Dinitrogen Cleavage by a Three-Coordinate Molybdenum(III) Complex

Cleavage of the relatively inert dinitrogen (N(2)) molecule, with its extremely strong N identical withN triple bond, has represented a major challenge to the development of N(2) chemistry. This report describes the reductive cleavage of N(2) to two nitrido (N(3-)) ligands in its reaction with Mo(NRAr)(3), where R is C(CD(3))(2)CH(3) and Ar is 3,5-C(6)H(3)(CH(3))(2'), a synthetic three-coordinate molybdenum(III) complex of known structure. The formation of an intermediate complex was observed spectroscopically, and its conversion (with N identical withN bond cleavage) to the nitrido molybdenum(VI) product N identical withMo(NRAr)(3) followed first-order kinetics at 30 degrees C. It is proposed that the cleavage reaction proceeds by way of an intermediate complex in which N(2) bridges two molybdenum centers.     

不同H9N2亚型鸭流感病毒NS1基因克隆和功能进化分析

禽流感病毒（AIV）在高免疫压力情况下会发生变异而逃避免疫系统的监视。其NS1蛋白共有230个氨基酸,其中前73个氨基酸残基以二聚体形式存在,包含了所有RNA的结合活性。NS1的氨基端1—73位是mRNA的结合区,氨基端1—100位是双股RNA依赖性蛋白激酶（PKR）的结合区。PKR抗病毒作用机制如下：病毒侵染宿主细胞时,在宿主干扰素的诱导下,双股RNA与PKR结合,同时真核翻译启动子α亚单位发生磷酸化,导致PKR的激活。激活的PKR能同时抑制宿主细胞和病毒mRNA的翻译,从而最终抑制入侵病毒在细胞中的有效繁殖和扩散。     

应用同工酶标记区分玉米多胞质系的研究

在以往培育成的含Ｍo１７细胞核的班米多胞质系（同核异质系）的基础上,开展了１１种多胞质系同工酶生化标记的筛选。通过在不同发育阶段选取不同部位组织样品,进行ＰＯＤ和ＥＳＴ同工酶的电泳分析结果表明,不同发育阶段不同部位组织样品,其同工酶带数与活性是不同的,选取３个发育阶段的不同组织,即授粉后９d籽粒、授粉后３４d籽粒乳和抽雄期雄穗作同工酶电泳分析,就可以将１１种多种胞质系区分开来。     

离子液体[BMIM]Cl与H5PV2Mo10O40双效催化降解麦草碱木质素的研究

采用常规合成法制备了杂多酸H₅PV₂Mo₁₀O₄₀,并通过FT-IR、XRD、SEM对其进行表征。研究了[BMIM]Cl单催化与{H₅PV₂Mo₁₀O₄₀+[BMIM]Cl}双效催化体系中,反应时间、温度以及H₅PV₂Mo₁₀O₄₀用量对麦草碱木质素降解的影响,并初步探讨了木质素的降解机理。结果表明:H₅PV₂Mo₁₀O₄₀中P、V、Mo相对原子质量满足1:2:10关系,并具有典型的Keggin结构;木质素降解反应中,仅离子液体[BMIM]Cl降解木质素的最佳条件为140 ℃下反应3 h,降解后固体产物中总羟基由3.49 mol/kg增加到10.92 mol/kg,液体产物中有香草醛与丁香醛生成,分别占2.00%和2.15%;{H₅PV₂Mo₁₀O₄₀+[BMIM]Cl}双效催化体系中,最佳反应条件为加入20%的H₅PV₂Mo₁₀O₄₀ 120 ℃下反应6 h,降解后固体产物中总羟基由3.49 mol/kg增加到14.12 mol/kg,摩尔质量由7.691 kg/mol降为1.589 kg/mol;液体产物中无丁香醛生成,香草醛占6.97%。初步认为:当单独[BMIM]Cl催化木质素时,H+首先进攻木质素中β-O-4键上的氧原子,正电荷转移到β位,然后水分子中氧原子向带有正电荷的β位进攻,从而催化剂的H+被消除,最后实现了β-O-4键水解断裂,生成愈创木酚,进而侧链发生氧化生成香草醛与丁香醛;当添加H₅PV₂Mo₁₀O₄₀时,[PV₂Mo₁₀O₄₀]5-中的VO₂+由V(V)→V(IV),故使模型化合物得以单电子的氧化,使木质素脱甲氧基,由紫丁香基木质素转变成愈创木基木质素,液体产物中无丁香醛生成,且香草醛质量分数升高。      

三元配合物[La( C9H6NO)2(C6H5COO)]·H2O浸种对水稻种子萌发及幼苗生长的影响

[目的]研究[La（C9H6NO）2（C6H5COO）].H2O浸种对水稻种子萌发及幼苗生长的影响。[方法]采用不同浓度（0.005×10-3、时,则抑制种子萌发及幼苗生长。[结论]适当浓度的[La（C9H6NO）2（C6H5COO）].H2O可促进种子萌发及幼苗生长。0.010×10-30、.050×10-3、0.100×10-3、0.300×10-3 mol/L）的[La（C9H6NO）2（C6H5COO）].H2O水溶液处理水稻种子。[结果][La（C9H6NO）2（C6H5COO）].H2O浓度为0.005×10-3～0.100×10-3mol/L时,促进种子萌发及幼苗生长,浓度大于0.300×10-3 mol/L时,则抑制种子萌发及幼苗生长。[结论]适当浓度的[La（C9H6NO）2（C6H5COO）]·H2O可促进种子萌发及幼苗生长。     

Structure of a three-dimensional, microporous molybdenum phosphate with large cavities

The synthesis, single-crystal x-ray structural characterization, and sorption properties of a microporous molybdenum phosphate, (Me(4)N)(1.3)(H(3)O)(0.7)[Mo(4)O(8)(PO(4))(2)] . 2H(2)O (Me, methyl), are presented. The three-dimensional framework is built up from Mo(4)O(8)(4+) cubes and PO(4)(3-) tetrahedra that are connected in such a way that large, cation-filled voids are generated; these voids constitute 25% of the volume of the solid. Absorption isotherms for water show the completely reversible uptake of 4 to 5 percent by weight water into the micropores of this compound, which corresponds to 10 to 12 percent by volume.     

The (Me5C5)Si+ cation: a stable derivative of HSi+

The reaction of decamethylsilicocene, (Me5C5)2Si, with the proton-transfer reagent Me5C5H2+B(C6F5)4- produces the salt (Me5C5)Si+ B(C6F5)4(2), which can be isolated as a colorless solid that is stable in the absence of air and moisture. The crystal structure reveals the presence of a cationic pi complex with an eta5-pentamethylcyclopentadienyl ligand bound to a bare silicon center. The 29Si nuclear magnetic resonance at very high field (delta = - 400.2 parts per million) is typical of a pi complex of divalent silicon. The (eta5-Me5C5)Si+ cation in 2 can be regarded as the "resting state" of a silyliumylidene-type (eta1-Me5C5)Si+ cation. The availability of 2 opens new synthetic avenues in organosilicon chemistry. For example, 2 reacted with lithium bis(trimethylsilyl)amide to give the disilene E-[(eta1-Me5C5)[N(SiMe3)2]Si]2(3).     

HPLC-ESI-MS联用法测定保健品中荷叶碱的含量

[目的]建立含荷叶碱类保健食品中高效液相色谱-电喷雾质谱(HPLC-ESI/MS)检测方法。[方法]色谱柱为Spherigel-C-18柱(5μm,4.6 mm×250.0 mm);流动相,A:0.1%三乙胺水溶液,B:乙腈,梯度洗脱;检测波长278 nm。[结果]荷叶碱在0.17~21.20μg/ml浓度范围内线性关系良好,r=0.999 6;最低检测限为0.01μg/ml(S/N=3);最低定量限为0.30μg/ml(S/N=10);3种样品的平均回收率为96.66%~98.57%,RSD≤2.52%。[结论]该方法具有流动相简单、分析时间短,且不要对样品进行衍生,操作简便,定量准确,抗干扰能力强等优点。     

Synthesis and Characterization of Molybdenum Carbide Clusters MonC4n, (n = 1 to 4)

Laser radiation (XeCl laser, 308-nanometer wavelength) focused into a cell containing Mo(CO)(6) vapor produced ultrafine particles in the extended waist of the laser beam. Negative ion mass spectrometry revealed molybdenum carbide cluster ions with a stoichiometry MonC4n (n = 1 to 4). The MonC4n(-) (n = 2 to 4) ions are completely unreactive with NH(3), H(2)O, and O(2), suggesting structures in which the molybdenum atoms are unavailable for coordination to additional ligands. Collision-induced dissociation studies of these anions show the loss of MoC(4) units as the main fragmentation pathway. This observation, together with the lack of addition reactions, provides a basis for structures in which a planar cluster of two, three, or four molybdenum atoms is surrounded by, and bonded to, carbon dimers.     

Synthesis of a stable compound with fivefold bonding between two chromium(I) centers

Although in principle transition metals can form bonds with six shared electron pairs, only quadruply bonded compounds can be isolated as stable species at room temperature. Here we show that the reduction of {Cr(mu-Cl)Ar'}2 [where Ar' indicates C6H3-2,6(C6H3-2,6-Pri2)2 and Pr indicates isopropyl] with a slight excess of potassium graphite has produced a stable compound with fivefold chromium-chromium (Cr-Cr) bonding. The very air- and moisture-sensitive dark red crystals of Ar'CrCrAr' were isolated with greater than 40% yield. X-ray diffraction revealed a Cr-Cr bond length of 1.8351(4) angstroms (where the number in parentheses indicates the standard deviation) and a planar transbent core geometry. These data, the structure's temperature-independent paramagnetism, and computational studies support the sharing of five electron pairs in five bonding molecular orbitals between two 3d5 chromium(I) ions.     

Synthesis, structure, and reactivity of an iron(V) nitride

Despite being implicated as important intermediates, iron(V) compounds have proven very challenging to isolate and characterize. Here, we report the preparation of the iron(V) nitrido complex, [PhB((t)BuIm)(3)Fe(V)≡N]BAr(F24) (PhB((t)BuIm)(3)(-) = phenyltris(3-tert-butylimidazol-2-ylidene)borato, BAr(F24) = B(3,5-(CF(3))(2)C(6)H(3))(4)(-)), by one electron oxidation of the iron(IV) nitrido precursor. Single-crystal x-ray diffraction of the iron(V) complex reveals a four-coordinate metal ion with a terminal nitrido ligand. M??bauer and electron paramagnetic resonance spectroscopic characterization, supported by electronic structure calculations, provide evidence for a d(3) iron(V) metal center in a low spin (S = 1/2) electron configuration. Low-temperature reaction of the iron(V) nitrido complex with water under reducing conditions leads to high yields of ammonia with concomitant formation of an iron(II) species.     

叶面喷施蚯蚓氨基酸肥对黄瓜品质的影响

[目的]分析叶面喷施蚯蚓氨基酸液肥对黄瓜品质的影响,为蚯蚓氨基酸肥在蔬菜上推广应用提供参考依据.[方法]设H1(喷施0.3%KH2PO4)、H2(喷施蚯蚓氨基酸800倍液+0.3%KH2PO4)、H3(喷施蚯蚓氨基酸500倍液+0.3%KH2PO4)、H4(喷施蚯蚓氨基酸300倍液+0.3%KH2PO4)、H5(喷施蚯蚓氨基酸800倍液)、H6(喷施蚯蚓氨基酸500倍液)、H7(喷施蚯蚓氨基酸300倍液)及清水对照(CK)处理,在黄瓜挂果期进行叶面喷施,采收时测定各处理黄瓜果实的维生素C(Vc)、蛋白质、可溶性还原糖、有机酸、硝酸盐含量及糖酸比.[结果]与CK相比,采收时H2、H3和H6处理黄瓜的Vc含量分别显著增加40.0%、53.5%和38.0%(P<0.05,下同);H2、H3、H4、H6和H7处理的硝酸盐含量显著降低55.2%、85.3%、67.5%、31.6%和49.6%;H3处理的蛋白质含量显著增加31.2%;各施肥处理的可溶性还原糖含量均降低,其中H4、H5和H6处理显著低于CK;H2和H3处理的有机酸含量分别显著降低14.2%和22.8%,H5、H6和H7处理分别显著降低39.1%、44.8%和36.8%;分别与H5、H6和H7处理相比,H2、H3和H4处理黄瓜的Vc含量增加,糖酸比降低,有机酸含量较高且差异显著,硝酸盐含量显著降低60.8%、78.5%和35.5%.[结论]在黄瓜挂果期喷施适当浓度的蚯蚓氨基酸液肥有利于整体提升黄瓜果实品质,其中喷施蚯蚓氨基酸500倍+0.3%KH2PO4混合液的效果最佳.     

Keggin型钼氧酸盐化合物{PMo7^ⅥMo4^ⅤV^ⅤO40（V^ⅣO）2[Co（bipy）2（H2O）]2}[Co（bipy）3]2{PMo7^ⅥMo4^ⅤV^ⅤO40（V^ⅣO）2}·6H2O的合成、结构及性质表征

合成了一种新颖的修饰型的Keggin结构多金属氧酸盐超分子化合物,并用单晶衍射仪测定了其晶体结构,元素分析及红外光谱等进一步佐证了化合物的结构.配合物为三斜晶系,P-1空间群,晶胞参数为a=12.969 4（11）,b=14.025 0（11）,c=24.518 0（19）,α=86.511 0（10）°,β=83.033 0（10）°,γ=62.777 0（10）°,V=3 936.4（5）3,Z=1.配合物是一种特殊的双帽双支撑型的多金属氧酸盐,它是由双帽假Keggin[PMo7ⅥMo5ⅤO40（VⅣO）2]^4-单元,{Co（2,2′-bipy）2（H2O）}和[Co（bipy）3]^2＋部分组成.其中,两个金属有机阳离子{Co（2,2′-bipy）2（H2O）}和两个盖帽的钒原子上的末端氧原子通过共价连接在[PMo7^ⅥMo4^ⅤV^ⅤO40（V^ⅣO）2]上,并通过氢键作用形成三维层状结构.     

产生红色素的竹红菌生物学特性研究

[目的]提高竹红菌素的产量。[方法]对从野生竹红菌中分离出产红色素的竹红菌菌株进行液体培养,研究适宜竹红菌生长的培养基、碳源、氮源和pH值。[结果]竹红菌在牛肉膏培养基上生长最快,色素分泌最多,颜色最浓。供试5种碳源处理中,竹红菌在乳糖培养基上生长最快,分泌色素最多,其次是麦芽糖、D-木糖、可溶性淀粉。不同氮源对竹红菌生长的影响有明显的差异。NH4NO3培养基上竹红菌生长速度最快,色素分泌多,NH4Cl培养基上长势最慢。不同pH值对竹红菌生长影响较明显,竹红菌在pH值3～9范围内都能生长,pH值为6时长势最好,色素分泌最多。[结论]竹红菌在牛肉膏培养基上生长速度最快,最易利用的碳源和氮源是乳糖、NH4NO3,pH值3～9时均可生长,以pH值为6最适合。     

木橑尺蠖的不同虫态过冷却点测定

[目的]测定木橑尺蠖(Culcula panterinaria)各虫态的过冷却点和结冰点,明确各虫态的耐寒性。[方法]采用数字万用电表和低温培养箱测定木橑尺蠖1~6龄幼虫、蛹和雌雄成虫的过冷却点和结冰点。[结果]木橑尺蠖的不同发育阶段过冷却点和结冰点大小顺序为1龄幼虫[(-10.01±0.24)、(-9.75±0.13)℃]、2龄幼虫[(-11.24±0.15)、(-10.89±0.16)℃]、3龄幼虫[(-12.64±0.23)、(-12.01±0.24)℃]、成虫[(-14.39±0.20)、(-13.76±0.22)℃]、4龄幼虫[(-14.56±0.15)、(-13.94±0.21)℃]、5龄幼虫[(-15.36±0.17)、(-14.85±0.18)℃]、6龄幼虫[(-17.87±0.13)、(-16.93±0.17)℃]和蛹[(-20.95±0.09)、(-19.78±0.19)℃]。木橑尺蠖的雌成虫过冷却点和冰点都低于雄成虫,木橑尺蠖雌成虫的过冷却点和结冰点分别为(-14.56±0.18)、(-14.61±0.19)℃,雄成虫分别为(-14.22±0.22)、(-12.91±0.25)℃。[结论]木橑尺蠖的不同发育阶段过冷却点和结冰点均存在显著差异,雌、雄成虫的过冷却点差异不显著,而结冰点差异显著。     

DNA synthesis in cartilage cells is stimulated by oscillating electric fields

External oscillating electric fields (1166 volts per centimeter, 5 hertz) enhanced the incorporation of [3H] thymidine into the DNA of chondrocytes isolated from the proliferative layer of embryonic (16 days) chick epiphysis. Verapamil or tetrodotoxin at 10(-6)M concentrations completely blocked the electric field effect. Tetracaine reduced the incorporation of [3H] thymidine in both control and electrically stimulated cells. The findings support the hypothesis that Na and Ca2 fluxes generated by the electrical perturbation trigger DNA synthesis in these cells.     

Motions of molecules in liquids: viscosity and diffusivity

The fluidity of a simple liquid is proportional to its degree of expansion over the volume, V(0), at which its molecules are so crowded as to inhibit self-diffusion and viscous (as distinguished from plastic) flow. The equation of proportionality is 1/eta = B[(V - V(0))/V(0)] where eta is the viscosity and V is the molal volume. Values of B are the same for normal paraffins from C(3)H(8) to C(7)H(16) and then decrease progressively as the paraffin lengths increase. Values for other liquids, C(6)H(6), CCl(4), P(4), CS(2), CHCl(3), and Hg, appear to vary with repulsive forces. liquids can be moderately fluid when expanded by less than 10 percent; this shows the unreality of some theoretical treatments of the liquid state. Diffusivity begins from the temperature at which V equals V(0) and can be correlated for temperature dependence, and for solute-solvent interrelations.     

Ordering of ruthenium cluster carbonyls in mesoporous silica

The anionic ruthenium cluster carbonylates [Ru6C(CO)16]2- or [H2Ru10(CO)25]2- interspersed with bis(triphenylphosphino)iminium counterions (PPN+) are incorporated from solution into the pores of MCM-41 mesoporous silica (3 nanometers in diameter), where they form tightly packed arrays. These arrays were shown by high-resolution transmission electron microscopy, Fourier transform optical diffraction, and computer simulations to be well ordered both along and perpendicular to the axis of the cylindrical pores. In their denuded state produced by gentle thermolysis, the cluster carbonylates yield nanoparticles of ruthenium that are less well ordered than their assimilated precursors but show good activity as hydrogenation catalysts for hexene and cyclooctene. In both their as-prepared and denuded states, these encapsulated clusters are likely to exhibit interesting electronic and other properties.     

燕麦发芽前后酚类物质的组成变化及结构鉴定

【目的】对燕麦发芽前后酚类物质的组成变化进行分析,对疑似燕麦蒽酰胺的组分进行结构鉴定。【方法】通过高效液相色谱分析未发芽燕麦、发芽6 d燕麦籽粒、芽和根提取物的多酚组成,利用高效液相色谱与串联四级杆飞行时间质谱仪联用技术（HPLC/Q-TOF-MS）获得燕麦蒽酰胺的精确分子量。【结果】燕麦发芽后籽粒中酚酸的种类和数量明显减少,相对含量由32.14%下降至5%以下,而燕麦蒽酰胺的相对含量由45.52%上升至79.21%。2c、2p、2f、t2和t3是原样和6 d籽粒中共有的主要蒽酰胺,其分子式（分子量）分别为C16H13O6N（315.0753）、C16H13O5N（299.0818）、C17H15O6N（329.0912）、C18H15O5N（325.0968）和C19H17O6N（355.1077）,其中t2和t3是发芽过程中含量上升最显著的组分。6 d芽和6 d根提取物中的成分与籽粒存在显著差异,主要组分w6—w10的分子量分别为564.1498、592.1808、494.1781、710.1834和192.0433。【结论】燕麦发芽前后酚类物质的组成产生了很大变化,明确了6种蒽酰胺的结构信息以及4种未知物质的精确分子量,为发芽燕麦的研究提供了新的理论依据。     

广西猪流感病毒H1N2亚型的血清学调查

【目的】了解广西猪群中猪流感（SI）的流行情况,为科学防控广西SI提供参考依据。【方法】以猪流感病毒（SIV）HIN2亚型毒株为抗原,采用微量血凝抑制试验（HI）方法,对2009年7月～2011年3月在广西12个市采集的997份猪血清进行SIV的血清学调查。【结果】2009年的H1N2亚型抗体阳性率为33．4％,比2010年和2011年1-3月的高;广西各市的H1N2亚型抗体阳性率为0—83．1％,其中河池和百色两市的H1N2亚型抗体阳性率较高,分别为83．1％和51．1％,崇左市为零,其他市的H1N2亚型抗体阳性为4．0％～32．1％。【结论】广西地区猪群在2009～2011年均受到猪源H1N2亚型不同程度的感染。