Synthesis and Characterization of Compounds Containing 1,2,3-Triazole via Click Reaction and Ag(Ⅰ) Complex

In this work, 1,4-bis(4-phenyl-1,2,3-triazole)benzene, 1,3-bis(4-phenyl-1,2,3-triazole)propane, bis(1-phenyl-1,2,3-triazole)-methylphenylsilane, and 1-ally-4-phenyl-1,2,3-triazole have been designed and synthesized via Click reaction. Fourier transform infrared spectroscopy(FT-IR) and nuclear magnetic resonance spectroscopy(NMR) were used to confirm the compounds’ structures. The effect of silicon atom on the optical properties has also been studied. The UV-vis absorption wavelength of silicon-containing compound is about ca. 10 nm red-shifted when compared with that of other three compounds. The fluorescence emission bands of the compounds in CHClsolutions were observed around ca. 440 nm. And the luminescent coordination compound, namely [AgL1?NO?3HO]n, based on the ligand 1-allyl-4-phenyl-1,2,3-triazole has been prepared. In addition, this complex exhibits a 1 D chain structure. The crystal structure has been determined by single-crystal X-ray diffraction, and the optical properties have been investigated by fluorescence spectrum. In summary, our work may provide new materials with luminescent property which is potentially useful in material fields.

Synthesis and Properties of pH and Temperature Responsive Copolymer with Pesudorotaxane Structure

pH and temperature responsive copolymers PNAM4VBCB of N-isopropyl acrylamide（NAM） and complex pseudorotaxane monomer N 1-（4-vinylbenzyl）-1,4-diaminobutane dihydrochloride with cucurbit[6]uril（CB[6]） threaded（4VBCB） were prepared via free-radical polymerization in aqueous solution.The copolymers were characterized by 1 H NMR,Fourier transform infrared（FTIR） spectrometry,elemental analysis,and static light scattering.The thermodynamic properties of the copolymers were studied by thermogravimetric analysis（TGA）,and the effects of pH and the concentration of the copolymer on the average hydrodynamic radius（R h） were studied by dynamic light scattering（DLS）.In addition,the thermal sensitivities of the copolymers were studied by DLS and UV-Vis.The experiment data show that CB[6] beads are localized on 1,4-diaminobutane units in the side chains of the copolymer.TGA data show that thermal stability of the copolymers increases with the adding of CB[6] threaded because of the enhanced rigidity and the bulky steric hindrance of 4VBCB in the side chain of PNAM4VBCB.DLS data show that the average hydrodynamic radius of copolymer increases with the increase of the copolymer concentration and has a jump with adjusting pH due to the existing of the small size CB[6] dethreaded from the copolymer with increasing pH.Both pH and electrical conductivity curves of the solution of PNAM4VBCB-4 have a jump because CB[6] could dethread from the copolymers with the addition of NaOH.In addition,the copolymers have thermal sensitivity and their phase-change temperatures could be controlled by adjusting the molar ratio of NAM to 4VBCB in the copolymers.

High strength mullite-bond SiC porous ceramics fabricated by digital light processing

Fabricating SiC ceramics via the digital light processing(DLP)technology is of great challenge due to strong light absorption and high refractive index of deep-colored SiC powders,which highly differ from those of resin,and thus significantly affect the curing performance of the photosensitive SiC slurry.In this paper,a thin silicon oxide(SiO_(2))layer was in-situ formed on the surface of SiC powders by pre-oxidation treatment.This method was proven to effectively improve the curing ability of SiC slurry.The SiC photosensitive slurry was fabricated with solid content of 55 vol%and viscosity of 7.77 Pa·s(shear rate of 30 s^(−1)).The curing thickness was 50μm with exposure time of only 5 s.Then,a well-designed sintering additive was added to completely convert low-strength SiO_(2) into mullite reinforcement during sintering.Complexshaped mullite-bond SiC ceramics were successfully fabricated.The flexural strength of SiC ceramics sintered at 1550℃in air reached 97.6 MPa with porosity of 39.2 vol%,as high as those prepared by spark plasma sintering(SPS)techniques.

Synthesis of polyacrylonitrile-block-polydimethylsiloxane-block-polyacrylonitrile triblock copolymers via RAFT polymerization

A new A-B-A type of block copolymers,polyacrylonitrile-block-polydimethylsiloxane-block-polyacrylonitrile（PAN-b-PDMSb-PAN）,which comprises two polymer blocks of different polarities and compatibilities,were synthesized for the first time via reversible addition-fragmentation chain transfer polymerization.Reaction kinetics was investigated.PAN-b-PDMS-b-PAN films were prepared by spin-coating on glass chips.Significant order on the film surface morphologies was observed.

Enhanced Fracture Toughness of Pressureless-sintered SiC Ceramics by Addition of Graphene

To enhance the fracture toughness of pressureless-sintered SiC ceramic, graphene was introduced as an additive. The effects of graphene contents on the fracture toughness, bending strength, micro-hardness, phase compositions, and microstructure evolutions of the SiC ceramics were investigated in detail by scanning electron microscopy, energy dispersive X-ray spectroscopy, and metallographic microscopy. The fracture toughness, bending strength and micro-hardness increased initially, and then decreased with the graphene content increasing from 0 to 5.0 wt%. The highest fracture toughness of 5.65 MPa m1/2 was obtained for sample with 1.0 wt% graphene sintered at 2130 ℃ for 1 h in At, which was about 22.6% higher than that of SiC sample without graphene. In addition, the highest bending strength and microhardness of 434.14 MPa and 29.21 GPa corresponded to the SiC samples with graphene content of 0.5 wt% and 2.0 wt%, respectively.

Synthesis and characterization of β-cyclodextrin modified hyperbranched carbosilane as stationary phase for GC

新 -cyclodextrin 修改了 hyperbranched carbosilane 为煤气的层析的静止阶段被与 hyperbranched carbosilane 代替 -cyclodextrin 的 OH 组综合并且在熔化硅石的内部墙上是涂的为气体的毛状的列层析。静止阶段的色析法的行为被学习。起始的测试结果证明它为几种混合物拥有了好分离能力，例如苯， acrylates，酉同类和 alkylchlorides。

Fluorescence enhancement and cytotoxicity reduction of bis-viologen biphenyl by complexation of cucurbit[7]uril

The effect of cucurbit[7]uril(CB[7]) on fluorescence properties and biocompatibility of the bis-viologen biphenyl molecule(BPV22+) was investigated by using 1 H NMR spectroscopy,fluorescence emission titration,and in vitro cytotoxicity experiments.CB[7] can be combined with BPV22+ in a stoichiometric ratio of 1:1 and 2:1.After the formation of host-guest complex,the fluorescence emission intensity of BPV22+ increased significantly,and the emission spectrum blue shifted.Meanwhile,the host-guest complexes showed better biocompatibility than BPV22+ in cell cytotoxicity studies.Results of this paper lay a foundation for the development of host-guest type of fluo rescent probes,biological imaging and so forth.

A fluorescent guest used to determinate the effective content of CB[8] and to further detect methyl viologen

A fluorescent pyrene derivate, N-allyl-l-pyrenemethylammonium hydrochloride （APA＊）, was reported to form a stable host-guest complex with cucurbit[8]uril （CB[8]）, and this property can be utilized to determinate the purity of CB[8] via emission titration. Moreover, the 1：1 complex of APA and CB[8] can further bind methyl viologen （MV^2＋）, which is the main ingredient of a widely used herbicide, providing a good method to detect MV^2＋, especially at low concentrations.

Cobalt-catalyzed Selective C--F Bond Activation and Alkylation of Polyfluoroaryl Imines

In this paper the C--F bond activation of polyfluoroaryl imines is explored at cobalt（0） center with an imine-N atom as an anchoring group. The reaction of F5C6-CH=N-（2＇-ClC6H4） （2） and FsC6-CH=N-C6H5 （3） with Co（PMe3h afforded the C-F bond activation products （ortho-F4C6-CH=N-（2＇-CIC6H4））Co（I）（PMe3）3 （5） and （ortho-F4C6-CH=N-C6Hs）Co（II）（F）（PMe3）2 （6）, while only n-（C=N） coordinated cobalt（0） complex （2,4,5- F3C6H2-CH=N-（4＇-ClC6H4））Co（0）（PMe3）3 （4） was obtained from 2,4,5-F3C6H2-CH=N-（4＇-C1C6H4） （1） without C--F bond activation. Complexes 4--6 were characterized through X-ray single crystal diffraction. It was also found that dialkylation of N-（perfluorobenzylidene）benzenamine with organozinc reagents could be catalyzed by Co（PMe3）4 via C,C-coupling reaction under mild conditions.

Facile construction of aggregation-induced emission molecular liquids via Piers-Rubinsztajn reaction for green fluorescent ink

Solvent-free luminescent molecular liquids(LMLs), which exhibit nonvolatile fluidic nature and active optoelectronic properties, were widely used. For further development, we introduced siloxane units into AIE molecules, designed and synthesized TPE derivatives with siloxane side chains via facile Piers-Rubinsztajn reaction. The obtained AIE molecular liquids exhibit unique photophysical properties. Compared with the obtained alkyl TPE-solids, siloxane TPE show liquid state, which proves that the siloxane units have stronger liquefaction effect than alkyl. Viscosity test shows that siloxane TPE-liquids has far more lower viscosity and better fluidity than the long-chain alkyl molecular liquids in previous research. All those properties are attributed to the weak interaction between flexible molecular chains of siloxane. Besides,fluorescence test shows temperature responsiveness of siloxane TPE-liquids. We developed this lowviscosity nonvolatile AIE molecular liquid as green fluorescent ink.

SYNTHESIS AND PROPERTIES OF COPOLYMERS CONTAINING CUCURBIT[6]URIL-BASED PSEUDOROTAXANE STRUCTURE

Novel copolymers based on acrylamide （AM） and complex pseudorotaxane monomer N＇-（3-vinylbenzyl）-l,4- diaminobutane dihydrochloride with cucurbit[6]uril （CB[6]） （3VBCB） were prepared via free-radical polymerization in aqueous solution, and characterized by XH-NMR, FT-IR, elemental analysis and static light scattering. The compositions of the copolymers （PAM3VBCB） with pseudorotaxane units were determined by 1H-NMR and elemental analysis. Thermal properties of the copolymers were studied by TGA, and the effects of the copolymer concentration and pH on the average hydrodynamic radius （Rh） of the copolymer molecules were studied by dynamic light scattering （DLS）. The experiment data show that CB[6] beads are localized on 1,4-diaminobutane units in side chains of the copolymers. TGA results show that thermal stability of the copolymer increases with increasing the content of pseudorotaxane unit because of the enhanced rigidity and the bulky steric hindrance of 3VBCB in side chains of PAM3VBCB. DLS data show that the average hydrodynamic radius of copolymer molecules increases with the increase in the copolymer concentration, and both the pH and electrical conductivity of PAM3VBCB solutions demonstrate an acute change with addition of NaOH because of CB[6] dethreading from the side chains of PAM3VBCB. CB[6] threading and dethreading of PAM3VBCB could be controlled by addition of BaC12 and Na2SO4.

Synthesis and Characterization of pH-Responsive Block Copolymers with Primary Amine Groups

A new pH-responsive block copolymer, methoxy poly（ethylene glycol）-b-poly[5-methacrylamido- pentylamine hydrochloride]（mPEG-b-PMAAPA） was synthesized and characterized in this paper. The monomer 5-methacrylamido-pentylamine hydrochloride（MAAPA） and the macroinitiator（mPEG-ACVA） were synthesized, re- spectively, and mPEG-b-PMAAPA was then obtained by free radical polymerization. The structure and molecular weight of mPEG-b-PMAAPA were cont]rmed by hydrogen nuclear magnetic resonance（~H NMR） spectroscopy and gel permeation chromatography with multiangle laser light scattering（GPC-MALLS） measurements. At a low pH, it is hydrophilic due to the protonation of the primary amine groups. With increasing pH value, deprotonation occurs and the hydrophobicity of PMAAPA block increases. This molecular feature leads to interesting aggregation behavior of mPEG-b-PMAAPA in aqueous solutions at different pH values as revealed by dynamic light scattering（DLS） measurements, transmission electron microscopy（TEM） observations and resonance light scattering（RLS） measure- ments.

Synthesis of ester-capped carbosilane dendrimers via a hybrid divergent–convergent method

A series of novel ester-capped carbosilane dendrimers（G0-COOCH3–G2-COOCH3） were designed and successfully synthesized via a hybrid divergent–convergent method through a facile hydrosilylation reaction. The structures of these dendrimers were confirmed by FTIR,1H NMR, and HRMS analyses.

Photo-induced tunable luminescence from an aggregated amphiphilic ethylene-pyrene derivative in aqueous media

An amphiphilic derivative with a large Stokes shift by introducing flexible hydrophilic long chains into a rigid ethylene-pyrene compound have been successfully synthesized.The alkylated compound exhibited a notable change in charge distribution,facilitating cation-π interactions.Through the process of amphiphilic self-assembly,the formation of highly ordered aggregates enabled effective photo-dimerization under 449 nm LED irradiation.Notably,this photo-responsive technology not only exhibited advanced multi-color emission effects,including white light emission but also exhibited environmentally friendly behavior in the aqueous phase.

A cationic amphiphilic tetraphenylethylene derivative with hydrochromic sensitive property:Applications in anti-counterfeiting ink and rewritable paper

Since the discovery of aggregation induced emission(AIE)phenomenon,various stimuli-responsive materials have been rapidly developed,but there are still great challenges in the application of ink printing due to the bad water solubility.In this research,a new cationic amphiphilic TPE-functionalized pyridine salt(TPE-OTs)was designed,which shows good water solubility and hydrochromic properties.The optical properties of the compound have been studied,which is equipped with the typical AIEE characteristics and TICT effect.The compound can self-assemble to form aggregates with a particle size of about 30 nm in water.What is more,the compound is responsive to the environmental humidity,whose fluorescent color changes from green to yellow as the humidity gradually increased.Based on this characteristic,we applied it to the fluorescent anti-counterfeiting ink,realizing the protection and encryption of information.

Triarylborane π-electron systems with intramolecular charge-transfer transitions

The incorporation of B element into π-conjugated system is an efficient strategy to tune the steric and electronic structure and thus optoelectronic properties of π-electron systems.The vacant p orbital on the tricoordinate B center makes it exhibit several electronic and steric features,such as electron-accepting ability through p-π~＊ conjugation,the high Lewis acidity to coordinate with Lewis bases,as well as the steric bulk arising from the aryl substituent on the B center to get enough kinetic stability.As a result,the boryl group is a very unique electron acceptor.When an electron-donating amino group is present,the triarylboranes would display intense intramolecular charge transfer transitions,which lead to interesting optoelectronic properties and great utilities.This short review summarizes the recent progress in π-electron systems,which contain both B and N elements and thus display intramolecular charge-transfer transitions.The triarylboranes are introduced based on their structural features,including the linear π-system with boryl and amino groups at the terminal positions,the lateral borylsubstituted π-system with amino groups at the terminal positions,the biphenyl π-system with an amino and a boryl groups at o,o＇-positions,nonconjugated U- and V-shaped π-system,macrocylcic π-system with B and N embedded in the ring,B,N-bridged ladder-type π-system,as well as the polycyclicπ-system with B embedded in the center.