Efficient palladium-catalyzed homocoupling reaction and Sonogashira cross-coupling reaction of terminal alkynes under aerobic conditions

An efficient method for palladium-catalyzed homocoupling reaction of terminal alkynes in the synthesis of symmetric diynes is presented. The results showed that both Pd(OAc)(2) and CuI played crucial roles in the reaction. In the presence of 2 mol % Pd(OAc)(2), 2 mol % CuI, 3 equiv of Dabco, and air, homocoupling of various terminal alkynes afforded the corresponding symmetrical diynes in moderate to excellent yields, whereas low yields were obtained without either Pd(OAc)(2) or CuI. Moreover, high TONs (turnover numbers; up to 940 000 for the reaction of phenylacetylene) for the homocoupling reaction were observed. Under similar reaction conditions, cross-coupling of 1-iodo-4-nitrobenzene with phenylacetylene was also carried out smoothly in quantitative yield. However, the presence of CuI disfavored the palladium-catalyzed Sonogashira cross-coupling reactions of the less active aryl iodides and bromides. In the presence of 0.01-2 mol % Pd(OAc)(2), a number of aryl iodides and bromides were coupled with terminal alkynes in good to excellent yields. It is noteworthy that this protocol employs mild, efficient, aerobic, copper-free, and ligand-free conditions.     

Highly Regioselective Sequential 1,1‐Dihydrosilylation of Terminal Aliphatic Alkynes with Primary Silanes

A regioselective double 1,1‐hydrosilylation of terminal aliphatic alkynes with primary silanes catalyzed by one cobalt catalyst has been developed. gem‐Bis(dihydrosilyl)alkanes containing four silicon‐hydrogen bonds are efficiently constructed in an atom‐economical manner. Tolerated substrates include simplest alkyne‐ethyne, a complicated drug derivative and various functionalized terminal aliphatic alkynes. Asymmetric approach using two catalysts is achieved with excellent enantioselectivities to access corresponding chiral products. The transformations of Si—H bonds into Si—C, Si—O, and Si—F bonds and the synthesis of enantioriched α‐hydroxysilane show synthetic utility.     

1-(2-pyridylazo)-2-naphthol (PAN) as extractant in solid-liquid extraction of some trivalent rare earth elements

In the present paper, solid-liquid extraction behaviour of RE(III) (RE La, Ce, Pr, Nd, Sm, Gd, Dy and Yb) by the use of 1-(2-pyridylazo)-2-naphthol (PAN, HL) as an extractant in paraffin (m.p. 48 approximately 50 degrees) has been investigated at 80 +/- 0.07 degrees. The effect of equilibrium time, pH of aqueous phase, concentration of extractant in paraffin and solid diluent as well as buffer solution used on the extraction efficiency of RE(III) have been discussed. The extraction reaction is RE(3+) + 2HL(o) + Cl(-) <==> REL(2)Cl(o) + 2H(+).     

A Facile Method of Synthesis of a Calix[4]arene Amide and the Crystal Structure of a Self-assembled Calix[4]arene Amide via van Der Waals Interaction

A new facile method of synthesis of calix[4]arene amide via the aminolysis of the calix[4]arene esters was reported. One ethyl ester of the compound (2) was aminolysized byn-butylamine. The crystal structure of compound (1)shows that one ethyl ester of compound (1) enters into thecavity of another compound (1) forming a long chainhost-guest supramolecule. From the 2D NMR data, the compound(1) does not assemble in THF or CHCl₃ solution. The CH- interaction and crystallization energy might be theimportant driving forces for forming the self-assembledcalix[4]arene.     

偶联酶催化分光光度法测定黄嘌呤

研究了以黄嘌呤氧化酶-辣根过氧化物酶-苯酚-4-氨基安替比林反应为显色体系测定不同样液中黄嘌呤浓度的新方法。确定该测定方法的最佳反应条件为:黄嘌呤氧化酶(XO)0·32U/mL,辣根过氧化物酶(HRP)7·0U/mL,4-氨基安替比林(AAP)1mmol/L,苯酚(PA)6mmol/L溶于100mmol/LTris-HCl缓冲液(pH8·4);反应温度为37℃,保温时间为20min;检测波长为508nm。本方法测定黄嘌呤浓度的线性范围为0·2～10·0mmol/L,线性关系良好(R=0·9978),检测限为0·05mmol/L。方法操作简单易行,测定结果准确可靠,可有效应用于普通实验室和常规临床血液生化检测。     

反相悬浮聚合法合成超强吸水剂

以两性高分子作悬浮稳定剂，用反相悬浮聚合法合成了聚（丙烯酸盐－丙烯酰胺）类超强吸水剂．研究了交联剂、稳定剂、引发剂等用量、中和程度、单体组成及链转移剂等聚合条件对吸水剂吸水性能的影响．得到了吸蒸馏水１０５０ｍＬ／ｇ及吸０．９％ＮａＣｌ溶液８６ｍＬ／ｇ的超强吸水剂．此外，还比较了含不同反离子的聚丙烯酸类吸水剂的吸水性能     

钙钛矿材料组分调控策略及其光电器件性能研究进展

近年来，钙钛矿太阳电池的光电转换效率取得了爆发式增长，这与电池中钙钛矿薄膜的制备工艺和材料组分密切相关.关于钙钛矿薄膜的制备方法，相关的研究报道及综述较多，然而钙钛矿材料组分调控方面的研究梳理工作相对缺乏.本综述总结了近年来不同组分体系钙钛矿材料的研究进展，包括有机无机铅卤钙钛矿、全无机铅卤钙钛矿、少铅钙钛矿以及无铅钙钛矿.重点介绍了不同体系中具有代表性的材料组分及其对器件性能的影响，旨在梳理通过组分调控提高钙钛矿电池的效率及稳定性的研究思路，最终实现商业化应用.     

氧化物载负型沸石催化剂的阈值效应

用一系列氧化物，如Ｂ２Ｏ３，Ｓｂ２Ｏ３和ＭｇＯ，对ＨＺＳＭ－５沸石以及用Ｓｂ２Ｏ３对Ｈβ沸石进行改性。实验结果表明，这些氧化物可在沸石上自发单层分散且大部分分散的氧化物处于沸石孔内。用ＸＲＤ及ＸＰＳ方法测得它们的分散阈值。实验中发现，在甲苯烷基化反应中，对二甲苯选择性随氧化物含量增加而迅速提高；当氧化物在ＨＺＳＭ－５上的载量接近其分散阈值时，对二甲葳选择性达到最大，对某些体系可高达９５％左右，百在     

Synthesis, characterization, photoluminescence and electroluminescence properties of new 1,3,4-oxadiazole-containing rhenium（I） complex Re（CO）3（Bphen）（PTOP）

A new 1,3,4-oxadiazole-contanining rhenium(I) complex,with the formula [Re(CO)_3(Bphen)(PTOP)],(Bphen=bathophe- nardine,PTOP=4-(5-p-tolyl-1,3,4-oxadiazd-2-yl)pyridine),is synthesized and characterized by elemental analysis,IR,~1H NMR, UV-vis and luminescence spectroscopy.The double-layer electroluminescence devices based on the Re(I) complex have been fabricated by spin-coating technique.The turn-on voltage,maximum efficiency,and brightness for green emission obtained from the devices are 9V,2.1cd/A and 165cd/m~2,respectively.     

HYDROPHOBICITY OF CONTAMINATED SILICONE RUBBER SURFACES

Silicone rubber (SIR) shows superior performance when used outdoors, but its surface can be transformed frominherently hydrophobic to hydrophilic by the adsorption of contaminants. Al(OH)_3, Al_2O_3, quartz powder and active carbonwere selected as authentic contaminants. Hydrophobicity of the surface was determined using contact angle measurement.The results indicate that the adsorbability of the contaminants can strongly affect the hydrophobicity of contaminated SIRsurface. The increasing rate of contact angle of specimens contaminated by Al(OH)_3 was much faster than that by Al_2O_3 andquartz due to the adsorption of migrated low molecular weight (LMW) polydimethylsiloxanes. Specimens contaminated byactive carbon could achieve sunde hydrophobicity within 15 min because active carbon has high adsorbability. Surfaces ofcontaminated ultrapure SIR, polytetrafluoroethylene (PTFE) and glass remain hydrophilic because they contain no mobileLMW components. The addition of oligomeric polydimethylsiloxanes has little effect on the hydrophobicity of contaminantscovered on SIR surface.