Unique solvent-dependent fluorescence of nitro-group-containing naphthalene derivatives with weak donor–strong acceptor system
作者:Sojiro Hachiya、Kengo Asai、Gen-ichi Konishi
DOI:10.1016/j.tetlet.2013.01.096
日期:2013.4
We synthesized nitro-group-containing pi-conjugated naphthalene derivatives with a weak donor-strong acceptor system and investigated their photophysical properties. The nitro group was introduced into naphthalene through the phenyl or phenylethynyl moiety at the C2 and C7 positions as the strong acceptor moiety, and a methoxy group was introduced into naphthalene directly at the position opposite to the nitro group, as a weak donor moiety. While 2-(4-nitrophenyl)naphthalene did not show fluorescence in various solvents, 2-methoxy-6-(4-nitrophenyl)naphthalene showed fluorescence in weakly polar solvents (Phi(F) = 0.11 in CH2Cl2), with a large Stokes shift (Delta nu = 12,000 cm(-1)). Additionally, 2-methoxy-6-(4-nitrophenyl)naphthalene did not show fluorescence in polar solvents (acetonitrile) and non-polar solvents (toluene). This unique solvent-dependent fluorescence is remarkable for environmental fluorescence sensor applications. (C) 2013 Elsevier Ltd. All rights reserved.
Synthesis of Diarylacetylenes Bearing Electron-Withdrawing Groups via the Smiles Rearrangement
作者:Robert Bujok、Mieczysław Mąkosza
DOI:10.1055/s-0037-1612423
日期:2019.8
above 40%. Nitrobenzyl benzothiazol-2-yl sulfones and nitrobenzyl 1-phenyl-1H-tetrazol-5-yl sulfones react with chlorides of aromatic acids to form β-acyl derivatives. These products undergo the Smilesrearrangement resulting in the formation of the corresponding nitrophenyl arylacetylenes in 50–60% overall yields (approx. 75% per step). Sulfones bearing CF3 or CN groups instead of a NO2 substituent form
This work investigated the influence of protonation and hydrogen bonding on intramolecular charge transfer (ICT) through different spacers. Three compounds, DS-NH2 (with a conjugated double bond), TS-NH2 (with a conjugated triple bond), and SS-NH2 (with a flexible saturated bond), possessing the same donor group (aniline) and the same acceptor group (naphthalene) but with different linkages were synthesized