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991.
Ezzatollah Najafi Mostafa M. Amini Omid Sadeghi Hamid Reza Khavasi Seik Weng Ng 《Heteroatom Chemistry》2011,22(6):699-706
The reaction of 4,4′‐bipy with dimethyltin(IV) chloride iso‐thiocyanate affords the one‐dimensional (1D) coordination polymer, [Me2Sn(NCS)Cl·(4,4′‐bipy)]n ( 1 ), whereas reaction of dimethyltin(IV) dichloride with sodium pyrazine‐2‐carboxylate in the presence of potassium iso‐thiocyanate affords the two‐dimensional (2D) coordination polymer, {[Me2Sn(C4H3N2COO)2]2 [Me2Sn(NCS)2]}n ( 2 ). Both coordination polymers were characterized by elemental analysis and infrared spectroscopy in addition to 1H and 13C NMR spectroscopy of the soluble coordination polymer ( 1 ). A single‐crystal structure determination showed that the asymmetric unit in 1 contains Me2Sn(NCS)Cl and 4,4′‐bipy moieties and a 1D infinite rigid chain structure forms through bridging of the 4,4′‐bipy ligand between tin atoms and the geometry around the tin atom is a distorted octahedral. Coordination polymer 2 contains two distinct tin atom geometrics in which one tin atom is seven coordinate, and the other is six coordinate. The two tin atom environments are best described as a pentagonal bipyramidal in the former and distorted octahedral in the latter where the carboxylate groups bridge the two tin atoms and construct a 2D‐coordination polymer. The 119Sn NMR spectroscopy indicates the octahedral geometry of 1 retains in solution. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:699–706, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/.20736 相似文献
992.
Gao Wu Molang Cai Yujia Cao Zhuoxin Li Zhongyan Zhang Weng Yang Xianggang Chen Dongxu Ren Yaqi Mo Miao Yang Xuepeng Liu Songyuan Dai 《Journal of Energy Chemistry》2022,(2):55-61
The quality of MAPbI3 film prepared by solvent engineering process highly depends on environment and antisolvent control.Here,we provided a simple methylamine chloride(MACl)solution treatment using a two-step process to enlarge the perovskite crystal grain sizes to more than 1 lm.Other than treatment on the film surface,the MACl solution diffuses into the MAPbI3 films to assist the recrystallization of small crystal at the bottom of perovskite film.The imitative contact between perovskite and substrate is formed.Meanwhile,the enlargement of grain size and ten times enhancement of crystalline reduce trap-assisted recombination of perovskite films.Thus,the significant improvement of cell efficiency of 20.89%as well as device stability is obtained with the MACl treatment. 相似文献
993.
The six new dihydro‐β‐agarofuranoid sesquiterpenes 1 – 6 and three known compounds were isolated from the whole plant of Celastrus paniculatus. The structures including relative configurations were elucidated by means of spectroscopic analyses. Compounds 1 – 6 were evaluated for cytotoxicity against a panel of three human‐tumor cell lines. 相似文献
994.
Fengping Zhan Guangyan Yu Bixia Yao Xueping Guo Ting Liang Minggen Yu Qingle Zeng Wen Weng 《Journal of chromatography. A》2010,1217(26):4278-4284
Enantioseparation of 1,1′-bi-2-naphthol (BINOL) was performed on a polysaccharide-based chiral stationary phase, Chiralcel OD-H, under normal-phase mode. The effects of polar modifier in the mobile phase on the retention, enantioseparation and elution order were investigated in detail. Solvent-induced reversal of elution order for BINOL was observed. When linear alcohols were adopted, R-BINOL was always eluted first. S-BINOL was eluted first when 2-propanol was used as a polar modifier. Enantioseparation could not be obtained when sec-butyl alcohol or tert-butyl alcohol was used as a polar modifier. When isoamyl alcohol or cyclohexanol was used as a polar modifier, favorable enantioseparation was obtained as with 1-pentanol or 1-hexanol; also, R-BINOL was the first-eluted enantiomer. It is worth emphasizing that significantly better enantioseparation was obtained when higher alcohols were used as polar modifier of the mobile phase. A nonlinear characteristic for the ln α against 1/T plots was universally observed in this study though the ln k against 1/T plots exhibited a linear feature. Associated with the obtained thermodynamic parameters, some interesting inferences about chiral recognition mechanism were proposed. 相似文献
995.
Fei Weng 《Tetrahedron letters》2010,51(19):2593-8500
A mild and efficient ligand-free palladium-catalyzed direct C-H bond arylation reaction was developed to afford 2-hydroxybenzophenones in good to excellent yields from easily available 2-hydroxybenzaldehydes and arylboronic acids. The given reaction provided one of the easiest pathways for accessing 2-hydroxybenzophenones, and a variety of functional groups could be tolerated in this process. 相似文献
996.
997.
998.
Titanium oxide films are of critical importance for the electrochromic device technology. The substrate, a conductive glass being coated with indium tin oxide (ITO) thin films, was deposited tungsten and titanium oxide by pulsed co-sputtering deposition system. The film thickness increased with the ion beam power. However, the slope of the curve of thickness against power at an ion beam power of less than 300 W was greater than that at a power of 400 or 500 W. A high ion beam power resulted produced a crystalline structure, as revealed by X-ray diffraction (XRD). Moreover, increasing the ion beam power resulted in the high Li-ions transport. The electrochromic behavior was optimal at an ion beam power of 200 W. 相似文献
999.
提出了一种基于Gabor小波变换的菲涅耳全息图的数值再现方法,实现无需空间滤波处理,即可对物光波进行数值再现.给出Gabor小波变换以及小波变换脊的定义,并从理论上证明通过对全息图进行Gabor小波变换,提取小波变换脊对应的小波变换系数,包括幅值与相位信息,即可直接获得与+1级频谱相对应的被测物光在全息面上的强度与相位分布,并同时直接消除零级衍射像以及孪生像的影响.通过计算机模拟再现光波经全息图衍射后的传播规律实现数值再现,得到清晰的再现像.通过计算机模拟一相位型物体以及实验证明该方法的有效性. 相似文献
1000.
Shouguo Ding Ping Yang Fuzhong Weng Bryan Baum 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(13):1190-1198
The bulk-scattering properties of dust aerosols and clouds are computed for the community radiative transfer model (CRTM) that is a flagship effort of the Joint Center for Satellite Data Assimilation (JCSDA). The delta-fit method is employed to truncate the forward peaks of the scattering phase functions and to compute the Legendre expansion coefficients for re-constructing the truncated phase function. Use of more terms in the expansion gives more accurate re-construction of the phase function, but the issue remains as to how many terms are necessary for different applications. To explore this issue further, the bidirectional reflectances associated with dust aerosols, water clouds, and ice clouds are simulated with various numbers of Legendre expansion terms. To have relative numerical errors smaller than 5%, the present analyses indicate that, in the visible spectrum, 16 Legendre polynomials should be used for dust aerosols, while 32 Legendre expansion terms should be used for both water and ice clouds. In the infrared spectrum, the brightness temperatures at the top of the atmosphere are computed by using the scattering properties of dust aerosols, water clouds and ice clouds. Although small differences of brightness temperatures compared with the counterparts computed with 4, 8, 128 expansion terms are observed at large viewing angles for each layer, it is shown that 4 terms of Legendre polynomials are sufficient in the radiative transfer computation at infrared wavelengths for practical applications. 相似文献