One-step Beckmann Rearrangement from Ketones and Hydroxylamine in Dry Media under Microwave Irradiation

TheBeckInannrearrangement,theacid-mediatedisomerizationofoximestoamides,wasfirstdiscoveredinl886l.Asoneoftheoldestandmostfamiliartransformationsinorganicchemistry,ithasbeenwidelystudiedandagreatvarietyofmethodstoconductthistfansformationhavebeenreported'.However,mostofthesemethodswerecarriedoutbyusingalargeamountofsolventswithlongreactiontime.Whatismore,thepriorpreparationofthecorrespondingketoximesisusuallyrequired,whichmakestheseprocessesinconvenientandlessattractive.Bytakingadvantageofboth…     

Electric-field-induced patterns in thin polymer films: weakly nonlinear and fully nonlinear evolution

A thin polymer melt on a substrate can be unstable to an electric field normal to the interface, a phenomenon that can be harnessed as a patterning technique with a range of potential applications. Motivated by the variety of patterns observed in experiments for polymers under both unpatterned and patterned masks, we describe here, from theoretical and numerical analyses, how nonlinear effects govern the growth of the instability and determine the final patterns. In particular, we discuss the nonlinear growth in terms of interactions among different Fourier modes and show that the second- and third-order nonlinearities favor the growth of hexagonal patterns under a featureless mask, in agreement with experimental observations. Also, numerical simulations based on the fully nonlinear model validate the prediction of the weakly nonlinear analysis: hexagonal patterns do emerge under an unpatterned mask. Furthermore, in one-dimensional simulations, we demonstrate the energetic evolution of this patterning process and reveal several "kinetically stable structures" along the path to the thermodynamically stable state. Two-dimensional simulations allow us to study the effects of both mask patterns and the initial film thickness. Generally, patterns on the mask guide the growth such that the pattern conforms to the geometric shapes. Interestingly, a small cylindrical protrusion at the center of the mask can produce exactly the same pattern as a large, flat, circular protrusion. The initial film thickness or the thickness ratio of the polymer layer to the air gap plays an important role in determining the final pattern formed. Finally, we demonstrate, by two simple examples, that the simulations can provide insights on "smart" mask designs for producing large areas of well-ordered patterns.     

Rapid determination of acetone in human blood by derivatization with pentafluorobenzyl hydroxylamine followed by headspace liquid-phase microextraction and gas chromatography/mass spectrometry

In the current work, a simple, rapid, accurate and inexpensive method was developed for the determination of acetone in human blood. The proposed method is based on derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA), followed by headspace liquid-phase microextraction (HS-LPME) and gas chromatography/mass spectrometry (GC/MS). In the present method, acetone in blood samples was derivatized with PFBHA and acetone oxime formed in several seconds. The formed oxime was enriched by HS-LPME using the organic solvent film (OSF) formed in a microsyringe barrel as extraction interface. Finally, the enriched oxime was analyzed by GC/MS in electron ionization (EI) mode. HS-LPME parameters including solvent, syringe plunger withdrawal rate, sampling volume, and extraction cycle were optimized and the method reproducibility, linearity, recovery and detection limit were studied. The proposed method was applied to determination of acetone in diabetes blood and normal blood. It has been shown that derivatization with HS-LPME and GC/MS is an alternative method for determination of the diabetes biomarker, acetone, in blood samples.     

超高效液相色谱法测定鱼体组织中地克珠利残留量

建立了鱼体血浆、肌肉、皮肤、肝脏、肾脏和鳃组织中地克珠利残留量测定的超高效液相色谱法(UPLC-TUV)。鱼体血浆、肝脏和肾脏组织采用乙酸乙酯提取,50 mmol/L KH2PO4溶液去除组织中的蛋白,正己烷去脂;鱼体肌肉、皮肤和鳃组织采用乙腈提取,用乙酸乙酯从40 g/L NaCl溶液中进行反萃取,正己烷去除脂肪;以乙腈-0.3%乙酸水溶液为流动相,以ACQUITY UPLC BEH C18为分离柱,柱温为30℃,紫外检测波长为280 nm。地克珠利质量浓度在0.05~10.0 mg/L范围内呈线性相关,相关指数r2=0.999。平均回收率为70.3%~93.5%,相对标准偏差为0.81%~8.6%,地克珠利在鱼体肌肉、皮肤、脂肪和腮组织组织中的检出限为25μg/kg,定量限为50μg/kg;地克珠利在鱼体血浆、肝脏和肾脏样品中组织中的检出限和定量限分别为75μg/kg和100μg/kg。方法适用于鱼体各组织中地克珠利残留量的测定。     

Ring-opening polymerisation of ɛ-caprolactone catalysed by Brønsted acids

Two new Brønsted acids [2,2′-ethylidene-bis (4,6-di-tert-butylphenol)] phosphoric acid (EDBPPOOH) and (3,3′,5,5′-tetra-tert-butylbiphenyl-2,2′-diol) phosphoric acid (TBPO-POOH) were synthesised and fully characterised by ¹H NMR and ¹³C NMR spectra and mass spectra. The ringopening polymerisation (ROP) of ?-caprolactone (?-CL) catalysed by the two Brønsted acids proceeded at 110°C without a solvent or at ambient temperature in toluene. Experimental results indicated that the two Brønsted acids were efficient catalysts for the ROP of ?-CL with moderate number-average molar mass (Mn) and narrow polydispersity indices (PDI). The catalytic activity of TBPO-POOH is higher than EDBP-POOH in the ROP of ?-CL. After benzyl alcohol was added, it was able to accelerate the polymerisation process. The polymerisation can also occur with the addition of water with a monomer/catalyst/initiator mole ratio of 100: 1: 1. The living polymerisation was ascertained by the linear relationships of the Mn vs. monomer conversion, then it was further confirmed by a second-feed experiment of a double monomer producing double Mn. A kinetic study of the relationships between monomer concentration and time revealed a first-order dependence on monomer concentration in the polymerisation. End-group analysis of ¹H NMR spectra and electrospray-ionisation mass spectra suggests that the two Brønsted acids are capable of catalysing and initiating the ROP of ?-CL.     

新型单核Zn（Ⅱ）配合物{Zn（H2O）6·（pbsa）2·2H2O}的合成、晶体结构及其光学性质

在水中采用回流法合成了Zn(Ⅱ)单核配合物{Zn(H2O)6·(pbsa)2·2H2O(1),pbsa=2-苯基苯并咪唑-5-磺酸阴离子},其结构和性能经UV-Vis,FL,X-射线单晶衍射和TG表征。1属单斜晶系,空间群C2/m,晶胞参数a=23.223(2),b=6.905 6(5),c=11.670 1(9),β=119.660(2)°,V=1 626.3(2)3,Z=2,Dc=1.544 mg·cm-3。1的中心离子为Zn(Ⅱ),与六个水分子配位;pbsa没有与中心离子配位,只起电荷平衡作用;未配位的水分子像节点一样通过氢键将1连接成三维网状的空间结构。1的λmax位于318 nm;在430 nm波长激发下,1的最大荧光发射峰位于425 nm和465 nm。     

Metal sulfide: An efficient promoter for the synthesis of 2-mercaptobenzothiazoles from 2-haloanilines and carbon disulfide

A convenient method has been developed for the preparation of a variety of 2-mercaptobenzothiazoles from 2-haloanilines and CS₂ mediated by metal sulfide. In this reaction, 2-haloanilines reacted with CS₂ in the presence of Na₂S?·?9H₂O to form 2-mercaptobenzothiazoles. Na₂S?·?9H₂O functioned both as an activator of CS₂ and as a base. Furthermore, NMR analysis was used to identify the different reaction mechanisms of 2-haloanilines and CS₂ mediated by Na₂S or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), which demonstrated that Na₂S interacted only with CS₂, while DBU reacted with both 2-iodoaniline and CS₂.     

Bifunctional Fluorescent Probe for Sequential Sensing of Thiols and Primary Aliphatic Amines in Distinct Fluorescence Channels

Thiols and primary aliphatic amines (PAA) are ubiquitous and extremely important species in biological systems. They perform significant interplaying roles in complex biological events. A single fluorescent probe differentiating both thiols and PAA can contribute to understanding the intrinsic inter‐relationship of thiols and PAA in biological processes. Herein, we rationally constructed the first fluorescent probe that can respond to thiols and PAA in different fluorescence channels. The probe exhibited a high selectivity and sensitivity to thiols and PAA. In addition, it displayed sequential sensing ability when the thiols and PAA coexisted. The application experiments indicated that the probe can be used for sensing thiols and PAA in human blood serum. Moreover, the fluorescence imaging of endogenous thiols and PAA as well as antihypertensive drugs captopril and amlodipine in living cells were successfully conducted.     

Chemical looping combustion characteristics of coal with Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> oxygen carrier

Chemical looping combustion (CLC) by direct use of coal as fuel is promising with its prominent advantages, but insufficient conversion of coal in the CLC system is a great limitation. In this research, in order to explore the limiting factor inherent for coal conversion in the CLC system, from the perspective of chemical structure of coal, reaction of a selected Chinese typical coal (designated as LZ) with Fe₂O₃ was systematically investigated. Thermogravimetric investigation of LZ coal reaction with Fe₂O₃ at the oxygen excess number Φ = 1.0 indicated that after dehydration, there existed three discernible reaction stages as observed, which were attributed to the combined reactions of Fe₂O₃ with the primary and secondary gaseous products evolved from LZ coal. Meanwhile, the Fe₂O₃ provided should be controlled around Φ = 1.0 aiming at effective conversion of LZ coal and simultaneous proper utilization of Fe₂O₃. And then, both gaseous Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy analysis of the gaseous and solid products formed from reaction of LZ coal with Fe₂O₃ at Φ = 1.0 indicated that full conversion of LZ coal was not reached with a little unconverted CO occurring, though partial Fe₂O₃ was over reduced to lower valence of oxides than Fe₃O₄. Furthermore, in order to explore the insufficient conversion of LZ coal at the molecular scale, X-ray photoelectron spectroscopy analysis revealed the distribution and evolution of the carbon functional groups involved in LZ coal after its reaction with Fe₂O₃ and further found that effective conversion of the aromatic/aliphatic C=C/C–H groups in LZ coal was the rate-limited step at the molecular scale with the relative content of these groups still dominated around 59% after LZ coal reaction with Fe₂O₃. Finally, solid IR (infrared) analysis and quantitative evaluation of the solid products of LZ coal reaction with Fe₂O₃ indicated that the length of aliphatic C–H groups decreased due to its partial disintegration, while the aromatization of the residual char was aggravated with the higher relative IR intensity ratio of the aromatic C=C groups, which reduced the reactivity of LZ residual char and hindered the full conversion of LZ coal.     

Supersaturation controlled growth of MAFAPbI<Subscript>3</Subscript> perovskite film for high efficiency solar cells

Controlling the nucleation and growth of organic-inorganic hybrids perovskite is of key importance to improve the morphology and crystallinity of perovskite films. However, the growth mechanism of perovskite films based on classical crystallization theory is not fully understood. Here, we develop a supersaturation controlled strategy (SCS) to balance the nucleation and crystal growth speeds. By this strategy, we are able to find an ideal supersaturation region to realize a balance of nucleation and crystal growth, which yields highly crystallized perovskite films with micrometer-scale grains. Besides, we provide a thoughtful analysis of nucleation and growth based on the fabrication of the perovskite films. As a result, the highest photovoltaic power conversion efficiencies (PCE) of 19.70% and 20.31% are obtained for the planar and the meso-superstructured devices, respectively. This strategy sheds some light for understanding the film growth mechanism of high quality perovskite film, and it provides a facile strategy to fabricate high efficiency perovskite solar cells.