coordination environment. The Cd(II) ions are connected by the bimb ligands, resulting in two-dimensional (4,4) layers, which are further pillared by the azdc(2-) ligands, affording a threefold interpenetrated three-dimensional α-Po topological framework with the Schläfli symbol 4(12)6(3). The thermal stability and solid-state fluorescence properties of (1) have been investigated.

Synthesis and study of fluorescence properties of novel pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidin-5(6H)-one derivatives

New pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidin-5(6H)-one derivatives 5 were prepared by cyclocondensation reaction between heterocyclic o-aminonitriles 3 and carboxylic acids 4 in the presence of sulfuric acid as catalyst. This procedure provides the desired compound in good yield with a simple one-step methodology. The obtained products show interesting fluorescence properties in both solution and solid state; in this way several spectra of absorption and emission were measured for selected compounds 5b, 5e, 5g and 5j, showing a broad and intense emission band around of 470nm. In other to understand the electronic transition processes, theoretical calculations were performed at TD-DFT level, using B3LYP as functional and 6-31(d,p) as basis set, finding a good agreement with experimental measurements.

Structural diversity of four 1D chain coordination polymers based on chiral N-tosyl-L-glutamic acid: Effect of metal ions and N-donor ancillary ligands

Four one-dimensional (1D) coordination polymers {[Cd2(tsgluO)2(3-ampy)5]·2.5H2O}n (1), {[Zn(tsgluO)(3-ampy)(H2O)]·2H2O}n (2), [Cd(tsgluO)(Him)(H2O)]n (3), and [Cd(tsgluO)(1,10-phen)]n (4) (H2tsgluO=N-tosyl-L-glutamic acid, Him=imidazole, 3-ampy=3-amino pyridine, phen=1,10-phenanthroline) were synthesized and characterized using elemental analysis, infrared spectra, thermogravimetric analysis, and single-crystal X-ray diffraction. Compound 1 crystallizes in space group C2/c, and features a 1D double helix structure. Compound 2 crystallizes in chiral space group P21, exhibits a 1D linear single-chain structure that is extended by hydrogen-bonding interactions to form a 2D supramolecular network. Compounds 3 and 4 crystallize in chiral space groups P21 and P212121, respectively; these compounds exhibit 1D ladder-like double-chain structures, and the chains of 3 are extended by hydrogen-bonding interactions to form a 2D supramolecular network. The structural diversity of these compounds is attributed to the effect of metal cations and N-donor ancillary ligand. Furthermore, the solid-state fluorescence properties of compounds 1–4 were studied at room temperature. The circular dichroism (CD) of compounds 2 and 3 was also investigated.

Synthesis, Structure and Fluorescent Property of a New Isolated Co6Mg9 Heteronuclear Cluster

A novel zero-dimensional Co6Mg9 heteronuclear cluster based on N-(phosphonomethyl)imino-diacetic acid (H4PMIDA) and 1,3,5-benzenetricarboxylate acid (H3BTC) multifunctional ligands, [Co6Mg9(PMIDA)6(H2O)24]·(BTC)2·22H2O (1), has been synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectra, thermal analyses, and single-crystal X-ray diffraction. The complex 1 exhibits a isolated cationic 15 heteronuclear cluster [Co6Mg9(PMIDA)6(H2O)24]6+, and its charges are balanced by two anionic BTC3−. Each isolated cluster is further extended into a 3D supramolecular network through very extensive O–H···O hydrogen bonds. Moreover, the solid-state fluorescent property of the complex 1 has also been investigated at room temperature.

Synthesis of tetra-substituted olefins via annulation by Pd-catalyzed carbopalladation/C–H activation and solid state fluorescence properties

Palladium-catalyzed and norbornene-mediated multiple C–C bond forming strategies to highly substituted helical olefin incorporated 1,2,3,4-tetrahydroisoquinolines have been developed via double carbopalladation/C–H activation of 2-bromo-N-benzylpropargylamines. The scope of the above carbocyclization process has been studied by varying the substitution on starting materials which have been synthesized using A3-coupling (mine–ldehyde–lkyne). Interestingly, the synthesized compounds show a pronounced solid state fluorescence property due to their restriction of intramolecular rotation in the condensed phase.

Lanthanide metal–organic frameworks with 2,2′-bipyridine-polycarboxylic acid: Synthesis, crystal structures and fluorescent properties

Four lanthanide metal–organic frameworks, namely, [{[Ln5(bptc)3(Hbptc)(H2O)12]·4H2O}n (Ln=Eu, 1; Gd, 2; Tb, 3) and {[Eu(bptc′)]}n (4), (H4bptc=2,2′-bipyridine-3,3′,6,6′-tetracarboxylic acid, H3bptc′=2,2′-bipyridine-3,6,6′-tricarboxylic acid) have been hydrothermally synthesized. Compounds 1–4 were structurally characterized by IR spectra, thermogravimetric analyses and single-crystal X-ray diffractions. Complexes 1–3 are the isostructural 2D layered structures, five crystallographic independent Eu(III) ions display the two different kinds of coordination environments. Complex 4 exhibits a 3D framework structure, while H4bptc was decarboxylated to transform into the tricarboxylate group of bptc′3− in the presence of Cu2+ ions under the hydrothermal conditions. The solid state fluorescent properties of 1, 3 and 4 were investigated at room temperature, respectively.

Preparation of new fluorophore lanthanide complexes-Cloisite nanohybrids using the tricationic Pr(III), Gd(III) and Dy(III) complexes with 9,10-phenanthrenequinone

New fluorophore lanthanide complexes-Cloisite (LCs-C) nanohybrids have been prepared by the intercalation reaction of Cloisite Na+ with the tricationic lanthanide complexes (1–3), [M(PQ)3(DMF)2(H2O)2]3+ (M=Pr(III) (1), Gd(III) (2), and Dy(III) (3); PQ=9,10-phenanthrenequinone), in aqueous solutions. The X-ray diffraction analysis of the modified clays (LCs-C) showed an increase in the interlayer distance (d) as compared to the pure Cloisite Na+. Field-emission scanning electron microscopy (FE-SEM) was used to study the morphology of the modified clays and the results were demonstrated a homogeneous morphology for the nanohybrids. The thermal behavior of the LCs-C nanohybrids was investigated using thermogravimetric analysis. Solid-state fluorescence properties of the LCs-C nanohybrids were also investigated. The results show that all tricationic complexes have a significant fluorescence at room temperature when the complexes are adsorbed onto Cloisite.

Two Novel Fe7Mg8 and Fe8Co7 Cluster-Based 3D Heterometallic Coordination Polymers with H4PMIDA and H3BTC as the Co-ligands: Synthesis, Structures, and Fluorescent Properties

Two novel Fe7Mg8 and Fe8Co7 cluster-based 3D heterometallic coordination polymers, [Fe7Mg8(PMIDA)6(BTC)2(H2O)12]·6H2O(1) and [Fe8Co7(PMIDA)6(BTC)2(H2O)12]·6H2O(2), constructed by multifunctional H4PMIDA (N-(Phosphonomethyl)imino-diacetic acid) and H3BTC(1,3,5-benzenetricarboxylate acid) as the co-ligands, have been synthesized under hydrothermal conditions, and characterized by elemental analysis, IR spectrum, powder X-ray diffraction, thermal analysis and single-crystal X-ray diffraction. The complexes 1 and 2 are basically isostructural and feature a cubic 3D open framework constructed by [M15(PMIDA)6(H2O)12]] (M15 = Fe7Mg8 for 1 and Fe8Co7 for 2) heteronuclear clusters and BTC3− ligands. Moreover, the solid-state fluorescence properties of the complexes have also been investigated at room temperature.

Ring-shaped silafluorene derivatives as efficient solid-state UV-fluorophores: synthesis, characterization, and photoluminescent properties.

Four ring-shaped silafluorene-containing compounds (1-4) were synthesized and characterized as potentially promising monomers for fluorescent polymers. Their optical properties in solution and solid state (thin film and powder) were studied. These compounds have low quantum yields in solution (Φ(fl)=0.13-0.15) with fluorescence maxima at about 355 nm, but high quantum yields in the solid state (powder, Φ(fl)=0.35-0.54) with fluorescence maxima at about 377 and 488 nm. Influence of the substituents and the number of silafluorene units in 1-4 on their optical properties was investigated. Extensive study of the X-ray crystal structures of 1-4 was undertaken to analyze and qualitatively estimate the role, extent, and influence of silafluorene moieties' interactions on solid-state fluorescent properties. Excited state UV/Vis and theoretical molecular orbital (MO) calculations were performed to explore possible fluorescence mechanisms and differences in quantum yields among these compounds.

Influence of the halogen atom on the solid-state fluorescence properties of 2-phenyl-benzoxazole derivatives

Four halogenated derivatives of 2-phenyl-benzoxazole and the unsubstituted analog were studied in solution and as powders by absorption and steady-state fluorescence spectroscopy. In solution, the fluorescence quantum yield was progressively decreased with increasing the size of the halogen atom, as explained by heavy atom effect. In the solid state, an increase in photoluminescence efficiency was observed when passing from the fluorinated to chlorinated derivative, and then the fluorescence efficiency was decreased for the brominated and iodinated derivatives, the latter compound being virtually not emissive. To explain the solid-state behavior, the influence of molecular arrangement on the emission properties was discussed on the basis of X-ray data. Finally, microcrystals were generated using a solvent-exchange method. An evolution from elongated platelets to cubic particles was observed with increasing the size of the halogen atom, providing preliminary information for the use of these compounds as micro- and nano-materials.

Engineering fused coumarin dyes: a molecular level understanding of aggregation quenching and tuning electroluminescence via alkyl chain substitution

Simple molecular structures capable of emitting over the entire visible range are still a challenge. Planar molecular structures have the drawback of fluorescence quenching in the solid state thus limiting their application fields. Combining long range excimer/exciplex emissions with a compound emission have been used to get white light. In this work, a series of new coumarin derivatives having a planar structure have been synthesized and characterized. The effects of systematic variation in alkyl chain functionalization providing morphological variations that permit interesting solid state emitting properties have been discussed simultaneously with electrochemical behavior and OLED (organic light emitting diode) device applications. Carbon chains containing 0–16 carbon atoms have been studied in order to conclude the results that systematic changes in alkyl group substitution can be utilized as a tool to tune the emitting color of these planar coumarins. Alkyl chains were introduced by O-acylation and O-benzoylation reaction on the hydroxyl group of parent coumarin 5. Thus the present strategy is also helpful in establishing a template to control the unproductive interchromophore electronic couplings. Solid state fluorescence properties support the crystal studies. Theoretical studies are also in agreement with experimental data. Electroluminescence of Device 2 with a turn on voltage (Von) around 5–6 V having s-CBP doped with 1% of 8 having alkyl substitution of 2-carbons is found to exhibit white emission with CIE co-ordinates of (0.29, 0.34) which is close to white emission while the alkyl substitution of 14-carbons (compound 17) in Device 7 (Von = 7 V) exhibited green emission. Thus a strategy helpful to tune the electroluminescence has been discussed.

Crystal structure, thermal and fluorescent properties of a 1D Cd(II) coordination polymer based on the bis(benzimidazole) ligand

A 1D cadmium (II) coordination polymer {[Cd2(L)3Cl3]·Cl}n (1) (L = 1,3-bis(benzimidazol-l-yl)-2-propanol) is synthesized by the hydrothermal reaction and characterized by elemental analysis, IR, TG, and X-ray single crystal diffraction. Compound 1 crystallizes in the hexagonal system, space group P63/m with a = 15.4857(11) A, b = 15.4857(11) A, c = 14.478(2) A, γ = 120°, V = 3006.8(5) A3, Z = 2. In the structure of complex 1, each cadmium center is hexahedrally coordinated by three chlorine atoms and three nitrogen atoms of three distinct L ligands. A detailed analysis reveals that compound 1 exhibits a 1D chain of beads and the adjacent chains are further linked by C-H…Cl hydrogen bonding to form a 2D supramolecular framework. Furthermore, the solid-state fluorescent property of 1 is investigated at room temperature.