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Phototransients of organoboranes generated by photolysis and flavin sensitization

Grant number: 12/19823-4
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): March 01, 2013
Effective date (End): March 05, 2017
Field of knowledge:Physical Sciences and Mathematics - Chemistry
Principal Investigator:Daniel Rodrigues Cardoso
Grantee:Willy Glen Santos
Home Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
Associated scholarship(s):15/13756-1 - Photochemistry and Excited-states dynamics of Tetraarylborates and Tetraarylborate-pyridinium complexes, BE.EP.PD

Abstract

The design proposed herein is intended to investigate the photochemical aromatic compound having boron atoms in the molecular structure via direct photolysis and sensitization in two component system: dye / organoborane. The presence of boron in the aromatic system is intended to facilitate the formation of free radicals which can be used in systems radical polymerization and photobiological studies. The formation of radicals in organoboranes can be obtained by photochemical means or by direct photolysis fotossensitização through dye such as riboflavin (vitamin B2). The photochemical organoborane in the presence and absence of donor / acceptor of electrons is a little explored area and that has aroused great interest in recent years. In this sense, the different photochemical interactions of flavins with organoboranes will be investigated in two main steps: (a) first, the organoboranes fotofísicamente will be characterized by electronic absorption, fluorescence, phosphorescence, transient absorption, EPR and lifetimes of singlet excited states and triplet. This stage will be determined the quantum yields of the radiative and non-radiative processes. Measurements of phosphorescence emission of singlet oxygen and will be held to determine the quantum yield of formation of singlet oxygen and triplet quantum yield calculation. (B) In the second step, the radical species formed from electron transfer reactions are characterized by the hyperfine structure of the EPR spectra and the formation of new transient absorption bands of semi-oxidized species and semirreduzidas of organoboranes and flavins (and Lumiflavina Riboflavin). Measurements of degradation of flavins be assessed by measures of fotodescoloramento degradation products and evaluated by mass spectrometry coupled to a HPLC. The results obtained by all techniques reported here will be important for the development of photochemical mechanism between flavins and organoboranes. This study has also intended to assist searches of photobiological flavins in the presence of organoboranes, since these compounds are used in the medical environment.

Scientific publications (6)
(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)
SANTOS, WILLY G.; BUDKINA, DARYA S.; DEFLON, VICTOR M.; TARNOVSKY, ALEXANDER N.; CARDOSO, DANIEL R.; FORBES, MALCOLM D. E. Photoinduced Charge Shifts and Electron Transfer in Viologen-Tetraphenylborate Complexes: Push-Pull Character of the Exciplex. Journal of the American Chemical Society, v. 139, n. 23, p. 7681-7684, JUN 14 2017. Web of Science Citations: 13.
TOMAZETT, VINICIUS K.; SANTOS, WILLY G.; LIMA-NETO, BENEDITO S. Infrared spectroscopy as an effective tool in ring-opening metathesis polymerization: monitoring the polymerization kinetics of norbornene with amine-based Ru catalysts in real time. Reaction Kinetics Mechanisms and Catalysis, v. 120, n. 2, p. 663-672, APR 2017. Web of Science Citations: 4.
SANTOS, WILLY G.; PINA, JOAO; BURROWS, HUGH D.; FORBES, MALCOLM D. E.; CARDOSO, DANIEL R. New insight into the photophysics and reactivity of trigonal and tetrahedral arylboron compounds. PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES, v. 15, n. 9, p. 1124-1137, 2016. Web of Science Citations: 6.
SALES, ERIC S.; SCHNEIDER, JULIANA M. F. M.; SANTOS, MARCOS J. L.; BORTOLUZZI, ADAILTON J.; CARDOSO, DANIEL R.; SANTOS, WILLY G.; MERLO, ALOIR A. Quinolines by Three-Component Reaction: Synthesis and Photophysical Studies. Journal of the Brazilian Chemical Society, v. 26, n. 3, p. 562-571, MAR 2015. Web of Science Citations: 7.
SANTOS, WILLY G.; SCURACHIO, REGINA S.; CARDOSO, DANIEL R. Photochemical behavior of Safranine-Riboflavin complex in the degradation of folic acid. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY, v. 293, p. 32-39, NOV 1 2014. Web of Science Citations: 9.
SANTOS, WILLY G.; CARDOSO, DANIEL R.; ARRIVETTI, LEANDRO DE O. R.; SCHMITT, CARLA C.; NEUMANN, MIGUEL G. DFT, spectroscopic, and photoproduct study of 2-aminoethyldiphenylborinate and tetraphenyldiboroxane. JOURNAL OF ORGANOMETALLIC CHEMISTRY, v. 755, p. 125-133, APR 1 2014. Web of Science Citations: 2.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.