A three‐dimensional cyano‐bridged copper(II) complex, [Cu(dien)Ag(CN)2]2[Ag2(CN)3][Ag(CN)2] ( 1 ) (dien = diethylenetriamine), has been prepared and characterized by X‐ray crystallography. Complex 1 crystallized in the monoclinic space group P21/n with a = 6.988(2), b = 17.615(6), c = 12.564(4) Å, β = 90.790(5)°. The crystal consists of cis‐[Cu(dien)]2+ units bridged by [Ag(CN)2]— to form a zig‐zag chain. The Ag atoms of the free and bridging [Ag(CN)2]— link together to form additional infinite zig‐zag chains with short Ag···Ag distances. The presence of Ag···Ag interactions effectively increases the dimensionality from a 1‐D chain to a 3‐D coordination polymer. 相似文献
A fluorescent aminoacid was designed for selective and sensitive detection of Cu(II) in aqueous solution. The designing of this Cu(II) fluorescent chemosensing molecule, N ± (1‐naphthyl). aminoacetic acid (NAA), was based on the binding of Cu(II) to aminoacetic acid and the novel charge transfer photophysics of 1‐aminonaphthalenes. The fluorescence of NAA was found quenched by Cu (II) and several other metal ions of similar electronic structure such as Co(II), Ni(II) and Zn(II). The quenching was shown to occur via electron transfer within the metal‐NAA complex, which required an optimal combination of high binding affinity and favorable redox properties of the components in the metal‐NAA complex and hence afforded selective fluorometric detection of Cu(II). The calibration graph obeyed Stern‐Volmer theory and was shown for Cu(II) over the range of 0–2.75 ± 10–4 mol/L. The quenching constant of Cu(II) was measured as 8.0 ± 103 mol/L that was two orders of magnitude higher than those of Co(II), Ni(II) and Zn(II). The 3SD limit of detection for Cu(II) was 8.00 ± 10?6 mol/L with a coefficient of variation of 1.65%. Linear range for quantitative detection of Cu(II) was 2.67 ± 10?5‐2.75 ± 10?4 mol/L. The method was applied to synthetic sample measurements which gave recoveries of 105%‐112%. 相似文献
The metal complexes [Hg2(tbim)2Br4]·2DMF ( 1 ) and [Hg2(tbim)I4]·1.5DMF ( 2 ) were prepared by reactions of 1,3,5‐tris(benzimidazol‐1‐ylmethyl)‐2,4,6‐trimethylbenzene (tbim) with HgBr2, HgI2, respectively, and [Hg2(tbim)I4]·0.5(FeCp2)·H2O ( 3 ) was obtained by the same method with addition of ferrocene (FeCp2) as additive. Their structures were determined by X‐ray crystallographic analyses. Complex 1 has a macrocyclic binuclear structure with one benzimidazole arm of the ligand free of coordination and the binuclear units are further connected by C‐H···N hydrogen bonds to give an infinite zigzag chain. Complexes 2 and 3 have a 2D network structure in which tbim serves as a tridentate ligand. The results showed that the halides of bromide and iodide have remarkable impact on the structure of the complexes. The FeCp2 molecules are trapped in the voids of framework 3 . 相似文献
The inside cover picture shows the journey of developing PIP amine directing group for C—H activation, from controlling the reactivity and diastereoselectivity to enantioselectivity. In the presence of Pd or base metal catalysts, PIP amine enabled the activation of inert C—H bonds to form diverse C—C and C—heteroatom bonds. Its tuneable structure has triggered the design of chiral auxiliaries for diastereoselective C—H activation. More recently, enantioselective activation of unbiased methylene C—H bonds has been achieved by cooperative effects between PIP amine and axial chiral ligands. More details are discussed in the article by Shi et al. on page 647–656.
Six new artificial products 11-16 were obtained from the reaction of acetyllycoctonine (10) with N-bromosuccinimide (NBS). The structures of these compounds were established on the basis of spectral data. It is emphasized that the varieties and yields of the products in this reaction depended greatly upon reaction conditions and the types of substrate. 相似文献
The electrochemistry of indium species was investigated at glassy carbon, tungsten and nickel electrodes in a basic 1‐ethyl‐3‐methylimidazolium chloride/tetrafluoroborate ionic liquid. Amperometric titration experiments suggest that In(III) chloride is complexed as [InCl5]2? in this ionic liquid. The electrochemical reduction of [InCl5]2? to indium metal is preceded by overpotential driven nucleations. The effective anodic dissolution of indium to indium(III) requires, however, the presence of sufficient chloride ions at the electrode surface. The electrodeposition of indium at glassy carbon and tungsten electrodes proceeds via three‐dimensional instantaneous nucleation with diffusion‐controlled growth of the nuclei. At the nickel electrode, the deposition proceeds via three‐dimensional progressive nucleation with diffusion‐controlled growth of the nuclei. Raising the deposition temperature decreases the average radius of the individual nuclei, r. Scanning electron microscopic and x‐ray diffraction data indicated that bulk crystalline indium electrodeposits could be prepared on nickel substrates within a temperature range between 30 and 120 °C. 相似文献
The reaction of prop‐1‐ene‐1,3‐sultone 1 with a variety of nitrile oxides 3 afforded novel [3+2] cycloaddition products 4 in good yield. The cycloaddition reaction achieved excellent regioselectivity. 相似文献
The reaction of N,N′‐di(2‐pyridyl)formamidine (HDpyF) with MnCl2‐4H2O afforded the complex MnCl2(HDpyF), which was characterized by X‐ray crystallography. The HDpyF ligand chelates to the Mn(II) center through the first and the third nitrogen atoms to form a six‐membered ring, leaving the second and the fourth nitrogen atoms uncoordinated. The HDpyF ligand is crystallographically disordered such that two different molecules can be solved. The neutral HDpyF ligand adopts the new s‐cis‐syn‐s‐trans conformation. 相似文献