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51.
Atta‐ur‐Rahman Shama Nasim Irfan Baig Ilkay Orhan Bilge Sener Filiz Ayanoglu M.Iqbal Choudhary 《Helvetica chimica acta》2003,86(10):3354-3362
Five new di‐ and triglycosides, irigenin 7‐[O‐β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐glucopyranoside] ( 1 ), 6‐hydroxygenistein 4′‐[O‐β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐glucopyranoside] ( 2 ), nigricin 4′‐[O‐β‐D ‐glucopyanosyl‐(1→6)‐β‐D ‐glucopyranoside] ( 3 ), nigricin 4′‐[O‐β‐D ‐glucopyanosyl‐(1→2)‐O‐[α‐L ‐rhamnopyranosyl‐(1→6)]‐β‐D ‐glucopyranoside] ( 4 ), and 7‐{4′‐{[2″‐O‐(4′′′′‐acetyl‐2′′′′‐methoxyphenyl)‐β‐D ‐glucopyranosyl]oxy}‐3′‐(β‐D ‐glucopyranosyloxy)phenyl]‐9‐methoxy‐8H‐1,3‐dioxolo[4,5‐g]‐[1 benzopyran‐8‐one‐] ( 5 ), along with a known compound, nigricin 4′‐(β‐D ‐glucopyranoside) ( 6 ), were isolated from the rhizomes of Iris germanica. The structures of these compounds were established by spectroscopic methods, including 2D NMR spectroscopic techniques. 相似文献
52.
We obtain an exact solution for the Einstein’s equations with cosmological constant coupled to a scalar, static particle in static, “spherically” symmetric background in (2+1)-dimensions. 相似文献
53.
Strongly self-dual Yang-Mills fields in even-dimensional spaces are characterised by a set of constraints on the eigenvalues of the Yang-Mills fieldsF
. We derive a topological bound on R8,
, wherep1 is the first Pontryagin class of the SO(n) Yang-Mills bundle, andk is a constant. Strongly self-dual Yang-Mills fields realise the lower bound. 相似文献
54.
Unruh's detector calculation is used to study the effect of the defect angle in a space-time with a cosmic string for both the excitation and deexcitation cases. It is found that a rotating detector results in a non-zero effect for both finite (small) and infinite (large) time. 相似文献
55.
The generalized Sinh-Gordon potential is solved within quantum Hamiltonian Jacobi approach in the framework of PT symmetry. The quasi exact solutions of energy eigenvalues and eigenfunctions of the generalized Sinh-Gordon potential are
found for n=0,1 states. 相似文献
56.
Bilge Taner Pervin Deveci Zafer Üstündaǧ Selda Keskin Emine Özcan Ali Osman Solak 《Surface and interface analysis : SIA》2012,44(2):185-191
3‐Aminophenylcalix[4]pyrrole (3APCP) was grafted to a glassy carbon (GC) surface during the electrochemical oxidation process in 0.1 M tetrabutylammoniumtetra‐fluoroborate (TBATFB) containing acetonitrile solution. The presence of a surface film was confirmed electrochemically by comparing voltammograms of dopamine and ferricyanide redox probes at the bare and modified electrodes. Reflection‐absorption infrared spectroscopy (RAIRS), XPS, atomic force microscopy (AFM), ellipsometry and the contact angle measurements were also employed to characterize 3APCP film on GC electrode. RAIRS analysis revealed that calix[4]pyrrole was bonded to the glassy carbon surface via the etheric linkage. The stability of the modified GC electrode was also studied. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
57.
Two novel calix[4]arene receptors containing ferrocene units in cone (L1) and 1,3-alternate (L2) conformations have been synthesized from 25,27-dihydroxy-26,28-bis[(3-aminopropyl)oxy]calix[4]arene 4 or 25,26,27,28-tetra[(3-aminopropyl)oxy]calix[4]arene 6 and ferrocenecarboxaldehyde via condensation, respectively. Their structures have been characterized by 1H, 13C, APT, COSY NMR, FTIR, HSMR, and UV–vis spectral data. The electrochemical behavior of L1 and L2 has been investigated in the presence of F?, Cl?, Br?, H2PO4?, CH3COO? anions. Electrochemical studies show that these receptors electrochemically recognize CH3COO?, H2PO4?, and Cl?, anions. Using an UV–vis study, the selectivity to these anions in DMSO solution was confirmed. 相似文献
58.
Zeynel Kılıç Aytuğ Okumuş Şemsay Demiriz Selen Bilge Aslı Öztürk Nagihan Çaylak Tuncer Hökelek 《Journal of inclusion phenomena and macrocyclic chemistry》2009,65(3-4):269-286
The condensation reactions of N2O3-donor type coronands (1–3) with hexachlorocyclotriphosphazatriene, N3P3Cl6, resulted in the formation of spiro-crypta phosphazene derivatives (4–6). These compounds with excess morpholine and 1,4-dioxa-8-azaspiro[4,5]decane (DASD) afford fully substituted morpholino (7 and 10) and 1,4-dioxa-8-azaspiro[4,5]deca (8)-substituted phosphazene derivatives, respectively. Whilst, in the same conditions, the reactions of 4, 5 and 6 with pyrrolidine, morpholine and DASD also produce partially pyrrolidino-substituted geminal (9 and 11), mono-substituted pyrrolidino (12), morpholino (13) and 1,4-dioxa-8-azaspiro[4,5]deca (14) phosphazenes. It has been clearly observed that the chloride replacement reactions of 4, 5 and 6 with pyrrolidine lead to the geminal products. Compounds 7, 8 and 10 are the first examples of anisochronic tetrakis (amino) phosphazenes according to 31P NMR data. The structures of 7, 8 and 10–14 have been determined by FTIR, MS, 1H, 13C and 31P NMR, DEPT, and HETCOR spectral data. The solid-state structures of 9, 13 and 14 have been examined by X-ray diffraction techniques. The sums of the bond angles around the spiro cyclic nitrogen atoms [344.8(4)° and 347.6(4)°] of 9, indicate that the nitrogen atoms have pyramidal geometries. Thus, the N atoms seem to have stereogenic configurations. Compounds 12–14 also have two stereogenic P-atoms, and they are expected to be in the mixture of enantiomers. The relationships between NPN (α and α′) bond angles and δPspiro values and the correlation of Δ(P–N) with δPspiro and Δ(δP) values are presented. 相似文献
59.
Bis‐C‐pivot macrocycles containing aminophosphonate functions ( 5–10 ) have been synthesized and characterized by elemental analysis, FTIR, MS, 1D 1H, 13C and 31P NMR, and 2D HETCOR techniques. The phosphorylation reaction of dibenzo‐bis‐imino crown ethers ( 1–4 ) with dimethyl and diethyl phosphite used here has the potential to provide bis‐C‐pivot macrocycles ( 5–10 ), which possess two stereogenic C‐centers giving rise to diastereoisomers (meso and racemic). Detailed spectral assignments for the meso and racemic forms of the compounds are reported on the basis of chemical shifts, signal intensities, spin–spin coupling constants, and splitting patterns. The bis‐C‐pivot macrocycles ( 5–10 ) may serve as a potential new class of supramolecular host molecules. 相似文献
60.
Koray Aydin Zhaofeng Li Serafettin Bilge Ekmel Ozbay 《Photonics and Nanostructures》2008,6(1):116-VII
We report on the transmission properties of the omega (Ω) type metamaterials. Transmission through the periodic Ω-only and Ω-wire metamaterials are studied experimentally and numerically. A resonance band gap is observed for the periodic Ω medium around the resonance frequency of the single Ω unit cell. A transmission band is observed below the resonance band gap, when the periodic Ω structure is embedded in a negative permittivity medium composed of thin metallic wire arrays. We also studied the effect of periodicity on the transmission spectra of Ω type metamaterials. 相似文献