The hybrid transition metal – alkali metal compound, [Ni(H2O)6·(μ‐H2O)2·K2(phth)4(H2O)], (phth = phthalate) ( 1 ), was synthesized from nickel(II) nitrate, KOH and potassium hydrogen phthalate, and was isolated by crystallization. Single‐crystal X‐ray analysis revealed that 1 belongs to the monoclinic system, space group P21/c with a = 10.455(2) Å, b = 6.8670(14) Å, c = 29.704(6) Å, γ = 98.14(3)°, R1 = 0.0585, wR2 = 0.1503. In the title compound, [K2(phth)4]2+ units are bonded to water‐bridged Ni chains forming 2D lamellar‐like compounds. 相似文献
A simple copper- and base-free palladium-catalyzed Sonogashira-type cross-coupling by the use of triarylantimony dicarboxylates is described. Reaction of triarylantimony diacetates with terminal alkynes in the presence of 1 mol % of PdCl2(PPh3)2 catalyst led to the formation of cross-coupling products in good to excellent yields. The reaction proceeded effectively under an aerobic condition, in that two of the three aryl groups on antimony could be transferred to the coupling products, whereas only one of them was involved in the reaction in an argon atmosphere. The reaction is sensitive to the electronic nature of the diacetates, and those bearing an electron-withdrawing group on the aromatic ring showed higher reactivity than those having an electron-donating group. 相似文献
In cooperation with the fragment-based design a new drug design method, the so-called "fragment-based quantitative structure-activity relationship" (FB-QSAR) is proposed. The essence of the new method is that the molecular framework in a family of drug candidates are divided into several fragments according to their substitutes being investigated. The bioactivities of molecules are correlated with the physicochemical properties of the molecular fragments through two sets of coefficients in the linear free energy equations. One coefficient set is for the physicochemical properties and the other for the weight factors of the molecular fragments. Meanwhile, an iterative double least square (IDLS) technique is developed to solve the two sets of coefficients in a training data set alternately and iteratively. The IDLS technique is a feedback procedure with machine learning ability. The standard Two-dimensional quantitative structure-activity relationship (2D-QSAR) is a special case, in the FB-QSAR, when the whole molecule is treated as one entity. The FB-QSAR approach can remarkably enhance the predictive power and provide more structural insights into rational drug design. As an example, the FB-QSAR is applied to build a predictive model of neuraminidase inhibitors for drug development against H5N1 influenza virus. 相似文献
Functional spheres : Monodisperse gold‐doped titania spheres with tunable sizes under high concentration of titanium precursor have been synthesized by introducing trace amounts of chloroauric acid into the reaction system. Surface photovoltage, surface photocurrent, and transient photovoltage measurements (see figure) of annealed samples reveal that gold nanodots can act as both electron acceptors and donors under the illumination of different wavelengths of light.
Small polyhedral superparamagnetic iron oxide (SPIO) nanoparticles (<10 nm) coated with a thin layer of silica were prepared (SPIO@SiO2 and SPIO@SiO2‐NH2). Surface modification of the small polyhedral silica‐coated SPIO nanoparticles with amines led to substantially higher mesenchymal stem cell (MSC) labelling efficiency without the use of additional transfecting agents. Therefore, amine surface‐modified nanoparticles (SPIO@ SiO2‐NH2) appeared to be the preferred candidate for MSC labelling. In vitro studies demonstrated that controlled labelling of SPIO@SiO2 and SPIO@SiO2‐NH2 did not cause MSC death or proliferation inhibition. MSCs labelled with SPIO@SiO2‐NH2 nanoparticles retained differentiation potential and showed osteogenic, adipogenic and chondrogenic differentiations. The noncytotoxic polyhedral SPIO@SiO2‐NH2 nanoparticle‐labelled MSCs were successfully implanted in rabbit brain and erector spinae muscle, and demonstrated long‐lasting, durable MRI labelling efficacy after 8–12 weeks. 相似文献
Electrophoretic deposition (EPD) method has been developed for the fabrication of hydroxyapatite (HA)–CaSiO3 (CS)–chitosan composite coatings for biomedical applications. The use of chitosan enabled the co-deposition of HA and CS particles and offered the advantage of room temperature processing of composite materials. The coating composition was varied by the variation of HA and CS concentrations in the chitosan solutions. Cathodic deposits were obtained as HA–CS–chitosan monolayers, HA–chitosan/chitosan multilayers or functionally graded materials (FGM) containing HA–chitosan and CS–chitosan layers of different composition. The thickness of the individual layers was varied in the range of 0.1–20 μm. The deposition yield was studied at different experimental conditions and compared with the results of modeling. It was shown that the moving boundary model for the two component system can explain the non-linear increase in the deposition yield with increasing HA concentration in chitosan solutions. The obtained coatings were studied by thermogravimetric analysis (TGA), differential thermal analysis (DTA) and scanning electron microscopy (SEM). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies showed that these coatings provided corrosion protection of stainless steel substrates in Ringer's physiological solution. The deposition mechanism and kinetics of deposition have been discussed. 相似文献
To find podophyllotoxin compounds with superior bioactivitiy and less toxicity, a series of novel conjugates of ring‐A‐modified 4‐epipodophyllotoxin and stavudine with amino acids as spacers were synthesized, i.e., the N‐[(2′,3′‐didehydro‐3′‐deoxythymidin‐5′‐O‐yl)carbonyl]‐substituted L ‐amino acid rel‐(3aR,4S,9R,9aR)‐1,3,3a,4,9,9a‐hexahydro‐6,7‐dimethoxy‐1‐oxo‐9‐(3,4,5‐trimethoxyphenyl)naphtho[2,3‐c]furan‐4‐yl esters 8a – 8f . 相似文献
One new ten-membered lactone (1) named (Z)-4,6,9-trihydroxy-10-nonyl-3,4,5,6,9,10-hexahydrooxecin-2-one along with 5-methoxycarbonylmellein (2) and cytochalasin D (3) were isolated from the culture of the endophytic fungus strain Tubercularia sp. TF5, originally separated from the inner bark of Taxus mairei obtained in Fujian Province, Southeast China. The structures of compounds 1–3 were elucidated by spectroscopic methods. The antimicrobial and cytotoxic activities of 1 were analyzed but it showed no significant activities. 相似文献