Syntheses, Crystal Structures, and Properties of Two Mixed-ligand Coordination Polymers： [Zn（bdc）（1,3-bimb）]_n and {[Mn_2（ox）_2（1,3,5-tib）_（4/3）]·4H_2O}_n

Two new coordination polymers,[Zn（bdc）（1,3-bimb）]n（1） and {[Mn2（ox）2（1,3,5tib）4/3]·4H2O}n（2）（H2ox = oxalic acid,H2bdc = terephthalic acid,1,3-bimb = 1,3-bis（imidazol-1ylmethyl）benzene,1,3,5-tib = 1,3,5-tri（imidazol-1-yl）benzene）,were synthesized and characterized by elemental analysis,IR,powder X-ray diffraction（PXRD）,and thermogravimetric（TG） analyses.X-ray diffracation analysis reveals that two kinds of zigzag chains [Zn（bdc）]n and [Zn（1,3-bimb）]n in compound 1 are interweaved to form a 3D 4-fold interpenetrated 66-dia framework.In compound 2,Mn（1） and Mn（2） are linked via 1,3,5-tib ligands to form two different nets of [Mn6（1,3,5-tib）6 ]n along the ab plane with inner-or outer-shape N–Mn–N angles,which are connected by 1D infinite [Mn2（ox）2 ]n chains via Mn–O bonds to result in a（3,3,3,4,4）-connected（4·8·10）3（4·82）3（4·83·102）6（82·104·3）3（83）4 topology.Moreover,the photoluminescence of 1 has been investigated.The crystal of 1 crystallizes in orthorhombic,space group Pna2 with a = 13.2267（6）,b = 9.1717（4）,c = 17.4492（8）,V = 2116.79（16）3,Z = 4,C22 H18N4O4 Zn,Mr = 467.77,Dc = 1.468 g/cm3,F（000） = 960 and μ（MoKα） = 1.197 mm-1.The final R = 0.0280 and wR = 0.0618 for 3695 observed reflections with I 2（I） and R = 0.0389 and wR = 0.0653 for all data.The crystal of 2 crystallizes in rhombohedral,space group R-3 with a = 22.080（8）,c = 31.19（2）,V = 13167（11） 3,Z = 18,C24 H25 Mn2 N8 O13,Mr = 743.40,Dc = 1.688 g/cm3,F（000） = 6822 and μ（MoKα） = 0.945 mm-1.The final R = 0.0429 and wR = 0.1035 for 5160 observed reflections with I 2（I） and R = 0.0824 and wR = 0.1244 for all data.     

Synthesis and photochromic properties of WO<Subscript>3</Subscript> powder induced by oxalic acid

Tungsten trioxide powder with the novel morphology was prepared via the hydrothermal method with oxalic acid as the organic inducer, the structure and shape of which were detected by X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET. Furthermore, photochromic properties of the as-prepared powder samples were tested by an ultraviolet-visible spectrophotometer combined with a color difference meter. The corresponding results indicated that the induced product was still hexagonal WO₃, made up of regularly spindle particles with 200–300 nm in length and 30–50 nm in width. The ratio of the length and width was from 4 to 10. Moreover, the special morphology improved its absorptive capacity to the excitation light source, resulting in its high photochromic properties. Supported by the National Natural Science Foundation of China (Grant No. 50702052) and the Hubei Province Key Laboratory of Macromolecular Material     

络合法除P507-N235体系中铁的研究

因铁离子具有强烈的水解倾向及易与其他离子形成配合物的性质,在溶剂萃取体系中的存在形式极为复杂。在稀土萃取体系中,采用P204或N235除铁,经盐酸反萃后,有机相中铁的反萃率较低,不能深度除去,影响萃取剂的萃取性能。而在P507-N235盐酸萃取体系中,Fe3+在低酸度下可被P507萃取,在高酸度下形成Fe Cl-4配合物被N235萃取,萃取率达99%以上,且难被反萃下来。研究采用草酸和EDTA络合法除去有机相中的铁,结果表明:草酸络合法除铁率较低,较难用草酸络合法将有机相中的铁反萃下来;在温度25℃、反萃时间14 min,相比1∶1的条件下,用EDTA络合法除铁,铁的反萃率可达97.51%,经4次错流反萃后,可将有机相中铁的浓度降至0.002 g·L-1,达到深度除铁的目的。     

Towards Understanding the Involvement of H+-ATPase in Programmed Cell Death of Psammosilene tunicoides after Oxalic Acid Application

Psammosilene tunicoides is a unique perennial medicinal plant species native to the Southwestern regions of China. Its wild population is rare and endangered due to over-excessive collection and extended growth (4–5 years). This research shows that H⁺-ATPase activity was a key factor for oxalate-inducing programmed cell death (PCD) of P. tunicoides suspension cells. Oxalic acid (OA) is an effective abiotic elicitor that enhances a plant cell’s resistance to environmental stress. However, the role of OA in this process remains to be mechanistically unveiled. The present study evaluated the role of OA-induced cell death using an inverted fluorescence microscope after staining with Evans blue, FDA, PI, and Rd123. OA-stimulated changes in K⁺ and Ca²⁺ trans-membrane flows using a patch-clamp method, together with OA modulation of H⁺-ATPase activity, were further examined. OA treatment increased cell death rate in a dosage-and duration-dependent manner. OA significantly decreased the mitochondria activity and damaged its electron transport chain. The OA treatment also decreased intracellular pH, while the FC increased the pH value. Simultaneously, NH₄Cl caused intracellular acidification. The OA treatment independently resulted in 90% and the FC led to 25% cell death rates. Consistently, the combined treatments caused a 31% cell death rate. Furthermore, treatment with EGTA caused a similar change in intracellular pH value to the La³⁺ and OA application. Combined results suggest that OA-caused cell death could be attributed to intracellular acidification and the involvement of OA in the influx of extracellular Ca²⁺, thereby leading to membrane depolarization. Here we explore the resistance mechanism of P. tunicoides cells against various stresses endowed by OA treatment.     

An effective route to improve the catalytic performance of SAPO-34 in the methanol-to-olefin reaction

An effective route to improve the catalytic performance of SAPO-34 in the methanol-to-olefin reaction by simple oxalic acid treatment was investigated.The samples were characterized by XRD,SEM,N2 adsorption-desorption,XRF,TG,29Si MAS NMR and NH3-TPD techniques.The results indicated that the external surface acidity of SAPO-34 was finely tuned by oxalic acid treatment,and the selectivity to C2H4 on SAPO-34 and the catalyst lifetime in the methanol-to-olefin reaction were greatly improved.     

Mixed-ligand complexes of copper VII. Polarographic studies on copper-carboxylate-aminocarboxylate complexes

The formation constants of mixed-ligand complexes with hetero donors of the type CuAB where A is a carboxylic acid such as lactic acid or oxalic acid and B is an α−or β-amino acid are studied by polarography. The mixed-ligand stabilisation constant clearly indicates the preferred formation of copper(II) mixedligand complexes with hetero donors over homo donors. The other driving forces leading to the favoured formation of mixed-ligand complexes are also discussed.     

在缓冲溶液中探究高锰酸钾与草酸的反应

以硫酸氢钠-硫酸钠缓冲溶液为反应介质,研究了温度、溶液pH、高锰酸钾浓度以及草酸浓度等因素对高锰酸钾与草酸反应的反应速率的影响。研究发现,升高温度、降低溶液pH（即增大氢离子浓度）以及增大草酸浓度均能加快反应速率,而高锰酸钾浓度对反应速率的影响规律性不强。     

Influence of electrolyte composition on photoluminescent properties of anodic aluminum oxide

Luminescent properties of anodic alumina fabricated in anodizing solutions containing oxalic, sulfuric, and phosphoric acids in addition to those modified by thermal annealing are investigated. Comparison of the obtained data shows that F⁺-centers are responsible for the luminescence band at 390 nm. The intense photoluminescence band of porous anodic alumina substrates at 450–500 nm is associated with oxalate anions. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 208–212, March–April, 2008.     

DFT study of the hydrogen bond strength and IR spectra of formic,oxalic, glyoxylic and pyruvic acids in vacuum,acetone and water solution

The molecular geometries of the possible conformations of formic, oxalic, glyoxylic and pyruvic acids have been fully optimized at DFT B3LYP/6‐311++G(d,p) levels of calculation in vacuum as well as in water and acetone solution. Solutions were treated according to the SCRF PCM approach but some formic acid–water and formic acid–acetone clusters as well as adducts of oxalic acid with two or four water molecules were also taken into account for testing the importance of specific solute–solvent effects. All the most stable isomers of the title compounds are characterized by weak intramolecular hydrogen bonds, whose strengths (E_HB) cannot be correctly estimated as stability difference between the open and chelate forms since the energy of the former isomer is, in turn, stabilized by a weak hydrogen bridge due to the formic acid moiety. Following the Rotation Barrier Method (RBM), proposed some years ago, E_HB in the examined molecules (gas phase) falls in the range of 18–22 kJ/mol for oxalic acid (9.6 kJ/mol for the c‐C‐t isomer), 16.8 kJ/mol for glyoxylic acid and 19.8 kJ/mol for pyruvic acid. Most of them disappear at all, or nearly at all, both in acetone and aqueous solution, in consequence of the solvent effect. The frequencies of the OH and C?O stretching modes, calculated according to the anharmonic oscillator model, are in very good agreement with the experimental literature data, where available. Copyright © 2009 John Wiley & Sons, Ltd.     

添加β沸石的烃类裂化催化剂性能研究

采用固体硅源、铝源和四乙基氢氧化铵（TEAOH）在极浓体系中成功合成了硅铝摩尔比（SiO₂/Al₂O₃）分别为30和150的β沸石。同时用硅铝摩尔比为30的β沸石为原料,在70℃下采用草酸脱铝制备了硅铝摩尔比接近150的样品。直接合成或经脱铝改性的β沸石采用XRD、SEM、吡啶吸附红外光谱和N2吸附对其晶相、酸性、比表面积和孔体积进行了表征。将三种β沸石分别作为烃类裂化催化剂的活性组分添加剂,对其催化剂的性能进行了评价。结果表明,三种β沸石的引入都可以提高裂化催化剂的活性和改善产品分布,低硅β沸石催化剂能改善催化剂的异构化反应性能和提高乙烯、丙烯的选择性,高硅β沸石或脱铝β沸石催化剂有利于裂化汽油中烯烃的芳构化和C4烯烃产率的提高,并可减少结焦。