Studies on nonlinear optical materials: structure of diphenylmethyl (Z)-1-(1-methylthio-2-nitrovinyl)tetrahydropyrrole-2-carboxylate

C21H22N2045, M r = 398.5, orthorhombic, P212~21, a = 9.799 (1), b = 11.853 (1), c = 17.316(2)/~, V=2011.4A 3, Z=4, Dm=l.320, Dx=1.314Mgm -3, CuKa, A=1.5418A, Iz= 1.63 ram-1, F(000) = 840.0, T = 293 K, R = 0.055 for 1735 significant reflections. In the 1-methylthio-2- nitrovinyl moiety the C--C bond, 1.368 (7)A, is significantly longer than in ethylene, 1.336 (2)/~. The second harmonic generation (SHG) efficiency of this compound is only 0.25 of the urea standard. The correlation between the molecular packing and SHG is discussed.

Copper( 11) Complexes of Novel Tripodal Ligands containing Phenolate and Benzimidazole/Pyridine Pendants: Synthesis, Structure, Spectra and Electrochemical Behaviour

Mononuclear copper(II) complexes of tri- and tetra-dentate tripodal ligands containing phenolic hydroxyl and benzimidazole or pyridine groups have been isolated. They are of the type (CuL(X)].nH2O, [CuL(H2O)]X.nH2O or [CuL].nH2O where X = Cl-, ClO4-, N3- or NCS- and n = 0-4. The electronic spectra of all the complexes exhibit a broad absorption band around 14000 cm-1 and the polycrystalline as well as the frozen-solution EPR spectra are axial, indicating square-based geometries. The crystal structure of [CuL(Cl)] [HL = (2-hydroxy-5-nitrobenzyl)bis(2-pyridyl-methyl)amine] revealed a square-pyramidal geometry around Cu(II). The mononuclear complex crystallises in the triclinic space group P1BAR with a = 6.938(1), b = 11.782(6), c = 12.678(3) angstrom and alpha = 114.56(3), beta = 92.70(2), gamma = 95.36(2)-degrees. The co-ordination plane is comprised of one tertiary amine and two pyridine nitrogens and a chloride ion. The phenolate ion unusually occupies the axial site, possibly due to the electron-withdrawing p-nitro group. The enhanced pi delocalisation involving the p-nitrophenolate donor elevates the E1/2 values. The spectral and electrochemical results suggest the order of donor strength as nitrophenolate < pyridine < benzimidazole in the tridentate and nitrophenolate < benzimidazole < pyridine in the tetradentate ligand complexes.

一秋龄性成熟中华绒螫蟹的生物学──1.外部形态特征及性腺变化

本文描述了一秋龄性腺成熟中华绒螯蟹（简称河蟹）的外部特征并与一秋龄未成熟及二秋龄成熟河蟹进行比较，同时给出了体重与壳宽的回归方程．保安湖的研究结果表明，对于一秋龄雌蟹，体重大于２９．８ｇ（壳宽为４．０３ｃｍ）全部成熟，而体重小于１３．１ｇ（壳宽为３．００ｃｍ）均不成熟，体重在１３、１－２９．８ｇ之间，既有成熟又有未成熟．对于一秋龄雄蟹，体重大于２６．０ｇ（壳宽３．９１ｃｍ），全部成熟，而于１２．０ｇ壳宽２．６６ｃｍ）均未成熟，体重在１２．０－２６．０ｇ之间，既有成熟者又有未成熟个体．对一秋龄成熟河蟹成熟系

甚短距离光传输（VSR-1）系统色散功率代价的分析

导出了一种用系统10％-90％上升时间所表示的最坏情况下多模光纤色散功率代价的计算方法。将最坏情况下的眼图闭合用光接收器在t0时刻的输出信号波形表示，从而得到了色散功率代价的数学表达式。为了得到光接收器输出信号波形的解析解，假设多模光纤链路是一个低通滤波器，其归一化脉冲响应是高斯形式的。用这种方法对甚短距离光传输系统VSRd的色散功率代价做了计算分析，所得结果可作为最坏情况下VSR-1链路功率预算分析的参考。

新型笼状同多钒酸盐[Ni(1,10′-phen)_3]_2·[V_2~ⅣV_8~ⅤO_(26)]的水热合成和晶体结构

尽管多金属氧酸盐 (POMs)的研究已有180多年的历史,但大量的POMs结构在最近几十年才被陆续解析出来[1～4].其中 ,同多钒酸盐由于钒配位几何形状的多样性,结构最为丰富 ,例如:[V4 O12 ]4-[5],[V5O14 ]3-[6],[V10 O2 8]6-[7] ,[V15O4 2 ]9-[8],[V13 O3 4 ]3-[9].值得注意的是,在这些化合物中,钒的化合价均处于最高氧化态+5价.由于+4价钒不易在溶液中(尤其是水中)稳定存在,因此在以往的常压溶液合成中具有混合价态的同多钒酸盐报道很少.与饱和价态的同多钒酸盐相比,混价多钒酸盐具有更为新奇的电荷分布和拓扑学几何构型,并且在 POMs的理论研究和抗病毒药物、电存储材料以及磁性材料等应用领域有特殊的研究和开发价值[1,10,11].因此,制备具有混价的新型同多钒酸盐一直倍受关注.近年来,水热合成技术的引入使同多钒酸盐合成化学迅速发展.水热体系提供了一个特殊的反应环境 [12 ],使制备各种具有混合价态的同多钒酸盐成为可能.Müller等[13]对这一领域开...

稀土钐离子与微过氧化物酶-11的相互作用初探

近年来,含稀土元素钐的药物研究已见报道犤1,2犦。但倪嘉缵等的研究犤3犦表明,Sm3+进入生物体内后可在肝细胞中分布、沉积,从而使肝细胞内细胞色素浓度降低。因此从分子水平研究Sm3+与某些生物分子的相互作用机理是十分必要的。众所周知,过氧化物酶能清除生物体内产生的过氧自由基,对机体具有抗逆、抗衰老的功效犤4,5犦。而微过氧化酶-11(MP-11)具有与过氧化物酶相同的活性中心和相似的生物活性犤6犦,因此,本文用循环伏安法、紫外-可见(UV-vis)吸收光谱以及圆二色(CD)谱技术研究了作为过氧化酶模型化合物的MP-11与Sm3+的相互作用。1实验部分MP-11购自美国Sigma公司,SmCl3按文献合成犤7犦。其他试剂均为分析纯,溶液均用三次蒸馏水配制。循环伏安测量在美国EG&G公司的M273恒电位仪上采用三电极系统进行,玻碳电极为工作电极,饱和甘汞电极为参比电极,铂丝为对电极。测量前用高纯氮除氧30min,在实验中用氮气保护。UV-Vis吸收光谱在岛津UV-265型紫外-可见分光光度计上进行,收集差光谱数据。CD谱在JASCOJ-715型圆二色谱仪上进行。MP-11和SmCl3的混合溶液配制后平衡1h,然后...

Novel hydrogen-bonded three-dimensional networks encapsulating one-dimensional covalent chains: [M(4,4 '-bipy)(H2O)4](4-abs)2 center dot nH(2)O (4,4 '-bipy=4,4 '-Bipyridine; 4-abs=4-aminobenzenesulfonate) (M=Co, n=1; M=Mn, n=2)

Two novel compounds, [Co(4,4'-bipy)(H2O)(4)](4-abS)(2).H2O (1) and [Mn(4,4'-bipy)(H2O)(4)](4-abs)(2).2H(2)O (2) (4,4'-bipy = 4,4'-bipyridine; 4-abs = 4-aminobenzenesulfonate), have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analyses, UV-vis and IR spectra, and TG analysis. X-ray structural analysis revealed that 1 and 2 both possess unusual hydrogen-bonded three-dimensional (3-D) networks encapsulating one-dimensional (1-D) covalently bonded infinite [M(4,4'-bipy)(H2O)(4)](2+) (M = Co, Mn) chains. The 4-abs anions in 1 form 1-D zigzag chains through hydrogen bonds. These chains are further extended through crystallization water molecules into 3-D hydrogen-bonded networks with 1-D channels, in which the [Co(4,4'-bipy)(H2O)(4)](2+) linear covalently bonded chains are located. Crystal data for 1: C22H30CoN4O11S2, monoclinic P2(1), a = 11.380(2) Angstrom, b = 8.0274(16) Angstrom, c = 15.670(3) Angstrom, alpha = gamma = 90degrees, beta = 92.82(3)degrees, Z = 2. Compound 2 contains interesting two-dimensional (2-D) honeycomb-like networks formed by 4-abs anions and lattice water molecules via hydrogen bonding, which are extended through other crystallization water molecules into three dimensions with 1-D hexagonal channels. The [Mn(4,4'-bipy)(H2O)(4)](2+) linear covalent chains exist in these channels. Crystal data for 2: C22H32WN4O12S2, monoclinic P2(1)/c, a = 15.0833(14) Angstrom, b = 8.2887(4) Angstrom, c = 23.2228(15) Angstrom, alpha = gamma = 90degrees, beta = 95.186(3)degrees, Z = 4.