72720-17-3Relevant academic research and scientific papers
Discovery and characterization of catalysts for azide-alkyne cycloaddition by fluorescence quenching
Lewis, Warren G.,Magallon, Fernando G.,Fokin, Valery V.,Finn
, p. 9152 - 9153 (2004)
Copper-based catalysts for the 1,3-dipolar cycloaddition of azides and alkynes were screened in parallel fashion using a fluorescence quenching assay. The method was designed to identify systems able to accelerate the coupling of reactants at micromolar concentrations in aqueous mixtures and to obtain quantitative comparisons of their activities. In addition to the tris(triazolylamines) previously reported, two types of compounds (bipy/phen and 2-pyridyl Schiff bases) were found to exhibit significant ligand-accelerated catalysis, with one complex showing especially dramatic rate enhancements. Preliminary explorations of the dependence of reaction rate on pH, ligand:Cu ratio, and Cu concentration are described. Copyright
Molecular orientation and angular distribution probed by angle-resolved absorbance and second harmonic generation
Simpson, Garth J.,Westerbuhr, Sarah G.,Rowlen, Kathy L.
, p. 887 - 898 (2000)
Second harmonic generation (SHG) and angle-resolved absorbance with photoacoustic detection were combined to evaluate both the mean orientation angle and the width of the angular distribution for two surface-bound molecular systems. Assuming a Gaussian distribution function, a physisorbed stilbene dye on fused silica exhibited a narrow distribution centered at 73° with a root-mean-square (rms) width of less than ～8°. In contrast, a covalently bound azo dye resulted in a broad orientation distribution (rms width of ～30°) centered at 60°. It was also demonstrated that the combination of nonlinear (SHG) and linear (absorbance) spectroscopic techniques provides valuable insight into molecular orientation that a combination of two linear techniques (such as fluorescence and absorbance) is unable to provide.
Photoactivity and pH sensitivity of methyl orange functionalized poly(propyleneamine) dendrimers
Dirksen,Zuidema,Williams,De Cola,Kauffmann,Voegtle,Roque,Pina
, p. 2743 - 2747 (2002)
For the first time a pH indicator that responds to two different external stimuli, i.e. pH and light, namely methyl orange, has been implemented in a dendrimer. Six generations (G0-G5) of methyl orange-functionalized poly(propyleneamine) dendrimers ( MO dendrimers ) have been synthesized and characterized using 1H NMR, 13C NMR, and MALDI-TOF mass spectrometry. Subsequently, the response of the MO dendrimers toward pH changes has been monitored using UV-vis spectroscopy and the photophysical properties have been investigated. Furthermore, the photoisomerization from E to Z and the thermal recovery from Z to E, have been studied using UV-vis and transient-absorption spectroscopy. Interestingly, the response of the MO units toward pH changes is found to be generation dependent. On the other hand, the photophysical properties are found to be similar for all generations, except for the ε value, which deviates significantly from the expected value in the case of G4 and G5. Also the isomerization processes show no generation dependence within the same solvent, but different rate constants for the Z/E isomerization have been observed for different solvents.
Sc(OTf)3-mediated silylation of hydroxy functional groups on a solid surface: A catalytic grafting method operating at room temperature
Yeon, Ye-Rim,Park, Young Jun,Lee, Ji-Sung,Park, Jung-Woo,Kang, Sin-Gun,Jun, Chul-Ho
, p. 109 - 112 (2008/09/19)
(Chemical Equation Presented) Surface paradise: Facile catalytic post-grafting of the surface of glass or indium tin oxide (ITO, see picture) with a variety of functional groups has been achieved. Methallylsilanes serve as the grafting reagent and the surfaces show remarkable chemical stability.
