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101.
102.
The isolation and characterization of 2-fluorophenyl imines and their metal complexes based upon physical (quantitative analyses, molecular weight determinations and conductivity measurements) and spectral evidence (i.r. and 1H-, 13C- and 19F-n.m.r.) are described. Structural assignments have been made from spectral studies. The donor sites of ligands have been located and geometries of the donor environment around the RuIII acceptor centre are proposed. In view of the potential therapeutic activity exhibited by the fluoro ligands, RuIII complexes, together with their parent 2-fluorophenyl imines, were screened for biological activity. The results are encouraging. 相似文献
103.
Subhash P. Chavan Pallavi Sharma R. Sivappa Uttam R. Kalkote 《Tetrahedron letters》2006,47(52):9301-9303
An efficient utilisation of RCM leading to a convenient synthesis of a pentacyclic indole alkaloid is described. 相似文献
104.
Distinctively different microstructures were obtained depending on the heating rate to which CdGeAs2 glasses were exposed during the devitrification process. Differential scanning calorimetry showed that under very slow heating rates, the single crystallization peak splits into three superimposed exotherms. Quenching from the temperature at which selected features appear on the DSC trace and using X-ray diffraction and transmission electron microscopy interactively, demonstrated the initial formation of a metastable doped precursor germanium crystalline phase. This crystalline structure continued to grow until it could no longer accommodate the impurities, and the transformation terminated. These regions then acted as heterogeneous nucleation sites for the growth of chalcopyrite structured CdGeAs2 with a spherulitic microstructure. The spherulites grew as stacked plates from the nucleation site. At higher temperatures, the metastable germanium structure converted, growing backwards toward the center of each precursor, into the stable chalcopyrite structure, permitted by appropriate ionic diffusion shifting composition toward stoichiometry. At faster heating rates, less of these germanium precursors formed, creating a visually bimodal grain size distribution in the microstructure, as compared to slower heating rates. Using the simplex algorithm, the mechanism and activation energy of each reaction are reported as well as the deconvoluted enthalpies of each transformation. 相似文献
105.
The present investigation reports the growth kinetics and diosgenin accumulation in callus cultures of Costus speciosus. Effect of explants, media and plant growth regulators was evaluated with respect to callus induction and growth. Out of the two explants viz pseudostem and seed, pseudostem showed maximum callus induction frequency of 90% on MS medium. The fresh weight of callus was maximum (9-folds) on 28th day on 1.0 mg/L picloram containing medium. The callus obtained was white compact hard (WCH). For growth kinetics study pseudostem derived callus was transferred on different media supplemented with 1.0 mg/L picloram. All phases of growth were seen in callus inoculated on all the three media except the absence of stationary phase on MS and SH media. MS medium proved to be the best for maximum biomass accumulation (9-fold) on 28th day of culture and callus in post-exponential phase showed maximum diosgenin accumulation (33 ppm). 相似文献
106.
Sharma Neeraj Bose B. Kaistha Atul Bhatt Sarvjeet S. Chaudhry Subhash C. 《Transition Metal Chemistry》2002,27(7):736-740
Niobium(V) chloride aryloxides [NbCl3(OAr)2] and [NbCl2(OAr)3] (Oar = —OC6H4Bu
t
-4 and —OC6H4OMe-4) have been prepared by reacting NbCl5 with two and three equivalents of the respective phenol in CCl4. The complexes have been characterized by elemental analysis, molecular weight determination, i.r., 1H-n.m.r., u.v.–vis. and MS techniques. Thermal behaviour (t.g.–d.t.) of the complexes has also been studied and decomposition schemes proposed. The kinetic and thermodynamic parameters namely, the activation energy 'E
*', the frequency factor 'A', entropy of activation 'S' and specific rate constant 'kr' etc. have been calculated employing the Coats–Redfern equation. The non-isothermal t.g. data has also been utilized to determine the most probable mechanism and corresponding activation energy for the decomposition of niobium(V) complexes by testing seven different theoretically possible decomposition mechanisms. 相似文献
107.
The formation of Pd(II) complexes with aminopolycarboxylate anions has been investigated using pH and UV.-spectrophotometric measurements at ionic strength 1 M and 20°. In some cases bromide or thiocyanate ions have been used as auxiliary ligands. Pd2+ forms the strongest complexes of the hitherto investigated divalent metal ions. The stability constants are discussed in relation to the particular stereochemistry of Pd(II) complexes. 相似文献
108.
Pankaj Gupta Vijay K. Sethi Subhash C. Taneja Bhahwal A. Shah Samar S. Andotra Surrinder Koul Swapandeep S. Chimni Ghulam N. Qazi 《Helvetica chimica acta》2007,90(1):196-204
A series of odoriferous cyclic ethers, including nerol oxide ( 1 ), Florol® ( 2 ), Florol methyl ether ( 3 ), and Pityol® methyl ether ( 4b ), were prepared by a versatile synthetic protocol based on co‐halogenation with 1,3‐dibromo‐5,5‐dimethylhydantoin (= 1,3‐dibromo‐5,5‐dimethylimidazolidine‐2,4‐dione; DDH) as the key step. The methodology provides a facile access to important perfumery molecules from abundantly available monoterpene alcohols. 相似文献
109.
Peter Rogl Subhash K. Naik Erwin Rudy 《Monatshefte für Chemie / Chemical Monthly》1977,108(6):1339-1352
The system VC0.88–HfC0.98–MoC was investigated by means of melting point, differential-thermoanalytical, X-ray diffraction and metallographic techniques on hot pressed and heat treated as well as melted alloy specimens and a constitutional diagram from 1500°C through the melting range established.The small miscibility gap within the HfC–MoC system (T
c=1630°C) interacts at lower temperatures with the solvus in a monotectoid-like reaction at 1575°C. Additions of VC to the HfC–MoC solid solution gradually increase its critical temperature.Solid state phase behaviour and melting behaviour was established within the isopleths VC0.88–MoC as well as within (V0.5Hf0.5)C–MoC and (V0.75Hf0.25)C–(Hf0.75Mo0.25)C.Phase equilibria within VC0.88–HfC–MoC are characterized by an extreme large miscibility gap at 1500°C connecting the VC–HfC and HfC–MoC systems.Originating at the VC–HfC binary an eutectic trough proceeds into the VC–HfC–MoC ternary with rising temperatures, connecting the maximum critical point of the disappearing miscibility gap [(V0.31Hf0.49Mo0.20)C] by a limiting tie line (2750±20°C). Isothermal sections have been calculated assuming regular solutions.With 5 Figures 相似文献
110.
A novel, efficient total synthesis of the naturally occurring antiviral nothapodytine B (2, mappicine ketone) is reported. The approach is based on the successful implementation of the Johnson orthoester rearrangement of allylic alcohol 7 for assembly of a pyridone D ring precursor with the necessary functionalities. Nothapodytine B is converted into mappicine 3 by NaBH4 reduction. 相似文献