化学合成的钯改性的NiFe2O4纳米颗粒的结构和磁性

采用溶胶-凝胶自动燃烧方法合成了镍铁-钯复合材料NiFe₂O₄-Pd的磁性纳米颗粒. 样品在800 ℃烧结6 h生成结晶相. X射线衍射证实样品呈尖晶石结构. 利用场发射扫描电子显微镜研究结构形态和纳米颗粒的大小. 饱和磁化强度在100和300 K时,随着钯含量增加达5%降低,但加入10%Pd时磁化强度突然上升.     

Synthesis, Characterization, and Biological Activity of n -Tributyltin Derivatives of Pharmaceutically Active Carboxylates

 Tributyltin(IV) derivatives of six different pharmaceutically active carboxylates were synthesized. The complexes were characterized by different analytical techniques (elemental analysis; infrared, NMR, and mass spectroscopy). ¹¹⁹Sn NMR data were also recorded in six different coordinating and non-coordinating solvents. The antibacterial activities of the compounds were tested using ten different bacteria relative to the reference drugs ampicillin and cephalexin.     

Crystal structure of 1,1-dibutyl-1,1-bis[(4-methyl-1-piperidinyl)dithiocarbamato)] tin(IV)

The dibutyltin(IV) complex of 4-methyl-1-piperidinedithioic acid has been synthesized and characterized by X-ray diffraction. It was found that tin atom has distorted tetragonal geometry with the space group P-1.     

Charge transfer complexes of picolines with sigma- and pi-acceptors

In the present study CT complexes of 2-, 3- and 4-Picolines with (DDQ) 2, 3-dichloro-5, 6-dicyano parabenzoquinone (pi-acceptor) and (I(2)) Iodine (sigma-acceptor) have been investigated spectrophotometrically in three different solvents (CCl(4), CHCl(3) and CH(2)Cl(2)) at six different temperatures. The formation constants of the CT complexes were determined by the Benesi-Hildebrand equation. The thermodynamic parameters were calculated by Van(')t Hoff equation. The DeltaH degrees , DeltaG degrees and DeltaS degrees values are all negative implying that the formation of studied complexes is exothermic in nature.     

Radio-frequency single-electron refrigerator

We propose a cyclic refrigeration principle based on mesoscopic electron transport. Synchronous sequential tunneling of electrons in a Coulomb-blockaded device, a normal metal-superconductor single-electron box, results in a cooling power of approximately k(B)T x f at temperature T over a wide range of cycle frequencies f. Electrostatic work, done by the gate voltage source, removes heat from the Coulomb island with an efficiency of approximately k(B)T/Delta, where Delta is the superconducting gap parameter. The performance is not affected significantly by nonidealities, for instance by offset charges. We propose ways of characterizing the system and of its practical implementation.     

Synthesis and characterization of Hg(II) and Zn(II) complexes based on 3-[(4-chlorophenylamido)]propenoic acid

3-[(4-Chlorophenylamido)]propenoic acid has been synthesized by reaction of maleic anhydride and 4-chloroaniline in 1:1 molar ratio in glacial acetic acid and its metal complexes have been synthesized by the reaction of 3-[(4-chlorophenylamido)]propenoic acid with HgCl₂ and [Zn(CH₃COO)₂] · 2H₂O in 2: 1 molar ratio, respectively. All the synthesized compounds have been characterized by the elemental analysis, IR, UV/Vis and NMR (¹H, ¹³C) spectroscopy. Conductance for the reported compounds has been recorded in ethanol and suggests the non-electro lytic nature of complexes. IR data of metal complexes shows that the ligand is bound to the metal via both carboxylate oxygen atoms and complexes exhibits 4-coordinated geometry in solid state. NMR (¹H, ¹³C) study confirms the structure of the 3-[(4-chlorophenylamido)]propenoic acid and the reported complexes.     

Organotin(IV) O-butyl carbonodithioates: Synthesis,characterization, in vitro bioactivities,and interaction with SS-DNA

Organotin(IV) O-butyl carbonodithioates [Me₂SnL₂], [Bu₂SnL₂], [Ph₂SnL₂], [Bu₃SnL], and [Ph₃SnL], where L = C₄H₉OCS ^–₂ , have been successfully synthesized and characterized by FT-IR, ¹H and ¹³C NMR, and single crystal X-ray analysis. The ligand coordinates to the tin atom via the carbonodithioate group. According to the X-ray diffraction data, the tin atom in [Me₂SnL₂] has distorted tetrahedral geometry. The synthesized compounds were screened in vitro for antibacterial, antifungal, antileishmanial, cytotoxic, and protein kinase inhibitory activities. The complexes [Bu₃SnL] and [Ph₃SnL] exhibited the highest anti-leishmanial activity that exceeded the activity of the reference drug amphotericin B, probably by blocking the function of parasitic mitochondria due to which it restricts further growth of the organisms. The ligand and the complexes have been shown to bind to DNA via intercalative interactions resulting in hypochromic effect with a minor red shift as confirmed by UV-Vis spectroscopic studies.

     

Isolation and structural determination of sorbinols A and B, new triterpenes from Sorbus cashmariana, by 1D and 2D NMR spectroscopy

Two new pentacyclic triterpenes, sorbinols A (1) and B (2) have been isolated from the ethyl acetate fraction of Sorbus cashmariana and their structures assigned from (1)H and (13)C NMR spectra, DEPT and by 2D COSY, NOE, HMQC and HMBC experiments. Both 1 and 2 showed moderate inhibitory potential against the enzyme lipoxygenase.     

Room Temperature Magnetic Behavior of Sol-Gel Synthesized Mn Doped ZnO

Mn doped ZnO nano-crystallites were synthesized by state of the art sol-gel derived auto-combustion technique. As-burnt powder was investigated with different characterization techniques to explore the properties of Mn doped ZnO dilute magnetic semiconductor. X-ray diffraction measurements indicate that Mn doped ZnO retain wurtzite type hexagonal crystal structure like ZnO. Compositional and morphological studies were carried out by energy dispersive X-ray analysis and scanning electron microscopy, respectively. Tempera-ture dependent resistivity of the sample exhibited the semiconducting behavior of the DMS material. Room temperature magnetic properties determined by vibrating sample magne-tometer, revealed the presence of ferromagnetic and diamagnetic contributions in Mn doped ZnO.