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

Author(s)

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

Affiliation

^[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

• Document type: Journal article
• Source: JOURNAL OF ORGANOMETALLIC CHEMISTRY; v. 755, p. 125-133, APR 1 2014.
• Web of Science Citations: 2

Abstract

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)

• FAPESP's process: 11/51555-7 - Bread and meat for the future
• Grantee: Daniel Rodrigues Cardoso
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/19656-0 - Photoinitiation of polymerization and degradation of polymers multicomponent
• Grantee: Carla Cristina Schmitt Cavalheiro
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/54040-8 - Acquisition of a high-resolution Orbitrap mass spectrometer for the discovery and structural analysis of biologically active compounds: applications in proteomics, biomarkers, synthesis, isolation, and characterization of natural products, studies of redox systems in food and enzymatic synthesis
• Grantee: Emanuel Carrilho
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 12/19823-4 - Phototransients of organoboranes generated by photolysis and Flavin sensitization.
• Grantee: Willy Glen Santos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral