普鲁士蓝类分子磁体研究的新进展

在分子磁体的研制中,多氰金属盐是一类非常合适的分子前体。它有可能组装成高自旋基态、高居里温度或具有各向异性的分子基磁体。本文将介绍此类分子磁体的研究新成果及发展前景。     

新颖一维配位聚合物[Ni(3，5-pdc)(H2O)4]·(H2O)的合成与晶体结构

The hydrothermal reaction of 3,5-pyridinedicarboxylic acid and NiCl₂·6H₂O results in a novel coordination polymer， [Ni(3,5-pdc)(H₂O)₄]·(H₂O). The crystal structure of the compound was determined by X-ray single crystal diffraction. The crystal belongs to monoclinic system with space group P2₁/n, a=1.136 1(3)nm, b=0.709 8(2) nm, c=1.459 7(4) nm, β=107.538(4)°， V=1.122 4(6) nm³, D_c=1.858 g·cm^-1, Z=4, F(000)=648, R₁=0.0264, wR₂=0.0665. CCDC: 224880.     

Screening for oxidative damage by engineered nanomaterials: a comparative evaluation of FRAS and DCFH

Several acellular assays are routinely used to measure oxidative stress elicited by engineered nanomaterials (ENMs), yet little comparative evaluations of such methods exist. This study compares for the first time the performance of the dichlorofluorescein (DCFH) assay which measures reactive oxygen species (ROS) generation, to that of the ferric-reducing ability of serum (FRAS) assay, which measures biological oxidant damage in serum. A diverse set of 28 commercially important and extensively characterized ENMs were tested on both the assays. Intracellular oxidative stress was also assessed on a representative subset of seven ENMs in THP-1 (phorbol 12-myristate 13-acetate matured human monocytes) cells. Associations between assay responses and ENM physicochemical properties were assessed via correlation and regression analysis. DCFH correlated strongly with FRAS after dose normalization for mass (R ² = 0.78) and surface area (R ² = 0.68). Only 10/28 ENMs were positive in DCFH versus 21/28 in FRAS. Both assays were strongly associated with specific surface area and transition metal content. Qualitatively, a similar response ranking was observed for acellular FRAS and intracellular reduced:oxidized glutathione ratio (GSH:GSSG) in cells. Quantitatively, weak correlation was found between intracellular GSSG and FRAS or DCFH (R ² < 0.25) even after calculating effective dose to cells. The FRAS assay was more sensitive than DCFH, especially for ENMs with low to moderate oxidative damage potential, and may serve as a more biologically relevant substitute for acellular ROS measurements of ENMs. Further in vitro and in vivo validations of FRAS against other toxicological endpoints with larger datasets are recommended.     

Intense up-conversion emissions of yb3＋/Dy3＋ co-doped A12O3 nanopowders prepared by non-aqueous sol-gel method＊

Yb 3+ /Dy 3+ co-doped Al2O3 nanopowders have been prepared by the non-aqueous sol-gel method and their up- conversion photoluminescence spectra are measured under excitation by a 980-nm semiconductor laser. The results show that there are comparatively abundant spectra of up-conversion emissions centered at 378, 408, 527 and 543, and 663 nm, corresponding to4G9/2 → 6H13/2,4G9/2→6H11/2 ,4I15/2 →6H13/2 , and 4F9/2 → 6H11/2 transitions of Dy 3+ , respectively. Two-photon and three-photon processes are involved in ultraviolet, violet, green, and red up-conversion emissions. The energy transition between Yb3+ and Dy3+ is discussed.     

Remarkable sensitivity of the electrochemical reduction of benzophenone to proton availability in ionic liquids

The reduction of benzophenone was investigated in five different ionic liquids by using transient cyclic voltammetry, near steady-state voltammetry, and numerical simulation. Two reversible, well-resolved one-electron-reduction processes were observed in dry (≤20 ppm water, ca. 1 mM)) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpyrd][NTf(2)]) and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide ([Bmpipd][NTf(2)]), which did not contain any readily available proton source. Upon addition of water, the second process became chemically irreversible and shifted to a more positive potential by approximately 600 mV; moreover, the two reduction processes merged into a single two-electron proton-coupled process when about 0.6 M H(2)O was present. This large dependence of potential on water content, which was not observed in molecular solvents (electrolyte), was explained by a reaction mechanism that incorporated protonation and hydrogen-bonding interactions of the benzophenone dianion with as many as seven water molecules. In the three imidazolium-based ionic liquids used herein, the first benzophenone-reduction process was again reversible, whilst the second reduction process became chemically irreversible owing to the availability of the C2-H imidazolium protons in these ionic liquids. The reversible potentials for benzophenone reduction were remarkably independent of the identity of the ionic liquids, thereby implying either weak interactions with the ionic liquids or relatively insignificant differences in the levels of ion-pairing. Thus, the magnitude of the separation of the potentials of the reversible first and irreversible second reduction processes mainly reflected the proton availability from either the ionic liquid itself or from adventitious water. Consequently, voltammetric reduction of benzophenone provides a sensitive tool for the determination of proton availability in ionic liquids.     

超音速蒸汽浸没射流凝结换热的实验研究

针对入口压力为0.20～0.50 MPa的饱和蒸汽在20～70℃过冷水中超音速浸没射流凝结换热进行了实验研究.结果表明入口蒸汽压力和过冷水温度是影响汽羽形状的主要因素.分子动力学理论得到的凝结换热系数在0.16～1.91 MW/(m2·℃)之间,随着过冷水温度的增加而增加;湍流强度理论得到的凝结换热系数在0.68～1.68 MW/(m2·℃)之间,随着过冷水温度的增加基本不变;对流换热理论得到的凝结换热系数在1.47～2.11 MW/(m2·℃)之间,随着过冷水温度的增加先增大后减小.     

A new class of rhodium complexes containing free donor atoms and their intramolecular substitution reaction

A new class of rhodium complexes with high catalytic activity as well as excellent stability,which was used as catalyst for carbonylation of methanol to acetic acid,is reported.It contains free donor (namely un-coordinated donor) atoms which enable to improve its stability by intramolecular substitution reaction.Its synthesis,characteristic and catalytic reaction were discussed here.     

含2-羟基-1-萘甲醛半碳酰腙配位体的铜(Ⅱ)配合物的合成与结构

标题配位体H₂L和它的铜(Ⅱ)配合物［Cu(HL)(py)₂］(OAc)(H₂O)(HL:C₁₂H₁₀N₃O₂单负离子)已被合成与表征。配合物结构测定的结果表明晶体学不对称单元由结构相似的两套分子构成。在每个分子内,铜(Ⅱ)的四角锥形的配位多面体中HL和一吡啶分子配位于它的底面。结合红外谱图讨论了H₂L在配位中的去质子化作用。从而确     

新型金属-双二硫杂戊烯(M-BDT)配合物的合成、表征及X射线的指标化

合成了4个新型NiBDT配位化合物,BDT为具有9个S原子的杂戊烯.元素分析、IR谱、UV谱确定这4个新配合物的化学式分别为[(CH₃)₄N]₂[Ni(C₅S₉)₂](1),[(C₂H₅)₄N]₂·[Ni(C₅S₉)₂](2),[(C₄H₉)₄N]₂[Ni(C₅S₉)₂](3),[(C₆H₅)(CH₃)₃N]₂[Ni(C₅S₉)₂](4).采用Ito法对配合物1的X射线粉末图进行了指标化,确定该晶体属单斜晶系,简单晶格,晶胞参数:a=0.680nm,b=0.714nm,c=2.302nm,γ=111.4°,Z=2.