Synthesis of oligo(p-phenylene vinylene)-porphyrin-oligo(p-phenylene vinylene) triads as antenna molecules for energy transfer

The oligo(p-phenylene vinylene)-porphyrin-oligo(p-phenylene vinylene) (P-OPVn, n=2, 4, where n is the number of phenyl rings) and the complex with Zn²⁺ based on P-OPVn were synthesized for investigating their photophysical properties via UV-vis, voltammetry, steady-state and time-resolved fluorescence spectra. In these molecules two OPV moieties as energy donors were linked to porphyrin center by virtue of Wittig reaction. The detailed studies of photophysical properties indicate that OPV group can act as an antenna unit for effective intramolecular energy transfer.     

Selective permeation of CO2 through poly 2-(N,N-dimethyl)aminoethyl methacrylate membrane prepared by plasma-graft polymerization technique

A membrane having an amine moiety was prepared by plasma-grafting 2-(N,N-dimethyl)aminoethyl methacrylate (DAMA) onto a microporous polyethylene substrate. Permselectivity of the membrane for CO₂ over N₂ was achieved in both dry and water swollen conditions. When the CO₂ partial pressure in the feed gas was 0.047 atm, the selectivity of CO₂ over N₂ reached 130 for the highly swollen water containing membrane. This value was found to agree with that obtained with a mobile carrier membrane (supported liquid membrane) using DAMA as the carrier. The effects of several experimental conditions such as degree of grafting, feed partial pressure and temperature on the membrane performance were studied. It was suggested that the membrane acted as a fixed carrier membrane for CO₂ facilitated transport in under the dry condition and acted as a fixed reaction site membrane in the water swollen condition. The carrier transport mechanism is discussed for dry and aqueous membranes.     

不同分子量N-琥珀酰壳聚糖的制备及其与K562肿瘤细胞间亲和性的初步探讨

用化学降解法制备不同分子量的壳聚糖 ,以其为原料合成了系列N 琥珀酰壳聚糖 ,然后用异硫氰酸荧光素进行荧光标记 ,再与K5 6 2肿瘤细胞共孵育 ,通过流式细胞仪检测细胞的荧光强度来确定不同分子量N 琥珀酰壳聚糖与K5 6 2肿瘤细胞间亲和性的强弱 ,为靶向抗肿瘤药物载体的研究提供初步的参考 .结果表明N 琥珀酰壳聚糖和K5 6 2肿瘤细胞间有较强的亲和性 ,随着分子量的增加 ,其亲和性逐渐减弱 .     

Time-resolved fluorescence analysis of the mobile flavin cofactor in p -hydroxybenzoate hydroxylase

Conformational heterogeneity of the FAD cofactor in p-hydroxybenzoate hydroxylase (PHBH) was investigated with time-resolved polarized flavin fluorescence. For binary enzyme/substrate (analogue) complexes of wild-type PHBH and Tyr222 mutants, crystallographic studies have revealed two distinct flavin conformations; the ‘in’ conformation with the isoalloxazine ring located in the active site, and the ‘out’ conformation with the isoalloxazine ring disposed towards the protein surface. Fluorescence-lifetime analysis of these complexes revealed similar lifetime distributions for the ‘in’ and ‘out’ conformations. The reason for this is twofold. First, the active site of PHBH contains various potential fluorescence-quenching sites close to the flavin. Fluorescence analysis of uncomplexed PHBH Y222V and Y222A showed that Tyr222 is responsible for picosecond fluorescence quenching free enzyme. In addition, other potential quenching sites, including a tryptophan and two tyrosines involved in substrate binding, are located nearby. Since the shortest distance between these quenching sites and the isoalloxazine ring differs only little on average, these aromatic residues are likely to contribute to fluorescence quenching. Second, the effect of flavin conformation on the fluorescence lifetime distribution is blurred by binding of the aromatic substrates: saturation with aromatic substrates induces highly efficient fluorescence quenching. The flavin conformation is therefore only reflected in the small relative contributions of the longer lifetimes.     

Homooxacalix[3]arene Derivatives as Ionophores for Serotonin‐Selective Membrane Electrodes

Homooxacalix[3]arene derivatives are effective ionophores for constructing serotonin‐selective membrane electrodes. An electrode based on one of the derivatives, tris(methoxyphenylpropyloxy)hexahomooxacalix[3]arene‐triethyl ether, with potassium tetrakis(p‐chlorophenyl)borate (20 mol% relative to the ionophore) as an ionic additive and bis(2‐ethylhexyl) sebacate as a solvent mediator in a poly(vinyl chloride) membrane matrix, displayed much better selectivity for serotonin than for various organic ammonium ions and inorganic cations. The electrode exhibited a near‐Nernstian response to serotonin in the concentration range of 2×10^?4 to 1×10^?2 M with a slope of 56.4 mV per concentration decade in physiological saline containing 150 mM NaCl and 10 mM Na₂HPO₄/NaH₂PO₄ (pH 7.4). The limit of the detection was 8×10^?5 M. The selectivity pattern of this electrode was quite different from that of an electrode using calix[6]arene‐hexaacetic acid hexaethyl ester, a well‐known ionophore for primary organic ammonium ions, which did not induce an enhanced response to serotonin. The developed electrode was used for the active loading of serotonin in liposomes induced by transmembrane pH gradients.     

四苯基卟啉氧合配合物的室温固相合成、表征及氧合性能

采用固相反应合成了四苯基卟啉与Fe2 、Co2 的配合物.在室温下,将其与分子O2作用,提纯后得到两种固态氧合配合物.通过元素分析、红外光谱、核磁共振氢谱、电导、热分析(TG/DTA)、紫外光谱等测试手段确定了氧合配合物的组成为[Co·TPP·O2](NO3):·2H2O、[Fe·TPP·O2]Cl2·2H2O,可知1mol配合物吸收了1mol O2.采用失重法测定了氧合配合物中的配位氧,确定1mol金属配合物吸收1mol O2形成超氧配合物.     

Aggregation-Induced Intermolecular Charge Transfer Emission for Solution-Processable Bipolar Host Material via Adjusting the Length of Alkyl Chain

Molecules with donor–spacer–acceptor configuration have been developed rapidly given their peculiar properties. How to utilize intermolecular interactions and charge transfers for solution-processed organic light-emitting diodes (OLEDs) greatly relies on molecular design strategy. Herein, soluble luminophores with D-spacer-A motif were constructed via shortening the alkyl chain from nonane to propane, where the alkyl chain was utilized as a spatial linker between the donor and acceptor. The alkyl chain blocks the molecular conjugation and induces the existence of aggregation-induced intermolecular CT emission, as well as the improved solubility and morphology in a solid-state film. In addition, the length of the alkyl chain affects the glass transition temperature, carrier transport and balance properties. The mCP-3C-TRZ with nonane as the spacer shows better thermal stability and bipolar carrier transport ability, so the corresponding solution-processable phosphorescent organic light-emitting diodes exhibit superior external quantum efficiency of 9.8% when using mCP-3C-TRZ as a host material. This work offers a promising strategy to establish a bipolar host via utilizing intermolecular charge transfer process in an aggregated state.     

肿瘤靶向PEI包覆磁性纳米凝胶的光化学制备及表征

以聚乙烯亚胺(Polyethyleneimine, PEI)为预聚体, H2O2为抽氢剂, 采用光化学方法制备了PEI包覆的磁性纳米凝胶(PEI-Fe3O4), 在PEI-Fe3O4表面共价偶联具有肿瘤靶向作用的叶酸分子(Folate, FA), 制备得到肿瘤靶向PEI包覆磁性纳米凝胶(FA-PEI- Fe3O4). 采用多种手段对PEI-Fe3O4及FA-PEI-Fe3O4进行了表征. 结果表明, FA-PEI-Fe3O4平均粒径为140 nm, 形状规则, 具有超顺磁性, 磁含量达到22.4%, 饱和磁化强度达65.6 A·m2·kg-1, 磁性纳米凝胶较高的磁响应性能和具有肿瘤靶向作用的叶酸分子的修饰, 为其作为潜在的肿瘤靶向载体奠定了基础.     

聚(2-甲氧基-5-辛氧基)对苯乙炔/TiO2纳米复合材料的光物理性能研究

通过原位强碱诱导下的脱氯化氢缩合聚合法制备了一系列不同纳米TiO2含量的聚(2-甲氧基-5-辛氧基)对苯乙炔/纳米二氧化钛(PMOCOPV/TiO2)光电复合材料。红外光谱和拉曼光谱证实了在纳米TiO2表面的包覆层为PMOCOPV。紫外-可见吸收光谱表明随着TiO2含量的增加PMOCOPV/TiO2纳米复合材料的吸收强度提高。高分辨透射电镜观察发现PMOCOPV/TiO2是具有核-壳结构的纳米复合粒子,直径约30 nm,其中PMOCOPV包覆层的厚度约为8~10 nm。荧光光谱研究表明,PMOCOPV/TiO2纳米复合材料的最大发射波长随着TiO2含量的增加发生红移,荧光寿命约为1 ns,且随着TiO2含量的增加荧光强度和荧光寿命得到显著提高,并通过PMOCOPV/TiO2纳米复合材料中的激子离化和电荷传输过程以及复合材料中的电势能级探讨了PMOCOPV/TiO2的荧光量子效率和荧光强度增加的机理。