Alternating copolymers of 2,6‐bis(p‐dihexylaminostyryl)anthracene‐9,10‐diyl and N‐octylcarbazole with large two‐photon cross sections

We report the synthesis, thermal, one‐ and two‐photon properties of poly(2,6‐bis(p‐dihexylaminostyryl)anthracene‐9,10‐diyl‐alt‐N‐octylcarbazole‐3,6‐/2,7‐diyl) ( P1/P2 ). The as‐synthesized polymers exhibit number‐average molecular weights of 1.7 × 10⁴ for P1 and 2.1 × 10⁴ g/mol for P2 . They emit strong one‐ and two‐photon excitation fluorescence with the peak around 502 nm, and the fluorescence quantum yields around 0.76 in chloroform. In film state, P1 and P2 show different red‐shift emission with the peaks at 512 nm and 523 nm, respectively. The DSC measurement reveals that as‐synthesized polymers are all amorphous aggregates with the glass transition temperatures of 131 °C for P1 and 152 °C for P2 . The solution two‐photon absorption (TPA) properties of P1 and P2 in chloroform are measured by the two‐photon‐induced fluorescence method using femtosecond laser pulses (120 fs). The TPA cross sections (δ) are measured over the range of 700–900 nm. The maximal δ of P1 and P2 all appear at ～800 nm and are 1010 GM and 940 GM per repeating unit, respectively. This suggests that no notable interactions among structure units that impair their fluorescence and TPA properties, and the polymers with large δ can be obtained by using the high TPA‐active units as building blocks. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Effect of Calcination Temperature on La-Modified Al2O3 Catalysts for Vapor Phase Hydrofluorination of Acetylene to Vinyl Fluoride

A La-modified Al₂O₃ catalyst was prepared with deposition-precipitation method. The effect of calcination temperature on the reactivity for vapor phase hydrofluorination of acetylene to vinyl fluoride. The catalysts calcined at different temperatures were characterized using NH₃-TPD, pyridine-FTIR, X-ray diffraction, and Raman techniques. It was found that the calcination process could not only change the structure of these catalysts but also modify the amount of surface acidity on the catalysts. The catalyst calcined at 400 oC exhibited the highest conversion of acetylene (94.6%) and highest selectivity to vinyl fluoride (83.4%) and lower coke deposition selectivity (0.72%). The highest activity was related to the largest amount of surface acidity on the catalyst, and the coke deposition was also related to the total amount of surface acidic sites.     

碱土－稀土氧化物在甲烷偶联反应中的催化性能

研究了两个典型轻稀土Ｌａ，Ｃｅ氧化物对甲烷氧化偶联反应的影响，具有较小比表面积的催化剂给出较高的Ｃ＿２选择性，但是催化剂的氧化还原性能对Ｃ＿２选择性的影响则更大，添加Ｌｉ的作用除产生Ｏ￣－中心外，还可抑制催化剂的氧化还原能力，从而改善Ｃ＿２选择性。甲烷氧化偶联反应属催化剂引发的自由基反应。     

利用Eu3+荧光特性研究CaO-La2O3催化剂结构

近年来，利用稀土窝子荧光特性作为探针研究无机、有机、生物大分子结构，日益引起人们的注意．因为稀土荧光特征可以灵敏地反映发光离子近部环境的对称性、所处格位及不同对称性的格位数、有无反演中。心等结构信息[1]．由于Eu3＋离子基态能级7F0和主要的发射能级5D0的总角动量数J都为零，不被晶体场所劈裂，而且Eu3＋在不同点群对称性时，7FJ（J＝1，2，3，4，5，6）的能级劈裂数和5D0→7FJ的跃过数均有报导[2]，所以，Eu3＋可用于探针分析减土金属氧化物和稀土金属氧化物都是甲烷氧化倡联较好的催化剂．前者具有较强的碱性，后者具…     

微量量热法筛选抑菌特效药的研究

用微量最热计连续测定细菌代谢过程中的热显变化，可获得反映细菌代谢规律的完整的热谱图以按指数生长模型对指数生长期进行处理，可计算出细菌正常代谢的生长速率常数L’．若在培养基中加入合成药物，使细菌在药物抑制作用下生长，也可获得完整的热谱图，从而计算出在药物抑制作用下细菌的生长速率常数．本义对福氏志贺氏Zb菌和金黄色葡萄球莉在四种合成药物抑制作用下的热谱进行了测定，并计算了生长速率常数，找出了细菌生长速率常数与所用药物浓度之间的定量关系，可为筛选抑菌药物和确定用药显提供定量依据’1基本原理设细菌在代谢过…     

钍(Ⅳ)与水杨醛二胺类双希夫碱配合物的合成与表征

钍（Ⅳ）与水杨醛二胺类双希夫碱配合物的合成与表征毕彩丰，范玉华，张家祥（山东建材学院应用化学系，济南２５００２２）关键词硝酸钍，双希夫碱，配合物过渡及希土金属离子的希夫碱类配合物已有不少报道，但钢系离子社（［Ｖ）的双希大碱类配合物研究未见报道．本文首...     

[Pb2(TNR)2(CHZ)2(H2O)2]·4H2O的结构及热分解机理

用碳酰肼 (CHZ ,NH2 NHCONHNH2 )、硝酸铅和三硝基间苯二酚 (TNR ,斯蒂酚酸 )的水溶液制备 [Pb2 (TNR) 2 (CHZ) 2 (H2 O) 2 ]·4H2 O .采用单晶分析的方法测定它的分子结构 ,并用TG DTG、DSC和　IR相结合的技术研究它的热分解机理 .所得晶体属单斜晶系 ,P2 1/n空间群 .晶体学参数为 :a=0 .6470 0 ( 10 )nm ,b =1.60 74 ( 3)nm ,c=1.4 883( 3)nm ,β =97.4 2 ( 2 )° ,V =1.534 9( 5)n ,Z =2 ,DC=2 .572 g·cm- 3,μ(Mo ,Kα) =11.0 80cm- 1,F( 0 0 0 ) =112 8.最终偏离因子R =0 .0 4 2 2 ,Rw=0 .0 735.该配合物分子呈中心对称 ,两个羰基O原子形成两个氧桥 ,TNR2 - ,CHZ和H2 O同时参与了与中心离子的配位     

Catalytic, asymmetric synthesis of the C(1)(')-C(10)(') segment of pamamycin 621A

[reaction--see text] This paper describes a catalytic, asymmetric approach to the C(1)(')-C(10)(') segment of pamamycin 621A. We synthesize this segment in a convergent manner, with each of the coupling partners ultimately deriving from enantiomerically enriched methylketene dimer.     

3-戊烯腈在零价镍催化体系中的平衡反应

在探索3-戊烯腈氢氰化合成己二腈反应的机理过程中,发现3-戊烯腈在零价镍体系中可能同时存在多个平衡反应,在不外加氰化氢条件下,3-戊烯腈可以生成甲基戊二腈和己二腈.采用零价镍、膦配体和无水ZnCl2组成的催化体系研究了该反应过程,考察了反应温度和配体的影响,并采用原位红外对反应进行监测,提出了可能的反应机理.