Low band gap copolymers consisting of porphyrins,thiophenes, and 2,1,3‐benzothiadiazole moieties for bulk heterojunction solar cells

Two novel low band gap conjugated copolymers containing porphyrins, thiophenes, and 2,1,3‐benzothiadiazole ( BTZ ) moieties were synthesized and applied in bulk heterojunction solar cells. The thermal, optical, electrochemical, and photovoltaic properties of the two copolymers were examined to investigate the effect of the introduction of BTZ moiety in the backbone of the porphyrin polymers. The copolymers exhibited good thermal stability and film‐forming ability. The absorption spectra indicated that the BTZ moiety has significant influence on the UV–visible region spectra of the copolymers: with increasing the molar amount of BTZ moieties in conjugated main chain, the absorption in the range of 450–700 nm is largely broadened and red‐shifted compared to the similar polymers without BTZ moiety, and the optical band gaps of copolymers were narrowed to ～1.50 eV. The photoluminescence spectra showed that there is effective charge transfer in the whole conjugated main chain. Cyclic voltammetry displayed that the band gaps were reduced effectively by the introduction of the BTZ moieties. The bulk heterojunction solar cells were fabricated based on the blend of the copolymers and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PC₆₁BM) in a 1:2 weight ratio. The maximum power conversion efficiency of 0.91% was obtained by using P2 as the electron donor under the illumination of AM 1.5, 100 mW/cm². © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Efficient synthesis of 1,3,5-trisubstituted benzenes via three Pd-mediated carbon-sulfur, carbon-nitrogen and carbon-carbon bond formation reactions

An efficient synthesis of 1,3,5-trisubstituted benzenes via a sequential Pd-mediated carbon-sulfur, carbon-nitrogen, and carbon-carbon bond formation reactions is reported. Selective amidation and sulfonamidation reactions are accomplished via Pd-catalyzed reactions between aryl chlorides and an acetamide or a methanesulfonamide.     

Bifunctional cobalt Salen complex: a highly selective catalyst for the coupling of CO2 and epoxides under mild conditions

A bifunctional cobalt Salen complex containing a Lewis acid metal center and two covalent bonded Lewis bases on the ligand was designed and used for the coupling of CO₂ and epoxides under mild conditions. The complex exhibited excellent activity (turnover frequency = 673/h) and selectivity (no less than 97%) for polymer formation in the copolymerization of propylene oxide (PO) and CO₂ at an appropriate combination of all variables. High molecular weight of 110 200 and yield 99% were achieved at a higher [PO]/[complex] ratio of 6000:1. The complex also worked satisfactorily for the terpolymerization of CO₂, PO and cyclohexene oxide (CHO), without formation of cyclic carbonate or ether linkages to give the polycarbonate. High cyclohexene carbonate unit content in the CO₂/PO/CHO terpolymers resulted in enhanced thermal stability. Copyright © 2011 John Wiley & Sons, Ltd.     

Efficient removal of unwanted signals in NMR spectra using the filter diagonalization method

It is often desirable to selectively remove corrupting or uninteresting signals from complex NMR spectra without disturbing overlapping or nearby signals. For biofluids in particular, removal of solvent and urea signals is important for retaining quantitative accuracy in NMR‐based metabonomics. This article presents a novel algorithm for efficient filtering of unwanted signals using the filter diagonalization method (FDM). Unwanted signals are modeled in the time domain using FDM. This modeled signal is subtracted from the original free induction decay. The resulting corrected signal is then processed using established workflow. The algorithm is found to be reliable and fast. By eliminating large, broad, uninteresting signals, many spectra can be subjected to fully automated absolute value processing, allowing objective preparation of spectra for pattern recognition analysis. Copyright © 2009 John Wiley & Sons, Ltd.     

Direct profiling of phospholipids and lysophospholipids in rat brain sections after ischemic stroke

Stroke, a deleterious cerebrovascular event, is caused by a critical reduction in the blood flow to the brain parenchyma that leads to brain injury and loss of brain functions. The inflammatory responses following ischemia often aggravate the neurological damage. Several pro‐inflammatory mediators released after stroke are closely related to the metabolism of phospholipids. In this study we directly profiled the changes in phospholipids in the infarcted rat cerebral cortex 24 hours after middle cerebral artery occlusion (MCAO) using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Several phosphatidylcholine (PC) species and sphingomyelin (SM) were significantly decreased after infarction. The cationization pattern of the remaining PCs showed a prominent shift from a mostly potassiated or protonated form to a predominantly sodiated pattern. Stroke also elevated the lysophosphatidylcholines (LPCs) and heme in tissue. The isobaric pairs in PC and LPC classes were resolved by masses through their respective alkali metal adducts in the presence of CsCl. The major fatty acyl LPC species were also structurally confirmed by MALDI‐MS/MS. Overall, the results described the changes in PC and LPC species in the infarcted rat cortex. The elevated tissue levels of LPCs and heme signify the ongoing pathological lipid breakdown and the state of parenchymal inflammation. The elevated LPC level in tissue suggests a means of intervention through lysophospholipid metabolism that could potentially benefit the management of stroke and other acute neurological injuries. Copyright © 2010 John Wiley & Sons, Ltd.     

Rare-Earth–Transition-Metal Organic–Inorganic Hybrids Based on Keggin-type Polyoxometalates and Pyrazine-2,3-dicarboxylate

Five rare-earth–transition-metal (RE–TM) heterometal organic–inorganic hybrids based on Keggin-type silicotungstates and mixed ligands H2pzda (pzda=pyrazine-2,3-dicarboxylate) and en (en=ethylenediamine) (enH2)[Cu(en)2(H2O)]2{[Cu(en)2][Cu(en)2(H2O)][(α-SiW11 O39)RE(H2O)(pzda)]}2⋅n H2O (n≈4; RE=YIII ( 1 ), DyIII ( 2 ), YbIII ( 3 ), and LuIII ( 4 )) and [Cu(en)2(H2O)]2{[Cu(en)2]2[Cu(pzda)2][(α-H2SiW11O39)Ce(H2O)]2}⋅n H2O ( 5 ; n≈8) have been hydrothermally synthesized and structurally characterized. Compounds 1–5 all contain the dimeric mono-RE substituted Keggin [RE(α-SiW11O39)]210− subunits linked by H2pzda ligands. Interestingly, 1–4 exhibit discrete structures, in which the H2pzda ligand acts as a tetradentate ligand to bind the RE and Cu cations, whereas 5 displays a 1D double-chain architecture, in which the H2pzda ligand adopts a new pentadentate mode to connect the Ce and Cu cations. To our knowledge, 1–5 represent the first monovacant Keggin-type silicotungstates containing both RE–TM heterometals and mixed ligands. The luminescence of 2 is derived from the combination of the DyIII cations and H2pzda ligands, whereas the luminescence properties of 1 and 3–5 are attributable to the H2pzda ligands.     

芴2,7位取代的9,9’-二芳基螺芴类化合物的合成及性能

设计并合成了一系列以三苯胺为核,芴衍生物为外围基团的有机蓝光小分子,该合成通过Suzuki反应在9-芳基芴的2位和(或)7位引入相同或不同取代基作为模块,并利用Friedel-Crafts反应将4-甲基三苯胺与这一系列模块结合.用NMR,MS和元素分析进行结构表征.荧光测试结果表明该类化合物溶液的荧光发射波长范围在442～466 nm之间,属蓝光发射.电化学测试显示该类材料的HOMO能级位于-5.15～-5.19 eV之间.差示扫描量热仪与热重分析得出化合物的玻璃化转变温度在166℃以上,热分解温度高于398℃,表明该类材料具有良好的热稳定性.     

Facile fabrication of porous pure and Ag nanoparticle-doped poly(4-vinylpyridine) films at the liquid-liquid interfaces

We reported an interfacial self-assembly of regularly layered porous poly(4-vinylpyridine)(P4VP) films at the interfaces of water-chloroform or -dichloroethane.The porous diameters were in the range from hundred nanometers to several micrometers.It was revealed that formation of such kind of porous materials was solvent dependent.Moreover,cyclic Ag nanoparticles could be grown in the porous P4VP films to form Ag-P4VP nanohybrids under radiation.     

Large-size oxyfluoride glasses used for vis–IR-transmitting windows

Windows for infrared sensors on missiles, aircraft and high energy laser systems must be of excellent spectral properties, high optical quality, large and durable enough to protect delicate sensors from harsh operating conditions. This paper describes work being done for IR window applications on heavy metal oxyfluoride (HMOF) glasses, which provide a combination of infrared transparency, strength, hardness, and environmental stability in a largely-sized formable material, and represents potential candidate materials for infrared windows.     

Photopromoted carbonylation of 1-bromo-6-chlorohexane under ambient conditions

Photopromoted carbonylation of 1-bromo-6-chlorohexane with CO catalyzed by CuBr2 and CdI2 has been carried out under ambient conditions. The results indicate that the carbonylation proceeds with the major product of chloroester ClCH2（CH2）5COOCH3 under catalysis of CuBr2. Furthermore, the activity of the carbonylation can be improved by addition of basic additives （NaOAc, Na3PO4 or （n-C4H9）3N）. Among these additives, （n-C4H9）3N is the most efficient in terms of the yield of ClCH2（CH2）5COOCH3. However, the methoxycarbonyl substituting chlorine product of BrCH2（CH2）5COOCH3 is not obtained in the presence of CdI2. This is quite different from the carbonylation of monochloroalkane.