Structure-property relationships for N-phosphoryl substituted E,E-3,5-bis(arylidene)piperid-4-ones

The structures and one- and two-photon absorption properties of a series of phosphoryl substituted 3,5-bis(arylidene)piperid-4-ones bearing amino groups, nitro groups or fluorine atoms in the para-positions of the arene rings have been investigated. The measurable two-photon absorption cross sections and low fluorescence quantum yields have been observed for piperidone compounds with the general D-π-A-π-D structure. However, no fluorescence and, consequently, two-photon absorption cross sections (in the frame of the experimental method used) have been observed for the compounds containing the electron withdrawing substituents, such as nitro groups or fluorine atoms in the side aryl ligands. The X-ray diffraction analysis revealed the tendency of increasing of cytotoxic activity with the increase of planarity of the main backbone of phosphoryl substituted piperidone molecules. The results obtained furnish a link between structural features of these molecules and their photo- and cytotoxic activities to allow a design of new compounds of this class with the tuning of biological properties.