DFT, spectroscopic, and photoproduct study of 2-aminoethyldiphenylborinate and tetraphenyldiboroxane

Autor(es)

Santos, Willy G. ^[1] ; Cardoso, Daniel R. ^[1] ; Arrivetti, Leandro de O. R. ^[1] ; Schmitt, Carla C. ^{[1, 2]} ; Neumann, Miguel G. ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, USP Consortium Photochem Technol, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF ORGANOMETALLIC CHEMISTRY; v. 755, p. 125-133, APR 1 2014.
• Citações Web of Science: 2

Resumo

The photochemistry and photophysics of 2-aminoethyldiphenylborinate (2APB) and tetraphenyldiboroxane (TPhB) were investigated by ab initio DFT, electronic paramagnetic resonance, steady-state and time-resolved spectroscopy and ESI-MS product analysis. UV-Vis spectra of the organoboranes in solvents of different dielectric constants showed bands at 200, 240 and 270 nm which were attributed to pi -> pi{*} and n -> pi{*} transitions and to the aggregate band, respectively. The exact position of the pi -> pi{*} bands were influenced by the dielectric character of the solvent leading to the inversion of the pi -> pi{*} and n -> pi{*} transition energies. For the 2APB molecule, the fluorescence quantum yield increases with increasing polarity, whereas the effect was opposite and less intense for TPhB. Dipole moments, energy levels of the singlet and triplet-excited states, HOMO-LUMO gaps, spin density populations calculated using the DFT method, were in good agreement with the experimental results for both organoboranes. The orbital composition and spin density population reveals a relevant contribution of the boron atom to form organoborane and phenyl radicals by photolysis, as detected by EPR and confirmed by high-resolution mass spectrometry experiments. (C) 2014 Elsevier B. V. All rights reserved. (AU)

• Processo FAPESP: 11/51555-7 - Pão e carne para o futuro
• Beneficiário: Daniel Rodrigues Cardoso
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 12/19656-0 - Fotoiniciação de polimerização e degradação de polímeros multicomponentes
• Beneficiário: Carla Cristina Schmitt Cavalheiro
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 09/54040-8 - EMU: aquisição de um espectrômetro de massas de alta resolução Orbitrap para descoberta e elucidação estrutural compostos biologicamente ativos: aplicações em proteômica e biomarcadores, síntese, isolamento e caracterização de produtos naturais, estudos de sistemas redox em alimentos e síntese enzimática
• Beneficiário: Emanuel Carrilho
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
• Processo FAPESP: 12/19823-4 - Fototransientes de organoboranos gerados por fotólise direta e sensitização por flavinas.
• Beneficiário: Willy Glen Santos
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado