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121.
Vijayakumar EK Roy K Chatterjee S Deshmukh SK Ganguli BN Fehlhaber HW Kogler H 《The Journal of organic chemistry》1996,61(19):6591-6593
Arthrichitin (1), C(33)H(46)N(4)O(9), is a new cell wall active depsipeptide isolated from the fermentation broth of Arthrinium phaeospermum (HIL Y-903022). Its structure was elucidated on the basis of spectroscopic and chemical degradation studies. Arthrichitin consists of serine, beta-keto tryptophan, glutamic acid, and 2,4-dimethyl-3-hydroxydodecanoic acid units. 相似文献
122.
Chatterjee M. Naskar M.K. Ganguli D. 《Journal of Sol-Gel Science and Technology》1999,16(1-2):143-149
Shaped tetragonal barium titanate (BaTiO3) particles were prepared by the sol-emulsion-gel method with systematic variation of the concentration of a non-ionic surfactant in the organic phase (oil phase) of water-in-oil (w/o) emulsions above or below the critical micelle concentration (CMC). An acetate-based sol with equivalent oxide ratio BaO : TiO2 = 1 : 1 was selected for the study. Micelle formation of the surfactant and their self-aggregation apparently played an important role in controlling the shape and size of the droplets and accordingly shape and size of the final barium titanate particles resulting therefrom. Transmission electron microscopy (TEM) revealed that with low concentration of the surfactant (2–5 vol%) ill-formed spheres were obtained. Spherical particles were formed with increasing the surfactant concentration to 7 vol%. At 12 vol% of the surfactant, rod-like particles were first found to form, which with further increase in surfactant concentration to 15–20 vol%, gradually transformed to cube-like/lamellar type particles. Attempts have been made to explain the various particle shapes in terms of surfactant aggregation. 相似文献
123.
Mukhopadhyay S Mandal D Chatterjee PB Desplanches C Sutter JP Butcher RJ Chaudhury M 《Inorganic chemistry》2004,43(26):8501-8509
Copper(II) complexes (1-3) of a sterically constrained phenol-based tetradentate N(2)O(2) ligand 1,4-bis(2-hydroxy-3,5-dimethylbenzyl)piperazine (H(2)L) have been reported. The associated anions of the copper(II) ion precursors have profound influence on the stoichiometry of the products. Thus, with perchlorate ion, the product is a binuclear compound [Cu(2)L(2)] (1), while with coordinating anions viz. Cl(-) and N(3)(-), the products [Cu(3)L(2)Cl(2)(H(2)O)].1/2H(2)L (2) and [Cu(3)L(2)(N(3))(2)(CH(3)OH)].4H(2)O (3) have triangulo trinuclear composition. The syntheses, X-ray structures, and spectroscopic and magnetic properties of these complexes are described. Compound 1 has a noncentrosymmetric structure with a rectangular Cu(2)(OPh)(2) core. It appears to be a rare example of a phenolato-bridged Cu(II) dimer exhibiting ferromagnetic interactions (J = 0.93 cm(-)(1)), a behavior in agreement with the theoretical predictions but seldom observed experimentally. In compounds 2 and 3, the copper centers are triangularly disposed, and the molecules have a shape much like that of a butterfly. The terminal copper centers Cu(1) and Cu(2) in 2 and 3 have distorted square pyramidal geometry, connected to each other by a bridging chloro- (in 2) or azido ligand (in 3) in "end to end" fashion. The central copper center (Cu(3) in 2 and Cu in 3) in both the compounds has distorted square planar geometry. The separations between the metal centers, viz. Cu(1)...Cu(2), Cu(2)...Cu(3), and Cu(3)...Cu(1), are 4.826, 3.214, and 3.244 A, respectively, in 2. The corresponding distances in 3 are 5.590, 3.178, and 3.485 A, respectively. The overall magnetic behaviors in 2 and 3 are consistent with antiferromagnetic interactions between the spin centers. In 3, the exchange couplings between the terminal and central copper centers J(Cu(1))(-)(Cu) and J(Cu(2))(-)(Cu) appear to be equal (-234 cm(-)(1)), resulting in an S = (1)/(2) ground state at temperatures near or below 77 K. 相似文献
124.
Complex formation between cationically modified gold nanoparticles and DNA: an atomic force microscopic study 总被引:1,自引:0,他引:1
Ganguli M Babu JV Maiti S 《Langmuir : the ACS journal of surfaces and colloids》2004,20(13):5165-5170
Atomic force microscopy has been used for direct visualization of the wrapping of DNA around 30-nm-sized functionalized gold nanoparticles for the first time. The morphology of the complexes seems to be dictated by the relative concentration of the nanoparticles and DNA. A higher concentration of the former leads to the formation of a network of nanoparticles assembled on DNA. This assembly pattern seems to be significantly different from the manner in which cationically modified gold nanoparticles of smaller size (< 5 nm) arrange linearly on DNA, as shown in the literature. A DNA-gold nanoparticle can be developed as a model system for in vitro studies on the mechanism of DNA condensation and also for developing novel methods of nanoparticle self-assembly on the DNA template. 相似文献
125.
In the framework of fusion process, ≈90% of which isg+g→c+ c, we have calculated rapidity correlation andp T /2 of charm particles produced in hadronic collisions. The experimental observation of rapidity correlation by the LEBC-EHS Collaboration is in good agreement with the calculation. From the ratio of double to single charm production an estimate of fusion cross section is made. 相似文献
126.
Suman Mehrotra Jayanti P. Barthwal Bhagwan R. Pandey Krishna P. Bhargava Surendra S. Parmar 《Journal of heterocyclic chemistry》1980,17(6):1213-1214
Several 2-aryl substituted thiosemicarbazido-4-methyl-6-methoxyquinolines and 2-aryl substituted semi-carbazido 4-methyl-6-methoxyquinolines were synthesized and evaluated for their antimalarial activity in mice infected with Plasmodium berghei. Two of these substituted quinolines were found to exhibit 50% clearance in a dose of 500 mg./kg. administered intraperitoneally for 5 days. 相似文献
127.
1. RF values of 12 amino acids were determined in phenol-water and benzyl alcohol-acetic acid-water using unidimensional and circular techniques of paper chromatography. 2. It has been observed that the square of circular RF values (considering frontal boundary of solute) equals the linear RF values, and this relation is valid for the amino acids as well as the sugars studied. 3. The relation is found to be independent of the distance traversed by the solvent in the case of both amino acids and sugars. 4. A theoretical support has been given to the experimental observations. 相似文献
128.
Reacting Re(CO)5Cl with the azopyridine ligand (1) (L) in boiling benzene afford the complex Re(CO)3Cl(L), (2) in excellent yield [L=2-(p-Cl-C6H4NN)C5H4N]. The chelation of the azopyridine ligand accompanied by displacement of the two carbon monoxide ligands furnish a five-membered chelate ring. Structure determination of complex (2) has revealed a distorted octahedral ReC3N2Cl coordination sphere. The Re–N(pyridine) and, Re–N(azo) distances are 2.158(3) and 2.153(6) Å respectively, and the N–N length [1.273(4) Å], implicate relatively weak Re-azo(π*) back–bonding. The Re(CO)3Cl(L) lattice consists of C–H...Cl hydrogen bonding and Cl...O non-bonded interactions constituting a supramolecular network. Extended Hückel calculations reveal that the LUMO of Re(CO)3Cl(L) is Ca. 57% azo in character. One-electron quasireversible electrochemical reduction of the complex occurs near −0.3 V versus Saturated Calomel electrode(s.c.e.) The redox orbital is believed to belong to the above noted LUMO. Electrogenerated Re(CO)3Cl(L•–) underwent spontaneous solvolytic chloride displacement in MeCN, resulting in the isolation of Re(CO)3(MeCN)(L•–). The latter complex in turn reacted with imidazole and triphenylphosphine, furnishing Re(CO)3(C3H4N2)(L•–) and Re(CO)3(PPh3)(L•–), respectively. The pattern of carbonyl stretching frequencies of these radical anion complexes is similar to that of Re(CO)3Cl(L) but with shifts to lower frequencies by 10–20 cm−1. All three radical anion systems are one-electron paramagnetic (1.7–1.8 μB). The unpaired electron is primarily localized on the azoheterocycle ligand in a predominantly azo-π* orbital, but a small metal contribution (185, 187Re, I=5/2) is also present. Thus Re(CO)3(MeCN)(L•–) and Re(CO)3(C3H4N2)(L•–) display six-line e.p.r. spectra (A ˜ 28 G). The line shapes and intensities are characteristic of the presence of g-strain. In the case of Re(CO)3(PPh3)(L•–) seven nearly equispaced lines are observed due to virtually equal coupling between the metal and 31P (I=&frac;) nuclei. The g-values of the radical species are slightly higher than the free-electron value of 2.0023. 相似文献
129.
M. Chatterjee M.K. Naskar P.K. Chakrabarty D. Ganguli 《Journal of Sol-Gel Science and Technology》2002,25(2):169-174
Fine grained, microcrystalline mullite (Al4+2x
Si2–2x
O10–x) fibre mats with a web-like structure were fabricated by a sol-gel spinning technique using a multi-orifice spinneret. Points of contact in gel fibre mats helped in the formation of a web-like fibrous body having reasonable strength and very little dust formation after calcination. Strong and resilient fibres with diameters in the range 3–12 m were obtained by a single-step sol-gel method from spinnable sols devoid of organics as the binder aid. Crystallization of -alumina and mullite at about 900°C and 1250°C, respectively was confirmed by differential thermal analysis (DTA) and X-ray diffraction (XRD). Thermogravimetry (TG) indicated the removal of most of the volatiles at about 500°C accompanied by a weight loss of about 48%. Scanning electron microscopy (SEM) shows the presence of small grains (80–150 nm in size) in the fibres calcined at 1250°C. Fourier transformed infrared spectroscopy (FTIR) indicated the sequence of transformations taking place during heat-treatment of gel fibres at different temperatures. The individual fibres in the mats calcined at 1250°C exhibited a tensile strength of 1300–1600 MPa. 相似文献
130.
M. Asai T. Aziz J. F. Bailly J. F. Baland S. Banerjee W. Bartl A. Batunin C. Caso F. Diez-Medo B. Epp A. Ferrando F. Fontanelli S. N. Ganguli V. G. Gavrjusev T. Gemesy P. Girtler A. Gurtu R. Hamatsu P. Herquet J. Hrubec Y. Iga V. Khalatyan E. Kistenev J. M. Kohli J. Mac Naughton J. C. Marin M. Markytan L. Montanet G. Neuhofer G. Pinter P. Porth R. Raghavan T. Rodrigo J. M. Salicio J. B. Singh S. Squarcia K. Takahashi L. A. Tikhonova U. Trevisan T. Tsurugai V. Yarba G. Zholobov S. Zotkin EHS-RCBC Collaboration 《Zeitschrift fur Physik C Particles and Fields》1987,34(4):429-435
Production properties and correlations forK s 0 K s 0 ,K s 0 Λ,K s 0 ¯Λ and Λ¯Λ systems in 360 GeV/cpp interactions are presented. All rapidity gap distributions are observed to peak at Δy=0 and the azimuthal angular distributions between the two particles are consistent with being flat. Experimental results are compared with the quark fusion and Lund models of particle production. 相似文献