D-A-π-D Synthetic approach for thienyl chalcones – NLO – a structure activity study

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2016-06, Vol.324, p.33-39
• Main Authors: Tejkiran, P.J., Brahma Teja, M.S., Sai Siva Kumar, P., Sankar, Pranitha, Philip, Reji, Naveen, S., Lokanath, N.K., Nageswara Rao, G.
• Format: Article
• Language: English
• Subjects: Nonlinear optical properties (NLO); Second harmonic generation (SHG); Thienyl chalcones; Three photon absorption; Z-Scan
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2016.03.009

[Display omitted] •Based on D-A-π-D SYNTHETIC APPROACH we could synthesize nine novel thienyl chalcones with high effective 3 photon absorption coefficient (3 PA) of order 10−28m3/W2.•Of these, T-CHL-NDM was found to have the highest 3PA coefficient of about 105.0×10−28m3/W2.•Structure activity relationship based on the functional group vis-à-vis its NLO properties was established, and making minor modifications in the structure of the chalcones, desired 3PA values could be obtained.•Structures of all compounds have been characterized adequately.•These compounds will be useful in various applications like optical devices, communications, etc. With the growing interest for organic molecules in Nonlinear Optical (NLO) applications, we have synthesized nine novel thienyl chalcones based on the D-A-π-D design. In order to establish the identity, these have been characterized in detail. Having followed the design based synthetic route, we have focused on two prime criteria for comparison; namely second harmonic generation (SHG) and non-linear absorption. In this work the role of the electron withdrawing groups, electron donating groups and extended conjugation, have been extensively studied vis-à-vis the NLO properties. The change in these properties by virtue of the molecular structure has been elucidated in this work as the structure activity relationship. Optical nonlinearity is studied using ultrafast (100fs) laser pulses at 800nm, employing the open aperture Z-scan technique. The compounds exhibit large effective three-photon absorption (3PA) coefficients, in the order of 10−28m3/W2. These observations show that these compounds possess potential for application in all-optical limiting and switching devices.