Entry of chiral phthalimides with significant second order nonlinear optical and piezoelectric properties

Three new chiral phthalimides have been synthesized and characterized. Phthalimides (1-3) possess an acentric structure as revealed by structural investigation. Compounds 1 and 2 crystallize in an orthorhombic system with the space group P2(1)2(1)2(1), however the monoclinic system with the chiral space group P2(1) is observed for 3. The presence of C-H center dot center dot center dot O hydrogen bonds in 1-3 facilitates the construction of several supramolecular structures. Helical structural motifs are also observed. The maximum value of hyperpolarizability (beta), 159.9446 x 10(-30) esu calculated for compound 3 is several times greater than that of urea. On the other hand 1 and 2 have hyperpolarizabilities of 10.8063 x 10(-30) and 121.9519 x 10(-30) esu, respectively. The polycrystalline samples of 1-3 were assessed for a second-harmonic generation response, which was found to be 8.8, 10.2 and 9.7 mV respectively. Further, compounds 1-3 showed d(33) values of 0.93, 1.97 and 1.88 pC N-1 respectively. The present investigation demonstrates chiral phthalimides as effective contenders for nonlinear optical and piezoelectric properties.