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51.
Umesh A. Fegade Suban K. Sahoo Amanpreet Singh Narinder Singh Sanjay B. Attarde Anil S. Kuwar 《Analytica chimica acta》2015
A fluorescent based receptor (4Z)-4-(4-diethylamino)-2-hydroxybenzylidene amino)-1,2dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (receptor 3) was developed for the highly selective and sensitive detection of Cu2+ and Zn2+ in semi-aqueous system. The fluorescence of receptor 3 was enhanced and quenched, respectively, with the addition of Zn2+ and Cu2+ ions over other surveyed cations. The receptor formed host-guest complexes in 1:1 stoichiometry with the detection limit of 5 nM and 15 nM for Cu2+ and Zn2+ ions, respectively. Further, we have effectively utilized the two metal ions (Cu2+ and Zn2+) as chemical inputs for the manufacture of INHIBIT type logic gate at molecular level using the fluorescence responses of receptor 3 at 450 nm. 相似文献
52.
53.
Umesh Balakrishnan Nallamuthu Ananthi Sakthivel Tamil Selvan Ravindra Pal Dr. Katsuhiko Ariga Dr. Sivan Velmathi Dr. Ajayan Vinu Dr. 《化学:亚洲杂志》2010,5(4):897-903
The immobilization of chiral oxazaborolidine complex in the well‐ordered mesochannels of SBA‐15 is demonstrated by a postsynthetic approach using 3‐aminopropyltriethoxysilane as a reactive surface modifier. The immobilized catalysts are characterized by various techniques, such as XRD, nitrogen adsorption, HRSEM, UV/Vis diffuse reflectance spectroscopy, and FTIR spectroscopy. The catalysts are used for the enantioselective reduction of aromatic prochiral ketones. The activity of the chiral oxazaborolidine complex immobilized SBA‐15 catalysts is also compared with that of the pure chiral oxazaborolidine complex, which is a homogeneous catalyst. It is found that the activity of the chiral complex immobilized SBA‐15 heterogeneous catalyst is comparable with that of the homogeneous catalyst. 相似文献
54.
Naik Anil D. Annigeri Satish M. Gangadharmath Umesh B. Revankar Vidyanand K. Mahale Vinayak B. 《Transition Metal Chemistry》2002,27(3):333-336
The binucleating ligand LH3, 2,6-diformyl-p-cresol-bis(phenylthioacetyldrazone), a Schiff base condensation product of 2,6-diformyl-p-cresol and phenylthioacetyldrazide forms complexes of the [M2ClL] type with CoII, NiII and CuII ions, which were characterized by elemental analysis, magnetic susceptibility, electronic spectra, molar conductance, i.r., n.m.r., e.p.r., t.g. and FAB mass spectral measurements. Sub-normal magnetic moments indicate the operation of antiferromagnetic coupling between the metal centres. The ligand and its copper complex show a pronounced fungistatic activity. 相似文献
55.
Symmetries, vibrational instabilities, and routes to stable structures of clusters of Al, Sn, and As 总被引:2,自引:0,他引:2
We investigate the stability of small clusters using density functional theory to compute the total energy, forces, and vibrational frequencies using linear response. We exhibit an efficient and computationally low-cost route to finding stable structures, by starting with high-symmetry structures and distorting them according to their unstable modes. We illustrate this by application to 4-, 6-, and 13-atom clusters of Al, Sn, and As. This technique also naturally elucidates the origins of stability of the lower symmetry structures, which is variously due to the linear or pseudo Jahn-Teller effect, combined with a lowering of various contributions to the total energy. We show that the situation is more complex than has generally been appreciated. 相似文献
56.
The molecular charge complex urea picrate (UP) was synthesized and its third order nonlinear optical properties have been investigated using a single beam Z-scan technique with nanosecond laser pulses at 532 nm. Open aperture data of the compound indicates two photon absorption at this wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient β, magnitude of effective third order susceptibility χ(3), the second order hyperpolarizability γh and the coupling factor ρ have been estimated. The experimentally determined values of β, n2, Re χ(3) and Im χ(3), γh and ρ of the compound UP are 2.146 cm/GW, −1.258×10−11 esu, −1.347×10−13 esu, 0.377×10−13 esu, 0.69×10−32 esu and 0.28, respectively. The compound exhibits good optical limiting at 532 nm with the limiting threshold of 80 μJ/pulse. Our studies suggest that compound UP is a potential candidate for optical device applications such as optical limiters. 相似文献
57.
Umesh N. Tripathi Ghanshyam Srivastava Ram C. Mehrotra 《Transition Metal Chemistry》1994,19(6):564-566
Summary Solids of the stoichiometric formulae [Fe{S2P(OPr-n)2}3] and [Fe{S2PO2G}3] (G = —CH2CMe2CH2—, CMe2–CMe2— or —CH2CH2CHMe—) are precipitated from the reactions of FeCl3 with ammonium dithiophosphates in water. Soluble complexes of the type [Fe{S2PO2G}2], formed by the reactions of FeCl2 with NH4[{S2PO2G}] in MeOH, can be extracted with benzene. Adducts of the types [Fe{S2PO2G}2L] and [Fe{S2PO2G}2(PPh3)2] are formed by the reaction of [Fe{S2PO2G}2] with L (L = 2,2-bipyridyl or 1,10-phenanthroline) and PPh3, respectively. All the compounds have been characterized by i.r. and u.v.-vis. spectroscopy and magnetic studies.This paper is dedicated to the late Dr. G. Srivastava, Associate Professor, Department of Chemistry, Rajasthan University, Jaipur. 相似文献
58.
Nehete UN Roesky HW Zhu H Nembenna S Schmidt HG Noltemeyer M Bogdanov D Samwer K 《Inorganic chemistry》2005,44(20):7243-7248
The cobalt(II) and iron(II) siloxane compounds were prepared by the reaction of lipophilic N-bonded silanetriol 1 with metal silylamides M[N(SiMe3)2]2 (M = Co (2), Fe (3)) in a 1:1 and 3:4 molar ratio, respectively. A plot of 1/chi versus temperature in the range of 2-300 K indicates the paramagnetic behavior of 2 and 3. The composition and molecular structures of 2 and 3 were fully determined by IR, elemental analysis, and X-ray crystal structural analyses. Compound 2 possesses a pseudo-4-fold (S4) symmetry, whereas 3 reveals an inversion center. Compound 2 represents a tetracobalt(II) drum while 3 exhibits an octairon(II) cage containing siloxane ligands. 相似文献
59.
Annigeri Satish M. Naik Anil D. Gangadharmath Umesh B. Revankar Vidyanand K. Mahale Vinayak B. 《Transition Metal Chemistry》2002,27(3):316-320
Four binuclear transition metal(II) complexes: [Co2L(-Cl)Cl2] · 2H2O, [Ni2L(-Cl)Cl2(H2O)2] · 2H2O, [Cu2L(-Cl)Cl2] · 2H2O and [Zn2L(-Cl)Cl2] · 2H2O, where LH is the binucleating ligand 2,6-diformyl-4-methylphenol bis(2-hydrazino benzothiazole), were prepared. Based on the i.r. spectra, elemental analysis, conductivity measurements and thermal analysis, we propose that these complexes contain an endogenous phenoxide bridge and an exogenous chloride bridge. Magnetic and spectral data supports the existence of a weak antiferromagnetic interaction between the metal ions, and octahedral for NiII and a square pyramidal environment for remaining complexes. The compounds show significant growth inhibitory activity against the fungi, Aspergillus niger and Candida albicans, as compared to antibacterial activity against Bacillus cirroflagellosus and Pseudomonas auregenosa. 相似文献
60.
K.P. Gopinathan Nair Channe Gowda J.Shylaja Kumari S.J. Anasuya T.K. Umesh Ramakrishna Gowda 《Radiation Physics and Chemistry》1994,43(6):581-584
Total attenuation cross sections for several amino acids have been measured for Ba133 photons in a narrow beam good geometry setup, using a hyper pure germanium detector. These values are compared with the values calculated using the mixture rule based on the data of Hubbell for the individual elements and found to be in good agreement. 相似文献