The crystal structure and spectroscopic characterization of 1-(N-ethyl-1-sulphonate-4-pyridinio)-2-[N-methylpyrrol-2-yl]ethene

The X-ray structure of 1-(N-ethyl-1-sulphonate-4-pyridinio)-2-[N-methylpyrr ol-2-yl]ethene . H2O is reported. The molecule belongs to the spatial group P2(1)/n with unit cell constants a=6.841(5), b=21.259(5), c=10.195(5), bet a=110.262(15)degrees. The compound was characterized by means of UV-vis and steady-state fluorescence spectroscopies. In the visible region the powder shows a blue shift of the main absorption band with respect to the solutio n. Analogously a marked red shift and decrease of intensity is observed in the fluorescence spectra. Packing effects are most likely at the origin of the difference. The molecule is expected to have promising proprieties for two-photon pumped (TPP) frequency-upconversion using experiments.