Structure, Z/E photoisomerization and an effect of (phenylene-)vinylene conjugation extension on absorption and fluorescence of methylidene-pyrrolinones
摘要:
Six methylidene-pyrrolinones with a conjugation chain extended by vinylene and phenylene-vinylene groups were studied: five of them were synthesized for the first time. Their structures were estimated theoretically by density functional theory (DFT) and proved by X-ray diffraction techniques in two cases. Structural changes upon Z/E photoisomerization in solution were studied by a combination of H-1 NMR spectroscopy and DFT CIAO method. Both types of conjugation extension caused a bathochromic shift in absorption. Vinylene extension produced the compounds fluorescent in solution. N-methylated derivatives have shown solid-state fluorescence. (C) 2012 Elsevier B.V. All rights reserved.