Characterization of Sharpless reaction intermediates by IRMPD spectroscopy at CLIO free-electron laser facility

• Grant number: 15/22811-6
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: March 07, 2016
• End date: July 06, 2016
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Thiago Carita Correra
• Grantee: André Santos Fernandes
• Supervisor: Maitre Philippe
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Université Paris-Sud (Paris 11), France
• Associated to the scholarship: 15/11769-9 - Isolation of Sharpless reaction intermediates epoxidation and characterization of these species by theoretical calculations, BP.IC

Abstract

The undergraduation research project 2015/11769-9, to which this proposal is linked, aims to support the study of the titanium tetrapropoxide/tartrate catalytic system that is applied for the Sharpless asymmetric epoxidation, an important reaction for synthetic chemistry. The choice of this system was due to the still debated nature of the effective catalytic structure, which controls the asymmetric oxidation of allyl alcohols. In this context, the specific goals of the current project are: i) to optimize the experimental conditions for the formation and extraction of target reactive intermediates by soft ionization methods (electrospray), ii) to identify these species by standard mass spectrometry techniques and, iii) to obtain the theoretical infrared spectra and the relative energy of the possible conformers of the identified intermediates, allowing subsequent IRMPD spectroscopy studies. Taking these goals into account, we propose to extend the current undergraduation fellowship in the framework of the research internship abroad program. This extension aims to allow the beneficiary to conduct the IRMPD analysis of the reactions intermediates, isolated by ESI sources, at CLIO free-electron laser. This can be achieved by a 4-month internship at the Laboratoire de Chimie Physique d'Orsay (LCP). During this internship, besides the IRMPD experiments to verify the geometry of the active catalyst, it will also be possible to evaluate the coordination of the other reactants, t-BuOOH and allyl alcohol, to the active catalyst. It would be also possible to evaluate the effect of the solvent molecules on the reaction mechanism, through microsolvation experiments in the LCP's FT-ICR mass spectrometer. (AU)