Synthesis quantitative structure–property relationship study of novel fluorescence active 2-pyrazolines and application

摘要

A variety of fluorescence-active fluorinated pyrazolines >13–33 was synthesized in good yields through cyclocondensation reaction of propenones >1–9 with aryl hydrazines >10–12. Some of the synthesized compounds provided promising fluorescence properties with quantum yield (Φ) higher than that of quinine sulfate (standard reference). Quantitative structure–property relationship studies were undertaken supporting the exhibited fluorescence properties and estimating the parameters governing properties. Five synthesized fluorescence-active pyrazolines (>13, >15, >18, >19 and >23) with variable Φ were selected for treating two types of paper sheets (Fabriano and Bible paper). These investigated fluorescence compounds, especially compounds >19 and >23, provide improvements in strength properties of paper sheets. Based on the observed performance they can be used as markers in security documents.