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Crystal and Molecular Structure of dl-Serine Hydrochloride Studied by X-Ray Dif...
Jarmelo, S.; Reva, I.; Rozenberg, M.; Silva, M. Ramos; Beja, A. M. Matos; Fausto, R.The structure of dl-serine·HCl was studied by three complementary techniques. Experimental Fourier transform infrared (FT-IR) spectra of pure NH/OH polycrystalline dl-serine·HCl [HO−CH2−CH(NH3+)−COOH·Cl−] and the respective deuterated derivatives [ND/ODAlcohol/Acid (<10% and ca. 60% D)] were recorded in the region 4000−400 cm−1 in the temperature range 300−10 K and interpreted. The assignments were confirmed by...
Low-temperature infrared spectra and hydrogen bonding in polycrystalline dl-ser...
Jarmelo, S.; Reva, I.; Rozenberg, M.; Carey, P. R.; Fausto, R.The FT-IR spectra of polycrystalline dl-serine [[alpha]-amino-[beta]-hydroxypropionic acid; HO-CH2-CH(NH3)+-COO-] and isotopically substituted [ND/ODAlcohol (<10% and >90% D); CD2 (>98% D)] dl-serine were recorded in the range 4000-500Â cm-1 in the temperature range 300-10Â K, and fully assigned. The isotopic-doping/low-temperature methodology, which allows for decoupling of individual proton vibrational modes ...
Spontaneous self-association of adenine and uracil in polycrystals from low tem...
Rozenberg, M.; Shohama, G.; Reva, I.; Fausto, R.FTIR spectra of solid samples of co-crystallized adenine and uracil were measured at 10 K in the range below 1000 cm−1. New bands ascribable to the N3H (uracil) and NH2 (adenine) out of plane vibrations, which disappear upon D-exchange, were revealed in comparison with the spectra of pure polycrystalline adenine and uracil obtained in the same conditions. The observed changes relate to the same groups that esta...
Low temperature FTIR spectroscopy and hydrogen bonding in cytosine polycrystals
Rozenberg, M.; Shoham, G.; Reva, I.; Fausto, R.The FTIR spectra of both the pure NH and isotopically substituted ND (<10% and >90% D) polycrystalline cytosine were recorded in the range 400–4000 cm−1 as a function of temperature (10–300 K). For the first time, uncoupled NH(D) stretching mode bands of amine and imine groups were observed in the spectra of isotopically diluted cytosine at low temperatures. These bands correspond to the three distinct H-bonds ...
Low temperature Fourier transform infrared spectra and hydrogen bonding in poly...
Rozenberg, M.; Shoham, G.; Reva, I.; Fausto, R.The FTIR spectra of pure NH and isotopically diluted (NH/ND and ND/NH) polycrystalline uracil and thymine were measured in the range 4000-400 cm-1 at temperatures from 300 to 10 K. For the first time, the essentially narrow bands corresponding to the uncoupled stretching ([nu]1) and out of plane bending ([nu]4) NH proton modes of uracil and thymine were observed in the solid phase. It was found that in the [nu]...
Low temperature FTIR spectroscopy and hydrogen bonding in cytosine polycrystals
Rozenberg, M.; Shoham, G.; Reva, I.; Fausto, R.The FTIR spectra of both the pure NH and isotopically substituted ND (<10% and>90% D) polycrystalline cytosine were recorded in the range 400-4000 cm-1 as a function of temperature (10-300 K). For the first time, uncoupled NH(D) stretching mode bands of amine and imine groups were observed in the spectra of isotopically diluted cytosine at low temperatures. These bands correspond to the three distinct H-bonds t...
Low-temperature Fourier transform infrared spectra and hydrogen bonding in poly...
Rozenberg, M.; Shoham, G.; Reva, I.; Fausto, R.The 400–4000 cm−1 FTIR spectra of pure NH and isotopically substituted (10 and 90% doped ND/NH) polycrystalline l-alanine were recorded in the temperature range 10–300 K. The observed temperature dependence and isotopic shifts behavior enabled to identify, in the spectra of the doped crystals, three well-separated bands ascribable to either the NH or ND stretching vibrations associated with the three different ...
Low-temperature Fourier transform infrared spectra and hydrogen bonding in poly...
Rozenberg, M.; Shoham, G.; Reva, I.; Fausto, R.The 400–4000 cm−1 FTIR spectra of pure NH and isotopically substituted (10 and 90% doped ND/NH) polycrystalline l-alanine were recorded in the temperature range 10–300 K. The observed temperature dependence and isotopic shifts behavior enabled to identify, in the spectra of the doped crystals, three well-separated bands ascribable to either the NH or ND stretching vibrations associated with the three different ...
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