RARE EARTH CONTAINING POLYMER TERNARY COMPLEXES AND THEIR FLUORESCENT PROPERTIES

Rare earth containing fluorescence active polymer ternary complexes were synthesized and their absorption and emission properties were investigated.

Two Metal-organic Coordination Polymers with Rigid Bis(triazole) Ligand： Assembly, Structures, and Fluorescence Properties

Two new coordination polymers containing rigid bis（triazole）, namely, [Ni（btb）_（0.5）（nph）（H_2O）]_n（1） and [Zn（btb）（SO_4）]_n（2）（btb = 4,4a-bis（1,2,4-triazolyl-1-yl）-biphenyl, H_2nph = 3-nitrophthalic acid） have been synthesized and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. Complex 1 shows a 3D trinodal（3,4,4）-connected sqc69 topology. Complex 2 presents a 2D uninodal 4-connected sql network, which is further packed into a 3D supramolecular framework by C-H···O hydrogen bonds. Thermal stabilities and fluorescence properties of two complexes have been discussed in detail.

Fluorescent Supramolecular Polymersomes Based on Pillararene/Paraquat Molecular Recognition for pH-controlled Drug Release

Researchers have put significant efforts on developing versatile fluorescent polymeric systems due to their promising biological/biomedical labelling, tracking, monitoring, imaging, and diagnostic applications. However, complicated organic/polymeric synthesis or post-modification of these functionalized platforms is still a big obstacle for their further application and thereby provides clear motivation for exploring alternative strategies for the design and fabrication of easily available fluorescent systems. The marriage of supramolecular polymers and fluorescent imaging can provide a facile and dynamic manner instead of tedious and time-consuming synthesis due to the dynamic and reversible nature of noncovalent interactions. Herein, based on water-soluble pillararene/paraquat molecular recognition, we successfully prepare two amphiphilic polypseudorotaxanes which can self-assemble into supramolecular polymersomes in water. These polymersomes can be reversibly destroyed and reformed by tuning the solution p H. Attributed to the aggregation-induced emission of tetraphenylethylene groups,intense fluorescence can be introduced into the obtained supramolecular polymersomes. Furthermore, p H-triggered release of an encapsulated water-insoluble drug(doxorubicin) from the self-assembled fluorescent supramolecular polymersomes is also investigated.

Two-Photon Fluorescence Properties and Ultrafast Responses of a Hyperbranched Diketo-Pyrrolo-Pyrrole Polymer with Triphenylamine as the Core

The two-photon fluorescence properties and ultrafast responses of a hyperbranched polyyne （hb-DPP-J2） with triphenylamine as the central core, Diketo-Pyrrolo-Pyrrole as the connecting unit and electron acceptor are studied. The polymer has a D-π-A-π-D conjugated structure along the extended polyyne w-bridge systems, and the effective condugated unit repeats itself in the whole hyperbranehed polymer chain. The polymer exhibits a large two-photon absorption cross section and high fluorescence quantum yields. The ultrafast dynamic results give a deep understanding of the excited energy transfer processes under excitation, and reveal a long relaxation lifetime of the intramolecular charge transfer （ICT） state.

Synthesis,Structure and Photoelectric Property of a 3D Supramolecular Zinc Coordination Polymer

Using a rigid azo ligand 4-[（8-hydroxy-5-quinolinyl）azo]-benzoic acid（H2 L）,a new supramolecular compound [Zn（L）（H2O）2]n（1） has been solvothermally synthesized and structurally characterized by X-ray single-crystal diffraction,infrared spectrum,elemental analysis,power X-ray diffraction and thermal analysis.Compound 1 crystallizes in monoclinic,space group C2/c with a = 30.372（8）,b = 11.415（3）,c = 9.248（3） A,β = 106.94（3）o,V = 3067.20（15）A3,C（16）H（13）N3O5Zn,Mr = 392.66,Z = 8,Dc = 1.701 Mg/m^3; F（000） = 1600,μ = 1.636 mm^-1,reflections collected：7290,reflections unique：2735,R（int）= 0.0282,R = 0.0351,wR（all data） = 0.0919,GOOF on F^2 = 1.036.Compound 1 exhibits a one-dimensional（1 D） zig-zag chain structure connected into a three-dimensional（3D） supramolecular network through hydrogen bonding interactions.Fluorescent property and electrochemical property were detected on compound 1.

Hydrothermal Syntheses, Crystal Structures and Fluorescence of a Copper(I) Polymer and a Salt with H_2SO_4 Based on a Pyrimidine Building Block

Based on the building block of 2-phenyl-4,6-di（pyridin-2-yl）pyrimidine （L = C20H14N4）, a Cu（I） polymer [（CuC20H14N4）（CuCl2）]∞ and a salt with H2SO4 [（C20H16N4）（HSO4）2] have been synthesized by hydrothermal method and characterized by X-ray single-crystal diffraction. In the Cu（Ⅰ） polymer, although the central metal ions of Cu（Ⅰ） directly coordinate with the building block L, they still do not assembly expected grid-type complexes and there exists a one-dimensional chain constructed through coordinate bonds. In the salt, hydrogen bonds along with two kinds of π…π supramoleuclar interactions fabricate two-dimensional （2D） networks which further generate a 3D supramolecular architecture via interlayer π…π interactions. Fluorescent spectra show that the L emits blue fluorescence and its Cu（Ⅰ） polymer and salt decrease the fluorescent intensity.

On-chip optical sources of 3D photonic integration based on active fluorescent polymer waveguide microdisks for light display application

In this work,on-chip three-dimensional(3D)photonic integrated optical sources based on active fluorescent polymer waveguide microdisks are proposed for light display application.Fluorescent green and red oligomers with high-efficiency photoluminescence are doped into epoxy crosslinking SU-8 polymer as the waveguide gain medium.The microdisk-based on-chip optically pumping light sources are designed and fabricated using the organic functionalized materials by direct UV written process.The promising stacking dual-microdisk structures with double gain layers could provide white signal light source generated perpendicular to the chip,and green signal light source stimulated in the chip.The approach could realize the monolithically on-chip assembled vertical and horizontal bright emitters.The optical pumping threshold power is obtained as 50 mW with continuous-wave(CW)pumping.The average gain coefficient of a white light source is measured by vertical fiber coupling as 112 dB/W,and that of green light source by horizontal fiber coupling as 137 dB/W,respectively.The rising and falling response time of the on-chip optical sources are 60 and 80μs under modulating pulsed pumping.This technique is very promising for achieving 3D integrated light display application,including photonic circuits and optical information encryption.

A Fluorescent Supramolecular Crosslinked Polymer Gel Formed by Crown Ether Based Host-Guest Interactions and Aggregation Induced Emission

Based on the combination of B21C7/dialkylammonium salt host-guest interactions and tetraphenylethylene （TPE）-based aggregation-induced emission （AIE） effect, a fluorescent supramolecular crosslinked polymer gel was successfully prepared. Compared with the solution of TPE-containing small molecules, this gel exhibited remarkable fluorescence enhancement due to the AIE effect of TPE units. The ＂gelation induced fluorescence emission＂ phenomenon can be explained by the hindered intramolecular rotation of phenyl rings of TPE. Because of the reversibility and stimuli-responsiveness of the B21C7/dialkylammonium salt host-guest interactions, the transition between the fluorescent supramolecular crosslinked polymer gel and the disassembled sol with very weak fluorescence can be realized by adding pH and thermal stimuli. This novel material contributes to the development of supramolecular chemistry, polymer science and fluorescent materials and offers a new method to construct functional supramolecular materials.

Fluorescent polymer-modified gold nanobipyramids for temperature sensing during photothermal therapy in living cells

The temperature monitoring of treated cancer cells is critical in photothermal therapy.Current methods of detecting intracellular temperatures have low accuracy and poor spatial resolution,which limits their application to photothermal therapy.Herein,a strategy for targeted recognition and selective capture of MCF-7 breast cancer cells based on fluorescent polymer poly(N-isopropylacrylamide-benzoxadiazole-2-vinyl-4,4-dimethyl azlactone,PNMV)and modified gold nanobipyramids(Au NBPs-PNMV)was developed for temperature sensing during photothermal therapy.A mucin-1 protein aptamer(Apt)was applied to selectively target mucin-1 protein overexpressed on the surfaces of the MCF-7 cells,which can reduce interference by affinity interaction between the Apt and proteins.During photothermal therapy,the significant Au NBPs photothermal effect increases the fluorescence intensity of PNMV with temperature.Irradiation of MCF-7 cells cultured with Au NBPs-PNMV@Apt by an 808 nm laser increases the temperature of the system,while the cells can be inactivated because of the remarkable Au NBPs-PNMV@Apt photothermal effect.The results indicate that variation in the fluorescence of Au NBPs-PNMV@Apt can be applied as thermometers to monitor the intracellular effect of photothermal therapy.

Folic Acid Functionalized PFBT Fluorescent Polymer Dots for Tumor Imaging

Folic acid functionalized PFBT-COOH and PFBT-NH2 polymer dots were prepared using a nano precipitation method, and their applications for tumor imaging in vitro and in vivo were demonstrated for the first time. The syn- thesized FA-PFBT-COOH polymer dots were 50--60 nm in diameter with a zeta potential of greater than -30 mV in water, while the synthesized FA-PFBT-NH2 polymer dots were 90-- 105 nm in diameter with a zeta potential of greater than -20 mV in water. Furthermore, the FA-PFBT-COOH polymer dots produced stronger fluorescence in- tensity in water solution as well as in the cells than the FA-PFBT-NH2 polymer dots, and were able to image H1299 tumors in living mice after intravenous injection. This study showed the great potentials of FA-PFBT-COOH poly- mer dots as fluorescent nanoprobes for biomedical imaging.

Peroxyoxalate Chemiluminescence Based on Fluorescent Conjugated Polymer for the Determination of Triton X-IO0

A novel peroxyoxalate chemiluminescence system has been designed for the determination of Triton X-100 （TX-100）, in which a hydrophobic fluorescent conjugated polymer, poly[2,5-bisnonyloxy-1,4-phenyleneethynylene-9,10-anthrylene] （PPEA） was employed as a fluorophor. A strong enhanced intensity of chemiluminescence （CL） was observed in the presence of TX-100, due to the improved emission efficiency of PPEA in the presence of TX-100. Under optimum conditions, the detection range of Triton X-100 is between 1.0 ×10 ^-7 and 1.0 ×10 ^-4 mol·L ^-1, with a detection limit at 6.0×10 ^-8 moloL 1. The relative standard deviation is 2.4% （n=6） for 1.0×10 ^-6 mol·L ^-1Triton X-100. This method provides satisfying results in the detection of TX-100 in nature water and biological samples with high sensitivity and wide linear range.

Temperature-responsive Behavior of Polymer Fluorescent System via Electrostatic Interaction Mediated Aggregation/Deaggregation

A simple and effective polymer fluorescent thermosensitive system was successfully developed based on the synergistic effect of excimer/monomer interconversion of pyrene derivatives and electrostatic interaction between polyelectrolyte and charged fluorophore. As for the system, the excimer-monomer conversion, thermosensitive behavior and thermo-responsive reversibility were investigated experimentally. Temperature variation and temperature-distribution induced fluorescence changes can be observed directly by naked eyes. Thus, this polymer system holds promise for serving as a fluorescent thermometer.

Color-tunable and bright nonconjugated fluorescent polymer dots and fast photodegradation of dyes under visible light

Nonconjugated polymer dots(PDs)without largely conjugated structures entitle their advantages such as environment friendliness,nontoxicity,and intrinsic fluorescence.However,color-tunable PDs remain a challenge.Herein,polyvinyl pyrrolidone(PVP)and ascorbic acid(AA)are used to synthesize nonconjugated PDs,namely,PA PDs with intensive blue emission.The introduction of a third component,m-phenylenediamine(MPD),redshifted the emission to green.The asprepared color-tunable blue to green emissive PDs exhibit excellent properties,whether in solution or in solid state,originated from the mechanism of clusteringtriggered emission(CTE)induced by the overlap of electron-rich atoms,the strong inter/intrachain interaction.The quantum yields of blue and green PDs reached up to 15.07%and 28.22%,respectively.Furthermore,PA PDs were successfully applied to the highly efficient photocatalytic degradation for dyes:methylene blue(MB)and methyl orange(MO)were degraded by 89.9%and 93.8%within 20 min under visible light,respectively.

Positioning a fluorescent probe at the core of a glassy star polymer for detection of local dynamics

Accessing local dynamics within a single macromolecule is the key to understand the physical origin of the viscoelasticity and especially the glass transition. In order to extract specific information on the dynamics of the branch point of a star polymer around its glass transition temperature, four-arm star poly （n-butyl methacrylate） with a fluorescent core was synthesized using perylene diimide as initiator and polymerization conducted via atom transfer radical polymerization. The process is found to be effective in positioning the fluorophore at the branch point with the fluorophore intact, which allows the successful application of single molecule fluorescence defocus imaging in examining the local site- sensitive dynamics. The power spectra of rotation trajectories, the population of rotating fluorophores as well as the distribution of angular displacement were used to revel the difference in local dynamics between branch point and the arm＇s end. It is discovered that the local dynamics at the core of the star polymer is much less activated than that at the arm＇s end. The results demonstrate the strong effect dues to the topological constrain at the branch point and the more free space at the arm＇s end.

New applications of poly(arylene ether)s in organic light-emitting diodes

Compared with conventional π-conjugated polymers,poly（arylene ether）s（PAEs） may take advantages of excellent thermal properties,well-defined effective conjugated length and no catalyst contamination.Recently,their applications have been extended from engineering plastics to optoelectronic materials.In this review,various kinds of functional PAEs used as fluorescent polymers,host polymers and phosphorescent polymers in organic light-emitting diodes（OLEDs） are outlined,and their molecular design,synthesis and device performance are overviewed.

Highly photostable nanogels for fluorescence-based theranostics

A novel photo-crosslinkable nanogel is prepared from a biodegradable polymer template with intrinsic photoluminescence and high photostability.The fluorescent nanogels display excellent biodegradability and cytocompatibility owed to the facile synthesis scheme involving a solvent-and surfactant-free onepot reaction,derived entirely from biocompatible monomers citric acid,maleic acid,L-cysteine,and poly(ethylene glycol).The resultant nanogels are less than 200 nm in diameter with a narrow size distribution and monodispersity,and demonstrate long-term structural stability in biological buffer for two weeks.To gauge potential in theranostic applications,the fluorescent nanogels were surface functionalized with biologically active RGD peptides and encapsulated with active anti-cancer drug Doxorubicin,resulting in a pH-responsive controlled drug release in acidic pH resembling tumor environments.The strong fluorescence of the nanogels enabled tracking of targeted drug delivery,showing that drug-loaded nanogels homed into the cytoplasmic regions of prostate cancer cells to significantly induce cell death.These photo-crosslinkable and biodegradable nanogels pose as a strong candidate for theranostic medicine,demonstrating versatile functionalization,high stability in biological buffers,and capacity for real-time fluorescence-based monitoring of targeted drug delivery.

Synthesis of a cationic poly(p-phenylenevinylene) derivative for Iysosome-specific and long-term imaging

The development of long-term imaging agents and subcellular imaging materials is of great importance in the research of cancer cell behaviors. In this work, a cationic poly（p-phenylenevinylene） derivative（PPV） is designed and synthesized to link quaternized N-methyl-imidazole groups as pendants which endow the polymer to bear positive charges. Absorption and fluorescence emission spectra of PPV display a large Stokes shift of 102 nm which is much larger than the commercial cell dyes. Positively charged polymer could adsorb onto the surface of cells via electrostatic interactions followed by cell endocytosis process to enter cells. Importantly, PPV barely has influence on the cell viability through cytotoxicity analysis. The colocalization data demonstrates that PPV and commercial lysosome-specific dye are highly colocalized in the same region, indicating that the green fluorescent PPV mainly distributes in the lysosomes. Moreover, the continuous imaging investigation shows that PPV could stay in cells for more than seven days while the commercial Lyso-Tracker would be extruded by cells after three days. PPV exhibits superior capabilities including strong fluorescence, large Stokes shift, good biocompatibility and high photostablity, which has great potential in the applications of cellular process monitoring.

Aggregation-induced emission polymer systems with circularly polarized luminescence

Functional materials with circularly polarized luminescence(CPL)have attracted tremendous attention due to their promising applications in three-dimensional dis-plays,chiral recognition and catalysis,photoelectronic devices,contrast imaging,information encryption,and otherfields.Among various CPL-active materials,poly-meric systems with aggregation-induced emission(AIE)have emerged as excellent candidates because of their efficient aggregate-statefluorescence,large solid-state dissymmetry factor,excellent processibility,diversified self-assembly behaviors,and readily switchable CPL properties.This review summarizes and discusses the recent progress as well as future perspective of diverse AIE polymer systems with CPL,including CPL-active covalent AIE polymers,CPL-active supramolecular AIE polymers,and AIEgen/polymer composites with CPL.According to the loca-tion or introduction method of AIEgen in polymer structures,this review further divides CPL-active covalent AIE polymers into three categories,including polymers with AIEgen in main chains,polymers with AIEgen in side chains,and CPL-active polymers with clusterization-triggered emission.CPL-active supramolecular AIE polymers are discussed based on the driving force for the formation of supramolecular polymers,including host–guest interactions,metal coordination,and other non-covalent interactions.Moreover,examples on the construction of CPL-active AIEgen/polymer composites by physically mixing AIEgens with chi-ral(supra)polymers are also presented.This review is anticipated to provide readers with an overall view on the design strategies of CPL-active AIE polymers,and facil-itate further research on the development of CPL materials and AIE polymers with advanced applications.