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Study of Nα-benzoyl-L-argininate ethyl ester chloride, a model compound for pol...
Fonseca, A. C.; Jarmelo, S.; Silva, M. Ramos; Beja, A. M. Matos; Fausto, R.; Gil, M. H.; Simões, P. N.Poly(ester amide)s (PEAs) are lacking in structural and spectroscopic information. This paper reports a structural and spectroscopic characterization of Nα-benzoyl-L-argininate ethyl ester chloride (BAEEH+·Cl−), an important amino acid derivative and an adequate PEAs’ model compound. Crystals of BAEEH+·Cl− obtained by slow evaporation in an ethanol/water mixture were studied by different complementary technique...
1H NMR Spectroscopic and Quantum Chemical Studies on a Poly(ester amide) Model ...
Fonseca, A. C.; Jarmelo, S.; Carvalho, R. A.; Fausto, R.; Gil, M. H.; Simões, P. N.The molecular structure of the l-arginine derivative, Nα-benzoyl-l-argininate ethyl ester chloride (BAEEH+·Cl−), was characterized by combining quantum chemical methods and 1H NMR spectroscopy. A conformational search on the potential energy surfaces of the three lowest-energy tautomers of BAEEH+ [A: R−N+H═(NH2)2; B: R−NH−C(═NH)N+H3; C: R−N+H2−C(═NH)NH2; R = C6H5C(═O)NH−CH(COOCH2CH3)CH2CH2CH2−] was carried out ...
Role of Guanidyl Moiety in the Insertion of Arginine and Nα-Benzoyl-l-argininat...
Fonseca, A. C.; Frías, M. A.; Bouchet, A. M.; Jarmelo, S.; Simões, P. N.; Fausto, R.; Gil, M. H.; Lairion, F.; Disalvo, E. A.Role of Guanidyl Moiety in the Insertion of Arginine and Nα-Benzoyl-l-argininate Ethyl Ester Chloride in Lipid Membranes AbstractFull Text HTMLHi-Res PDF[1247 KB]PDF w/ Links[216 KB]FiguresReferencesA. C. Fonseca‡, M. A. Frías†, A. M. Bouchet†, S. Jarmelo‡§, P. N. Simões‡, R. Fausto§, M. H. Gil‡, F. Lairion† and E. A. Disalvo*† Laboratory of Physical Chemistry of Lipid Membranes, Department of Analytical Che...
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...
Matrix-Isolated Diglycolic Anhydride: Vibrational Spectra and Photochemical Rea...
Jarmelo, S.; Reva, I. D.; Lapinski, L.; Nowak, M. J.; Fausto, R.The structure of diglycolic anhydride (1,4-dioxane-2,6-dione; DGAn) isolated in a low-temperature argon matrix at 10 K was studied by means of FTIR spectroscopy. Interpretation of the experimental vibrational spectrum was assisted by theoretical calculations at the DFT(B3LYP)/aug-cc-pVTZ level. The optimized structure of the isolated DGAn molecule adopts an envelope conformation, which was found to resemble clo...
Infrared and Raman spectroscopic characterization of the hydrogen-bonding netwo...
Jarmelo, S.; Reva, I.; Carey, P. R.; Fausto, R.The IR spectra (4000-400Â cm-1) of neat and isotopically substituted (ND/ODÂ <=Â 10% D and [congruent with]30% D) polycrystalline l-serine ([alpha]-amino-[beta]-hydroxypropionic acid; HO-CH2-CH(NH3)+-COO-) were recorded in the temperature range 300-10Â K and assigned. The isotopic-doping/low-temperature methodology, which allows for decoupling of individual proton vibrational modes from the crystal bulk vibrati...
The Raman spectra of serine and 3,3-dideutero-serine in aqueous solution
Jarmelo, S.; Carey, P. R.; Fausto, R.The Raman spectra of serine [[alpha]-amino-[beta]-hydroxypropionic acid; HOCH2CH(NH3)+COO-] and 3,3-dideutero-serine [HOCD2CH(NH3)+COO-] in aqueous solution were studied in the range 4000-300 cm-1. The data obtained for the deuterated compound are novel and provide compelling evidence that previously reported assignments for the undeuterated amino acid should be revised. ; http://www.sciencedirect.com/scienc...
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 ...
Entropy effects in conformational distribution and conformationally dependent U...
Jarmelo, S.; Fausto, R.Monomeric serine can be trapped in low temperature argon matrices in different conformers, which can be classified in three groups (A, B, C) accordingly to the main intramolecular interaction they exhibit: A (OHA...N hydrogen bond), B (OHC...N) and C (OHA...O) (subscripts A and C stand for alcohol and carboxylic group, respectively). The OHC...N intramolecular interaction found in B-type conformers is considera...
Preferred Conformers and Photochemical (λ > 200 nm) Reactivity of Serine and 3,...
Jarmelo, S.; Lapinski, L.; Nowak, M. J.; Carey, P. R.; Fausto, R.A systematic investigation of the conformational potential energy surface of neutral serine [HOCH2CHNH2COOH] and 3,3-dideutero-serine [HOCD2CHNH2COOH] was undertaken, revealing the existence of 61 different minima. The structures and vibrational spectra of the most stable conformers, which were estimated to have relative energies within 7 kJ mol-1 and account for ca. 93% of the total conformational population a...
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