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41.
Ihsan Ullah Rasheed Ahmad Khera Muhammad Nawaz Inam Iqbal Alexander Villinger Peter Langer 《Tetrahedron》2010,66(21):3824-3835
Sterically encumbered biaryls are prepared in two steps by combination of the CuI-proline-catalyzed arylation of acetylacetone with formal [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-dienes. In addition, the synthesis of 4,6- and 5,6-diarylsalicylates based on [3+3] cyclizations is reported. 相似文献
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Anand S Varnavski O Marsden JA Haley MM Schlegel HB Goodson T 《The journal of physical chemistry. A》2006,110(4):1305-1318
The origin of excitations in multi-chromophore carbon network substructures based on dodecadehydrotribenzo[18]annulene has been investigated by steady-state and photon echo spectroscopy, configuration interaction (CIS and CIS(D)), and time-dependent density functional theory (TD-DFT). 1,4-diphenylbutadiyne, the simplest structural subunit within the annulene, was used in modeling the spectroscopic studies to explain the origin of excitations in the macrocycles. The optical excitations in longer linear systems were found to be similar to its diphenylacetylene analogue. However, the results from dodecadehydrotribenzo[18]annulene and other multichromophore networks systems illustrate the possibility of strong intramolecular interactions and the formation of delocalized excited states. Calculations were carried out to explain the basic similarities and differences in excitations of the model compounds such as diphenylbutadiyne and the macrocycles. The fundamental excitation in these systems can be primarily described as a pi --> pi* transition. Two low-energy resonances were observed from experiment for the annulene systems, and possible explanations for these low-energy resonances in the macrocycles are explored. The significant difference found in the calculated oscillator strength of the two low-energy bands for the macrocycles as well as the dynamics of solvent interactions was further investigated by three-pulse photon echo measurements. A simple exciton model was developed to discuss the excitations in the larger macrocycles. The results from this model were found to be in good agreement with the TD-DFT calculations. 相似文献
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Smriti Singh Julia Blöhbaum Martin Möller Andrij Pich 《Journal of polymer science. Part A, Polymer chemistry》2012,50(20):4288-4299
This article reports the synthesis of biohybrid nanogels by crosslinking six‐arm acrylate functionalized star shaped P(EO‐stat‐PO) with the amine groups of various amino acids of a hen egg ovalbumin in W/O emulsion. PEG Poly(ethylene glycol)‐diamines of different molecular weights (368.5 g/mol, 897.1 g/mol, 3000 g/mol, and 6000 g/mol) were used to optimize the crosslinking reactions in aqueous droplets. The increase of molecular weight of the PEG‐diamine led to decrease of the nanogel size due to better stabilization by longer PEG chains. The size of the ovalbumin nanogels was independent of the acrylate‐sP(EO‐stat‐PO):ovalbumin ratio in the reaction mixture. The bicinchoninic acid (BCA) assay proved that the ovalbumin has been effectively crosslinked by reactive prepolymers. From the results of BCA assay, it can also be established that there exists a limiting amount of ovalbumin which can be incorporated into the nanogels. Both Diamine and ovalbumin‐based nanogels exhibit amphoteric behavior and display a positive charge in acidic and a negative charge in basic environment. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
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Navpreet Kaur Himkusha Thakur Smriti Pathak 《International journal of environmental analytical chemistry》2015,95(12):1134-1147
The development of an optical biosensor for the determination of malathion based on acetylcholinesterase (AChE) inhibition using Ellman’s reagent is reported. The AChE has been immobilised onto the eggshell membrane (ESM) using glutaraldehyde as a cross-linking agent. Scanning Electron Microscopic (SEM) studies and Fourier Transformed Infra-Red (FTIR) characterisations have been carried out to affirm the successful immobilisation of AChE onto the ESM. Under optimum conditions, the developed biosensor estimated the pesticide concentration in the range of 0.1–50 ng/mL with a limit of detection (LOD) of 0.1 ng/mL within 30 min. Parameters affecting the biosensor response such as concentration of enzyme, substrate and inhibition time were optimised. The stability and reusability of the AChE/ESM sensor have been observed as 31 days at 4°C and two times, respectively. 相似文献
46.
Smriti Singh Dan Eugen Demco Khosrow Rahimi Radu Fechete Jos Carlos Rodriguez‐Cabello Martin Mller 《Macromolecular rapid communications》2016,37(2):181-186
The investigation of the coacervation (self‐aggregation) behavior of biomicrogels which can potentially be used as drug carriers is an important topic, because self‐aggregation can not only cause loss of activity, but also toxicity and immunogenicity. To study this effect microgels from elastin‐like recombinamer are synthesized using miniemulsion technique. The existence of coacervation for such microgels, at different concentrations and temperatures, is studied and proved by cryo‐field emission scanning clectron microscopy (cryo‐FESEM), cryo‐transmission electron microscopy (cryo‐TEM), and by a novel 1H high‐resolution magic angle sample spinning (HRMAS), nuclear magnetic resonance (NMR) spectroscopy, and relaxometry methods. The findings by 1H HRMAS NMR spectroscopy and relaxometry show simultaneous processes of volume phase temperature transition and coacervation with different sensitivity for hydrophobic and hydrophilic amino acid side‐chains in the microgel. The coacervation process is more evidential by the behavior of glycine α‐CH2, 1H NMR peak as compared to the proline β‐CH2.
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A series of [Cp2TiL]+[RR′NCS2]? complexes, where L is the conjugate base of acetylacetone, benzoylacetone or 8-hydroxyquinoline and R = CH3, R′ = C6H5CH2; R = C2H5, R′ = C6H4CH3; R = H, R′ = C5H9; RR′ = C6H12, have been synthesised in aqueous medium by the reaction of [Cp2TiL]+Cl? with RR′NCS?2Na+. Conductivity measurements in nitrobenzene solution indicate that these complexes are electrolytes. Both the IR and NMR studies demonstrate that the ligand L is chelating in all these complexes. Consequently, tetrahedral coordination about the titanium atom is proposed. In addition to these studies, elemental analyses and magnetic susceptibility have been carried out for these complexes. 相似文献
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Chandra S Raizada S Rani S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,71(2):720-724
Palladium(II) and platinum(II) complexes having the general composition [M(L)] X2 (where M=Pd(II) and Pt(II), L=3,4,12,13-tetraphenyl-2,5,11,14,19,20-hexaaza tricyclo [13.3.1.1.(6-10)] cosa-1(19), 2,4,6,8,10,(20),11,13,15,17-decaene (L1); 3,4,13,14-tetraphenyl-2,5,12,15-tetraaza tricyclo [11,0,0,(6-11)] cosa-1(16),2,4,7,9,6(11),12,14,17, 19-decaene (L2); 2,3,8,9-tetraphenyl-1,4,7,10-tetraaza cyclododeca-1,3,7,9-tetraene (L3) and X=Cl(-)) have been synthesized. The ligands were characterized on the basis of elemental analyses, IR, 1H NMR and EI mass spectral studies while that of the complexes were characterized on the basis of elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, and electronic spectral techniques. All the complexes were found to be diamagnetic. The structures consist of monomeric units in which the Pd(II) and Pt(II) atoms exhibit square planar geometry. 相似文献
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Russian Journal of Organic Chemistry - A series of new triazole ligands has been synthesized via copper-catalyzed cycloaddition reaction of readily available azides and alkynes. The synthesized... 相似文献