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81.
Munir M. Ahmad Martin R. Bryce Joan Halfpenny Larry Weiler 《Tetrahedron letters》1984,25(38):4275-4278
Bis(triphenylphosphoranylidene)ammonium iodide (PPN+I?) forms a 2:3 complex with TCNQ [(PPN)2(TCNQ)3(CH3CN)2] that provides an example of a TCNQ complex containing acetonitrile in the crystal lattice; the material is a semi-conductor with trimerised TCNQ stacks. 相似文献
82.
Diastereoisomers (1S,2R,3S)-, (1R,2R,3S)-, (1R,2S,3S)- and (1S,2S,3S)-2-methyl-1-phenyl-1,3-butanediols were prepared by simple and convenient strategies using two different chemo-enzymatic approaches for the reduction of racemic 2-methyl-1-phenyl-1,3-butanedione, both involving in situ racemization. The first method comprised a one-pot microbial reduction coupled with a chemical reduction, while in the second method, stepwise chemo-enzymatic reductions were performed. 相似文献
83.
G. A. El-Shobaky A. S. Ahmad A. N. Al-Noaimi H. G. El-Shobaky 《Journal of Thermal Analysis and Calorimetry》1996,46(6):1801-1808
Basic cobalt and copper carbonates were prepared by precipitation from solutions of their nitrates using KHCO3 at room temperature in CO2 atmosphere. The thermal decomposition of the prepared basic carbonates was studied by means of TG and DTA techniques and the phases produced were identified by XRD measurements. The products obtained at 400C were subjected to different doses of gamma-rays (40–160 M rad) and the thermal stabilities of these solids were investigated.The results obtained revealed that basic cobalt carbonate decomposed at 335C to produce Co3O4 which remained stable up to 850 and then decomposed above this temperature giving CoO which transformed into Co3O4 on cooling to room temperature. Basic copper carbonate dissociated at 290C yielding CuO which yielded Cu2O and metallic copper at 1060 and 1150C, respectively. However, the produced cuprous oxide and metallic copper solids were converted into CuO and CU2O, respectively by cooling in air to room temperature.Gamma-irradiation decreased the thermal stability of Co3O4 to an extent proportional to the dose employed. On the other hand, this treatment increased the thermal stability of both CuO and Cu2O. 相似文献
84.
Summary Potassium dihydro-bis-(1-indazolyl)borate, synthesized from potassium borohydride and indazole, has been used as a reagent to yield complexes with copper(II), nickel(II), cobalt(II), manganese(II) and iron(III) ions. From i.r. spectral studies the ligand is uninegative and bidentate and coordination occurs through the nitrogen atom at position 2 of the indazole ring system in all cases. With the sole exception of the copper(II) complex, the nitrogen atom at position 1 is also involved in forming a bridge with an adjacent metal ion. On the basis of electronic spectral studies and magnetic susceptibility measurements a distorted square planar structure involving chlorine bridges has been proposed for the copper complex. An octahedral geometry with ligand bridges for all complexes is tentatively proposed and it appears that all are polymers. 相似文献
85.
Two series of 2-(N-aryl-2-oxo-2-arylethanehydrazonoyl)-6-methyl-4(3H)-pyrimidinones 11 (12) were prepared by coupling of diazotized anilines with 2-(aroylmethylene)-1,2-dihydro-6-methyl-4(3H)-pyrimidinones 2 (3). The spectral data of such compounds together with their 3-methyl analogs 13 (14) indicated that they exist predominantly in the hydrazone tautomeric form. 相似文献
86.
Nisar Ahmad M. Akram K.P. Gill S.P. Asdaq R.M. Akhtar M. Saleem M.A. Baig 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1997,41(3):159-163
A narrow bandwidth ring dye laser pumped by an argon ion laser has been used to investigate the hyperfine structure of the even and odd parity levels of tantalum by optogalvanic spectroscopy in the wavelength range 5640 to 6050 Å. Seventeen transitions have been observed and eight of these have not been reported in the literature so far. These transitions involve 27 levels with 15 odd and 12 even parity configurations. The magnetic dipole hyperfine interaction constants A and the electric quadrupole interaction constants B for these levels have been computed and compared with the data available in literature. The results for the levels at 34799.71 cm?1, 26960.46 cm?1 and 19657.78 cm?1 are reported for the first time. 相似文献
87.
88.
A series of chelating reagents, 1-phenyl-3-methyl-4-(2-fluorobenzoyl)-5-pyrazolone, 1-phenyl-3-methyl-4-(3-fluorobenzoyl)-5-pyrazolone and 1-phenyl-3-methyl-4-(4-fluorobenzoyl)-5-pyrazolone, has been synthesized. The extraction of Ln(III), (Ln = La, Eu and Lu) into chloroform with these reagents at 30 +/- 1 degrees has been studied. The composition of the complexes extracted has been determined by the slope method, and the extraction constants K(ex), were measured. The presence of the fluorine atom in the reagents does not make the K(ex), values much different from those obtained with the parent pyrazolone. 相似文献
89.
Norimah Yusof Ros Anita Ahmad Ramli Foziah Ali 《Radiation Physics and Chemistry》2007,76(11-12):1882-1884
A study was carried out to determine optimum decontamination dose for a locally manufactured coconut cream powder. Samples were gamma irradiated (0–15 kGy) and ageing process was achieved using GEER oven at 60 °C for 7 days, which is equivalent to one-year storage at room temperature. Iodine value (IV), ranging from 4.8 to 6.4, was not affected by radiation doses and storage, however peroxide value and thiobarbituric acid (TBA) generally increased with radiation doses. In most samples, peroxide value (meq/kg) reduced after storage, whilst the TBA (mg malonaldehyde/kg), indicator for product quality, slightly increased. The sensory evaluation conducted using 25 taste panellists indicated that scores on odour, creamy taste and overall acceptance for all irradiated samples at more than 5 kGy were significantly lower (P<0.05) than the control. However, the panellists could not detect any significant differences among the irradiation doses (P>0.05). All stored products were significantly different in colour, creamy taste, odour and overall acceptance (P<0.05) when compared to the non-stored non-irradiated control. Microbiological count of the samples prior to irradiation was in the range of 1×102–1.7×103 cfu/g with no detection of Salmonella sp. and Escherichia coli. No microbial colonies were detected after irradiation. Based on the TBA and overall sensory acceptance, gamma irradiation of 5 kGy was found to be the optimum dose and lower doses can be considered to decontaminate coconut cream powder. 相似文献
90.
Carine Livage Ahmad Safari Lisa C. Klein 《Journal of Sol-Gel Science and Technology》1994,2(1-3):605-609
A new sol-gel system using ethylene glycol was developed for the fabrication of PZT thin films with compositions near the morphotropic phase boundary Pb(Zr0.52Ti0.48)O3. Ethylene glycol was used as both a chelating agent and a solvent to replace the highly toxic methoxyethanol used in previous formulations. Thin films were deposited by spin coating the solutions onto platinized silicon substrates. Films were completely crystallized by about 600°C and contained the ferroelectric perovskite phase. A dielectric constant of about 750–800 at 1 KHz was obtained for thin films of 0.3 µm thickness. The hysteresis measurements revealed a remanent polarization of 15 mC/cm2 with a coercive field of 60 kV/cm. 相似文献