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1.
Sridevi V. Shinde Sarika Sinha Prof. Dr. Kumaravel Somasundaram Prof. Dr. Ashoka G. Samuelson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(39):12278-12291
Neutral half‐sandwich organometallic ruthenium(II) complexes of the type [(η6‐cymene)RuCl2(L)] ( H1 – H10 ), where L represents a heterocyclic ligand, have been synthesized and characterized spectroscopically. The structures of five complexes were also established by single‐crystal X‐ray diffraction confirming a piano‐stool geometry with η6 coordination of the arene ligand. Hydrogen bonding between the N? H group of the heterocycle and a chlorine atom attached to Ru stabilizes the metal–ligand interaction. Complexes coordinated to a mercaptobenzothiazole framework ( H1 ) or mercaptobenzoxazole ( H6 ) showed high cytotoxicity against several cancer cells but not against normal cells. In vitro studies have shown that the inhibition of cancer cell growth involves primarily G1‐phase arrest as well as the generation of reactive oxygen species (ROS). The complexes are found to bind DNA in a non‐intercalative fashion and cause unwinding of plasmid DNA in a cell‐free medium. Surprisingly, the cytotoxic complexes H1 and H6 differ in their interaction with DNA, as observed by biophysical studies, they either cause a biphasic melting of the DNA or the inhibition of topoisomerase IIα activity, respectively. Substitution of the aromatic ring of the heterocycle or adding a second hydrogen‐bond donor on the heterocycle reduces the cytotoxicity. 相似文献
2.
Sarika Goyal 《Mathematische Nachrichten》2019,292(10):2189-2202
In this article, we study the eigenvalues of p‐fractional Hardy operator where , , , and Ω is an unbounded domain in with Lipschitz boundary containing 0. The weight function V may change sign and may have singular points. We also show that the least positive eigenvalue is simple and it is uniquely associated to a nonnegative eigenfunction. Moreover, we proved that there exists a sequence of eigenvalues as . 相似文献
3.
A simple wet chemical method is used to prepare zinc oxide nanoflowers (ZnO NFs) which were subjected to various characterization techniques such as XRD, FTIR, UV–Vis, FE-SEM, and XPS. XRD pattern indicates pure, crystalline, and monodispersed form with hexagonal wurtzite phase. The 3-D flower shape morphology with hexagonal ZnO nanorods was confirmed in FE-SEM. The synthesized ZnO NFs was used to study catalytic behavior in Kabachnik–Fields reaction under controlled ultrasound cavitation technique. High surface-to-volume ratio of ZnO NFs and the effect of ultrasonication enhances the yield of α-aminophosphonate. The catalyst was recycled and reused four times without any significant loss of its catalytic activity. Moreover, existing method becomes attractive and practical due to its easy, clean, fast, cost-effective, and eco-friendly procedure. 相似文献
4.
Rajendiran V Murali M Suresh E Sinha S Somasundaram K Palaniandavar M 《Dalton transactions (Cambridge, England : 2003)》2008,(1):148-163
A series of mixed ligand ruthenium(II) complexes [Ru(pdto)(diimine)](ClO4)2/(PF6)2 1-3 and [Ru(bbdo)(diimine)](ClO4), 4-6, where pdto is 1,8-bis(pyrid-2-yl)-3,6-dithiooctane, bbdo is 1,8-bis(benzimidazol-2-yl)-3,6-dithiooctane and diimine is 1,10-phenanthroline (phen), dipyrido-[3,2-d:2',3'-f]-quinoxaline (dpq) and dipyrido[3,2-a:2',3'-c]phenazine (dppz), have been isolated and characterised by analytical and spectral methods. The complexes [Ru(pdto)(phen)](PF6)2 la, [Ru(pdto)(dpq)(Cl](PF6) 2a, [Ru(bbdo)(phen)](PF6)2 4a and [Ru(bbdo)(dpq)](ClO4)2 5 have been structurally characterized and their coordination geometries around ruthenium(II) are described as distorted octahedral. In la, 4a and 5 the two thioether sulfur and two py/bzim nitrogen atoms of the tetradentate pdto/bbdo ligand are folded around Ru(II) to give predominantly a "cis-alpha" configuration. (I)H NMR spectral data of the complexes support this configuration in solution. In [Ru(pdto)(dpq)Cl](PF6) 2a with a distorted octahedral coordination geometry, one of the two py nitrogens of pdto is not coordinated. The DNA binding constants (Kb: 2, 2.00 +/- 0.02 x 10(4) M(-1), s = 1.0; 3, 3.00 +/- 0.01 x 10(6) M(-1), s = 1.3) determined by absorption spectral titrations of the complexes with CT DNA reveal that 3 interacts with DNA more tightly than 2 through partial intercalation of the extended planar ring of coordinated dppz with the DNA base stack. The DNA binding affinities of the complexes increase with increase in the number of planar aromatic rings in the co-ligand, and on replacing both the py moieties in pdto complexes (1-3) by bzim moieties to give bbdo complexes (4-6). Upon interaction with CT DNA the complexes 1, 2, 5 and 6 show a decrease in anodic current in the cyclic voltammograms. On the other hand, interestingly, 3 and 4 show an increase in anodic current suggesting their involvement in electrocatalytic guanine oxidation. Interestingly, of all the complexes, only 6 alters the superhelicity of DNA upon binding with supercoiled pBR322 DNA. The cytotoxicities of the dppz complexes 3 and 6, which avidly bind to DNA, have been examined by screening them against cell lines of different cancer origins. It is noteworthy that 6 exhibits selectivity with higher cytotoxicity against the melanoma cancer cell line (A375) than other cell lines, potency approximately twice that of cisplatin and toxicity to normal cells 3 and 90 times less than cisplatin and adriamycin respectively. 相似文献
5.
Elim HI Jeon SH Verma S Ji W Tan LS Urbas A Chiang LY 《The journal of physical chemistry. B》2008,112(32):9561-9564
Highly enhanced nonlinear absorption cross section values of C60(>DPAF-C2M), C60(>DPAF-C9), and C60(>DPAF-C10) dyads were detected up to 5400, 9700, and 14000 GM, respectively, in the 2.0 ps region in toluene at the concentration of 1.5 x 10(-3) M. They were correlated to a trend showing higher efficiency in light transmittance attenuation down to 39-46% for the dyads C60(>DPAF-C10) and C60(>DPAF-C9) with the increase of irradiance intensity up only to 140 GW/cm(2). The phenomena were attributed to additional enhancement on the excited-state absorption of (1)C60*(>DPAF-Cn ) in the subpicosecond to picosecond region over the two-photon absorption of C60(>DPAF-Cn ) in the femtosecond region. Its accumulative 2.0 ps absorption cross sections were estimated to be 8900 GM for (1)C60*(>DPAF-C9), roughly one order of magnitude higher than its intrinsic femtosecond 2PA cross sections. 相似文献
6.
We show how a simple scheme of symbolic dynamics distinguishes a chaotic from a random time series and how it can be used to detect structural relationships in coupled dynamics. This is relevant for the question at which scale in complex dynamics regularities and patterns emerge. © 2009 Wiley Periodicals, Inc. Complexity 2009 相似文献
7.
The present study describes the potential of the synchrotron radiation based X-ray fluorescence spectroscopy technique for the rapid, sensitive, user friendly and simultaneous monitoring of the changes in the elemental profile of the wheat seedlings stressed by excess manganese (Mn). For this, X-ray fluorescence spectra of the leaves of the control and Mn treated wheat seedlings have been recorded by synchrotron radiation X-ray of energy 15?keV. The analyses of the recorded spectra show the presence of elements chlorine, potassium, calcium, manganese, iron, copper, nickel, and zinc. A calibration-free approach, PyMca has been used for the quantitative estimation of the detected elements in the leaves of the control and Mn treated wheat seedlings. The excess supply of Mn to wheat seedlings results in the accumulation of manganese in the leaves of the seedlings. The accumulation of manganese in wheat seedlings negatively affects the uptake and translocation of calcium, potassium, and iron while it has stimulating effect on the uptake of copper and zinc. 相似文献
8.
We review some recent work on the synchronization of coupled dynamical systems on a variety of networks. When nodes show synchronized
behaviour, two interesting phenomena can be observed. First, there are some nodes of the floating type that show intermittent
behaviour between getting attached to some clusters and evolving independently. Secondly, two different ways of cluster formation
can be identified, namely self-organized clusters which have mostly intra-cluster couplings and driven clusters which have
mostly inter-cluster couplings. 相似文献
9.
Srivastava S Chandran S Kandar AK Sarika CK Basu JK Narayanan S Sandy A 《The Journal of chemical physics》2010,133(15):151105
We present the results on the evolution of microscopic dynamics of hybrid nanoparticles and their binary mixtures as a function of temperature and wave vector. We find unexpectedly a nonmonotonic dependence of the structural relaxation time of the nanoparticles as a function of the morphology. In binary mixtures of two of the largest nanoparticles studied, we observe re-entrant vitrification as a function of the volume fraction of the smaller nanoparticle, which is unusual for such high diameter ratio. Possible explanation for the observed behavior is provided. 相似文献
10.
El-Khouly ME Padmawar P Araki Y Verma S Chiang LY Ito O 《The journal of physical chemistry. A》2006,110(3):884-891
Photoinduced intramolecular processes in a tricomponent molecule C60(>(CN)2-DPAF), consisting of an electron-accepting methano[60]fullerene moiety (C60>) covalently bound to an electron-donating diphenylaminofluorene (DPAF) unit via a bridging dicyanoethylenyl group [(CN)2], were investigated in comparison with (CN)2-DPAF. On the basis of the molecular orbital calculations, the lowest charge-separated state of C60(>(CN)2-DPAF) is suggested to be C60*-(>(CN)2-DPAF*+) with the negative charge localized on the fullerene cage, while the upper state is C60(>(CN)2*--DPAF*+). The excited-state events of C60(>(CN)2-DPAF) were monitored by both time-resolved emission and nanosecond transient absorption techniques. In both nonpolar and polar solvents, the excited charge-transfer state decayed mainly through initial energy-transfer process to the C60 moiety yielding the corresponding 1C60, from which charge separation took place leading to the formation of C60*-(>(CN)2-DPAF*+) in a fast rate and high efficiency. In addition, multistep charge separation from C60(>(CN)2*--DPAF*+) to C60*-(>(CN)2-DPAF*+) may be possible with the excitation of charge-transfer band. The lifetimes of C60*-(>(CN)2-DPAF*+) are longer than the previously reported methano[60]fullerene-diphenylaminofluorene C60(>(C=O)-DPAF) with the C60 and DPAF moieties linked by a methanoketo group. These findings suggest an important role of dicyanoethylenyl group as an electron mediating bridge in C60(>(CN)2-DPAF). 相似文献