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121.
We report efficient bulk heterojunction solar cells fabricated by inserting a discotic triphenylene derivative into poly (3-hexylthiophene): [6, 6]- phenyl-C61-butyric acid methyl ester. A layer of molybdenum oxide was inserted between anode and active layer. Power conversion efficiency of 2.0% was achieved for these photovoltaic solar cells containing self-organised discotic liquid crystals in the active layer under one sun condition. The influence of varying the thickness of liquid crystal layer and annealing on these solar cells was also studied. Post annealing the bulk heterojunction devices with discotic liquid crystal layer of thickness 20 nm in them yielded an open circuit voltage of 0.41 V, short circuit current density of 17.0 mA cm?2, a Fill factor of 0.35 and power conversion efficiency of 2.5%. 相似文献
122.
A new class of glycolipids were generated by the incorporation of lipid entities at the C-6 position of D-glucose through oxidation of the primary hydroxyl group of tetrabenzylated D-glucose to form corresponding aldehyde, which in turn was subjected to Grignard reaction with C8 and C16 alkyl magnesium halides. The resulting lipidated secondary alcohol was further subjected to esterification with long-chain carboxylic acids to afford novel glycolipids. All of the derivatives 4a–b, 6a–d, and 8a–b exhibited low cytotoxicity and induced strong T and B cell proliferation and IL-2, IL-4, and IFN-γ expression from stimulated splenocyte culture, signifying their potent immunostimulating activity. 相似文献
123.
124.
Sandeep Kumar Savit Andotra Mandeep Kaur Vivek K. Gupta Rajni Kant Sushil K. Pandey 《Crystallography Reports》2016,61(5):810-814
Complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine [{(2,4- (CH3)2C6H3O)2PS2}2Fe{NC5H4(C2H5)-4}2] is synthesized and characterized by elemental analysis, magnetic moment, IR spectroscopy and single crystal X-ray analysis. Complex crystallizes in the monoclinic sp. gr. P21/n, Z = 2. Crystal structure consists of mononuclear units with Fe(II) ion chelated by four S atoms of the two diphenyldithiophosphate ligands in bidentate manner. N atoms from two 4-ethylpyridine ligands are axially coordinated to the Fe(II) atom leading to an octahedral geometry. 相似文献
125.
A glycine-rich, short pentapeptide conjugate 6, derived from the highly conserved copper-binding octarepeat region of the prion protein, exhibits a tendency to self-aggregate in a time-dependent fashion. Aging of 6 afforded an insight into the phased growth of spherical prefibrillar structures to fibers of long persistence length, as observed by a combination of microscopic techniques. Interestingly, growth of these fibers was inhibited by colchicine, a known inhibitor of microtubule polymerization in a concentration dependent fashion. This study offers an intriguing insight into the occurrence of prefibrillar intermediates on the path to the formation of full length peptide fibers. It is also envisaged that constructs such as 6 may also serve as simple models to study chemical intervention of protein aggregation. 相似文献
126.
Foster SL Handa S Krafft M Rowling D 《Chemical communications (Cambridge, England)》2007,(45):4791-4793
The first reported intramolecular pinacol coupling of cyclopropyl ketones has been achieved, demonstrating that cyclisation competes favourably with ring-opening of the cyclopropyl ketyl radical. 相似文献
127.
Sankar J Rath H Prabhuraja V Gokulnath S Chandrashekar TK Purohit CS Verma S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(1):105-114
The synthesis and characterization of the first examples of core-modified corrole dimers linked through the meso positions are described. The dimers are obtained by a simple Ag(I)- or Fe(III)-catalyzed coupling reaction in near-quantitative yields. The corroles obtained are metalated with metal ions, such as Cu(II) and Ni(II). The electronic-absorption spectral studies reveal weak electronic interaction between the two subunits and the exciton coupling observed for the free-base corrole dimer (1717 cm(-1)) is lower than that for the corresponding protonated derivative (4081 cm(-1)). The solution-state structure derived from (1)H and two-dimensional NMR spectral studies reveals a noncoplanar arrangement of two corrole units. Geometry optimization at the B3LYP-631G level also confirms the noncoplanar arrangement of corroles with a dihedral angle of 64.8 degrees between two corrole planes. The electron paramagnetic resonance (EPR) and magnetic characterization studies on the paramagnetic copper-metalated dimer indicate that both copper ions behave as independent spins without any noticeable interaction. Results of fluorescence studies reveal a bathochromic shift of about 60 nm upon dimerization. The first hyperpolarizability (beta) measured by using the hyper Rayleigh scattering (HRS) method reveals doubling of the beta values on progressing from monomer to dimer, attributed to enhanced pi conjugation. The use of copper dimers in the photocleavage of DNA is also explored. It is shown that the bimetallic copper dimer selectively cleaves the nucleic acids without affecting the proteins, suggesting a possible application of the copper complex in the removal of nucleic acid contaminants from protein extracts through a simple photolytic pathway. 相似文献
128.
Koley M Sarkar B Ghumaan S Bulak E Fiedler J Kaim W Lahiri GK 《Inorganic chemistry》2007,46(9):3736-3742
The complex dication of the diruthenium(II) compound {(mu-tppz)[Ru(bik)Cl]2}(ClO4)2 can be oxidized and reduced in two one-electron steps each. In CH3CN/0.1 M Bu4NPF6, the odd-electron intermediates{(mu-tppz)[Ru(bik)Cl]2}n+, n=1 and 3, have comproportionation constants of 7x10(8) and 1x10(5), respectively. Both exhibit near-infrared absorptions, in the case of n=3 the 1640 nm band (epsilon=1200 M-1 cm-1, Deltanu1/2=1560 cm-1) is attributed to an intervalence charge-transfer transition. While the mixed-valent intermediate (n=3) is EPR silent even at 4 K, the n=1 form shows g(parallel) 2.005 and g( perpendicular) 1.994 at that temperature, signifying a diruthenium(II) complex of the tppz*- radical anion. The variation of energy and intensity of nuCO and of the ring vibration band around 1590 cm-1 has been monitored not only for {(mu-tppz)[Ru(bik)Cl]2}n+, n=0-4, but also for the mononuclear {(tppz)Ru(bik)Cl}n+, n=0-2. In the dinuclear complex the carbonyl stretching bands of the spectator ligand bik are shifted by about 15 cm-1 on each one-electron-transfer step, increasing with the positive charge. The mixed-valent {(mu-tppz)[Ru(bik)Cl]2}3+ shows a perceptibly broader nuCO band, suggesting incomplete valence averaging (partial localization). 相似文献
129.
Kumar PS Pal SK Kumar S Lakshminarayanan V 《Langmuir : the ACS journal of surfaces and colloids》2007,23(6):3445-3449
A new method of forming stable dispersions of alkanethiol and aromatic thiol stabilized gold nanoparticles in two different lyotropic liquid crystalline mediums, namely, a columnar hexagonal phase made up of a Triton X-100/water system and an inverse columnar hexagonal phase made up of pure AOT, are presented. The dispersions have been characterized using small-angle X-ray scattering (SAXS) and polarizing optical microscopy. Our studies show that the gold nanoparticles are distributed outside the columns formed by both the surfactants. Such dispersions can find applications in the study of nanoparticles as well as in the development of devices based on some unique properties of metal nanoparticles. 相似文献
130.
Kumar S Davis TM Ramanan H Penn RL Tsapatsis M 《The journal of physical chemistry. B》2007,111(13):3398-3403
Precursor silica nanoparticles can evolve to silicalite-1 crystals under hydrothermal conditions in the presence of tetrapropylammonium (TPA) cations. It has been proposed that in relatively dilute sols of silica, TPA, water, and ethanol, silicalite-1 growth is preceded by precursor nanoparticle evolution and then occurs by oriented aggregation. Here, we present a study of silicalite-1 crystallization in more concentrated mixtures and propose that growth follows a path similar to that taken in the dilute system. Small-angle X-ray scattering (SAXS), cryogenic transmission electron microscopy (cryo-TEM), and high-resolution transmission electron microscopy (HRTEM) were used to measure nanoparticle size and to monitor zeolite nucleation and early-stage crystal development. The precursor silica nanoparticles, present in the clear sols prior to crystal formation, were characterized using two SAXS instruments, and the influence of interparticle interactions is discussed. In addition, SAXS was used to detect the onset of secondary particle formation, and HRTEM was used to characterize their structure and morphology. Cryo-TEM allowed for in situ visual observation of the nanoparticle population. Combined results are consistent with growth by aggregation of silica nanoparticles and of the larger secondary crystallites. Finally, a unique intergrowth structure that was formed during the more advanced growth stages is reported, lending additional support for the proposal of aggregative growth. 相似文献