Low-potential electrosynthesis of conducting and electroactive oligocatecholborane with blue light-emitting properties

Novel conducting oligocatecholborane (OCOB) with electrical conductivity of 3.73 × 10-2S cm-1 was successfully synthesized by low-potential electropolymerization of catecholborane (COB) in boron trifluoride diethyl etherate at 0.70 V versus Ag/AgCl. FT-IR and 1H-NMR spectra, together with the computational results, proved that COB was polymerized through the coupling at C(4) and C(5) positions and the reactive B―H bond was stable during the electrochemical polymerization. The resulting product was mainly composed of oligomers with short chain lengths by GPC and mass spectral results. The as-formed OCOB film showed good electrochemistry in monomer-free electrolytes with the electrochromic property from opaque blue to sap green. Fluorescence studies indicated that soluble OCOB can emit bright blue light under excitation of 365 nm UV light with the maximum emission at 396 nm and a fluorescence quantum yield of 0.21. The deposited OCOB also exhibited favorable thermal stability and smooth and compact morphology even at high magnifications.     

Syntheses,Structure and Properties of a Strontium(Ⅱ) Complex with 5-Sulfoisophthalic Acid Monosodium

A new Sr(Ⅱ) complex, [Sr(Hsip)(H2O)](1, NaH2sip = 5-sulfoisophthalic acid monosodium), has been synthesized by solvothermal reaction of Sr CO3 and NaH2sip at 120 ℃, and characterized by single-crystal X-ray diffraction studies, elemental analysis and FT-IR. Singlecrystal X-ray diffraction reveals that compound 1 has a 3D architecture, and there is only one crystallographically independent Sr(Ⅱ) ion in 1. The coordination geometry of Sr(Ⅱ) is a distorted tetragonal anti-prism. The whole Hsip2- ligand performs a μ6-coordination model. In the solid state, complex 1 shows luminescence with the maximum emission intensity at 417 nm upon excitation at 320 nm. Thermal stability of complex 1 was also investigated.     

酸碱处理后纳米微晶纤维素的热行为分析

Nanocrystalline cellulose (NCC) was prepared from microcrystalline cellulose (MCC) by acid hydrolysis. It was observed that the diameter of NCC particles mainly distributed over 30-50nm by transmission electron microscope (TEM) . The crystal form and degree of crystallinity were detected by X-Ray diffraction. The results showed that NCC and MCC have the same crystal form of cellulose I, and that the reactions mainly occurred in the amorphous region of MCC during the acid hydrolysis process. The thermal behavior of NCC in different pH conditions was characterized by differential scanning calorimetry (DSC) . The consequences indicate that the thermal stability of NCC distinctly decreased by contrast with the thermal stability of MCC, and that the thermal stability of NCCs in alkali conditions was higher than that of NCCs in acid conditions. The specific surface area distinctly increased with sharp decreasing of the particle size of NCC. This induced the end carbons and active groups of surface of NCC to increase sharply, therefore caused the thermal stability of NCC to distinctly abate. That NCC has very strong adsorption affinity is the cause of the obvious difference of thermal behavior of NCC in different pH. In acid conditions the surface of NCC adsorbed a great lot of H^ , which induced the cellulose chains of surface of NCC to decompose at low temperature catalyzed by H^ . When adding sodium hydroxide solution, on one hand the H^ of surface of NCC was neutralized; on the other hand, the cellulose chains of low molecular weight were dissolved in sodium hydroxide solution and the defects of surface of NCC rearranged and stable structure formed. These factors improved the thermal stability of NCC in alkali conditions.     

Fluorescent and thermal properties of siloxane-polyurethanes based on 1,8-naphthalimide

A series of fluorescent siloxane-polyurethanes(HPMS-PUs) containing an amino-functionalized,1 8-naphthalimide,fluorescent monomer(AABD) as a chain extender were synthesized.The properties of the HPMS-PUs were investigated by UV–vis and fluorescence spectroscopies,thermogravimetric analysis and thermal migration behavior.The maximum absorption and emission wavelengths of HPMS-PUs showed a red shift of about 4 nm and a blue shift of about 9 nm,respectively,compared to those of AABD.The Stokes shifts of AABD and HPMS-PU2 were 3514 and 2931 cm 1,respectively.The quantum yield of HPMS-PU2 was 0.79,which was six times higher than that of AABD.Concentration self-quenching was observed in both AABD and HPMS-PUs.The fluorescence of HPMS-PUs was quite stable with respect to both temperature and fluorescence quencher effects.The thermal stability of HPMS-PUs increased with AABD content.The fluorophore units in the HPMS-PUs did not readily migrate.     

FLUORENE-BASED LIGHT-EMITTING POLYMERS

Several series of fluorene-based light-emitting polymers with the emphasis on achieving efficient and stable bluelight emission are reported. Spiro-functionalization may narrow the emission spectra (with smaller tail at Ionger wavelengths)of fluorene homopolymers to provide purer blue emission. The thermal spectral stability of the polymers could also beimproved because of the elevation of the glass transition temperature caused by the spiro-functionalization. However, theexcimer emission in fluorene homopolymers is not suppressed by the spiro-functionalization. Alternate copolymers of 9,9-dihexylfluorene and substituted phenylenes may emit efficient blue ligh both in solution and in film. The optical propertiesare dependent on the substituion on the phenylene ring. The alkoxy-substituted polymers displayed efficient PL and EL andgood thermal spectral stability. The HOMO and LUMO energy levels of the polymers based on the backbone structure couldbe tuned in a wide range by attaching different functional groups on the phenylene ring. By attaching europium(III) complexat the ends of the side chains in the alternate copolymers, we have demonstrated a new approach to achieving red emissionwith a very narrow spectrum. The copolymers of 9,9-dihexylfluorene and thiophene and bithiophene with differentsubstitutions were also synthesized to study the effect of substitution and regioregularity on the optical and other physicalproperties of the polymers.     

Novel redox-active ionic thermotropic liquid crystalline complexes of polyelectrolyte and ferrocenyl surfactants

Redox-active polyelectrolyte-surfactant complexes(PSC) were prepared via the ionic self-assembly of sodium poly(styrenesulfonate) (PSS) and ferrocenyl surfactant,(11-ferrocenylundecyl)trimethylammonium bromide(FTMA) in aqueous solution. The PSS-FTMA complex exhibited an ordered interdigitated monolayer mesomorphous structure with the long period of d = 3.13 nm,and was in the ionic thermotropic liquid crystal SmA state at room temperature.Interestingly,in the solid complex, the ferrocenyl moieties formed H-aggregation showing an increase in theπ-π~* energy transfer of cyclopentadienes in the ferrocene moieties as known from the blue-shift in the UV spectrum.The complexes showed higher thermal stability compared with their components due to the ionic interaction.The PSS-FTMA film had a good redox reversibility,which promised to be used in electrochemical sensors.     

A new oxidovanadium(Ⅳ) Schiff base complex containing asymmetric tetradentate ONN0O0Schiff base ligand:Synthesis,characterization,crystal structure determination,thermal study and catalytic activity

After synthesis of an asymmetric tetradentate ONN0O0 Schiff base ligand(H2L) followed by reaction of the synthesized H2 L with an equimolar mixture of methanolic solutions of the VO(acac)2, a new oxidovanadium(IV) Schiff base complex(VOL) was synthesized. The Schiff base ligand and its complex were characterized by FT-IR and UV–vis spectra and C, H, N analysis. The crystal structure of VOL was also determined by single crystal X-ray analysis. The VOL complex crystallizes in monoclinic space group Cc. The Schiff base ligand acts as a tetradentate ligand through its two iminic nitrogens and two phenolic and acetylacetonate oxygens. Thermogravimetric analysis of the VOL showed that it decomposes in two steps and converts to mixed vanadium oxides at 477 8C. In addition, thermal decomposition of the VOL complex in air at 660 8C leads to formation of V2O5 nanoparticles with the average size estimated from XRD 49 nm. The catalytic activity of the VOL complex was investigated in the epoxidation reaction and different reaction parameters were optimized. The results showed that the cyclic alkenes were efficiently converted to the corresponding epoxides, whereas the VOL did not appreciably convert the linear alkenes.     

Pi Stacking Interactions in Two TPT Derivatives and Their Photoluminescence Characters

π-π Stacking in the 2,4,6-tris（4-pyridyl）-1,3,5-triazine aromatic nitrogen-containing ligand and its metal-ligand complex Zn（TPT）2（H2O）4（OH）2 1 has been investigated by single-crystal X-ray diffraction analyses. The stacking mode of the ligand changes from the offset conformation to a perfect face-to-face alignment with the coordination to the zinc centers. The structure features are correlated with their solid-state luminescence properties. With excitation at 360 nm, free TPT ligand gives a strong fluorescent emission at 455 nm and the ligand-centered emission of the metal-ligand complex occurs at the same wavelength with lower emission intensity. The distance between the aromatic rings responds to the difference of luminescence characters.     

Preliminary Synthesis and Characterization of Mesoporous Nanocrystalline Zirconia

A novel method to prepare mesoporous nano-zirconia was developed. The synthesis was carried out in the presence of PEO surfactants via a solid-state reaction. The materials exhibit a strong diffraction peak at low 28 angle and their nitrogen adsorption/desorption isotherms are typical of type IV with H1 hysteresis loops. The pore structure imaged by TEM can be described as wormhole domains. The tetragonal zirconia nanocrystals are uniform in size (around 1.5 nm) and their mesopores focus on around 4.6 nm. The zirconia nanocrystal growth is tentatively postulated to be the result of an aggregation mechanism. This study also reveals that the PEO surfactants can interact with the Zr-O-Zr framework to reinforce the thermal stability of zirconia. The ratio of NaOH to ZrOC12, crystallization and calcination temperature play an important role in the synthesis of mesoporous nano-zirconia.     

Synthesis,Structure and Properties of a New Terbium(Ⅲ) Complex Tb_2(C_(15)H_(11)O_3)_6(phen)_2

A new terbium(Ⅲ) complex Tb_2(C_(15)H_(11)O_3)_6(phen)_2 has been synthesized with 2-(4-methylbenzoyl)benzoic acid and 1,10-phenanthroline as ligands.Crystal data for the complex are as follows:monoclinic,space group P2_1/n,a=15.0786(6),b=13.5762(5),c=22.9683(9) A,β=104.130(4)°,V=4559.6(3) A~3,D_c=1.540_g/cm~3,Z=2,μ(MoKα)=1.615 mm~(-1),F(000)=2136,the final R=0.0528 and wR=0.0740.The Tb(Ⅲ) ion is coordinated by eight atoms to give a distorted square antiprism coordination geometry.The complex shows four fluorescence emission bands arising from the transitions of Tb~(3+5)D_4→~7F_6(490 nm),~5D_4→~7F_5(546 nm),~5D_4→~7F_4(588 nm) and ~5D_4→~7F_3(622 nm).The complex is an antiferromagnet in the range of 300～2 K.Also reported in the paper is the thermal stability property of the title complex.     

聚N-异丙基丙烯酰胺-丙烯酸共聚微凝胶与Tb(Ⅲ)相互作用的研究

聚N-异丙基丙烯酰胺(PNIPAM)微凝胶是一类具有独特的温度响应性,即具有最低临界溶解温度(LCST)的高分子化合物,由于具有了LCST性能,当PNIPAM微凝胶受热时,在较窄的温度范围内,溶胀于微凝胶内的溶剂被挤出,从而导致微凝胶的粒子尺寸、粒子形态、亲水性、胶体稳定性以及微凝胶分散液的粘度、电泳流动性发生较大改变的现象。     

Lanthanide-sensitized lanthanide luminescence: terbium-sensitized ytterbium luminescence in a trinuclear complex

A heterotrinuclear lanthanide complex has been prepared which contains two terbium ions in DO3A-derived binding sites and a single ytterbium ion in a DTPA-like site. The luminescence properties of the system have been investigated, showing that the terbium remains in a seven-coordinate binding site throughout the synthesis, while the ytterbium occupies the eight-coordinate site. Pumping the 488 nm absorption band of the terbium ion results in energy transfer to ytterbium with emission at 980 nm.     

微量铽的萤光光度测定——铽与吡啶-2,6-二羧酸螯合物的萤光

铽与吡啶-2,6-二羧酸(以下简称DPA)形成螯合物的萤光有人从生物化学角度作过一些研究^[1],但对测定稀土氧化物中微量铽的研究未见报导。本文系统地研究了Tb³⁺-DPA螯合物萤光产生的条件,拟订了测定稀土氧化物中微量铽的萤光光度法,探讨了螯合物萤光强度与其组成的关系。     

多功能合一的含稀土铽高聚物的性质表征

制备了一种新型的含稀土铽高聚物光电材料, 结合元素分析和X射线光电子能谱(XPS)对材料的组成进行分析并确认它的结构. 荧光光谱表明含稀土铽高聚物是一类发纯绿光的发光材料. 用循环伏安法研究它的电化学行为, 测定材料的HOMO和LUMO能级. 研究结果表明, 这种材料同时具有空穴与电子传输功能, 其HOMO和LUMO能级可与电致发光器件的工作电极相匹配.     

Tunable Emissive Lanthanidomesogen Derived from a Room‐Temperature Liquid‐Crystalline Schiff‐Base Ligand

A novel photoluminescent room‐temperature liquid‐crystalline salicylaldimine Schiff base with a short alkoxy substituent and a series of lanthanide(III) complexes of the type [Ln(LH)₃(NO₃)₃] (Ln=La, Pr, Sm, Gd, Tb, Dy; LH=(E)‐5‐(hexyloxy)‐2‐ [{2‐(2‐hydroxyethylamino)ethylimino]methyl}phenol) have been synthesized and characterized by FTIR, ¹H and ¹³C NMR, UV/Vis, and FAB‐MS analyses. The ligand coordinates to the metal ions in its zwitterionic form. The thermal behavior of the compounds was investigated by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The ligand exhibits an enantiotropic hexagonal columnar (Col_h) mesophase at room temperature and the complexes show an enantiotropic lamellar columnar (Col_L) phase at around 120 °C with high thermal stability. Based on XRD results, different space‐filling models have been proposed for the ligand and complexes to account for the columnar mesomorphism. The ligand exhibits intense blue emission both in solution and in the condensed state. The most intense emissions were observed for the samarium and terbium complexes, with the samarium complex glowing with a bright‐orange light (ca. 560–644 nm) and the terbium complex emitting green light (ca. 490–622 nm) upon UV irradiation. DFT calculations performed by using the DMol3 program at the BLYP/DNP level of theory revealed a nine‐coordinate structure for the lanthanide complexes.     

Enantiopure lanthanide complexes incorporating a tetraazatriphenylene sensitiser and three naphthyl groups: exciton coupling,intramolecular energy transfer,efficient singlet oxygen formation and perturbation by DNA binding

In cationic nine-coordinate chiral terbium and europium complexes incorporating exciton-coupled naphthyl groups and a tetraazatriphenylene sensitising chromophore, efficient intramolecular energy transfer occurs leading to population of the naphthyl triplet state. With the terbium complex, the absolute quantum yield of singlet oxygen formation is 51% (lambda(exc) 355 nm), and for the Eu complex the intensity of metal-based emission increases by up to 350% on binding to poly(dGdC) or calf-thymus DNA, and was greater for the delta-isomer.     

Photoluminescence of terbium-containing sol-gel glasses

Glasses of the following composition: T glass SiO₂, TL glass SiO₂/ligand, T-Tb glass SiO₂/terbium complex were obtained by the method of acid catalyzed hydrolytic homo- and cocondensation of tetraethoxysilane (the source of SiO₂) with 3-(3-triethoxysilylpropyl)pentane-2,4-dione (the ligand) and terbium(III) tris[3-3-triethoxysilylpropyl)pentane-2,4-dionate] (terbium complex). The study of the fluorescence spectra showed that the cationic luminescence is achieved by the excitation of terbium-containing glasses at the absorption band of the ligand (λ_exc 275–280 nm). Energy transfer from the matrix (SiO₂) to the ligand and cation with the following emission of Tb³⁺ is possible on exciting the T-Tb glass by the light with the wavelength 360 nm. However, this method of generating terbium cation emission seems to be less efficient.     

SiO2凝胶中铕(铽)-间甲基苯甲酸-邻菲咯啉配合物的热稳定性及发光性能研究

采用溶胶 凝胶法 ,以掺杂方式制备了含有铕 (铽 ) 间甲基苯甲酸 邻菲咯啉配合物的SiO2凝胶复合发光体 ,研究了其热分解曲线、激发光谱和发射光谱 ,并与固体粉末进行了比较 ,讨论了将配合物引入该凝胶后对其热稳定性及发光的影响。     

Emissive terbium probe for multiphoton in vitro cell imaging

A polymeric terbium complex that can be excited by near-infrared excitation at 800 nm via multiphoton absorption processes has been synthesized. This complex has been demonstrated to show strong, observable, three-photon-induced f-f emission in cell imaging. In vitro studies carried out in three carcinoma cell lines (A549, HONE1, and HeLa) have been performed and shown to have low cytotoxicity. This complex is therefore a potential candidate for future infrared excitation imaging dyes.     

Chemiluminescence during thermal degradation of sodium persulfate in the presence of terbium sulfate: 1. The catalytic effect of terbium(III) ions

Chemiluminecscence (CL) generated during the thermal degradation of sodium persulfate in the presence of terbium(III) sulfate was studied. The CL spectrum corresponds to emission from excited terbium ions. It was found that Tb(III) acts not only as a photon emitter but also a catalyst for the thermal degradation of sodium persulfate. A scheme of reactions resulting in the formation of excited-state Tb(III) was proposed.