Stereoelectronic interactions and their effects in the conformational preferences of 3-carene halohydrins and dihalo-derivatives.

• Grant number: 10/08785-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2010
• End date: July 31, 2011
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Roberto Rittner Neto
• Grantee: Thaís Mendonça Barbosa
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

This project involves the study of 4-chloro- and 4-bromo-4,7,7-trimethyl-bicyclo[4.1.0]-3-heptanol (3-carene halohydrins) conformacional stabilities, as well as of 3,4-dichloro- and 3,4-dibromo-3,7,7-trimethyl-bicyclo[4.1.0]heptane, through NMR and IR spectroscopies, supported by electronic structure theoretical calculations. The compounds will be synthesized and identified by their H-1 and C-13 NMR spectra. Low temperature NMR experiments will be performed to obtain their conformer populations. The theoretical calculations will use the B3LYP method with the Density Functional Theory (DFT) and with MP2 method and ab initio theory, employing the aug-cc-pVTZ basis set available in the Gaussian03 package, to obtain the geometries and energies of the stable conformers in the vapor phase. NBO (natural bond orbitals) analysis will allow to find which stereoelectronic interactions are responsible for the conformational stability. All these data will give the information which are the main effects which drive the conformational equilibria for the studied compounds.