Summary A series of new five-coordinate complexes of cobalt(II) of the type, dihalotris-(2-substituted imidazole)cobalt(II), of formulae Co(2-MeIm)3Cl2, Co(2-EtIm)3X2 (X = Cl, Br, I) and Co(2-i-PrIm)3I2, were synthesized and characterized by elemental analyses, electrolytic conductivity, diffuse reflectance as well as by solution spectra, i.r. and far i.r. spectra, x-ray powder pattern and magnetic susceptibility measurements. The mass spectra of the complexes did not exhibit peaks due to the molecular ions, but only showed the ligand fragmentation patterns. The t.g.a. and d.t.a. measurements were also carried out for the complexes. 相似文献
Summary The new macrocyclic ligand 7,14-o-hydroxyphenyl-5,12-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene (1=L) has been prepared and complexes with copper(II), nickel(II) and cobalt(III) characterised. The nickel(II) complex is a yellow square-planar species, while the purple-red copper(II) complex is probably tetragonal in both the solid state and solution. The complexes appear to have an N-meso arrangement of the chiral nitrogen centres with the HOC6H4 groups occupying equatorial sites so that axial interactions with the metal do not occur. A variety oftrans-[CoLX2]ClO4 complexes (X=Cl, Br, NO2, or N3) have been characterised. 相似文献
Template-free cross-linking of single-stranded DNA bearing octadiynyl side chains at the 7-position of 8-aza-7-deazapurine moieties with bisfunctional azides is reported employing a Cu(I)-catalyzed azide-alkyne "bis-click" reaction. Bis-adducts were formed when the bis-azide:oligonucleotide ratio was 1:1; monofunctionalization occurred when the ratio was 15:1. Four-stranded DNA consisting of two cross-linked duplexes was obtained after hydridization. Cross-linked duplexes are as stable as individual duplexes when ligation was introduced at terminal positions; ligation at a central position led to a slight duplex destabilization. 相似文献
A non-destructive, in situ current normalized particle induced gamma-ray emission methodology has been standardized for quantification of fluorine (F) in soil samples from Punjab state, India. The samples were irradiated using 4 MeV proton beam from the Folded Tandem Ion Accelerator at BARC, Mumbai. The gamma rays of energies 197 and 478 keV arising from 19F(p, p′γ)19F and 7Li(p, p′γ)7Li nuclear reactions were measured using high resolution gamma-ray spectrometry. The concentration of fluorine in soil samples was found to vary between 414 and 5,746 mg kg?1. 相似文献
Nuclear analytical methods namely in situ current normalised Particle Induced Gamma Ray Emission (PIGE) and conventional Instrumental Neutron Activation Analysis (INAA) were utilized for determining major, minor and trace concentrations of eighteen elements in five soda-lime (automobile) glass samples. Concentration of four major elements (Si, Na, Mg and Al) by PIGE and fourteen elements including ten trace elements by INAA were determined. For forensic application, major elements were used for confirming the class of glass samples, whereas concentration results of trace elements like transition and rare earth elements were utilized for finding similarity or differences among the glass samples.
In the present work angular momenta of the fragments corresponding to132Im,g have been deduced from the radiochemically determined independent isomeric yield ratios and statistical model based analysis in neutron induced fission of235U,239Pu and245Cm and spontaneous fission of252Cf. These data along with similar data on134I, reported earlier from this laboratory, bring out the effects of deformed 66n and spherical 82n shells on fragment angular momentum showing also an inverse correlation of the latter with elemental yields. Quantitative estimates of fragment scission point deformation and the coefficient of change of fragment angular momentum with kinetic/excitation energy have been deduced and are seen to be in good agreement with the expected theoretical estimates. 相似文献
In conventional fracture-toughness testing, the line of application of the loads remains fixed with respect to specimen geometry. In this testing machine, the load moves with the advancing crack front, and displacement is used as the controlled variable to propagate and arrest a crack. The energy-release rate at the onset of crack propagation and, hence, the plane-strain fracture toughnessKIc can be measured directly without compliance calibration or stress-intensity evaluation. The specimen is in the form of a flat plat 25 by 50 cm which is simple to machine and provides about 30 values ofKIc. The versatility of the machine is demonstrated by making a statistical analysis ofKIc for 7075-T6 Al by showing the effect of plate thickness on the fracture toughnessKc using a tapered specimen, and by evaluatingKc in 7075 Al as a function of aging temperature in a thermal-gradient-treated specimen. 相似文献
The condensation reaction involving an aldehyde and diketone was efficiently promoted by the Ionic liquid, [Hbim]BF(4) (IL) as a reaction medium with methanol as co-solvent at ambient temperature under ultrasonic irradiation to afford the corresponding 1,8-dioxo-octahydro-xanthene (xanthene) derivatives in excellent yields. The advantages of this method include among others the use of a recyclable, non-volatile ionic liquid, which promotes this protocol under ambient temperature without the requirement of any added catalyst. The reaction times and yields are compared with p-TSA catalyzed synthesis of xanthenes under thermal conditions, which is also reported for the first time under our reaction conditions. 相似文献
Amorphous ribbons of different thicknesses of Co64.5Fe3.5Si16B14Ni2 alloy were synthesized using the melt spinning technique by varying wheel speed. The effect of cooling rate on the ribbon thickness and their soft magnetic properties have been studied. The amorphous structure has been characterized in terms of structural free volume and medium range order (MRO) by positron annihilation spectroscopy and fluctuation electron microscopy techniques. Positron lifetime spectra of amorphous samples showed two lifetime components. The first component was found to be correlated with MRO whereas, the second lifetime component was found to be associated with nanovoid type of defects, and the second component was strongly dependent on processing conditions. It could be established that the coercivity of the amorphous samples produced by the rapid solidification technique mainly depends on the defects formed during processing rather than change induced in MRO. 相似文献