Browsing by Title

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    1,2-Cyclopropanated sugars \b reactions and synthetic utility
    (University of Hyderabad, 1997-09-20) Ramana, C.V.
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    1,2-Diketones from alkylbromides using na < inf > 2 < /inf > fe(co) < inf > 4 < /inf > /cucl system
    ( 1992-02-25) Davasagayaraj, Arockiasamy ; Periasamy, Mariappan
    Reaction of alkylbromides with Na2Fe(CO)4 under carbon monoxide atmosphere followed by CuCl treatment gives the corresponding 1,2-diketones in 70-90% yields. © 1992.
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    1,2-Ene dithiolate bridged diiron carbonyl-phosphine and -phosphite complexes in relevance to the active site of [FeFe]-hydrogenases: Synthesis, characterization and electrocatalysis
    ( 2012-10-15) Durgaprasad, Gummadi ; Das, Samar K.
    A series of binuclear {Fe IFe I} complexes, such as, [Fe 2{μ-6,7-qdt}(CO) 6], [Fe 2{μ-diph-6,7- qdt}(CO) 6] and [Fe 2{μ-btdt}(CO) 6] have recently been reported by us. These complexes have now been examined to explore structural, electronic and electrochemical effects on substituting one or two CO group(s) with other donor ligands, e.g., phosphine and phosphite ligands. Mono-phosphine substituted compounds [Fe 2{μ-6,7-qdt}(CO) 5PPh 3] (1), [Fe 2{μ-diph-6,7-qdt}(CO) 5PPh 3] (2) and [Fe 2{μ-btdt}(CO) 5PPh 3] (7) are synthesized by the reactions of [Fe 2{μ-6,7-qdt}(CO) 6], [Fe 2{μ-diph-6,7-qdt} (CO) 6] and [Fe 2{μ-btdt}(CO) 6] respectively with PPh 3 in the presence of Me 3NO. Interestingly, treatment of [Fe 2{μ-6,7-qdt}(CO) 6], [Fe 2{μ-diph-6,7-qdt}(CO) 6] and [Fe 2{μ-btdt} (CO) 6] with controlled amount of P(OEt) 3 affords the mono-substituted phosphite derivatives [Fe 2{μ-6,7-qdt}(CO) 5P(OEt) 3] (3), [Fe 2{μ-diph-6,7-qdt}(CO) 5P(OEt) 3] (4), [Fe 2{μ-btdt}(CO) 5 P(OEt) 3] (8) respectively. The same reaction with an excess amount of P(OEt) 3 affords the di-substituted phosphite derivatives [Fe 2{μ-6,7-qdt}(CO) 4{P(OEt) 3} 2] (5), [Fe 2{μ-diph-6,7-qdt}(CO) 4{P(OEt) 3} 2] (6) and [Fe 2{μ-btdt}(CO) 4{P(OEt) 3} 2] (9) correspondingly. These new complexes 1-9 have been characterized by IR, 1H, 13C, and 31P{ 1H} NMR and mass spectroscopy including elemental analysis. The solid state structures for all compounds have been determined by single-crystal X-ray structure analyses. The electrochemistry of 1-9 was performed by cyclic voltammetry to evaluate the effects of phosphine and phosphite ligands on the reduction potentials of the all carbonyl di-iron model complexes [Fe 2{μ-6,7-qdt}(CO) 6], [Fe 2{μ-diph-6,7-qdt}(CO) 6] and [Fe 2{μ-btdt} (CO) 6]. The electrocatalytic activities of model complexes 7-9 toward proton reduction of a strong acid p-HOTs have been described. © 2012 Elsevier B.V. All rights reserved.
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    1,2-Phenylene-Incorporated Smallest Expanded Calix[4]pyrrole via One-Step Synthesis of Tetrapyrrane: A Fluorescent Host for Fluoride Ion
    ( 2021-08-06) Kumar, B. Sathish ; Chandra, Brijesh ; Jovan Jose, K. V. ; Panda, Pradeepta K.
    Synthesis of tetrapyrrane 8 from acetone and pyrrole via one-step condensation was achieved for the first time along with a much-improved yield of the tripyrrane 9. Diborylation of the tetrapyrrane and subsequent "1 + 1"cyclocoupling with 1,2-diiodobenzene following the Suzuki protocol generated novel o-phenylene incorporated macrocycle belonging to the smallest meso-expanded calix[4]pyrrole family. The latter macrocycle displays exclusive turn-on fluorescence sensing of fluoride ion upon complexation via a unique partial cone conformation supported by DFT analysis in acetonitrile solvent.
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    1,2-Shift in the anodic oxidation of aromatic compounds
    ( 1979-01-01) Bhat, Gajanan A. ; Periasamy, Mariappan ; Vivekananda Bhatt, M.
    The 1,2-shift observed during oxidation of organic substrates can arise by involvement of cation radicals. © 1979.
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    1-Benzopyran-4(4H)-ones as novel activated alkenes in the Baylis-Hillman reaction: A simple and facile synthesis of indolizine-fused-chromones
    ( 2003-06-02) Basavaiah, Deevi ; Jaganmohan Rao, Anumolu
    1-Benzopyran-4(4H)-one derivatives have been successfully employed as novel activated alkenes in the Baylis-Hillman coupling with heteroaromatic-aldehydes, nitrobenzaldehydes and isatin-derivatives and the corresponding adducts, derived from pyridine-2-carboxaldehyde, have been transformed into a novel indolizine-fused-chromone framework. © 2003 Elsevier Science Ltd. All rights reserved.
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    1-Dimensional and 2-dimensional coordination network structures in the Ba-Ce-dipicH < inf > 2 < /inf > system (dipicH < inf > 2 < /inf > = dipicolinic acid)
    ( 2005-08-25) Prasad, T. K. ; Sailaja, S. ; Rajasekharan, M. V.
    Reaction of dipicolinic acid with ammonium ceric nitrate and barium chloride produces, by self-assembly, three coordination polymers having similar stoichiometry but very different network structures. The structure of Ba(dipicH2)(OH2)4Ce(dipic)3· 4.6H2O (1) is built up of 1-D alternating chains of nine-coordinate Ce and Ba polyhedra, each having tricapped trigonal prismatic geometry. The structure of Ba(OH2)6Ce(dipic)3 (2), wherein a chain of nine-coordinate aquo-Ba polyhedra is threaded through the channel formed by a trigonal arrangement of the Ce(dipic)32- anions, is analogous to that of SrCl2·6H2O· Ba(OH2) 4Ce(dipic)3·2H2O (3), a polymorph of 2 (formally its hydrate isomer), exhibits a layered network in which Ce and Ba coordination polyhedra are linked by dipic ligands to form a corrugated sheet structure and may be considered as a metal-organic analog of the PbO lattice. © 2005 Elsevier Ltd. All rights reserved.
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    1/N expansion and the uncertainty principle
    ( 1985-12-01) Chatterjee, A.
    The leading-order term of the 1/N expansion is derived in a new way and is thus given a simple physical interpretation.
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    1/N expansion for Gaussian potential
    ( 1985-12-01) Chatterjee, A.
    The method of large-N expansion has been applied to an attractive radial Gaussian potential to obtain its bound state energy levels. It has been shown that the shifted 1/N expansion technique provides a better approximation than the method of unshifted 1/N expansion and yields energy values which are in good agreement with the accurate numerical and analytic results.
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    1/N expansion for the Yukawa potential revisited
    ( 1985-06-01) Chatterjee, Ashok
    In a recent paper, Moreno and Zepeda have applied the 1/N expansion to obtain an approximate analytic formula for the ground state energy of a panicle bound by a Yukawa potential. Using the method of Mlodinow and Shatz we caiculate the energies of the ground state and the first excired state of the system to show that the results provided by the i/N expansion are identical with tiiose obtained by applqing either the analytic perturbation theory or the hypenirial equations with the Hellman-Feynman theorem..Also an approximate analytic formula for the ground state energq is proposed. © 1985 The Institute of Physics.
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    1/N expansion for the Yukawa potential revisited: II
    ( 1986-12-01) Chatterjee, A.
    Using the form prescribed by Moreno and Zepeda for the N-dimensional Yukawa potential and employing the method of 1/N expansion we have obtained in a recent paper the energies of the ground state and the first excited state of a three-dimensional Yukawa potential. In the present addendum we introduce a modified prescription for the N-dimensional Yukawa potential which enables us also to calculate the energies of the higher angular momentum states. Our results are in very good agreement with the accurate numerical values.
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    10,10′-Dibromo-9,9′-bianthryl
    ( 2003-11-01) Sarkar, Moloy ; Samanta, Anunay
    In the title compound, C28H16Br2, the two anthryl moieties are almost perpendicular to each other; the dihedral angles between the anthryl planes are 89.42 (9) and 82.36 (7)° in the two independent molecules, one of which lies on a crystallographic twofold rotation axis. An interesting feature of the crystal structure is the presence of C - H⋯π interactions. © 2003 International Union of Crystallography Printed in Great Britain - all rights reserved.
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    10,15-Bis (ethoxycarbonyl)-5-(4-methoxycarbonylphenyl) B(III)subchlorin: A photosensitizer with high singlet oxygen producing efficiency
    ( 2021-10-01) Bhat, Ishfaq A. ; Soman, Rahul ; Chandra, Brijesh ; Sahoo, Sameeta ; Thaltiri, Vikranth ; Panda, Pradeepta K.
    A novel A2B-type B(III)subchlorin has been synthesized for the first time in two ways possessing two different ester moieties upon macrocyclic periphery from meso-diethoxycarbonyl tripyrrane. Its photophysical and electrochemical properties have been explored. Introduction of the third meso-substituent resulted in the synthesis of the B(III)subchlorin as the major product with the formation of minor oxidized B(III)subporphyrin analogue. This subchlorin derivative was found to generate singlet oxygen much efficiently with quantum yield (φΔ) 0.88.
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    10-fold enhancement in light-driven water splitting using niobium oxynitride microcone array films
    ( 2016-07-01) Shaheen, Basamat S. ; Hafez, Ahmed M. ; Murali, Banavoth ; Kirmani, Ahmad R. ; Amassian, Aram ; Mohammed, Omar F. ; Allam, Nageh K.
    We demonstrate, for the first time, the synthesis of highly ordered niobium oxynitride microcones as an attractive class of materials for visible-light-driven water splitting. As revealed by the ultraviolet photoelectron spectroscopy (UPS), photoelectrochemical and transient photocurrent measurements, the microcones showed enhanced performance (~1000% compared to mesoporous niobium oxide) as photoanodes for water splitting with remarkable stability and visible light activity.
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    11-Hydroperoxyeicosatetraenoic acid is the major dioxygenation product of lipoxygenase isolated from hairy root cultures of Solanum tuberosum
    ( 1992-12-30) Ramakrishna Reddy, G. ; Reddanna, Pallu ; Channa Reddy, C. ; Curtis, Wayne R.
    The profile of primary dioxygenation products of arachidonic acid catalyzed by lipoxygenase isolated from hairy root cultures of Solanum tuberosum treated with a fungal elicitor was compared to that obtained for the enzyme from potato tubers. 11-Hydroperoxyeicosatetraenoic acid (11-HPETE) was the most abundant dioxygenation product formed followed by 8- and 5-HPETEs in the decreasing order of abundance. In contrast, 5-HPETE is the predominant oxidation product of lipoxygenase from potato tubers. Differences in the defense requirements of storage tuber as compared to roots may be the basis of the differences in regiospecificity demonstrated in this work. © 1992.
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    12-membered macrocycles containing ditelluroxane and selenotelluroxane units
    ( 2012-01-01) Srungavruksham, Nagarjuna Kumar ; Baskar, Viswanathan
    The reaction of benzeneseleninic acid with bis(p-methoxyphenyl)tellurium dihalide [halide = Cl (1), Br (2)] afforded colorless crystals in moderate yield. Single-crystal X-ray diffraction revealed the formation of 12-membered macrocycles [(p-MeO-C6H4)2Te(μ-O)(μ- PhSeO2)(μ4-X)]2 [X = Cl (1), Br (2)] where the halogen atoms, which are stabilized by Te-X interactions, cap the macrocycle on both sides. The reaction of NaI with 1 afforded the iodo-capped macrocycle [(p-MeO-C6H4)2Te(μ-O)(μ-PhSeO 2)(μ4-I)]2 (3) in good yield. In the solid-state structures of 1-3, the alignment of the phenyl group on Se changes with respect to the macrocycle. Macrocycle 3 shows rare Se-π interactions, which lead to the formation of a supramolecular polymeric network. Further reaction of methaneseleninic acid with bis(p-methoxyphenyl)tellurium dichloride in methanol in the presence of triethylamine afforded a 12-membered macrocycle [(p-MeO-C6H4)2Te(μ-O)(μ-MeSeO 2)(μ4-Cl)]2 (4), which is structurally similar to 1-3.
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    120 MeV Ag ion induced effects in Au/HfO < inf > 2 < /inf > /Si MOSCAPs
    ( 2018-05-08) Manikanthababu, N. ; Prajna, K. ; Pathak, A. P. ; Rao, S. V.S.Nageswara
    HfO2/Si thinfilms were deposited by RF sputtering technique. 120 MeV Ag ion irradiation has been used to study the electrical properties of Au/HfO2/Si MOSCAPs. SHI (120 MeV Ag) induced annealing, defects creation and intermixing effects on the electrical properties of these systems have been studied. Here, we have observed that the high electronic excitation can cause a significant reduction of leakage currents in these MOSCAP devices. Various quantum mechanical tunneling phenomenon has been observed from the I-V characteristics.
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    120 MeV Ag ion irradiation induced intermixing, grain fragmentation in HfO < inf > 2 < /inf > /GaO < inf > x < /inf > thin films and consequent effects on the electrical properties of HfO < inf > 2 < /inf > /GaO < inf > x < /inf > /Si-based MOS capacitors
    ( 2020-01-02) Vinod Kumar, K. ; Arun, N. ; Mangababu, A. ; Ojha, Sunil ; Nageswara Rao, S. V.S. ; Pathak, A. P.
    On p-type Silicon (100) substrates GaOx (150 nm) and HfO2 (30 nm) thin films have been synthesized using the RF magnetron sputtering method. After 120 MeV Ag SHI irradiation, ion-induced inter-diffusion/inter-mixing of Hf and Ga elements has been observed which leads to the development of inter-mixing of layers at the interfaces. As deposited films have randomly oriented large, inhomogeneous and non-uniform grains with an average size of 34.5 nm, while at the highest fluence, the formation of homogeneous and uniform individual spherical grains with an average size of 13.8 nm has been observed. Furthermore, HfO2/GaOx/Si-based MOS capacitors have been fabricated and the consequent effects on the electrical properties of these devices have been discussed in detail.
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    15(S)-HETE-induced angiogenesis in adipose tissue is mediated through activation of PI3K/Akt/mTOR signaling pathway
    ( 2013-12-01) Soumya, Sasikumar J. ; Binu, Sheela ; Helen, Antony ; Reddanna, Pallu ; Sudhakaran, Perumana R.
    Chronic low-grade inflammation underlies obesity and associated metabolic dysfunctions. Lipoxygenase pathways are activated in adipose tissue during obese conditions. Since adipogenesis is associated with angiogenesis, the present study was designed to examine the role of 15-lipoxygenase metabolite, 15(S)-hydroxyeicosatetraenoic acid [15(S)-HETE] on angiogenesis in adipose tissue. Results showed that 15(S)-HETE induced sprouting in fat pad stromovascular tissues, induced morphological changes relevant to angiogenesis in endothelial cells derived from adipose tissue, upregulated the production of CD31, upregulated the gene level expression and production of vascular endothelial growth factor (VEGF), indicating the pro-angiogenic effect of 15(S)-HETE. LY294002, an inhibitor of PI3K-Akt pathway, and rapamycin, inhibitor of mammalian target of rapamycin (mTOR), significantly reversed the effect of 15(S)-HETE. 15(S)-HETE also induced activation of Akt and mTOR. These observations suggest that 15(S)-HETE stimulates angiogenesis in adipose tissue through activation of PI3K/Akt/mTOR signaling. © 2013 Published by NRC Research Press.