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301.
Monga V Thompson KH Yuen VG Sharma V Patrick BO McNeill JH Orvig C 《Inorganic chemistry》2005,44(8):2678-2688
Four mixed O,S binding bidentate ligand precursors derived from maltol (3-hydroxy-2-methyl-4-pyrone) have been chelated to vanadium to yield new bis(ligand)oxovanadium(IV) and tris(ligand)vanadium(III) complexes. The four ligand precursors include two pyranthiones, 3-hydroxy-2-methyl-4-pyranthione, commonly known as thiomaltol (Htma), and 2-ethyl-3-hydroxy-4-pyranthione, commonly known as ethylthiomaltol (Hetma), as well as two pyridinethiones, 3-hydroxy-2-methyl-4(H)-pyridinethione (Hmppt) and 3-hydroxy-1,2-dimethyl-4-pyridinethione (Hdppt). Vanadium complex formation was confirmed by elemental analysis, mass spectrometry, and IR and EPR (where possible) spectroscopies. The X-ray structure of oxobis(thiomaltolato)vanadium(IV),VO(tma)(2), was also determined; both cis and trans isomers were isolated in the same asymmetric unit. In both isomers, the two thiomaltolato ligands are arranged around the base of the square pyramid with the V=O linkage perpendicular; the vanadium atom is slightly displaced from the basal plane [V(1) = 0.656(3) A, V(2) = 0.664(2) A]. All of the new complexes were screened for insulin-enhancing effectiveness in streptozotocin-induced diabetes in rats, and VO(tma)(2) was profiled metabolically for urinary vanadium and ligand clearance by GFAAS and ESIMS, respectively. The new vanadium complexes did not lower blood glucose levels acutely, possibly because of rapid dissociation and excretion. 相似文献
302.
Dr. Asha D. Jangale Ratan W. Jadhav Dinesh N. Nadimetla Mahesh D. Burud Vishal G. More Prof. Sheshanath V. Bhosale 《ChemistryOpen》2019,8(4):403-405
Sheshanath V. Bhosale received his PhD from Freie University Berlin (Germany) in supramolecular chemistry under the supervision of Prof. J. H. Fuhrhop in 2004. He then pursued his postdoctoral studies with Prof. S. Matile at University of Geneva (Switzerland) under the auspices of a Roche Foundation Fellowship. This was followed by a stay at Monash University (Australia) for 5 years as an ARC-APD Fellow. He worked at RMIT University, Melbourne (Australia) for 6 years as ARC-Future Fellowship. Currently, Prof. Bhosale is working at the Department of Chemistry, Goa University (India) as a UGC-FRP Professor, His research interests lie in the design and synthesis of π-functional materials, especially small molecules, for sensing, biomaterials, and supramolecular chemistry applications. So far, Prof. Bhosale has produced 185 research articles and his work has been cited more than 4400 times, giving him an h-index of 32. He currently serves as an active Editorial Board member for ChemistryOpen. 相似文献
303.
Vishal Kumar Rajput 《Tetrahedron letters》2006,47(33):5939-5941
Sulfuric acid immobilized on silica proved to be an efficient catalyst for the synthesis of O-isopropylidene sugar derivatives from reducing sugars. The method is very simple and economic for large-scale synthesis in which the catalyst is recovered and reused several times. Reactions with d-glucose, d-galactose, d-mannose, l-rhamnose, l-arabinose, d-xylose and l-sorbose led to the formation of the corresponding thermodynamically stable di-O- and/or mono-O-isopropylidene derivatives in good to excellent yields. 相似文献
304.
Vishal Kumar Arora Vishal Sharma Monika Sachdeva 《International Journal of Communication Systems》2019,32(9)
To accomplish the primary objective of data sensing and collection of wireless sensor networks (WSN), the design of an energy efficient routing algorithm is very important. However, the energy constrained sensing nodes along with the intrinsic properties of the (WSN) environment makes the routing a challenging task. To overcome this routing dilemma, an improved distributed, multi‐hop, adaptive, tree‐based energy‐balanced (DMATEB) routing scheme is proposed in this paper. In this scheme, a relay node is selected in view of minimum distance and high energy from a current sensing node. Further, the parent node is chosen among the selected relay nodes on the basis of high residual energy and less power consumption with due consideration of its associated child nodes. As each sensing node itself selects its parent among the available alternatives, the proposed scheme offers a distributive and adaptive approach. Moreover, the proposed system does not overload any selected parent of a particular branch as it starts acting as a child whenever its energy lowers among the other available relay nodes. This leads to uniform energy utilization of nodes that offers a better energy balance mechanism and improves the network lifespan by 20% to 30% as compared with its predecessors. 相似文献
305.
Vishal Sharma P. K. Diwan Pratibha Tanu Sharma Shyam Kumar D. K. Avasthi 《Indian Journal of Physics》2009,83(7):937-941
The energy loss of Li, C and O ions in polypropylene absorber foils has been measured using 15 UD Pelletron Accelerator facility
at Inter University Accelerator Centre (IUAC), New Delhi, India. The actual experiment has been performed in low flux chamber
attached to the General Purpose Scattering Chamber (GPSC). These experimental energy loss values have been compared with the
computed values based on various empirical/semi-empirical formulations. Some interesting trends have been observed.
相似文献
306.
A mild and efficient one-pot visible light-induced method has been developed for the aerobic oxidation of saturated carbon conjugated with pyridine moiety with an important conversion in medicinal and synthetic organic chemistry. This eosin Y based organic transformations, exhibit a novel approach towards site selective functionalization of pyridine with enhance integrity and capability. This novel synthetic route may hold great potential for diverse functionalization of a wide range of pyridine moiety with an economical and sustainable manner. 相似文献
307.
In this paper, the authors have studied the dynamics of a novel complex chaotic system with fractional order derivative and found the existence of chaos. The novel complex system is simulated for integer as well as fractional orders which shows some unusual phenomena. The main contribution of this effort is an implementation of the Largest Lyapunov Exponent (LLE) criteria based on Wolf’s algorithm. The conditions for chaos control based on the fractional Routh–Hurwitz stability conditions and feedback control are given. Also synchronization between a fractional order novel chaotic system and a controlled fractional order novel system using the modified adaptive projective synchronization method for different scaling matrices has been obtained. Numerical simulation results are carried out using the Adams–Bashforth–Moulton method. 相似文献
308.
Four mixed O,S binding ligand precursors derived from maltol (3-hydroxy-2-methyl-4-pyrone) have been chelated to gallium(III), indium(III), and lanthanide(III) ions to yield a series of metal complexes. The four ligand precursors include two pyranthiones, 3-hydroxy-2-methyl-4-pyranthione, commonly known as thiomaltol (Htma), and 2-ethyl-3-hydroxy-4-pyranthione, commonly known as ethylthiomaltol (Hetma), and two pyridinethiones, 3-hydroxy-2-methyl-4(H)-pyridinethione (Hmppt) and 3-hydroxy-1,2-dimethyl-4-pyridinethione (Hdppt). Dimeric forms of the pyridinethiones, Hmppt dimer and Hdppt dimer, were also isolated and characterized. Complete characterization of the monomeric organic compounds is reported including acidity constants and crystal structures of Htma, Hetma, and Hdppt dimer. Reacting the four monomeric ligand precursors with Ga(3+) and In(3+) ions yielded new tris(bidentate ligand) complexes. X-ray-quality crystals of the fac isomer of Ga(tma)(3) were also obtained. New complexes with a range of lanthanides (Ln(3+)) were also synthesized with the two pyranthiones, Htma and Hetma. The synthesis reactions yielded complexes of the type LnL(3).xH(2)O and LnL(2)(OH).xH(2)O, as indicated by elemental analysis and spectroscopic evidence such as mass spectral data and IR and NMR spectra. 相似文献
309.
The EMR study of Mn2+ doped potassium trihydrogen selenite is performed and the site of Mn2+ in the lattice is discussed. The zero field parameters providing good fit to the observed EMR spectra are estimated. The spin-Hamiltonian parameters g, A, B, D, and a are (2.0003 +/- 0.0002), (31 +/- 2) x 10(-4), (20 +/- 2) x 10(-4), (87 +/- 2) x 10(-4), and (-9 +/- 1) x 10(-4) cm(-1), respectively. The percentage of covalency of the metal-ligand bond is also determined. The optical absorption study suggests the lattice distortion in the crystal. The electron repulsion and crystal field parameters having good fit to the observed optical spectra are evaluated. The band positions are fitted with the Racah parameters (B and C), the cubic crystal field splitting parameters (Dq), and the Trees correction (alpha). The values of B, C, Dq, and alpha are 871, 2967, 670, and 76 cm(-1), respectively. 相似文献
310.
Summary The formation of red coloured chelates of vanadium(V) and niobium(V) with xylenol orange (DCAC) having max at 490 nm (at pH 5.0) and 530 nm (at pH 5.5) have been reported. The colour formation has been applied to the spectrophotometric determination of metal ions. The colour has been found to be stable between pH 3.5–6.5 and 2.0–7.0 respectively. The sensitivity of the reagent is 0.051g/cm2 of vanadium and 0.093g/cm2 of niobium. Maximum colour intensity has been found for Nb-DCAC chelate at pH 5.5 whereas no appreciable change has been found for V-DCAC chelate between pH 4.5 and 6.5.
Zusammenfassung Über die Bildung rot gefärbter Chelate von Vanadin und Niob mit Xylenolorange wurde berichtet. Deren Absorptionsmaxima liegen bei 490 nm (pH 5,0) bzw. bei 530 nm (pH 5,5). Die Farbreaktion wurde für die Bestimmung der beiden Metalle verwendet. Die Farbe ist zwischen pH 3,5 und 6,5 bzw. zwischen pH 2,0 und 7,0 stabil. Die Empfindlichkeit für Vanadin beträgt 0,051g/cm2, für Niob 0,093g/cm2. Die Farbe des Niobchelates erreicht bei pH 5,5 ein Maximum, während die des Vanadinchelates zwischen pH 4,5 und 6,5 keine wesentlichen Änderungen erkennen läßt.相似文献