Ion flotation of rhodium(III) and palladium(II) with anionic surfactants

The ion flotation of rhodium(III) and palladium(II) with some anionic surfactants has been investigated. Two flotation procedures are proposed for the separation of some platinum metals, based on differences in the kinetic properties of the chloro-complexes of rhodium(III), palladium(II) and platinum(IV). The first involves the selective flotation of Rh(H(2)O)(3+)(6) from PdCl(2-)(4) and PtCl(2-)(6) in dilute hydrochloric acid with sodium dodecylbenzenesulfonate (SDBS). After precipitation of the hydroxide and redissolution in dilute acid, the Rh(III) is converted into Rh(H(2)O)(3+)(6), Pd(II) and Pt(IV) remaining as PdCl(2-)(4) and PtCl(2-)(6) respectively, and separation is achieved by floating the Rh(H(2)O)(3+)(6) with SDBS. The second is for separation of Pd(II). Prior to flotation, the solution of PdCl(2-)(4) and PtCl(2-)(6) is heated with ammonium acetate to convert PdCl(2-)(4) into Pd(NH(3))(2+)(4). The chloro-complex of Pt(IV) is unaffected. The complex cation, Pd(NH(3))(2+)(4), is then selectively floated with SDBS. The procedures are fast, simple and do not require expensive reagents and apparatus.     

酸碱软硬度的电势原子势标度

软硬酸碱原则在化学的各个领域都得到了广泛的应用。在其定量化标度方面也做了不少工作,例如Yingst等的酸度量|α/β|,Klopman的E_n~≠和E_m~≠值,parr和pearson的绝对硬度以及Yatsimirski的ΔA_(FH)等。但是,他们的工作在理论性和应用上都无法统一起来。本文提出一种具有广泛应用性的酸碱软硬度的键参数标度。Mulliken在研究一类弱lewis加合物的光谱时,首先用量子力学原理阐述了lewis     

CRYSTALLIZATION AND MELTING OF POLY（ETHYLENE OXIDE） CONFINED IN NANOSTRUCTURED PARTICLES WITH CROSS-LINKED SHELLS OF POLYBUTADIENE

Small fixed aggregates of a poly(ethylene oxide)-block-polybutadiene diblock copolymer(PEO-b-PB)in THFsolution were obtained by adding a selective solvent for PB blocks,followed by cross-linking the PB shells.Themorphologies of the nanostructured particles with a cross-linked shell were investigated by atomic force microscopy andtransmission electron microscopy.The average behaviors of the PEO crystallization and melting confined within thenanostructured particles were studied by using differential scanning calorimetry experiments.For the deeply cross-linkedsample(SCL-1),the crystallization of the PEO blocks was fully confined.The individual nanoparticles only crystallized atvery low crystallization temperatures(T_cs),wherein the homogenous primary nucleation determined the overallcrystallization rate.For the lightly cross-linked sample(SCL-2),the confinement effect was T_c dependent.At T_c(?)42℃,thecrystallization and melting behaviors of SCL-2 were similar to those of the pure PEO-b-PB diblock copolymer.At T_c>42℃,SCL-2 could form PEO lamellae thicker than those of the pure PEO-b-PB crystallized at the same T_c.     

Magic-angle spinning solid-state NMR spectroscopy of the beta1 immunoglobulin binding domain of protein G (GB1): 15N and 13C chemical shift assignments and conformational analysis

Magic-angle spinning solid-state NMR (SSNMR) studies of the beta1 immunoglobulin binding domain of protein G (GB1) are presented. Chemical shift correlation spectra at 11.7 T (500 MHz 1H frequency) were employed to identify signals specific to each amino acid residue type and to establish backbone connectivities. High sensitivity and resolution facilitated the detection and assignment of every 15N and 13C site, including the N-terminal (M1) 15NH3, the C-terminal (E56) 13C', and side-chain resonances from residues exhibiting fast-limit conformational exchange near room temperature. The assigned spectra lend novel insight into the structure and dynamics of microcrystalline GB1. Secondary isotropic chemical shifts report on conformation, enabling a detailed comparison of the microcrystalline state with the conformation of single crystals and the protein in solution; the consistency of backbone conformation in these three preparations is the best among proteins studied so far. Signal intensities and line widths vary as a function of amino acid position and temperature. High-resolution spectra are observed near room temperature (280 K) and at <180 K, whereas resolution and sensitivity greatly degrade substantially near 210 K; the magnitude of this effect is greatest among the side chains of residues at the intermolecular interface of the microcrystal lattice, which we attribute to intermediate-rate translational diffusion of solvent molecules near the glass transition. These features of GB1 will enable its use as an excellent model protein not only for SSNMR methods development but also for fundamental studies of protein thermodynamics in the solid state.     

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.     

铑配合物的抗肿瘤活性及其作用机制研究

自从Rosenberg等人发现顺铂具有抗肿瘤活性以来，金属配合物的抗肿瘤活性引起了人们的广泛关注。本文综述了近年来铑配合物抗肿瘤活性的研究进展，并对铑配合物的抗肿瘤机制和构效关系进行了探讨，为进一步寻找高效低毒和抗肿瘤谱广的新药物揭示了可循的途径。     

丙烯聚合络合催化剂形成过程的研究

以倍半物为还原剂还原TiCl_4,经异戊醚络合处理,然后在TiCl_4己烷溶液中35℃条件下热处理,制得对丙烯聚合具有高活性和高定向度的络合催化剂。研究了制备过程中各步反应产物的组成和结构特征,并讨论了TiCl_3低温晶型转变机理。     

Ionic limiting molar conductivity calculation of Li-ion battery electrolyte based on mode coupling theory

A method is proposed based on mode coupling theory in which the ion transference number is introduced into the theory. The ionic limiting molar conductivities of LiPF6, LiClO4, LiBF4, LiCF3SO3, Li(CF3SO3)2N, LiC4F9SO3, and LiAsF6 in PC(propylene carbonate), GBL(gamma-butyrolactone), PC(propylene carbonate)/EMC(ethylmethyl carbonate), and PC(propylene carbonate)/DME(dimethoxyethane) are calculated based on this method, which does not involve any adjustable parameter. The results fit well to the literature data which are calculated by an empirically adjusted formula. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes.     

中性磷(膦)类稀土萃合物的结构研究(Ⅲ)——三(三苯基氧膦)合硝酸镧的合成及结构测定

合成了三(三苯基氧膦)合硝酸镧络合物, 经鉴定确定络合物化学式为La(NO_3)_3·3ph_3PO·C_2H_5OH·CHCl_3。其中C_2H_5OH和CHCl_3为溶剂化分子。经X射线单晶衍射, 测定了该络合物属单斜晶系P2_1/n空间群, 晶体学参数如下a=1.3111(5) nm Z=4b=2.5075(10) nm F(000)=2687.65c=1.8725(6) nm μ吸收系数=9.83(cm~(-1))β=98.53(3)° d计算=1.45 gcm~(-3)V=6.088 nm d实验=1.43 gcm~(-3)La与9个氧直接配位, 其中六个氧来自三个双卤配位硝酸根, 另三个氧分别由三个苯基氧膦上的膦酰基所提供。La-O平均键长0.2549 nm。     

Construction and analytical application of ion-selective piezoelectric sensor for atropine sulfate

The method describes the use of a piezoelectric quartz crystal (PQC) as a substitute for ion-selective electrodes. The approach is feasible when the membrane materials are electrically non-conductive and membrane potential measurements are consequently not possible. An ion-selective piezoelectric sensor sensitive to atropine sulfate was constructed by coating a PVC membrane containing activant on one the side of a PQC. On the basis of selective adsorption of atropine ions across the modified film and the sensitive mass response of PQC, the method exhibits a sensitive, rapid response and is easy to operate without pretreatment of the sample. The logarithm of the frequency shift gave a linear relationship with the logarithm of atropine sulfate concentration in the 1.0 x 10(-8)-1.0 x 10(-3) M range with a detection limit of 5.0 x 10(-9) M at pH 7.0. Recoveries were from 98.7-102.2%. Two activants, atropine tetraphenylborate and atropine dipicrylaminate, were synthesized and investigated. Influencing factors were also examined and optimized. The results for real samples obtained by the proposed method agreed with those obtained by conventional methods.