Single-crystal X-ray structure and properties of K-10[Ni-4(H2O)(2)(AsW9O34)(2)]center dot 4H(2)O

The rational synthesis and the structural and magnetic characterization of a nickel cluster are presented. The compound comprises a rhomblike Ni4O16 group encapsulated between two-heptadentate tungstoarsenate ligands [AsW9O34](9-). The crystal structure of K-10[Ni-4(H2O)(2)(AsW9O34)(2)](.)4H(2)O was solved in monoclinic, P2(1)/n symmetry, with a = 12.258(3) Angstrom, b = 21.232(4) Angstrom, c = 15.837(3) Angstrom, beta = 92.05(3)degrees, V = 4119.1(14) Angstrom(3), Z = 2, and R = 0.0862. The crystal structure of the Ni(II) derivative was compared with that of the Cu(II), Zn(II), Co(II) and Mn(II) derivatives. The Ni4O14(H2O)(2) unit in the compound shows no Jahn-Teller distortion. On the other hand, the Ni(II) derivative shows ferromagnetic exchange interactions within the Ni4O16 group (J = 7.8 cm(-1), J' = 13.7 cm(-1)) and an S = 4 ground state, the highest spin state reported in a heteropoly complex. Its redox electrochemistry has been studied in acid buffer solutions using cyclic voltammetry. It exhibited two steps of one-electron redox waves attributed to redox processes of the tungsten-oxo framework. The new catalyst showed an electrocatalytic effect on the reduction of NO2-.

Silica sol-gel composite film as an encapsulation matrix for the construction of an amperometric tyrosinase-based biosensor

An amperometric tyrosinase enzyme electrode for the determination of phenols was developed by a simple and effective immobilization method using sol-gel techniques. A grafting copolymer was introduced into sol-gel solution and the composition of the resultant organic-inorganic composite material was optimized, the tyrosinase retained its activity in the sol-gel thin film and its response to several phenol compounds was determined at 0 mV vs. Ag/AgCl (sat. KCI). The dependences of the current response on pH, oxygen level and temperature were studied, and the stability of the biosensor was also evaluated. The sensitivity of the biosensor for catechol, phenol and p-cresol was 59.6, 23.1 and 39.4 muA/mM, respectively. The enzyme electrode maintained 73% of its original activity after intermittent use for three weeks when storing in a dry state at 4 degreesC. (C) 2000 Elsevier Science S.A. All rights reserved.

1,1 '-di(tert-butyl)metallocenium cations. The x-ray crystal structures of [M((C5H4Bu)-Bu-t)(2)]PF6 (M = Fe, Co) and [Co((C5H4Bu)-Bu-t)(2)](2)CoCl4

The hexafluorophosphate salts [Fe((C5H4Bu)-Bu-t)(2)]PF6 (1) and [Co((C5H4Bu)-Bu-t)(2)]PF6 (2) crystallize in isotypic structures with centrosymmetric cations which have a staggered (transoid) conformation of the exactly parallel ring Ligands (conformational angle tau = 180 degrees). The tetrachlorocobaltate salt, [CO((C5H4Bu)-Bu-t)(2)](2)CoCl4 (3), contains one almost eclipsed (tau = 140.4 degrees) and one almost staggered (tau = 101.4 degrees) cobaltocenium cation; in both cases, the cyclopentadienyl ring planes are slightly inclined (by alpha = 5.4 degrees and 4.1 degrees, respectively) to give more room to the tert-butyl substituents which are bent away from the metal in all three complexes 1 - 3.

Hydrothermal synthesis and crystal structure of a novel layered compound [Ni(C10H8N2)(2)V3O8.5]

A novel layered compound, [Ni(C10H8N2)(2)V3O8.5], was hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. The compound crystallizes in monoclinic system, space group P21/c with a = 1.551 8(3) nm, b = 1.476 1(3) nm, c = 1.048 3(2) nm, beta = 92.02(3), V = 2.399 8(8) nm(3), Z = 4, R = 0. 046 7, wR(2) = 0. 085 9.

Crystal structure of mixed sodium-potassium paradodecatungstate 6-hydrate

The crystal structure of K7Na3[H2W12O42]3 . 6H(2)O was determined by X-ray crystallography,and refined to R=0.0864 based on 7024 observed reflections (I>2 sigma(I)). The crystallographic parameters are a=11.755(2), b=13.0493(3), c=16.289(3) Angstrom; alpha=77.13(3)degrees, beta=82.92(3)degrees, gamma=89.65(3)degrees, triclinic, space group, P (1) over bar, V=2416.7(8) Angstrom(3), Z=2, M-r=3330.98, D-cal=4.578Mg/m(3), F(000)=2904; mu (MoK alpha)=29.170mm(-1), T=293K. Two independent polyanions are centered respectively at 1,1,1/2 and 1/2, 1/2, 0, approximately perpendicular to each other with dihedral angle between the equatorial planes of the molecules at 96 degrees. K+ and Na+ respectively occupy the clefts of the two discrete polyanions.

Synthesis and structure of 1:1 complex of ethylphenyltin dichloride with N-4-methoxyphenyl-2-hydroxynaphthylideneimine

A novel organotin complex, EtPhSnCl(2) . 2HOC(10)H(6)CH = NC6H1OCH3 was synthesized, and its crystal structure was determined by X-ray diffraction method. The crystal is triclinic, belonging to space group, bar> with unit cell parameters a = 1.150 8(5) nm, b = 1. 153 1(5) gm, c = 1. 004 6 (3) nm, alpha = 94. 15 (3)degrees, beta = 115.47 (3)degrees, r = 85. 94 (4)degrees, V = 1199 7(1) nm(3), Z=2, D-c=1.68 g/cm(3), mu=13. 20 cm(-1), F(000)=618 for 4 131 reflections tions. R=0. 047, R(w)=0. 047. The ligand coordinates to tin atom via phenolic oxygen atom. The complex has a distored trigonal bipyramidal structure, the phenolic oxygen atom of the ligand and one of two chlorine atoms occupy the axial position. The distance between noncoodinated nitrogen atom with phenolic oxygen atom is 0. 257 4 nm, which indicates that the intramolecular hydrogen bond of Schiff base ligand is retained in the complex.

PREPARATION AND PROPERTIES OF BACUO2.5 AND ITS RELATED OXIDES

The compound BaCuO2.5 Was obtained using BaO2 and CuO as starting materials, and its various properties were investigated. It belongs to the orthorhombic system with a = 8.55 angstrom, b = 10.56 angstrom, and c = 7.62 angstrom. The p-type semiconductor Ba

STUDIES ON OLEFIN-COORDINATING TRANSITION-METAL CARBENE COMPLEXES .20. SYNTHESIS OF 1,3-CYCLOHEXADIENE(DICARBONYL) [ETHOXY(ARYL)-CARBENE]IRON COMPLEXES AND THEIR PHOSPHINE ADDUCTS - CRYSTAL-STRUCTURE OF C6H8(CO)2FEC(OC2H5)C6H4CH3-O

Reaction of 1,3-cyclohexadiene(tricarbonyl)iron (1) with ortho-substituted aryllithium reagents ArLi (Ar=o-CH3C6H4, o-CH3OC6H4, o-CF3C6H4) in ether at low temperature, and subsequent alkylation of the acylmetalates formed with Et3OBF4 in aqueous solution at 0-degrees-C or in CH2Cl2 at -60-degrees-C gave the 1,3-cyclohexadiene(dicarbonyl)[ethoxy(aryl)carbene]iron complexes (eta4-C6H8)(CO)2FeC(OC2H5)Ar (3, Ar = o-CH3C6H4; 4, Ar = o-CH3OC6H4), and the isomerized product (eta3-C6H8)(CO)2FeC(OC2H5)C6H4CF3-o (5), respectively, among which the structure of 3 has been established by an X-ray diffraction study. Complex 3 is monoclinic, space group P2(1) with a = 8.118(4), b = 7.367(4), c = 14.002(6) angstrom, beta = 104.09(3)-degrees, V = 812.2(6) angstrom3, Z = 2, D(c) = 1.39 g cm-3, R = 0.056, and R(w) = 0.062 for 976 observed reflections. Complexes 3 and 5 were converted into the chelated allyliron phosphine adducts(eta3-C6H8)(CO)2(PR31)FeC(OC2H5)Ar (6, Ar = o-CH3C6H4, R1 = Ph; 7, Ar = o-CH3C6H4, R1 = OPh; 9, Ar = o-CF3C6H4, R1 = Ph), by reaction with phosphines in petroleum ether at low temperatures.

SYNTHESIS, THERMAL-STABILITY AND X-RAY CRYSTAL-STRUCTURE OF THE BIS(CYCLOPENTADIENYL)YTTERBIUM NAPHTHOXIDE DERIVATIVE (C5H5)2YB(OC10H7)(THF)

Cp3Yb (Cp = C5H5) reacts with a-naphthol (HNP) in THF to form Cp2Yb(NP)(THF) (1), which crystallizes in the space group P2(1)/n with unit cell dimensions a = 8.084(2), b = 15.996(6), c = 15.973(7) angstrom, beta = 98.95(3), V = 2040.3 angstrom and D(calc.) = 1.69 g cm-3 for Z = 4. Least-squares refinement based on 2242 observed reflections converged to a final R value of 0.081. The average Yb-C(Cp) distance is 2.60(2) angstrom and Yb-O(THF) and Yb-O(NP) distances are 2.30(1) and 2.06(1) angstrom, respectively. The title compound loses the coordinated THF molecule readily by heating under vacuum to give dimeric [Cp2Yb(NP)]2 (2), which undergoes disproportionation to give Cp3Yb and Yb(NP)3 on heating above 230-degrees-C.

大豆食心虫性信息素的化学结构触角电位及田间诱蛾效果

用气相色谱(GC)和气相色谱-质谱(GC-MS)分析,证明反-8,反-10-十二碳二烯醇醋酸(B)是大豆食心虫[Leguminivora glycinivorella(Mats.)]性信息素的组分。通过触角电位(EAG)测试,发现反-10-十二碳烯醇醋酸酯(A)、B 和反-7,顺-9-十二碳二烯醇醋酸酯(C)对该虫雄蛾触角有强烈刺激作用。大量田间诱蛾试验表明,由 A 和 B 两化合物组成的性引诱剂,对该虫雄蛾有很高的引诱活性。其中 A 和 B 按5∶2混合,剂量50μg/诱捕盆,单盆每日最多诱捕雄蛾达776头,诱捕雄蛾总数是1头活雌蛾的16.8倍。顺-10-十二碳烯醇醋酸酯(D)和反-10-十四碳烯醇醋酸酯(E)降低 AB 的引诱活性,甘油作为缓释剂,能延长诱芯的有效期,即诱蛾活性。上述结果表明,我国大豆食心虫性信息素不同于日本大豆食心虫性信息素。小面积防治应用试验效果明显。

从胶州湾海洋放线菌中发现的新型星形孢菌素等7种新结构化合物

本课题组自1999年以来，将培养条件优化、生物活性跟踪及化学跟踪技术应用到胶州湾海洋放线菌的次级代谢产物研究中，发现了一批具有生物活性的新结构化合物。 本研究从青岛胶州湾分离出各类海洋微生物423株，包括海洋放线菌287株，海洋细菌116株，海洋真菌20株，对胶州湾海洋微生物的资源和分布规律有了基本的认识。对其中海洋放线菌的次级代谢产物进行了活性和化学筛选，获得了它们对八种病原微生物的抑制活性数据。发现胶州湾海洋放线菌对至少一种受试微生物具有中等以上拮抗能力的比例为50%。 从三株海洋放线菌的发酵粗提物中鉴定出7个新结构化合物和31个已知化合物。具体是：①从菌株M518中鉴定出21个化合物，包括3个新结构天然化合物：N-Foramidostaurosporine，5,7-Dihydroxy-5,6,7,8-tetrahydro-1H-azocin-2-one，Selina-4(14),7(11)-diene-8,9-diol和1个新结构衍生物Trimer 3。其中化合物5,7-Dihydroxy-5,6,7,8-tetrahydro-1H-azocin-2-one为新骨架类型的天然化合物。② 从菌株M491 中鉴定出10个化合物，包括3个新结构化合物10α-14-Dihydroxyamorph-4-en-3-one，10α,11-Dihydroxyamorph-4-ene，5α,10α,11-Triydroxyamorphan-3-one； 并首次从微生物中分离得到已知化合物10α-Hydroxyamorph-4-en-3-one；③从菌株M311中鉴定出7个已知化合物。 发现天然化合物5,7-Dihydroxy-5,6,7,8-tetrahydro-1H-azocin-2-one很容易发生重排反应，分离出了两个重排反应产物，并得出该化合物可能的重排反应过程及三聚体形成的方式。 生物活性实验结果表明新型星形孢菌素N-Formamidostaurosporine具有很强的抗肿瘤活性：对于37株人类肿瘤细胞的平均IC50，IC70和IC90分别为0.016µg/ml，0.171µg/ml和2.352µg/ml。对37株肿瘤细胞株的抗肿瘤选择性为27%。还首次发现Staurosporine类化合物具有抑制微藻生长的活性。 对产生新化合物的菌株M518 和M491 进行了形态、生理生化及分子鉴定，提交两株菌的16S rDNA 序列到GenBank（DQ184649 和DQ184648）。结合形态、生理生化特征及系统 发育树分析表明：菌株M518 属于链霉菌属，并可能属于该属中的粉红孢类群；菌株M491属于链霉菌属，并可能属于该属中的青色类群。

Dibenzyl bromophenols with diverse dimerization patterns from the brown alga Leathesia nana

Six novel dibenzyl bromophenols (1-6) with different dimerization patterns and two propyl bromophenol derivatives (7 and 8), together with 11 known bromophenol derivatives, were isolated from the ethanolic extract of the brown alga Leathesia nana. On the basis of spectroscopic methods the structures of the new compounds were determined as 5,6'-diethyloxymethyl-3,4,2'-tribromo-2,3',4'-trihydroxydiphenyl ether (1), 2-(2,3-dibromo-4,5-dihydroxybenzyl)-3,5-dihydroxy-4-methoxybenzyl alcohol (2), 6-(2,3-dibromo-4,5dihydroxybenzyl)-2,3-dibromo-4,5-dihydroxy benzyl methyl ether (3), 9,10-dihydro-9,10-dimethoxy-3,4,7,8-tetrabromo-1,2,5,6-tetrahydroxyanthracene (4), (+)-3-(2,3-dibromo-4,5-dihydroxyphenyl)-4-bromo-5,6-dihydroxy-1,3-dihydroisobenzofuran (5), rel-(4aS*,10aR*)-(+/-)-6,7-dibromo-4a-hydroxy-3,8-dihydroxymethyl-10a-methoxy- 1,4,4a, 10a-tetrahydrodibenzo[b,e][1,4]dioxin-1-one (6), (E)-2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propenal (7), and 2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)-1-propanol (8). Some compounds including 3 showed in vitro selective cytotoxicity against several human cancer cell lines. This is the first brown alga to be reported containing bromophenols.

增强的UV-B辐射对黄瓜（Cucumis sativus）不同叶位叶片生长、光合作用和呼吸作用的影响

在植物生长室中 ,黄瓜植株第 1片真叶出现后 ,用人工UV B光源照射 6 0d ,测定植物各叶位叶片的生长和生理活动 .结果表明 ,UV B辐射条件下 ,植物出叶时间被延迟 ;叶面积和叶干重下降 ,降幅与叶位高低正相关 ;叶片含水量降低 ,老龄叶片 (第 1叶 ,下位叶 )和幼龄叶片 (第 5叶 ,上位叶 )的水分降幅均高于成年叶片 (第 3叶 ,中位叶 ) ;叶片的伸展速度、叶片数目以及单叶面积减少 ,致使黄瓜总叶面积下降 ;植株节间长度缩短 ,是植株矮化的重要原因 ;根、茎、叶等器官之间的相关生长变化不大.叶片生长在其中起重要的协调作用. UV-B 降低Pn和EAQE ,对光合作用的抑制程度随叶位升高而增加. UV-B 辐射后,黄瓜叶片的光呼吸显著提高,增幅与叶片发育阶段有关. UV-B 对黄瓜第1叶的暗呼吸没有影响,第2 、3 叶略微下降,第4 叶显著升高. 分析认为,植株矮化和叶面积减少有利于植物适应UV-B辐射;水分含量和光合作用减少、呼吸作用增强是黄瓜生长受抑制的生理基础。

紫外线—B辐射对3种植物幼苗光合作用和呼吸作用的影响研究初报

UV - B 辐射明显降低大豆、豌豆和黄瓜3 种植物幼苗的净光合速率和量子效率, 降幅随UV - B辐射时间延长而增加, 是一定UV - B 强度下,UV - B 辐射剂量的累积效应。豌豆和大豆幼苗的暗呼吸速率受UV - B 辐射抑制, 其中, 豌豆叶片暗呼吸受抑程度与UV - B 辐射时间正相关。

中国煤中22种环境敏感微量元素的地球化学研究

本论文按照统一的采样和统一的分析测试方法对全国煤中22种环境敏感微量元素及全硫含量进行了系统的研究。通过统计学的方法不仅给出了中国煤炭部分环境敏感微量元素的分布范围、算术均值、标准差、几何均值、几何偏差，中位数，而且首次给出了95％置信度下算术均值、几何均值以及元素含量分布的置信区间等，并与前人大量样品的统计结果进行比较。还通过统计分析了部分环境敏感微量元素在我国煤中的主要赋存状态，以及选煤对这部分微量元素的脱除机理和脱除效果等，得到以下几点认识： 1. 通过与前人大量样品统计所得到的结果进行比较，进一步证明了论文中使用的这批样品是中国煤炭平均化学成分的良好代表。本次所分析的23种元素中，As、Be、Co、Cr、Cu、Hg、Pb、Se、Th、Tl、U、F、S等13元素与前人数10年研究的统计结果在分布范围、均值含量等上非常一致，但本次的结果更为可信，更接近中国煤炭平均化学成分的真实状况。此外，本次对这B、Sn这2种元素的分析数据也是目前反映我国煤中分布最具有代表性的数据。 2. 根据样品的无偏性，对平均值的置信区间进行计算。首次给出了全国煤中各元素在95％置信度下的算术均值的置信区间、几何均值的置信区间以及元素含量分布的置信区间等。可以为后人研究各元素在绝大多数煤中的含量及均值情况时作为参考。同时统计分析表明，按照95％置信度计算，16元素的真实平均值在我们所得到的平均值±11％范围之内，最大偏差为硒，在±20％之间。 3. 平均值作为最常用的统计量之一，中国煤中不同元素的不同均值之间有一定的差异，反映了元素在煤中不同的分布状态。论文中通过对23种元素在全国煤中的5种不同的均值比较，一般元素的产量加权均值与总体样品均值之间都比较接近；绝大多数元素的储量加权均值比较低，这与西北、华北地区未开采利用的煤炭资源量大，煤质好有关。 4. 通过与Swaine（1990）给出世界煤中元素的分布范围进行比较，22种环境敏感微量元素在我国煤中的分布处于世界煤的有限范围之内。其中，Cr、Cu、Mn、Mo、Se、Sn、Th、Tl、U、V、F等微量元素在我国煤中的分布与世界煤比较接近，而As、B、Ba、Be、Cd、Co、Cl、Hg、Ni、Pb、Sb等微量元素在我国煤中较世界煤低很多。 5. 与世界主要煤炭资源大国和Swaine（1990）给出的世界煤元素均值含量的比较显示，大部分环境敏感微量元素在我国煤中的均值含量与世界主要煤炭资源大国煤中的均值含量也比较接近。其中，我国煤中B、Co、Cu、Hg、Pb、U等6种元素含量均值与美国煤比较接近，As、Cd、Sb、Tl等4种元素含量均值与澳大利亚煤比较接近，Ba、Cr、Mo、Ni、V等4种元素含量均值与前苏联煤比较接近，Be、Mn、Se、Th、F等5种元素含量均值与世界煤比较接近。 6. 随着煤炭变质程度的增高，各元素均值含量没有表现出明显规律性的增高或降低。但22种环境敏感微量元素在褐煤、弱粘煤、不粘煤、气煤等较低变质程度煤中的含量整体水平不高，绝大多数微量元素主要在中高变质程度煤中较为更为富集。不同成煤时期以及不同聚煤区煤中各种环境敏感微量元素不同的富集程度，从总体上反应了绝大部分环境敏感微量元素在华南煤中更为富集，而占全国储量3/4的华北和西北煤中的总体水平相对较低。 7. 通过对环境敏感微量元素与灰分及主要灰成分之间的关系进行分析，初步了解了它们在煤中的主要赋存状态。煤中绝大部分环境敏感微量元素还是具有非常明显的无机亲和性，在煤中主要以矿物无机形态存在。主要与粘土矿物、黄铁矿及硫化物相结合，而与碳酸盐矿物关系不大。 8. 脱除率的分析显示，15种元素的脱除率与灰分的脱除率之间具有显著的正相关性，说明煤中绝大部分环境敏感微量元素主要以无机形态存在，因此提高原煤入洗率，降低原煤灰分的同时也可以在很大程度上降低环境敏感微量元素的燃煤排放。 9. 部分环境敏感元素的脱除率受到其在煤中的赋存状态、矿物形态、煤级以及选煤厂洗选工艺等诸多因素的影响，在不同样品中脱除率的差异较大。某些样品中微量元素的脱除率较高，最高脱除率可达到70％以上。从平均脱除率来看，灰分、硫分及绝大多数环境敏感微量元素处于30％－70％之间，只有少数几个元素不到20％。