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Molecular structure of some amino acids and dipeptides

Grant number: 14/25903-6
Support Opportunities:Regular Research Grants
Duration: May 01, 2015 - April 30, 2017
Field of knowledge:Physical Sciences and Mathematics - Chemistry - Organic Chemistry
Principal Investigator:Roberto Rittner Neto
Grantee:Roberto Rittner Neto
Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil


The conformational analysis of some amino acids derivatives, esterified and acetylated, as well as of some dipeptides is proposed. This is an advanced project in comparison to a previous one since it will focus on more complex structures and also on the application of the most recent theoretical methods, used in physical organic chemistry. The experimental work will be based in NMR spectroscopy (1H, 13C and 15N) and in infrared spectroscopy. The theoretical calculations will be performed at MP2 and DFT level of theory, using several basis sets, and including Zero-Point corrections (ZPE), which will provide the energies and geometries of the most stable conformers in the isolated form. Calculations using the IEF-PCM model will give similar data for these compounds in several solvents. The analysis of the carbonyl band (fundamental and 1st overtone) in several solvents will give the populations of the more stable rotamers in solution. The NMR spectra will provide JHH coupling constants, geminal and vicinal, involving the CH and CH2 groups, in solution, which can indicate changes in conformer populations according to the permittivity of the solvent. Values obtained from theoretical calculations of the carbonyl stretching vibration and of the coupling constants, in the studied solvents, will be compared with the experimental data in the assessment of the populations of the more stable conformers. Lastly, the contributions of the classical intramolecular interactions (steric and electrostatic) and quantum interactions (hyperconjugation) to stabilize a given conformer will be evaluated through topological analyses from the Quantum Theory of Atoms in Molecules (QTAIM), Non Covalent Interactions (NCI) and Electron Localization Function (ELF) and also the Natural Bond Orbitals (NBO) analysis. A joint analysis with these techniques may allow unequivocally the main effects which are responsible for the conformer stabilities of these important systems. (AU)

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Scientific publications (11)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
SILVA, WESLLEY G. D. P.; BRAGA, CAROLYNE B.; RITTNER, ROBERTO. Conformational study of L-methionine and L-cysteine derivatives through quantum chemical calculations and 3J(HH) coupling constant analyses. Beilstein Journal of Organic Chemistry, v. 13, p. 925-937, . (12/18567-4, 14/25903-6, 16/12005-5)
CORMANICH, RODRIGO A.; KEDDIE, NEIL S.; RITTNER, ROBERTO; O'HAGAN, DAVID; BUEHL, MICHAEL. Particularly strong C-H center dot center dot center dot pi interactions between benzene and all-cis 1,2,3,4,5,6-hexafluorocyclohexane. Physical Chemistry Chemical Physics, v. 17, n. 44, p. 29475-29478, . (11/01170-1, 14/25903-6)
BARBOSA, T. M.; MORRIS, G. A.; NILSSON, M.; RITTNER, R.; TORMENA, C. F.. H-1 and F-19 NMR in drug stress testing: the case of voriconazole. RSC ADVANCES, v. 7, n. 54, p. 34000-34004, . (14/25903-6, 15/19229-3, 15/08541-6, 14/12776-6)
CORMANICH, RODRIGO A.; BUEHL, MICHAEL; RITTNER, ROBERTO. Understanding the conformational behaviour of Ac-Ala-NHMe in different media. A joint NMR and DFT study. ORGANIC & BIOMOLECULAR CHEMISTRY, v. 13, n. 35, p. 9206-9213, . (11/01170-1, 14/25903-6)
BRAGA, CAROLYNE B.; RITTNER, ROBERTO. Combined Utilization of H-1 NMR, IR, and Theoretical Calculations To Elucidate the Conformational Preferences of Some L-Histidine Derivatives. Journal of Physical Chemistry A, v. 121, n. 3, p. 729-740, . (12/18567-4, 14/25903-6)
ROZADA, THIAGO DE CASTRO; PONTES, RODRIGO MENEGHETTI; RITTNER, ROBERTO; BASSO, ERNANI ABICHT. Stereoelectronic effects of the glycosidic linkage on the conformational preference of D-sucrose. RSC ADVANCES, v. 6, n. 114, p. 112806-112812, . (14/25903-6)
BARBOSA, T. M.; RITTNER, R.; TORMENA, C. F.; MORRIS, G. A.; NILSSON, M.. Convection in liquid-state NMR: expect the unexpected. RSC ADVANCES, v. 6, n. 97, p. 95173-95176, . (14/25903-6, 15/19229-3, 15/08541-6, 14/12776-6)
CORMANICH, RODRIGO A.; RITTNER, ROBERTO; O'HAGAN, DAVID; BUEHL, MICHAEL. Inter- and Intramolecular CF center dot center dot center dot C=O Interactions on Aliphatic and Cyclohexane Carbonyl Derivatives. Journal of Computational Chemistry, v. 37, n. 1, SI, p. 25-33, . (11/01170-1, 14/25903-6)
BARBOSA, THAIS M.; VIESSER, RENAN V.; ABRAHAM, RAYMOND J.; RITTNER, ROBERTO; TORMENA, CLAUDIO F.. Experimental and theoretical evaluation of trans-3-halo-2-hydroxy-tetrahydropyran conformational preferences. Beyond anomeric interaction. RSC ADVANCES, v. 5, n. 45, p. 35412-35420, . (13/03477-2, 14/25903-6, 14/12776-6)
BATISTA, PATRICK R.; KARAS, LUCAS J.; VIESSER, RENAN V.; DE OLIVEIRA, CYNTHIA C.; GONCALVES, MARCOS B.; TORMENA, CLAUDIO F.; RITTNER, ROBERTO; DUCATI, LUCAS C.; DE OLIVEIRA, PAULO R.. Dealing with Hydrogen Bonding on the Conformational Preference of 1,3-Aminopropanols: Experimental and Molecular Dynamics Approaches. Journal of Physical Chemistry A, v. 123, n. 40, p. 8583-8594, . (17/20890-1, 17/17750-3, 15/08541-6, 14/25903-6, 18/07308-4)
SHARMA, GAGAN; BRAGA, CAROLYNE B.; CHEN, KAI-EN; JIA, XINYING; RAMANUJAM, VENKATRAMAN; COLLINS, BRETT M.; RITTNER, ROBERTO; MOBLI, MEHDI. Structural basis for the binding of the cancer targeting scorpion toxin, ClTx, to the vascular endothelia growth factor receptor neuropilin-1. CURRENT RESEARCH IN STRUCTURAL BIOLOGY, v. 3, p. 179-186, . (14/18233-4, 14/25903-6)

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