1357027-05-4Relevant articles and documents
New triazaborine chromophores: Their synthesis via oxazaborines and electrochemical and DFT study of their fundamental properties
Josefík, Franti?ek,Mikysek, Tomá?,Svobodová, Markéta,?im?nek, Petr,Kvapilová, Hana,Ludvík, Ji?í
, p. 4931 - 4939 (2015/04/27)
Eight new and stable triazaborine chromophores featuring various substituents as donor and acceptor moieties were prepared and investigated. An interpretation of the measured electrochemical data (CV, RDV, and dc polarography) and UV - vis spectra and quantum chemical calculations are presented. In the homologous series the first reduction proceeds as a one-electron reversible process localized at the - N=C - C=N - part of the central heterocycle being in conjugation with the attached carbonyl. The first oxidation of triazaborines proceeds as a two-electron irreversible process, most probably of the ECE type, localized at the negatively charged boron atom and surrounding unsaturated structures, including the substituted phenyl ring. For a better understanding of the relationship between the structure and redox properties, the LFER approach was applied for the first oxidation as well as reduction potential using the Hammett σ (para) substituent constants. The energies of the longest-wavelength absorption bands taken from UV-vis spectra were compared with the experimentally found differences Eox - Ered and with calculated HOMO-LUMO gaps, and no systematic influence of substitution was found. The calculated optimized structures and displacement of the frontier orbitals confirmed the interpretations presented above. (Figure Presented)
A new bicyclic oxazaborines with a bridged nitrogen atom, their thermic rearrangement and fluorescence properties
Josefík, Franti?ek,Svobodová, Markéta,Bertolasi, Valerio,?im?nek, Petr,MacHá?ek, Vladimír,Almonasy, Numan,?erno?ková, Eva
experimental part, p. 75 - 81 (2012/02/16)
Cyclic β-enaminones bearing secondary amino group react with 4-substituted benzenediazonium tetraphenylborates in dichloromethane to form substituted bicyclic [1,3,2λ4]oxazaborines The oxazaborines rearrange, on heating to 200 °C in the absence of solvent or in DMF or DMSO, to isomeric 2H-[1,2,4,3λ4]triazaborines. Previously prepared [1,3,2λ4]oxazaborines derived from acyclic β-enaminones bearing secondary amino group either did not undergo the rearrangement or with a lot of difficulties and with negligible yield. The fluorescence behaviour of the prepared triazaborines was observed. These compounds fluoresce in 2-methyltetrahydrofurane and in solid state under low temperatures.
