对氟苯甲醛水杨酰腙镍(II)配合物的合成、表征及其晶体结构

A nickel(II) complex Ni(C₁₄H₁₀N₂O₂F)₂ was synthesized from p-fluorobenzaldehyde salicylhydrazone and Ni(CH₃COO)₂·4H₂O and crystallized by diffusion, the structure of which was characterized by IR spectrum, ¹H NMR, and X-ray single-crystal diffraction. The complex crystallizes in monoclinic space group C2/c with a=2.460 6(2) nm, b=0.774 1(1) nm, c=1.534 9(1) nm, β=122.300(1)°, and V=2.471 1(4), Z=8, D_c=1.541 g·cm^-3. We reported the IR, ¹H NMR, crystal structure. CCDC: 638652.     

2',3'-二脱氧-2',3'-二去氢鸟嘌呤核苷构象稳定性的理论研究

采用密度泛函方法在B3LYP/6-31＋G**水平上研究了2',3'-二脱氧-2',3'-二去氢鸟嘌呤核苷分子(D4G)的构象. 分别研究在气相中的孤立分子和一水合物异构体的相对稳定性和异构体之间的相互转变过程, 分析了水分子的参与对D4G异构体的相对稳定性和几何结构参数以及自然电荷的影响. 结果表明, 孤立的D4G分子在气相中存在8种稳定构象, 其中构象d4g-2是所有构象中最稳定的, 气相中D4G主要以d4g-2存在. 气相中各构象的相对稳定性为: d4g-2＞d4g-1＞d4g-5＞d4g-3＞d4g-6＞d4g-4＞d4g-8＞d4g-7. 计算得到的各构象键长和键角数据与实验值接近. 一个水分子的加入对D4G分子的构型参数有所影响, 基本不改变D4G分子各构象的稳定性顺序, 但构象转变的能垒有所提高. 氢键在分子构象中发挥了重要作用.     

Quantification of tripdiolide in human whole blood by liquid chromatography coupled with atmospheric pressure chemical ionization tandem mass spectrometry

A liquid chromatographic-tandem mass spectrometric (LC-MS/MS) assay was developed and validated to determine tripdiolide in human whole blood using dexamethasone acetate as an internal standard (I.S.). Liquid-liquid extraction with ethyl acetate was used to isolate them from the biological matrix. Detection was performed on a mass spectrometer coupled with a negative atmospheric pressure chemical ionization (APCI) in the multiple-reaction monitoring (MRM) mode. The calibration curve was linear (r² = 0.9973) in the concentration range of 0.5-100.0 ng/mL in human whole blood with a lower limit of quantification of 0.5 ng/mL. Intra-day and inter-day relative standard deviations (R.S.D.s) were less than 7.0 and 10.1%, respectively. Extraction recoveries of tripdiolide ranged from 80.5 to 90.1%. This assay can be used to determine trace tripdiolide in human whole blood.     

硼离子对铕掺杂SiO2干凝胶发光性能的影响

采用溶胶-凝胶法制备了Al单掺和B，Al共掺的Eu掺杂SiO2干凝胶。利用荧光光谱、IR，XRD，DSC，TG／DTG等技术研究了硼离子、退火温度对样品发光性质的影响。经500℃以上退火处理用248nm激发的样品，产生Eu^3＋离子^5D0→^7FJ的特征发射，^5D0→^7F1的跃迁分裂为两个峰。比较615nm处的发光强度，掺硼酸样品的发光强度是不加硼酸发光强度的3．3倍。这是因为B离子的加入，在材料中形成了Si—O—B键，破坏了网络的对称性，加强了Eu^3＋的红光发射。当退火温度上升到850℃用350nm激发时，样品有很强的Eu^2＋蓝光发射。Al单掺的发射中心在437nm处，发射半峰宽约为70nm，而B，Al共掺样品的发光中心蓝移到425nm处，单掺样品的蓝光强度几乎是共掺样品强度的2倍。这是由于硼酸的加入改变了基质的网络结构，从而导致单掺和共掺样品发射峰位和强度的改变。     

C36填充单壁碳纳米管的结构和电子性质

The structures and electronic properties for C36 encapsulated in four single-wall armchair carbon nanotubes (C36@(n,n), n=6-9) were calculated using ab initio self-consistent field crystal orbital method based on density functional theory. The calculations show that the interwall spacing between the carbon nanotube and C36 plays an important role in the stabilities of resultant structures. The optimum interwall spacing is about 0.30 nm and the tubes can be considered as inert containers for the encapsulated C36. The Fermi levels and relative position of energy bands also have something to do with the interwall spacing. The shifts of Fermi level and C36-derived electron states modulate the electron properties of these structures. The extra electrons fill the bands of C36@(8,8) with the optimum interwall spacing almost in a rigid-band manner.     

Synthesis, crystal structure and in vitro antitumor activity of di-n-butyltin 4′-(7-oxabicyclo [2,2,1]-5-heptane-2,3-dicarboximide) benzoates

Dibutyltin(IV) oxide reacts with the cantharidin analogue, 4′-(7-oxabicyclo [2,2,1]-5-heptane-2,3-dicarboximide) benzoic acid, A, to give the complexes [(p-C₈H₈NO₃-C₆H₄-COOBu₂Sn)₂O]₂ (1) and (p-C₈H₈NO₃-C₆H₄-COO)₂SnBu₂ (2) which had been characterized by IR and ¹H, ¹³C, ¹¹⁹Sn NMR. Single X-ray crystal structure analysis has been determined for compound (1), which was analogue to most other [(RCOOBu₂Sn)₂O]₂. The dimer features central of Bu₄Sn₂O₂ unit with the two Bu₂Sn groups being linked via bridging oxygen atom. Each tin atom adopts distorted trigonal bipyramidal structures via two carbons from a dibutyl moiety and three oxygen atoms from cantharidin derivative and bridging oxygen atom. In vitro tests show compounds 1 and 2 exhibit high cytotoxicity against P388 and HL-60.     

Calculations on the octupolar molecules with enhanced two-photon absorption cross sections based on the Zn (II) and Cu (I) as centers

The equilibrium geometries, electronic structures, as well as one- and two-photon absorption cross sections of a series of octupolar chromophores with Zn(2+) or Cu(+) as coordinate centers and 4,4'-bis(dibutylaminostyryl)-[2,2']-bis(bipyridyl) as ligands have been determined by using B3LYP/6-31G and ZINDO methods. These molecules are designed by controlled combination of two or three bipyridyl ligands with the metal centers. The results show that Zn(2+) is an effective template for the design of octupolar structures which enable it to form tetrahedral and octahedral coordinated complexes; while Cu(+) only exists in a tetrahedral coordinated complex, comparing the tetrahedral complex with Zn(2+) as the center with that of Cu(+) as the center, it is found that the complex with the Cu(+) center is a better two-photon absorption material than the former as far as the transparency/nonlinearity is concerned. Furthermore, for the same metal center of Zn(2+), both one- and two-photon absorptions of the tetrahedral complex are redshifted relative to those of the octahedral complex, is attributed to the spiroconjugation effect in the tetrahedral complex. Our theoretical findings are consistent with recent experimental observations and provide an important foundation for the design of improved transparency-nonlinearity two-photon absorption materials.     

Electrocatalysis of the SiC Particle‐Modified Glassy Carbon Electrode for the Oxidation of Adrenaline

The electrocatalytic properties of the SiC particle‐modified glassy carbon electrode (MGC) for adrenaline oxidation were studied by cyclic voltammetry (CV), double‐potential step chronocoulometry (DPSCC), and electrochemical impedance spectroscopy (EIS) techniques in McIlvaine buffer solution. It was shown that the electrode modified with SiC particles markedly displayed an electrocatalytic effect on the process of the electrochemical reaction of adrenaline, i.e., the activity and the reversibility of the MGC electrode has been significantly improved. This was attributed to the adsorption effect of the electroactive adrenaline molecules on the MGC electrode surface.     

Preparation and Characterization of Trimethylsilylpyridylacetylene Bridged,Dicobalt Carbonyl Complexes Containing Bis(diphenylphosphino)methylene or Bis(diphenylphosphino)ethylene Ligand

Reaction of an alkyne‐bridged dicobalt complex, [Co₂(CO)₆(μ‐Me₃SiC=Cpy)] 4 , with bis(diphenylphosphino)methylene (DPPM) or bis(diphenylphosphino)ethylene (DPPE) in THF at 55 °C yielded a DPPM or DPPE doubly bridged dicobalt compound, [{μ‐P,P‐PPh₂CH₂PPh₂}Co₂(CO)₄(μ‐Me₃SiC=Cpy)] 5 or [{μ‐P,P‐PPh₂CH₂CH₂PPh₂}Co₂(CO)₄(μ‐Me₃SiC≡Cpy)] 6 . Compound 5 and 6 were characterized by spectroscopic means as well as X‐ray crystal structure determination.     

OH自由基与CO反应的研究

用时间分辨-傅立叶变换红外发射光谱法研究了OH自由基与CO的反应.OH自由基由248 nm的激光光解硝酸得到.在实验中首次观测到了产物CO2的非对称伸缩振动(ν3)的激发态.对CO2发射光谱的拟合结果显示,其振动态的布居在量子数v=2时最大 ,而最高振动量子数达到v=6.由实验得到的CO2振动布居与Schatz等人用全量子化计算该反应的中间物HOCO解离动力学得到的CO2布居结果能很好地吻合.