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991.
Six kinds of benzo-15-crown-5 (L) adducts having the stoichiometric formula M(Pic)2 · L · xH2O (M=Mn, Cu, x=2; M=Co, Ni, Zn, Cd, x=4; Pic means picrate anion) have been synthesized and characterized by EA, IR, UV and molar conductance. The X-ray crystal structural analysis of the benzo-15-crown-5 adduct with hydrated copper(II) picrate revealed that the benzo-15-crown-5 molecule virtually acts as a second-sphere ligand, which associates with the copper(II) ion by hydrogen bonding of the coordinating water molecule. By the comparison of the IR, UV spectra and molar conductance of the new adducts prepared, it can be deduced that the other adducts exhibit the similar coordination environment to that of the copper adduct. 相似文献
992.
MEN Xiu-Qin WANG Jin-Xian SHI Xiao-Ning WANG Ke-Hu 《有机化学》2003,23(Z1):307-307
Carbon-carbon double bond-forming reactions have always been great importance in organic synthesis. Manymethods have been described for C =C bond formation. We[1] have reported the new method of C =C bond formation of nickel catalyzed organozinc with aromatic aldehydes in the presence of Me3SiC1. 相似文献
993.
ZhuanNiYU XiRong HUANG ShaoFangSONG DanWANG XueMeiLU YueZhongLI YinBoQU PeiJiGAO 《中国化学快报》2003,14(8):836-839
The inhibition of lingninase by hydrogen peroxide in the presence of cationic surfactant CTAB was studied by kinetic speetrophotometdc technique. Results showed that addition of CTAB enhanced the inhibition by H202, but it did not alter the inhibition pattern and the inhibition constant changed little with theco-ncentration of CTAB. Modification of the enzymic protein by the surfactant monomer may be responsible for the above mentioned results. 相似文献
994.
The synthesis of some new N‐[1‐(2,5‐dichlorophenyl)‐5‐methyl‐1,2,3‐triazol‐4‐yl]‐carbamic acid ester derivatives are reported in this paper. The yielded products 6a‐l were confirmed by Elemental analyses, NMR, MS, and IR spectra. 相似文献
995.
Xianpeng Yin Hao Dong Shiqiang Wang Yun Liang Ning Gao Wanlin Zhang Li Tian Fuwei Sun Guangtao Li 《中国化学快报》2019,30(1):179-182
In this work, large area gold-nanoparticle-cluster pillar array with a gold mirror as high-performance SERS substrate was facilely fabricated by combined use of nanosphere lithography and self-assembly approach. 相似文献
996.
Fuxiang Ji Feng Wang Libor Kobera Sabina Abbrent Jiri Brus Weihua Ning Feng Gao 《Chemical science》2021,12(5):1730
Although lead-free halide double perovskites are considered as promising alternatives to lead halide perovskites for optoelectronic applications, state-of-the-art double perovskites are limited by their large bandgap. The doping/alloying strategy, key to bandgap engineering in traditional semiconductors, has also been employed to tune the bandgap of halide double perovskites. However, this strategy has yet to generate new double perovskites with suitable bandgaps for practical applications, partially due to the lack of fundamental understanding of how the doping/alloying affects the atomic-level structure. Here, we take the benchmark double perovskite Cs2AgInCl6 as an example to reveal the atomic-level structure of double perovskite alloys (DPAs) Cs2AgIn1−xFexCl6 (x = 0–1) by employing solid-state nuclear magnetic resonance (ssNMR). The presence of paramagnetic alloying ions (e.g. Fe3+ in this case) in double perovskites makes it possible to investigate the nuclear relaxation times, providing a straightforward approach to understand the distribution of paramagnetic alloying ions. Our results indicate that paramagnetic Fe3+ replaces diamagnetic In3+ in the Cs2AgInCl6 lattice with the formation of [FeCl6]3−·[AgCl6]5− domains, which show different sizes and distribution modes in different alloying ratios. This work provides new insights into the atomic-level structure of bandgap engineered DPAs, which is of critical significance in developing efficient optoelectronic/spintronic devices.Through Fe3+-alloying, the bandgap of benchmark double perovskite Cs2AgInCl6 can be tuned from 2.8 eV to 1.6 eV. The atomic-level structure of Cs2AgIn1−xFexCl6 was revealed by solid-state nuclear magnetic resonance (ssNMR). 相似文献
997.
H. -W. Sun W. -J. Kang J. Ha S. -X. Liang S. -G. Shen 《Journal of the Iranian Chemical Society》2004,1(1):40-46
The species of Cr(III) and Cr(VI) in water samples were determined by flow injection on-line preconcentration and separation on two-microcolumn system-derivative flame atomic absorption spectrometry during a collaborative analysis for certification. The Cr(III) and Cr(VI) in water samples were retained on two microcolumns with ion exchange resin and were eluted directly to nebulizer by 15% HNO3 and 8% NH4NO3, respectively. The characteristic concentration (at the sensitivity grade of 2 mV min?1 for 1 min of preconcentration time) for Cr(III) and Cr(VI) were 0.130 and 0.0985 μg l?1, in the order which were 332- and 431-fold better than those of FAAS, and 45- and 47-fold better than those of FI-FAAS, respectively. The relative standard deviations were 3.27% and 3.66% with corresponding detection limits (3σ) of 0.244 and 0.235 μg l?1, respectively. The linear ranges of determinations for Cr(III) and Cr(VI) were 0~100 μgm l?1 with correlation coefficients of 0.9984 to 0.9996. The satisfactory recovery of 94.4%~106% for Cr(III) and Cr(VI) could be obtained from water samples. 相似文献
998.
1INTRODUCTIONIntheearly1970'sthreegroupsofinvestigatorsL,~,'foundthatlow-valenttita-nium,preparedbythereactionofstrongreducingagentswithtitaniumtrichlorideortitaniumtetrachlorideintetrahydrofuran,canabstractoxygenfromketonesoraldehydes,leadingtotheforma-tionofolefins.Theinterestinthereactioninducedbylow--valenttitaniumreagentsisincreasingandalargenumberoffunctionalgroupscanbereduceds4-6).Recent-ly,wefoundthatthetitlecompoundisObtainedbycy-cllzatlonreactionof(3--oxo-1,3-diphenyl)propyl-pro… 相似文献
999.
A method is proposed for the simultaneous determination of copper and nickel by third-derivative spectrophotometry based on the absorption spectra of their complexes with cyanide ion in the ultraviolet range. The method allows the determination of 0.55-5.8 mug/ml of copper and 0.55-6.8 mug/ml of nickel. The relative standard deviation for 11 determinations of 1.5 mul/ml of copper and nickel were 0.78 and 0.72%, respectively. The detection limits were 0.10,mug/ml for nickel and 0.13 mug/ml for copper. The method has been applied to direct determination of copper and nickel in iron alloys and an aluminium alloy without any separation. 相似文献
1000.