83858-83-7Relevant academic research and scientific papers
Synthesis of selectively 15N- or 13C-labelled malachite green
DeFina, Steven C.,Dieckmann, Thorsten
, p. 241 - 248 (2002)
Two complimentary syntheses of selectively 15N- or 13C-labelled malachite green hydrochloride were developed in order to provide labelled ligands for structural studies of RNA aptamer/ligand complexes. The 15N- and 13C-labelled versions of the dye have been used in NMR studies to probe the changes in the electronic charge distribution and dynamics of the dye upon binding to RNA. Copyright
Parahydrogen-Induced Polarization in Hydrogenation Reactions Mediated by a Metal-Free Catalyst
Chernichenko, Konstantin,Repo, Timo,Sorochkina, Kristina,Telkki, Ville-Veikko,Yang, Shengjun,Zakharov, Danila O.,Zhivonitko, Vladimir V.
supporting information, (2022/01/22)
We report nuclear spin hyperpolarization of various alkenes achieved in alkyne hydrogenations with parahydrogen over a metal-free hydroborane catalyst (HCAT). Being an intramolecular frustrated Lewis pair aminoborane, HCAT utilizes a non-pairwise mechanism of H2 transfer to alkynes that normally prevents parahydrogen-induced polarization (PHIP) from being observed. Nevertheless, the specific spin dynamics in catalytic intermediates leads to the hyperpolarization of predominantly one hydrogen in alkene. PHIP enabled the detection of important HCAT-alkyne-H2 intermediates through substantial 1H, 11B and 15N signal enhancement and allowed advanced characterization of the catalytic process.
Solvent and solvent density effects on the spectral shifts and the bandwidths of the absorption and the resonance Raman spectra of phenol blue
Yamaguchi,Kimura,Hirota
, p. 9050 - 9060 (2007/10/03)
We have measured the absorption and the resonance Raman spectra of a solvatochromic dye, phenol blue, in liquid and supercritical solvents. We have found anomalous solvent dependence of the absorption bandwidth in liquid solvents: the width has apparently no correlation with the absorption peak shift. On the other hand, we have found good linear correlation between the absorption peak shift and the peak position of the resonance Raman bands (the C=N and the C=O stretching modes). The relative intensities of the Raman bands and the bandwidth of the C=N stretching mode also show correlation with the absorption peak shift. Incorporating these Raman data, the anomalous bandwidth of the absorption spectrum is explained by the change of the intramolecular vibrational contribution to the absorption bandwidth due to the electronic structure change by the solvent, which cancels the change of the solvent contribution. We have estimated the solvent reorganization energy assuming linear dependence of the intramolecular contribution on the absorption band center and neglecting the solvent reorganization energy in alkanes such as ethane and cyclohexane. In liquid solution, the estimated solvent reorganization energy is correlated fairly well with the absorption peak shift. Solvent dependence of the Raman bandwidth of the C=N stretching mode resembles the solvent dependence of the solvent reorganization energy estimated in this way. Relatively large bandwidths of both absorption and resonance Raman spectra have been observed in supercritical solvents compared with those in liquid solvents of a similar absorption peak shift. We interpreted this as due to the small refractive indices of the supercritical solvents relative to the liquid solvents; the large refractive indices of the liquid solvents only make the absorption peak shifts without broadening the absorption spectra.
