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91.
Balaban MC Eichhöfer A Buth G Hauschild R Szmytkowski J Kalt H Balaban TS 《The journal of physical chemistry. B》2008,112(17):5512-5521
The title dicyano compound was synthesized via cyanation and it self-assembles in nonpolar solvents giving red-shifted and broad absorption maxima just as the bacteriochlorophylls which are encountered in the light-harvesting organelles of early photosynthetic bacteria. In the crystal, stacks are formed through a hierarchic combination of pi-stacking and a CN-Zn electrostatic interaction. Push-pull 15-N,N-dialkylamino-5-cyano congeners could be obtained in high yields using a solvent- and catalyst-free direct amination of meso-bromoporphyrins. Importantly, the fluorescence of the self-assembled species due to the very orderly manner in which the chromophores are arranged is not entirely quenched and has a surprisingly long lifetime of over 1 ns. This lends hope of using the trapped energy in biomimetic hybrid solar cells. 相似文献
92.
Laura Mureşan Ruben Ronda Valera Ivo Frébort Ionel Catalin Popescu Elisabeth Csöregi Mihaela Nistor 《Mikrochimica acta》2008,163(3-4):219-225
A selective and sensitive method is presented for biogenic amines (BA) determination. The novelty consists in coupling a highly selective electrochemical biosensor to a weak acid cation-exchange column for online detection of amines. A bienzyme design, based on a recently isolated amine oxidase from grass pea and commercial horseradish peroxidase, was used for the biosensor construction. The enzymes were co-immobilized on the surface of a graphite electrode together with the electrochemical mediator (Os-redox polymer). The electrochemical detection was performed at a low applied potential (?50 mV vs. Ag/AgCl, KCl0.1 M), where biases from interferences are minimal. The separation and determination of six BA, with relevance in food analysis (tyramine, putrescine, cadaverine, histamine, agmatine and spermidine), were investigated. Irrespective of the BA nature, the amine oxidase-based biosensor showed a linear response up to 5 mM, and its sensitivity decreases in the following order: cadaverine, putrescine, spermidine, agmatine, histamine and tyramine. The approach was used to estimate the BA content in fish samples, after their extraction with methanesulfonic acid. 相似文献
93.
Comparative study on different carbon nanotube materials in terms of transparent conductive coatings 总被引:1,自引:0,他引:1
Li Z Kandel HR Dervishi E Saini V Xu Y Biris AR Lupu D Salamo GJ Biris AS 《Langmuir : the ACS journal of surfaces and colloids》2008,24(6):2655-2662
We compared conductive transparent carbon nanotube coatings on glass substrates made of differently produced single-wall (SWNT), double-wall, and multiwall carbon nanotubes. The airbrushing approach and the vacuum filtration method were utilized for the fabrication of carbon nanotube films. The optoelectronic performance of the carbon nanotube film was found to strongly depend on many effects including the ratio of metallic-to-semiconducting tubes, dispersion, length, diameter, chirality, wall number, structural defects, and the properties of substrates. The electronic transportability and optical properties of the SWNT network can be significantly altered by chemical doping with thionyl chloride. Hall effect measurements revealed that all of these thin carbon nanotube films are of p-type probably due to the acid reflux-based purification and atmospheric impurities. The competition between variable-range hoping and fluctuation-assisted tunneling in the functionized carbon nanotube system could lead to a crossover behavior in the temperature dependence of the network resistance. 相似文献
94.
95.
Caprioara M Fiammengo R Engeser M Jäschke A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(7):2089-2095
In order to expand the repertoire of DNA sequences specifically interacting with transition metals, we report here the first examples of DNA sequences carrying mono- and bidentate phosphane ligands as well as P,N-ligands. Aminoalkyl-modified oligonucleotides have been reacted at predetermined internal sites with carboxylate derivatives of pyrphos, BINAP and phosphinooxazoline (PHOX) 2 b-d. Carbodiimide coupling in the presence of N-hydroxysuccinimide provided the DNA-ligand conjugates in 38-78 % yield. Phosphane-containing oligonucleotides and their phosphane sulfide analogues were characterized by mass spectrometry (MALDI-TOF and FT-ICR-ESI) and their stability after purification and isolation was systematically investigated. While DNA-appended pyrphos ligand was quickly oxidized, BINAP and PHOX conjugates showed high stabilities, making them useful precursors for incorporation of transition metals into DNA. 相似文献
96.
97.
Linda Leme Mihaela Gulea Monique Saquet Serge Masson Noël Collignon 《Heteroatom Chemistry》1999,10(4):281-289
New variously substituted 1‐dimethylamino or 1‐methylthio but‐3‐enylidene‐bis‐phosphonates have been prepared from readily availableα‐dimethylamino or α‐methylthio methylene‐bis‐phosphonates by postulated [2,3]‐Wittig rearrangements of the corresponding N‐ or S‐allylic intermediate ylides. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 281–289, 1999 相似文献
98.
Theodora-Venera Apostol Luminita Gabriela Marutescu Constantin Draghici Laura-Ileana Socea Octavian Tudorel Olaru George Mihai Nitulescu Elena Mihaela Pahontu Gabriel Saramet Cristian Enache-Preoteasa Stefania-Felicia Barbuceanu 《Molecules (Basel, Switzerland)》2021,26(16)
In order to develop novel bioactive substances with potent activities, some new valine-derived compounds incorporating a 4-(phenylsulfonyl)phenyl fragment, namely, acyclic precursors from N-acyl-α-amino acids and N-acyl-α-amino ketones classes, and heterocycles from the large family of 1,3-oxazole-based compounds, were synthesized. The structures of the new compounds were established using elemental analysis and spectral (UV-Vis, FT-IR, MS, NMR) data, and their purity was checked by reversed-phase HPLC. The newly synthesized compounds were evaluated for their antimicrobial and antibiofilm activities, for toxicity on D. magna, and by in silico studies regarding their potential mechanism of action and toxicity. The 2-aza-3-isopropyl-1-[4-(phenylsulfonyl)phenyl]-1,4-butanedione 4b bearing a p-tolyl group in 4-position exhibited the best antibacterial activity against the planktonic growth of both Gram-positive and Gram-negative strains, while the N-acyl-α-amino acid 2 and 1,3-oxazol-5(4H)-one 3 inhibited the Enterococcus faecium biofilms. Despite not all newly synthesized compounds showing significant biological activity, the general scaffold allows several future optimizations for obtaining better novel antimicrobial agents by the introduction of various substituents on the phenyl moiety at position 5 of the 1,3-oxazole nucleus. 相似文献
99.
Nicoleta Mihaela Sulca Adriana Lungu Sorina Alexandra Garea Horia Iovu 《Journal of Raman spectroscopy : JRS》2009,40(11):1634-1640
The kinetic behavior of the urethane dimethacrylate (UDMA) copolymerized and reinforced by different concentrations of polyhedral oligomeric silsesquioxane (POSS) with methacrylic groups was studied through Raman spectroscopy. UDMA‐POSS networks have been synthesized with three different types of POSS, two monofunctional POSS (1‐propylmethacrylate)‐heptaisobutyl substituted (HISO‐POSS) and heptacyclopentyl‐octasiloxan‐1‐yloxy) dimethylsilyl] propyl methacrylate (CPENTYL‐POSS) and one octafunctional POSS‐methacryl substituted (MA‐POSS). In order to show the influence of POSS on the final conversion, the hybrid systems were cured using three types of initiators which decompose at different temperatures: azobisisobutyronitrile (AIBN) (65 °C), benzoyl peroxide (BP) (80 °C) and di‐tert‐butyl peroxide (DTBP) (120 °C). The structure of the hybrid's surface was investigated by X‐ray photoelectron spectroscopy (XPS) and the Tg values were calculated from dynamic mechanical analysis (DMA) tests. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
100.
Mihaela Badea Rodica Olar Dana Marinescu Valentina Uivarosi Daniela Iacob 《Journal of Thermal Analysis and Calorimetry》2009,97(2):735-739
A series of new complexes with mixed ligands of the type RuL2(DMSO)
m
Cl3·nH2O ((1) L: norfloxacin (nf), m = 1, n = 1; (2) L: ciprofloxacin (cp), m = 2, n = 2; (3) L: ofloxacin (of), m = 1, n = 1; (4) L: enrofloxacin (enro), m = 0.5, n = 4; DMSO: dimethylsulfoxide) were synthesised and characterised by chemical analysis and IR data. In all complexes both
fluoroquinolone derivative and DMSO act as unidentate. The thermal behaviour steps were investigated in synthetic air flow.
The thermal transformations are complex processes according to TG and DTG curves including dehydration, quinolone derivative
and DMSO degradation respectively. The final product of decomposition is ruthenium (IV) oxide. 相似文献