Conformational equilibria studies by nuclear magnetic resonance spectroscopy, infrared spectroscopy and theoretical calculations

• Grant number: 00/07692-5
• Support Opportunities: Research Projects - Thematic Grants
• Start date: December 01, 2000
• End date: November 30, 2005
• 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
• Pesquisadores principais: Paulo Roberto Olivato
• Associated research grant(s): 05/01241-5 - Hybrid density functional dependence of nmr 1jch coupling constants for 2-halocyclohexanes., AR.EXT

Abstract

This project aims the establishment and consolidation of a new methodology for the study of conformational equilibrate through two complementary spectroscopic techniques - NMR and infrared spectroscopy, together with theoretical calculations (at a high level of exactness). This new method is an absolute method, which do not depend on any models or on estimations used up to now by all known methods. In order to achieve those objectives and to allow a wide generalization, it is intended to select a large number of compounds which shall encompass different systems and different behaviors. Three classes of compounds were selected for this purpose: I. a-Heterosubstituted carbonyl compounds, which may present the cis, gauche (one or more) and trans (or anti) rotamers; II. 1,3-Disubstituted cyclohexanes, as alicyclic compounds, which may present two cis conformers and one or two trans conformers for alike or dislike substituents, respectively; III. a-Heterasubstituted cyclohexanones, which may show a cis conformer (equatorial substituent)and a trans conformer (axial substituent). NMR spectrometers (Varian Gemini-300; Bruker AC-300P e Varian INOVA-500) and infrared spectrometers (Bomem MB-100 e Bomem DA-08) are available at this Department, for performing the proposed experiments. Personal computers from our laboratory and the ones which shall be purchased with funds from this project, as well as the CENAPAD-SP system through remote access, will be used in the theoretical calculations. The target compounds will be synthesized in our laboratories. (AU)

Scientific publications

(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)

MARTINS, CARINA R.; RITTNER, ROBERTO; TORMENA, CLAUDIO FRANCISCO. Conformational preferences for N,N-dimethyl-2-haloacetamides (halo= F, Cl, Br and I) through theoretical and experimental studies: An unexpected orbital interaction. JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, v. 728, n. 1/3, p. 79-84, Sept. 2005. (00/07692-5)

TORMENA, CLAUDIO FRANCISCO; YOSHINAGA, FABIANA; DOI, TELMA R.; RITTNER, ROBERTO. Conformational preferences and orbital interactions for methyl haloacetates. SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, v. 63, n. 3, p. 511-517, Mar. 2006. (00/07692-5)

BOCCA‚ C.C.; GAUZE‚ G.F.; BASSO‚ E.A.. Substituent effects on the reduction of 2-OMe‚ 2-SMe and 2-SeMe cyclohexanones by LiAlH₄: An investigation of conformational equilibrium and transition states. Chemical Physics Letters, v. 413, n. 4, p. 434-439, 2005. (00/07692-5)