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101.
[reaction: see text] Acylcyclopropanemethanol tosylates undergo rapid ring opening at room temperature by the action of lithium telluride to produce the enolate of a homoallylic ketone. The enolate can be protonated to yield the corresponding ketone or treated with benzaldehyde to give the aldol product with good syn or anti diastereoselectivity depending on the conditions. 相似文献
102.
Neslihan Saki Engin U. Akkaya 《Journal of inclusion phenomena and macrocyclic chemistry》2005,53(3-4):269-273
A novel dimeric calixpyrrole has been synthesized. The dimer forms stable complexes with p-nitrophenolate ion with a concomitant reduction in extinction coefficient. The chromogenic anion is displaced by the addition of various anions like fluoride and acetate. Effective optical sensing of these anions is accomplished using the calixpyrrole dimer. 相似文献
103.
A novel distyryl-substituted boradiazaindacene (BODIPY) dye displays interesting properties as a sensitizer in DSSC systems, opening the way to further exploration of structure-efficiency correlation within this class of dyes. 相似文献
104.
Performance of a fast fiber based UV/Vis multiwavelength detector for the analytical ultracentrifuge
Holger M. Strauss Engin Karabudak Saroj Bhattacharyya Andreas Kretzschmar Wendel Wohlleben Helmut Cölfen 《Colloid and polymer science》2008,286(2):121-128
The optical setup and the performance of a prototype UV/Vis multiwavelength analytical ultracentrifuge (MWL-AUC) is described
and compared to the commercially available Optima XL-A from Beckman Coulter. Slight modifications have been made to the optical
path of the MWL-AUC. With respect to wavelength accuracy and radial resolution, the new MWL-AUC is found to be comparable
to the existing XL-A. Absorbance accuracy is dependent on the light intensity available at the detection wavelength as well
as the intrinsic noise of the data. Measurements from single flashes of light are more noisy for the MWL-AUC, potentially
due to the absence of flash-to-flash normalization in the current design. However, the possibility of both wavelength and
scan averaging can compensate for this and still give much faster scan rates than the XL-A. Some further improvements of the
existing design are suggested based on these findings. 相似文献
105.
Havva Nur Demirtas Selahattin Bozkurt Mustafa Durmaz Mustafa Yilmaz Abdulkadir Sirit 《Tetrahedron: Asymmetry》2008,19(17):2020-2025
Two novel chiral calix[4]azacrown ethers 4 and 5 bearing a furfuryl group on the nitrogen atom were developed by the reaction of dibromo- or ditosyl derivatives of p-tert-butylcalix[4]arenes 2 and 3 with a chiral diol, 1. The enantioselective recognition of these receptors towards the enantiomers of racemic carboxylic acids has been studied by 1H NMR spectroscopy. The molar ratio and the association constants of the chiral compounds 4 and 5 with each of the enantiomers of guest molecules were determined by using Job plots and a nonlinear least-squares fitting method, respectively. The Job plots indicate that both of the hosts form 1:1 instantaneous complexes with (R)- or (S)-mandelic acid and (l)- or (d)-dibenzoyltartaric acid. The receptors exhibited different chiral recognition abilities towards the enantiomers of racemic guests. 相似文献
106.
The influence of the LT-AlN(NL) growth times on the mosaic structure parameters of the AlN layer grown on the LT-AlN(NL)/6H-SiC structures as well as the dislocation densities and the strain behaviours in the AlN epilayers has been investigated using XRD measurements. The growth times of the LT-AlN(NL) were changed to 0, 60, 120, 180, and 240?s. We observed that the mosaic structure parameters of the AlN epilayers were slightly affected by the LT-AlN(NL) growth times. However, the dislocation densities in the AlN layer are affected by the growth times of the LT-AlN(NL) layer. The highest edge dislocation density (5.48?×?1010?±?2.3?×?109?cm?2) was measured for the sample in which 120?s grown LT-AlN(NL) was used. On the other hand, highest screw type dislocation density (1.21?×?1010?±?1.7?×?109?cm?2) measured in the sample E that contains 240?s growth LT-AlN(NL). The strain calculation results show that the samples without LT-AlN(NL) suffered maximum compressive in-plane strain (?10.9?×?10?3?±?1.8?×?10?4), which can be suppressed by increasing the LT-AlN(NL) growth times. The out-of-plane strain also has a compressive character and its values increase with LT-AlN(NL) growth times between 60 and 180?s. Same out-of-plane strain values were measured for the LT-AlN(NL) growth times of 180 and 240?s. Furthermore, the form of the biaxial stress in the AlN epilayer changed from compressive to tensile when the LT-AlN(NL) growth times were greater than 120?s. 相似文献
107.
Ismail Özdemir Nevin Gürbüz Yetkin Gök Bekir Çetinkaya Engin Çetinkaya 《Transition Metal Chemistry》2005,30(3):367-371
Six rhodium–carbene complexes (2a–f) have been prepared and the new compounds characterized by C, H, N analyses, 1H-n.m.r. and 13C-n.m.r. Phenylboronic acid reacts with aldehydes in the presence of a catalytic amount of rhodium(I)–carbene complex, RhCl(COD)(1,3-dialkylbenzimidazolidin-2-ylidene), (2a–f), to give the corresponding aryl secondary alcohols in good yields. 相似文献
108.
109.
Erhan Demirel Hakan Durmaz Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2016,54(4):480-486
The aliphatic polyurethane with pendant alkyne, perfluorophenyl, and anthracene moieties (PU‐anthracene) was prepared from polycondensation of anthracene, alkyne, and perfluorophenyl functional‐diols with hexamethylenediisocyanate in the presence of dibutyltindilaurate (DBTL) in CH2Cl2 at room temperature for 10 days. Thereafter, the PU‐(anthracene‐co‐alkyne‐co‐perfluorophenyl) (Mn,GPC = 15,400 g/mol, Mw/Mn= 1.37, relative to PS standards) was sequentially clicked with benzyl azide, octylamine, and 4‐(2‐hydroxyethyl)?10‐oxa‐4‐azatricyclo[5.2.1.02,6]dec‐8‐ene‐3,5‐dione (adduct alcohol) via copper‐catalyzed azide‐alkyne cycloaddition, active ester substitution and Diels–Alder reactions, respectively, to finally yield PU‐(hydroxyl‐co‐benzyltriazole‐co‐octylamine). The PUs were characterized using 1H NMR, GPC, and DSC. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 480–486 相似文献
110.
Binnur Aydogan Yasemin Yuksel Durmaz Muhammet U. Kahveci Mustafa Uygun M. Atilla Tasdelen Yusuf Yagci 《Macromolecular Symposia》2011,308(1):25-34
Summary: New photoiniting systems for cationic polymerization acting at near UV and visible range are described. The applicability of acylgermanes as a new class of free radical promoters for photoinitiated cationic polymerization is demonstrated. Moreover, the use of substituted vinyl halides as source for readily oxidizable free radicals is presented. The polymerization of vinyl ethers can be initiated by the irradiation of substituted vinyl halides in the presence of Lewis acids such as zinc halide. Furthermore, possibilities for conducting cationic polymerization at visible range by using highly conjugated thiophene derivatives are demonstrated. Mechanistic aspects of all initiating systems are discussed. 相似文献