Aptamer based fluorescent probe for serum HER2-ECD detection: The clinical utility in breast cancer

HB5 aptamer-based probe has been developed for serum HER2-ECD test in auxiliary clinical diagnosis and treatment for HER2-positive breast cancer patients.     

d^0过渡金属化合物对氧气反应性：合成和反应机理研究

众所周知,过渡金属如卟啉中的铁与氧气的结合和反应对许多生物功能和催化氧化至关重要．在这些反应中,过渡金属一般含d价电子,并且金属被氧化往往是其中一个重要的反应步骤．近年来,氧气与d^0过渡金属化合物如Hf（NR2）4（R=烷基）的反应被广泛用来制备金属氧化物薄膜以作为新型微电子器件中的栅（门）绝缘材料．这篇专题文章讨论我们近期对这些反应以及TiO2薄膜形成的研究．在许多氧气与d^0过渡金属化合物的反应中,总是金属被氧化．然而,在d^0过渡金属化合物如Hf（NMe2）4和Ta（NMe2）4（SiR3）与氧气的反应中通常是配体被氧化．如-NMe2和--SIR3配体分别形成了-0NMe2和--OSiR3配体．反应机理和理论方面的研究显示了微电子金属氧化物薄膜形成的途径．     

Formation and composition of the precipitates of various metal 8-selenoquinoline complexes

The effect of acidity on the precipitation of various bivalent metal 8-selenoquinoline and 8-mercaptoquinoline complexes has been systematically studied and compared. The metal ions were Zn(2+), Cd(2+), Pb(2+), Mn2+, Ni(2+), Cu(2+) and Co(2+). Most of the metal ions, except copper(II) and cobalt(II), precipitate as a. 1:2 complex, metal :ligand. However, in hydrochloric acid solution cadmium precipitates as CdR(2).2HCl and lead as PbR(2).2HCl or PbR.Cl. Copper(II) is reduced to copper(I) and precipitates as CuR.RH at pH above 2.0 and as CuR in strongly acidic solution. Cobalt(II) does not give a precipitate of composition but appears to precipitate as a mixture of CoR(2).RH and fixed CoR(2) or as other complexes. The reasons for the formation of the various types of precipitate are considered.     

Reaction chemistry of complexes containing Pt--H, Pt--SH, or Pt--S fragments: from their apparent simplicity to the maze of reactions underlying their interconversion

The relevance of platinum in the reaction of thiophene and derivatives with homogeneous transition-metal complexes as models for hydrodesulfurization has led us to the study of the reaction chemistry of complexes containing Pt--H, Pt--SH, and Pt--S fragments. Exploration of the reactions triggered by addition of controlled amounts of Na2S or NaSH to [Pt2(H)2(mu-H)(dppp)2]ClO4 (1) has provided evidence of the formation of complexes [Pt2(mu-H)(mu-S)(dppp)2]ClO4 (2), [Pt(H)(SH)(dppp)] (3), [Pt2(mu-S)2(dppp)2] (4), [Pt2(mu-S)(dppp)2] (5) and [Pt(SH)2(dppp)], in which dppp denotes 1,3-bis(diphenylphosphanyl)propane. Consequently, complexes 1, 2, and 5 as well as the already reported 3, 4, and [Pt(SH)2(dppp)] have been obtained and fully characterized spectroscopically. Also the crystal structures of 1 and 2 have been solved. Complexes 1-5 constitute the main framework of the network of reactions that account for the evolution of 1 under various experimental conditions as shown in Scheme 1. Apparently, this network has complexes 2 and 4 as dead-ends. However, their reciprocal interconversion by means of the replacement of one bridging hydride or sulfide ligand in the respective {Pt(mu-H)(mu-S)Pt} and {Pt(mu-S)2Pt} cores enables the closure of the reaction cycle involving complexes 1-5. Theoretical calculations support the existence of the undetected intermediates proposed for conversion from 1 to 2 and from 3 to 2 and also account for the fluxional behavior of 1 in solution. The intermediates proposed are consistent with the experimental results obtained in comparable reactions carried out with labeled reagents, which have provided evidence that complex 1 is the source of the hydride ligands in complexes 2 and 3. Overall, our results show the strong dependence on the experimental conditions for the formation of complexes 1-5 as well as for their further conversion in solution.     

Synthesis of 1-aryl-1H-indazoles via palladium-catalyzed intramolecular amination of aryl halides

Palladium-catalyzed cyclization of arylhydrazones of 2-bromoaldehydes and 2-bromoacetophenones to give 1-aryl-1H-indazoles has been studied in detail. The cyclization of arylhydrazone of 2-bromobenzaldehydes can be performed with good to high yields using Pd(dba)2 and chelating phosphines, of which the most effective are rac-BINAP, DPEphos, and dppf, in the presence of Cs2CO3 or K3PO4 as a base. Electron-rich, bulky ligands commonly employed for intermolecular amination such as PtBu3 and o-PhC6H4PtBu2 were shown to be ineffective for cyclization and to lead instead to extensive oligomerization and tarring. The method developed is applicable for preparation of a wide scope of indazoles bearing electron-donating or electron-withdrawing substituents, among them, unprotected carboxyl, as well as various indazole heteroanalogues. The cyclization of arylhydrazones of less reactive halides such as 2-chlorobenzaldehyde, as well as 2-bromoacetophenone and bromotetralone, has been achieved. The purity of the starting hydrazone has been shown to be a critical parameter, as various impurities inhibit the cyclization.     

TiO2花状纳米结构的制备及光催化性能

TiO2 nanostructures were fabricated by a reaction of Ti foils in H2O2 solution at mild temperature. Porous TiO2 nanostructures, well-adhered to Ti foil surfaces, were formed at 80 ±C in 10 min, and then flower- like and rod nanostructures formed in succession after a longer reaction time. Samples prepared at 80 ±C for 4 h are amorphous, and anatase-dominated crystal phase emerged in the sample prepared for as long as 10 h. Almost pure anatase phase were obtained in TiO2 nanostructures by annealing the samples at a temperature of 300 ±C. Photocatalysis of the TiO2 nanostructures was characterized by the degradation of RhB dye molecules in an aqueous solution exposed to ultraviolet light. Results show a 7 cm2 annealed TiO2 flower-like nanostructure having the degradation rate of RhB as fast as 29.8 times that of the dye solution exposed to ultraviolet light alone.     

Oxo- and oxoperoxo-molybdenum(VI) complexes with aryl hydroxamates: synthesis, structure, and catalytic uses in highly efficient, selective, and ecologically benign peroxidic epoxidation of olefins

A solution obtained by dissolving MoO3 in H2O2 reacts separately with secondary hydroxamic acids (viz., N-benzoyl N-phenyl hydroxamic acid (BPHAH), N-benzoyl N-ortho-, -meta-, -para-tolyl hydroxamic acids, (BOTHAH, BMTHAH, and BPTHAH, respectively), and N-cinnamoyl N-phenyl hydroxamic acid (CPHAH) affording [MoO(O2)(BPHA)2] (1), [MoO(O2)(BOTHA)2] (2), [MoO(O2)(BMTHA)2] (3), [MoO(O2)(BPTHA)2] (4), and [Mo(O)2(CPHA)2](5), respectively. The O and O2 are situated cis to each other in 2-4, but in each case, they are disordered and distributed over four sites. This disorder does not exist in the 6-coordinate cis dioxo complex 5, to which crude MoO(O2)(CPHA)2 (5') was converted during recrystallization. An aqueous molybdate solution readily reacts with all those hydroxamic acids producing [Mo(O)2(hydroxamate)2] (6). While 2, 3, and 4 possess a very distorted pentagonal bipyramidal structure, 5 has a distorted octahedral geometry. In the solid state, as well as in solution, 5 exists as two apparently enantiomerically related molecules differing in the orientation of the pendant phenyl rings. To emphasize that the formation and structural uniqueness of 5 compared to 1-4 is caused by the influence of the cinnamoyl residue, one compound of the 6 series, namely, [Mo(O)2(BPHA)2] (6A), was structurally characterized to prove directly that the special stereochemical properties of 5 rely on the special electronic structure of CPHA- ligand. Complexes 1-5, as well as 6, show high potential and selectivity as catalysts in the epoxidation of olefins at room temperature in the presence of NaHCO3 as a promoter and H2O2 as a terminal oxidant. A comparative epoxidation study has been performed to determine the relative efficiency of the catalysts. To make the epoxidation method cost effective, a study to optimize the use of H2O2 has also been performed. To obtain evidence in favor of our suggested mechanism to this homogeneous olefin --> epoxide conversion, it was necessary to synthesize a peroxo-rich compound, namely, [MoO(O2)2BMTHA]- (7), but the attempted synthesis culminated in the isolation of [MoO(O2)2(C6H5COO)]- (8), obviously, via the hydrolysis of coordinated BMTHA.     

The synthesis of (N2O2S2)-Schiff base ligands and investigation of their ion extraction capability from aqueous media

Two new Schiff bases (I) and (II) containing nitrogen-sulfur-oxygen donor atoms were designed and synthesized in a multi-step reaction sequence. The Schiff base (I) was used in solvent extraction of metal chlorides such as Cu2+ and Cr3+ as well as metal picrates such as Hg2+ and UO2(2+) from aqueous phase to the organic phase. The influences of the parameter functions, such as pH, solvent, ionic strength of aqueous phase, aqueous to organic phase and concentration of the extractant were investigated to shed light on their chemical extracting properties upon the extractability of metal ions. The effect of chloroform, dichloromethane and nitrobenzene as organic solvents over the metal chlorides extraction was investigated at 25±0.1 °C by using flame atomic absorption and the result is that the ability of extraction in solvents as follows: C6H5NO2>CHCl3>CH2Cl2 and the compositions of the extracted species have been determined. The metal picrate extraction was investigated at 25±0.1 °C by using UV-visible spectrometry. As well that the extraction of picrates metal such as UO2(2+) and Hg2+ with Schiff base(I) in absence and presence of 2-(2-aminoethyl) pyridine was investigated in chloroform. The extraction results revealed the presence of neutral donors 2-(2-aminoethyl) pyridine shifts the extraction percentage curves towards higher pH region, indicating a synergistic effect of this donors on extraction of UO2(2+) and Hg2+ by the studied Schiff base (I).     

Fluorophilicity switch by solvation

A new type of fluorous distannoxanes, [XRf2SnOSnRf2Y]2 (Rf = C6F13C2H4; X, Y = C6F13SO3 (2) and (C6F13SO2)2N, Cl (3)) was prepared successfully as hydrates from the reaction of [ClRf2SnOSnRf2Cl]2 with C6F13SO3Ag and (C6F13SO2)2NAg, respectively. Despite their high fluorine content (59.85 and 59.27% F), these distannoxanes were completely insoluble in fluorocarbons as well as hydrocarbons and halo alkanes. In contrast to this, fluorous distannoxanes 2 and 3 were soluble in polar organic solvents, such as EtOAc, acetone, and THF. When 2 and 3 were added to a two-phase mixture of fluorocarbon and EtOAc, the mixture turned miscible in proportion to the amount of 2 and 3 added, and finally, the mixture turned to a homogeneous solution.     

游离和膜固定化脂肪酶在双液相介质中催化二肽合成的研究

以N－乙酰－L－苯丙氨酸乙酯和L－亮氨酰胺、L－丙氨酰胺、L－苯丙氨酰胺 、L－缬氨酰胺等L－氨基酰胺为底物，以游离或膜固定化脂肪酶为催化剂，在水、 有机溶剂单相和水－有机相双相体系反应介质中，合成了N－乙酰－L－苯丙氨酰基 －L－亮氨酰胺、N－乙酰－L－苯丙氨酰基－L－丙氨酰胺、N－乙酰－L－苯丙氨酰 基－L－苯丙氨酰胺、N－乙酰－L－苯丙氨酰基－L－缬氨酰胺等二肽。研究证明， 由于反应和纯化的同步进行，二肽可以在双液相酶膜反应器中达到高纯度和高收率 合成。     

PRODUCTION OF LIGHT OLEFINS FROM CO_2 HYDROGENATION OVER Fe/SILICALITE-2 CATALYSTⅢ. PROMOTION EFFECT OF K_2O PROMOTER

ThisprojectissllpportedbytheNationalNaturalScienceFotmdationofChina.IntroductionRecentstUdyonCOZhydrogenationfortheformationofhydrocarbonshascausedagreatinterest,especiallyintheproductionoflightalkenes.msreactionwillprovideanalternativeroutetoproducebasic…     

Electronic structures and molecular properties of chalcogen nitrides Se2N2 and SeSN2

The electronic structures and molecular properties of S2N2 as well as the currently unknown chalcogen nitrides Se2N2 and SeSN2 have been studied using various ab initio and density functional methods. All molecules share a qualitatively similar electronic structure and can be primarily described as 2pi-electron aromatics having minor singlet diradical character of 6-8% that can be attributed solely to the nitrogen atoms. This diradical character is manifested in the prediction of their molecular properties, in which coupled cluster and multiconfigurational approaches, as well as density functional methods, show the best performance. The conventional ab initio methods RHF and MP2 completely fail to describe these systems. Predictions for the vibrational frequencies, IR intensities, Raman activities, and 14N, 15N, and 77Se chemical shifts, as well as singlet excitation energies of Se2N2 and SeSN2, have been made. The computed high-level spectroscopic data will be of considerable value in future efforts aimed at the preparation of the conducting polymers (SeN)x and (SeNSN)x.     

Competition between Li+ and Mg2+ in metalloproteins. Implications for lithium therapy

Lithium is used (in the form of soluble salts) to treat bipolar disorder and has been considered as a possible drug in treating chronic neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's diseases. One of the proposed mechanisms of Li(+) action involves a competition between the alien Li(+) and native Mg(2+) for metal-binding sites and subsequent inhibition of key enzymes involved in specific neurotransmission pathways, but not vital Mg(2+) proteins in the cell. This raises the following intriguing questions: Why does Li(+) replace Mg(2+) only in enzymes involved in bipolar disorder, but not in Mg(2+) proteins essential to cells? In general, what factors allow monovalent Li(+) to displace divalent Mg(2+) in proteins? Specifically, how do the composition, overall charge, and solvent exposure of the metal-binding site as well as a metal-bound phosphate affect the selectivity of Li(+) over Mg(2+)? Among the many possible factors, we show that the competition between Mg(2+) and Li(+) depends on the net charge of the metal complex, which is determined by the numbers of metal cations and negatively charged ligands, as well as the relative solvent exposure of the metal cavity. The protein itself is found to select Mg(2+) over the monovalent Li(+) by providing a solvent-inaccessible Mg(2+)-binding site lined by negatively charged Asp/Glu, whereas the cell machinery was found to select Mg(2+) among other competing divalent cations in the cellular fluids such as Ca(2+) and Zn(2+) by maintaining a high concentration ratio of Mg(2+) to its biogenic competitor in various biological compartments. The calculations reveal why Li(+) replaces Mg(2+) only in enzymes that are known targets of Li(+) therapy, but not in Mg(2+) enzymes essential to cells, and also reveal features common to the former that differ from those in the latter proteins.     

4-(4-吡啶基)嘧啶-2-磺酸钠与过渡金属组装的三维氢键网络结构

4-(4-吡啶基)嘧啶-2-磺酸钠(NaL²)与金属盐(M=Mn,Zn,Co,Fe)组装分别得到4个配合物,其分子式为[ML₂·4H₂O]·2H₂O。氢键在这些化合物的超分子结构中起了重要作用。4种配合物中磺酸基的氧原子没有螯合金属离子,而是作为氢键的受体,同时水分子作为氢键给体和受体起到双重作用。另外,在配合物2～4中,杂环上的碳原子也起到供体的作用与磺酸基的氧原子形成氢键。     

嗜中性粒细胞中过氧化氢及其释放过程的电化学检测

活性氧（ROS）是细胞代谢的重要产物之一,其浓度与多种生理、病理现象密切相关;H2O2是ROS的重要代表,对细胞内H2O2及其释放过程的测定有助于理解相关疾病的形成机制,因而具有重要的意义.本文报道一种检测细胞内H2O2浓度、监测其生成和释放过程的电化学方法,该方法利用固定在天然矿物凹土（attapulgite,全称凹凸棒石黏土）表面的血红蛋白（Hb）对H2O2还原的电催化作用实现H2O2的定量测定.将Hb固定到凹土表面制备了Hb-凹土（Hb-Atta）纳米复合材料,用透射电子显微镜（TEM）、原子力显微镜（AFM）、红外光谱（FTIR）、紫外-可见光谱（UV-vis）等对其进行了表征;将该复合物修饰到玻碳（GC）电极表面制成了Hb-Atta/GC电极,用伏安法考察了Hb在凹土表面的直接电子转移性能,结果表明,Hb能进行有效的直接电子转移反应,其伏安曲线上呈现出一对良好的氧化还原峰,式量电位（E0′）约为-350mV（vs.SCE,50mV/s）;进一步的结果表明,Hb-Atta对H2O2的电化学还原具有良好的催化性能,并能用于H2O2的定量测定,具有响应速率快、线性范围宽、检测限低等优点.将Hb-Atta/GC电极应用于嗜中性粒细胞内H2O2的测定,结果表明,该电极不仅能定量地检测细胞内的H2O2含量,还能监测细胞内H2O2生成和释放的过程,而且细胞内其他ROS和电活性物质如OCl-、NO.、ONOO-和抗坏血酸等不产生干扰.本文的结果为测量细胞内H2O2浓度、研究其生成及释放过程动力学以及进一步阐明由H2O2导致的相关疾病机制等提供了一个新的平台,可望在生物电化学、细胞生物学和病理生理学等领域得到应用.     

苯直接一步氧化合成苯酚

苯直接一步氧化合成苯酚是开辟苯酚合成路线具有挑战性的热点课题之一.近年来研究和开发了以N2O、H2O2和O23种不同氧化剂体系为核心和主流的苯氧化合成苯酚路线.本文详细综述了目前3种不同氧化体系的研究进展和趋势,分析了各种合成路线的特点和工业应用前景.以N2O为氧化剂合成苯酚路线,技术趋于成熟,但N2O来源受限而影响其经济性和推广应用;以H2O2为氧化剂合成苯酚路线,是环境友好过程,有开发潜力,但技术还很不成熟,而且也因H2O2价格昂贵带来了经济成本问题;以O2为氧化剂、氢气为还原剂体系合成苯酚路线,是环境清洁可持续发展制备路线,具有很好的开发潜力,此外无机膜催化合成苯酚路线也更具吸引力.     

Complexation of the vulcanization accelerator tetramethylthiuram disulfide and related molecules with zinc compounds including zinc oxide clusters (Zn4O4)

Zinc chemicals are used as activators in the vulcanization of organic polymers with sulfur to produce elastic rubbers. In this work, the reactions of Zn(2+), ZnMe(2), Zn(OMe)(2), Zn(OOCMe)(2), and the heterocubane cluster Zn(4)O(4) with the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and with the related radicals and anions Me(2)NCS(2)(*), Me(2)NCS(3)(*), Me(2)NCS(2)(-), and Me(2)NCS(3)(-) have been studied by quantum chemical methods at the MP2/6-31+G(2df,p)//B3LYP/6-31+G* level of theory. More than 35 zinc complexes have been structurally characterized and the energies of formation from their components calculated for the first time. The binding energy of TMTD as a bidendate ligand increases in the order ZnMe(2)相似文献   

溶胶-凝胶薄膜光纤传感器法测定空气中二氧化氮

以四乙氧基硅烷合成溶胶-凝胶薄膜,包埋偶氮试剂制备得到对二氧化氮具有灵敏响应的传感膜;与分支光纤等元件耦合成光纤传感器,通过累积吸收法能够现场测定空气中的低浓度二氧化氮．其检出限为每小时5ng／L;测定相对标准偏差为4．4％（n=6,C（NO2）=200ng／L,1h）。实验表明,CO2、NO、SO2、NO等共存气体在低浓度下对传感器测定NO2无明显干扰。     

Nanostructured pure gamma-Fe2O3 via forced precipitation in an organic solvent

Pure maghemite, gamma-Fe(2)O(3), was prepared as ultra fine particles in the nanometer-sized range via the forced precipitation method in an organic solvent. The precipitation of iron(III) ions, from iron(III) chloride in 2-propanol led selectively to highly dispersed particles of ferrihydrite, which upon treatment with temperatures higher than 200 degrees C under dynamic vacuum resulted in high-surface-area particles of gamma-Fe(2)O(3). Precipitation in water also led to ferrihydrite, but the final product, after heating at 300 degrees C, contained a mixture of gamma-Fe(2)O(3) and alpha-Fe(2)O(3) (hematite). The precipitation from iron(III) nitrate in water resulted in goethite which was converted to hematite upon heating. On the other hand, the final product in 2-propanol was a mixture of maghemite and hematite. The products were characterized by FTIR, TGA, XRD, and gas sorption analysis. Nitrogen gas adsorption studies for the pure gamma-Fe(2)O(3) samples revealed mesoporous particles with high surface areas in the range of 70-120 m(2) g(-1) after heat treatment at 300 degrees C. The gamma-Fe(2)O(3) particles retained their gamma-phase as well as their mesoporous structure at relatively high temperatures, as high as 400 degrees C.     

自然水体生物膜体系中过氧化氢浓度的影响因素

以过氧化氢(H₂O₂)为自然水体生物膜产生的活性氧(ROS)的代表, 通过模拟实验, 研究了水-自然水体生物膜体系中光/暗变化、 生物膜的避光预处理与数量、 有机配体和pH值对体系中H₂O₂浓度的影响. 结果表明, 光照可快速增加体系中H₂O₂浓度, 光照转为无光时体系H₂O₂浓度下降(约为光照时的2/3); 避光预处理会显著降低体系中H₂O₂的产生速率和浓度; 生物膜数量的增减会导致体系H₂O₂浓度的相应增减; 有机配体的存在会使体系内H₂O₂浓度下降(约1/2~1/3); pH=7和5的体系中H₂O₂的浓度高于pH=9的体系(高出约1.5倍). 上述各因素主要通过影响生物膜生产H₂O₂、 H₂O₂自然分解和生物膜去除H₂O₂ 3种作用来影响体系H₂O₂浓度.