固态上转换材料制备及其性能研究

摘要：有机上转换（UC）是一种通过双光子机制将低能量（长波长）的光转换为高本文尝试选择固态聚合物聚二甲基硅氧烷（PDMS）为基质,将光敏剂四苯基卟啉钯（PdTPP）和发光剂9,10-二苯基蒽（DPA）分散其中,制得了固态上转换材料（PdTPP/DPA/PDMS）,有效隔绝了空气中的氧气对光敏剂与发光剂三线态的淬灭,在空气气氛中固态上转换的稳定时间可延长至10 h以上;更重要的是,其上转换效率（uc）最高可达26.3%,这是目前文献报道的最高值。     

环糊精增强金属卟啉/蒽衍生物上转换及其应用

以2-氯-9,10-二甲苯基蒽(DTACl)为发光剂,分别与不同的光敏剂[四苯基卟啉钯(PdTPP)和四苯基卟啉铂(Pt TPP)]构成二元体系(PdTPP/DTACl和Pt TPP/DTACl),并用不同的环糊精(a-CD、b-CD或g-CD)包络发光剂,构成光敏剂/发光剂/CD三元体系。利用紫外分光光度计、荧光光谱仪、二极管泵浦固态激光器、色度计对二元体系及三元体系进行了光谱性能测试,考察了光敏剂的三线态寿命和环糊精包络效应对上转换效率的影响。结果表明,在532 nm低功率(60 m W/cm2)半导体激光器激发下,PdTPP/DTACl和Pt TPP/DTACl体系的上转换效率分别达10.33%和7.15%;PdTPP的三线态寿命(9.63ms)长于Pt TPP的三线态寿命(6.41ms)。在PdTPP/DTACl体系中加入b-CD,上转换效率可提高至12.82%;将获得的蓝光上转换PdTPP/DTACl/b-CD辐照香豆素水溶液(Pt/WO3半导体为催化剂),20 min后即出现7-羟基香豆素的荧光发射峰(469 nm),表明蓝光上转换PdTPP/DTACl/b-CD可催化香豆素转化为7-羟基香豆素。     

固态上转换材料制备及其性能

以聚二甲基硅氧烷(PDMS)为固态介质,将PDMS浸泡于光敏剂四苯基卟啉钯(Pd TPP)和发光剂9,10-二苯基蒽(DPA)的甲苯溶液中,干燥后得到上转换固态树脂(Pd TPP/DPA/PDMS)。利用紫外吸收光谱仪、稳态-瞬态荧光光谱仪和半导体激光器考察了液态(Pd TPP/DPA/甲苯)和固态(Pd TPP/DPA/PDMS)两种体系的上转换效率(Фuc)及在空气中的稳定性。结果表明,在相同条件下(半导体激光器发射波长532 nm,功率密度60 m W/cm2),固态上转换效率最高可达26.3%,固态树脂在空气中保持22%的上转换效率可持续在10 h以上,而液态二元体系在空气中保持22%的上转换效率只能持续2 min。     

靶向光敏剂NaYF4:Yb,Tm@ NaGdF4:Yb@TiO2@PEI-PAA-FA的制备和性能

采用水解法用TiO_2包覆上转换纳米粒子Na YF4:Yb,Tm@NaGdF4:Yb,然后修饰聚乙烯亚胺(PEI)和聚丙烯酸(PAA)并偶联叶酸(FA),制备了叶酸受体靶向纳米光敏剂(NaYF4∶Yb,Tm@NaGdF4∶Yb@TiO_2@PEIPAA-FA)。借助XRD和TEM表征NaYF4∶Yb,Tm@NaGdF4∶Yb@TiO_2的物相和形貌,FTIR和Zeta电位证实有机成分的成功修饰,并测试了产物的上转换发光光谱。结果表明:在980 nm近红外光(NIR)下,纳米光敏剂存在下的1,3-二苯基异苯并呋喃溶液吸收光谱的降低证明了单线态氧的产生。此外,纳米光敏剂可以载带阿霉素(DOX),最大载药率为50.8%,包封率为84.7%。载药后的纳米光敏剂中DOX释放对介质具有pH响应性,在NIR照射的酸性介质(pH=5.0)中12 h的累积缓释率为38.1%,远高于中性介质(pH=7.4)的10.4%。     

头孢类药物制备过程的HPLC中控分析方法研究

3-乙酰氧基甲基-7β-特丁氧羰基氨基-3-头孢-4-羧酸(3-ATC)是头孢类药物制备的重要中间体,它可通过7-氨基头孢烷酸(7-ACA)和二碳酸二叔丁酯(BOC)反应合成,本文采用高效液相色谱法(HPLC)建立了该反应的中控分析方法。方法采用反相C18色谱柱,以270nm为检测波长,乙腈-离子对试剂(0.01mol/L四丁基溴化铵+0.005mol/L磷酸氢二钠的水溶液,pH7.0)为流动相的条件下分离检测了7-ACA和3-ATC,7-ACA的相对标准偏差、平均回收率、线性范围分别为0.66%(n=5),103.0%(n=3),0.21～2.68×102μg/mL(r=0.9923),3-ATC的相对标准偏差、平均回收率、线性范围分别为0.51%(n=5),99.8%(n=3),0.075～1.06×103μg/mL(r=0.9992)。     

反相液相色谱法测定7-羟基-3,4-二氢-2(1H)-喹啉酮的含量

建立了反相液相色谱测定7-羟基-3,4-二氢-2(1H)-喹啉酮含量的方法。采用shim-pack C18柱(5μm,4.6mmi.d.×250mm),流动相为v(甲醇)∶v[缓冲溶液(含事先配制好的0.075mol/L的磷酸二氢铵,磷酸调至pH=3)]=50∶50,流速为0.8mL/min,检测波长为250nm。外标法定量,7-羟基-3,4-二氢-2(1H)-喹啉酮1～100μg/mL浓度范围内呈良好的线性关系,线性回归系数r为0.9997,平均回收率为99.26%,RSD=1.17%(n=9)。     

1,2-二苯乙炔的合成研究

以溴苯和苯乙炔为原料,经过Sonogashira偶联反应得到1,2-二苯乙炔,产物结构经1H NMR、13C NMR和ESI-MS确证。并对Sonogashira偶联反应条件进行研究,确定最佳条件为:物料比为n (溴苯)∶n (苯乙炔)=1.5∶1;催化剂Pd(PPh3)2Cl2用量为n(Pd(PPh3)2Cl2)∶n(苯乙炔)=0.04∶1;PPh3用量为n(PPh3)∶n(苯乙炔)=0.3∶1;Cu I用量为n(Cu I)∶n(苯乙炔)=0.1∶1;反应溶剂为N,N-二甲基甲酰胺和三乙胺的混合溶剂(V∶V=2∶1);反应温度70℃;反应时间8 h;产物收率为88.7%。按照最佳反应条件,4-甲氧基溴苯与4-甲氧基苯乙炔反应得到1,2-双(4-甲氧基苯基)乙炔,收率为84.3%。     

高效液相色谱法测定降香叶中γ-氨基丁酸的含量

建立降香叶中γ-氨基丁酸的含量测定方法。样品经过2,4-二硝基氟苯衍生化后,高效液相色谱法测定含量。色谱测定采用Kromasil C18色谱柱(150 mm×4. 6 mm,5μm),流动相A为V(乙腈)∶V(超纯水)=1∶1,流动相B为pH值6. 8的磷酸盐缓冲液(含有3%四氢呋喃),A∶B=35∶65;检测波长360 nm。γ-氨基丁酸在0. 01～0. 1 mg/mL范围内呈良好线性关系(R~2=0. 9994),加样回收率在83. 64%～86. 77%,RSD=3. 3%(n=9)。该方法具有良好的专属性和稳定性,可用于降香叶中γ-氨基丁酸的定量分析。     

聚二甲基硅氧烷基上转换材料的制备与光催化应用

将光敏剂四苯基卟啉钯(Pd TPP)和湮灭剂9,10-二苯基蒽(DPA)溶解于甲苯,在Tween 20的乳化作用下与去离子水配制成O/W上转换微乳液;进一步与二甲基硅氧烷共混,将O/W上转换微乳液体系负载于固化后的聚二甲基硅氧烷(PDMS)中,制得基于三线态-三线态湮灭(TTA)机制的PDMS固态上转换树脂材料。在半导体激光器(532nm,60m W/cm2)激发下,固态上转换材料可发射强的绿转蓝上转换荧光,固态上转换效率最大可达22%。将该材料应用于光电流响应和光催化降解过程中:三电极体系在PDMS固态上转换树脂上转换荧光的照射下,获得了0.9μA的光电流,证明了光电流的产生源于上转换蓝光对ZnCdS薄膜的照射;Pt/WO3粉末存在和固态上转换蓝光照射的条件下,罗丹明B染料降解作用显著,最大光降解效率达到82.3%。     

两性聚酰胺-胺树状聚合物的合成及絮凝性能

用Michael加成反应对G4.0聚酰胺-胺(PAMAM)树状聚合物分子进行了表面修饰改性。分别以丙烯酰氧基乙基三甲基氯化铵(DAC)、丙烯酸钠(SAA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为端基改性剂,在N2气氛下50℃甲醇溶液中,反应投料比n(PAMAM)∶n(DAC)∶n(SAA或AMPS)=1∶16∶16时,反应96 h,合成出了两性聚酰胺-胺树状聚合物。絮凝性能实验结果表明,合成产物具有一定的絮凝性能,且与聚丙烯酰胺复配效果更好,最佳絮凝效果条件为:m(G4.0/DAC/AMPS)∶m(PAM)=1∶4;投药量16 mg/L;絮凝沉降时间20 min;pH=8~9。     

O/W型微乳液应用于三线态湮灭上转换介质研究

光子上转换是吸收低能量（长波长）的光发射高能量（短波长）光的过程,在太阳能光伏、光催化等领域具有潜在应用价值而受到广泛研究,然而通常介质采用有机溶剂及绝氧处理都大大限制了上转换的实际应用.本文报道了可用于三线态湮灭上转换过程的新介质-O/W型微乳液,该体系制备简单、无毒环保,无需除氧脱气条件下,上转化发光稳定,具有未来实际应用的潜力.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.