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

A variety of fluorescence-active fluorinated pyrazolines was synthesized in good yields through cyclocondensation reaction of propenones with aryl hydrazines . Some of the synthesized compounds provided promising fluorescence properties with quantum yield () 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 (, , , and ) with variable were selected for treating two types of paper sheets (Fabriano and Bible paper). These investigated fluorescence compounds, especially compounds and , provide improvements in strength properties of paper sheets. Based on the observed performance they can be used as markers in security documents.