Hydrogen spectroscopy Protons

The complex [Ru(tpy)Cl3] binds to DNA, and is active as a cytostatic in L1210 leukemia cells. Its activity lies between those of cisplatin and carboplatin. Model complexes [Ru(tpy)L(H20)] + in which L = 9-ethylguanine or 9-methylhypoxanthine, have been prepared and characterized using NMR spectroscopy. " Proton NMR spectroscopy has been applied to a study of hydrogen bonding between 2, 3 -isopropylidine adenosine and [Ru(tpy)2] derivatives bearing a thymine group. 

Fig. 1. The different values for the rms charge radius of the proton as obtained from electron scattering experiments (full symbols) and hydrogen spectroscopy (open symbols)...

Ultrafast UV/vis spectroscopy has until now been used extensively in the case of excited state intramolecular hydrogen or proton transfer (ESIHT/ESIPT) [25-27], where donor and acceptor groups, linked by the hydrogen or proton, are part of the same molecule [28, 29]. The dynamics and microscopic mechanisms of... 

Water-protein interactions in microcrystalline Crh were measured by H- C solid state NMR. Using H- C dipolar correlation spectroscopy, proton exchange on the millisecond time scale was observed between water molecules and protein protons in a solid sample. These interactions were related to important structural features of the protein such as hydrogen-bonding or salt-bridge networks. 

Spectroscopic methods have been applied to the elucidation of the structures in coal from very early in the development of the methods (Speight, 1978). In the initial stages of the evolution of the spectroscopic methods, the data derived by their application to coal were more of a diagnostic nature as, for example, determination of functional entities or carbon-hydrogen bonds by means of infrared spectroscopy or determination of aromatic and aliphatic hydrogen by proton magnetic resonance spectroscopy. However, virtually all of the methods have at one time or another been applied to coal as a means of deriving more detailed information about coal structure with special emphasis on the... 

Nuclear magnetic resonance (NMR) spectroscopy of polymers in solution is a very important method of studying polymer configuration since noncrystalline as well as crystalline compounds can be studied. The method depends on the fact that the chemical shift of the signals of bonded hydrogen atoms (protons), and atoms, etc., in fixed chemical environments depends on the configuration of the main chain. In theory, the technique represents an absolute method, but, on technical grounds, it can often only be used as a relative method. An example of this is the analysis of the spectra of poly(methyl methacrylates) of various tacticities. 

In 2002, Goward et al. carried out the first study of proton conductivity using the high-resolution solid-state MAS NMR [25], They characterized the ethylene oxide tethered imidazole heterocycles by variable temperature experiments, as well as 2D homonuclear DQ NMR and 2D exchange spectroscopy (EXSY). The MAS NMR identified three types of hydrogen-bonded N—resonances, and DQ NMR identified hydrogen-bonded protons which are mobile on the time scale of the experiment and participate in proton transport. The local mobifity of protons was characterized by spin—spin relaxation times as a function of temperature,... 

D.L. Bryce, G.D. Sward, Chlorine-35/37 NMR spectroscopy of solid amino acid hydrochlorides refinement of hydrogen-bonded proton positions using experiment and theory, J. Phys. Chem. B 110 (2006) 26461-26470. 

Keywords l-Ethyl-3-methyliinidazoliuin acetate Acid-base equilibria Basic ionic liquids Carbene Catalysis CO2 capture DFT calculations Hydrogen bonding Ionic liquids Mass spectroscopy N-Heterocyclic carbenes Organocatalysis Photoelectron spectroscopy Proton transfer Synthesis Vaporization mechanism... 

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