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Sumanta Kumar Padhi Dipankar Saha Rojalin Sahu Japyesan Subramanian Vadivelu Manivannan 《Polyhedron》2008
Three complexes of composition [CrL(X)3], where L = 4′-(2-pyridyl)-2,2′:6′,2″-terpyridine and X = Cl−, N3−, NCS− are synthesized. They are characterized by IR, UV–Vis, fluorescence, EPR spectroscopic, and X-ray crystallographic studies. Structural studies reveal that the Cr(III) ion is coordinated by three N atoms of L in a meridional fashion. The three anions occupy the other three coordination sites completing the mer-N3Cl3 (1) and mer-N3N3 (2 and 3), distorted octahedral geometry. The Cr–N2 has a shorter length than the Cr–N1 and Cr–N3 distances and the order Cr–N(NCS−) < Cr–N(N3−) < Cr–Cl is observed. They exhibit some of the d–d transitions in the visible and intra-ligand transitions in the UV regions. The lowest energy d–d transition follows the trend [CrLCl3] < [CrL(N3)3] < [CrL(NCS)3] consistent with the spectrochemical series. In DMF, they exhibit fluorescence having π → π∗ character. All the complexes show a rhombic splitting as well as zero-field splitting (zfs) in X-band EPR spectra at 77 K. 相似文献
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Cyclometalated ruthenium(II) complexes having acridine moieties have been synthesized and characterized by spectroscopic methods. Protonation of the acridine nitrogen of the ruthenium(II) complexes not only causes dynamic equilibrium with remote N-heterocyclic carbene Ru═C complexes but also generates the NAD(+)/NADH redox function driven by a proton-coupled two-electron transfer accompanying a reversible C-H bond formation in the pyridinium ring. 相似文献
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Sufficient conditions have been obtained for the existence of at least two non-negative periodic solutions to a system of first-order nonlinear functional differential equations. Applications to some ecological models are given. 相似文献
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K
β-to-K
α X-ray intensity ratios of Fe and Ni in pure metals and in Fe
x
Ni1−x
alloys (x=0.20, 0.50, 0.58) exhibiting similar crystalline structure have been measured following excitation by 59.54 keV γ-rays from a 241Am point source, to understand as to why the properties of permalloy Fe0.2Ni0.8 is distinct from other alloy compositions. It is observed that the valence electronic structure of Fe0.2Ni0.8 alloy is totally different from other alloys which may be attributed to its special magnetic properties. 相似文献
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N-(2-Pyridylmethyl)pyridine-2-methylketimine (L1) was synthesized from equimolar quantities of (2-pyridyl)methylamine and 2-acetylpyridine. Methanolic solution of L1 reacted readily with Cu(NO3)2.3H2O in air, affording green solid of composition {[Cu(L2)(OH)(NO3)][Cu(L2)(NO3)2]}.2H2O, where L2 is 4'-(2-pyridyl)-2,2':6',2' '-terpyridine. Oxidation of the active methylene group of L1 to an imide and then condensation with 2-acetylpyridine involving a C-C bond-forming reaction, mediated by a Cu2+ ion, are the essential steps involved in the conversion of L1 to L2. L2 is isolated by extrusion of Cu2+ with EDTA(2-). The copper center in [Cu(L2)(OH)(NO3)] has a mer-N3O3 environment, and that in [Cu(L2)(NO3)2] has a distorted trigonal-bipyramidal geometry. Two H2O molecules held by C-H...O interactions are present in the predominantly hydrophobic channels of approximate cavity dimension 7.60 x 6.50 A created by aromatic rings through pi-pi interactions. 相似文献
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Subash C. Verma Chhoten L. Jain Amita Kumari Madan M. Padhi Ramesh B. Devalla 《Journal of separation science》2013,36(7):1255-1262
Ursolic acid (UA) is the most important bioactive phytoconstituent of Eucalyptus × hybrida Maiden leaves and exhibits anticancer, antimutagenic, anti‐inflammatory, antioxidative, and antiprotozoal activities. In this study, microwave‐assisted extraction technique was employed for rapid isolation of UA from the leaves of Eucalyptus × hybrida and simultaneously HPLC‐diode array method was developed for the quantification of UA. Effects of several experimental parameters on the extraction efficiencies of UA, such as type and volume of extraction solvents, microwave power and extraction time, were evaluated. The optimal extraction conditions were found to be 20 mL of a mixture of chloroform/methanol, 60:40; liquid‐to‐material ratio, 4:1; preleaching time, 10 min; microwave power, 600 W; temperature, 50°C; and microwave irradiation time, 5 min. Under the optimum conditions, the yield of UA was found to be 1.95 ± 0.08% in the dry leaves of Eucalyptus × hybrida. The results showed that microwave‐assisted extraction is a more rapid extraction method with higher yield and lower solvent consumptions than the conventional method. It is a faster, convenient, and appropriate method and it may be used for rapid isolation and quantification of UA and other important phytoconstituents present in the leaves of Eucalyptus × hybrida. 相似文献
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Cyclometalated Ru(II) complexes having a 3-phenylbenzo[b][1,6]naphthyridine (phbn) ligand have been synthesized and characterized by spectroscopic methods. The photo- and electrochemical redox behavior of the complexes are demonstrated. Complex [Ru(phbn)(bpy)(2)]PF(6) ([1]PF(6)) readily undergoes proton coupled two electron reduction by chemical, electrochemical, and photochemical methods to generate [Ru(phbnHH)(bpy)(2)]PF(6) ([1HH]PF(6)). The photochemical oxidation of [1HH]PF(6) was also observed in presence of p-chloranil. 相似文献
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Santanu Kumar Padhi Nicoletta Baglieri Valentina Bonino Angelo Agostino Lorenza Operti Nicolae Dan Batalu Mariana Carmen Chifiriuc Marcela Popa Mihail Burdusel Mihai Alexandru Grigoroscuta Gheorghe Virgil Aldica Dana Radu Petre Badica Marco Truccato 《Molecules (Basel, Switzerland)》2021,26(16)
We report for the first time on the antimicrobial activity of MgB2 powders produced via the Reactive Liquid Infiltration (RLI) process. Samples with MgB2 wt.% ranging from 2% to 99% were obtained and characterized, observing different levels of grain aggregation and of impurity phases. Their antimicrobial activity was tested against Staphylococcus aureus ATCC BAA 1026, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Candida albicans ATCC 10231. A general correlation is observed between the antibacterial activity and the MgB2 wt.%, but the sample microstructure also appears to be very important. RLI-MgB2 powders show better performances compared to commercial powders against microbial strains in the planktonic form, and their activity against biofilms is also very similar. 相似文献
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