Fifteen chalcone derivatives having D–A–D, D–A–A and A–A–D architectures have been synthesized by Claisen–Schmidt condensation reaction and characterized by UV–Vis, IR, 1H-NMR, 13C-NMR and Mass spectrometry. In order to unambiguously establish the structure–activity relationship for the non-linear optical activity of these compounds, for the first time to our knowledge, we use the femtosecond degenerate four wave mixing (DFWM) technique to quantify and compare the third-order non-linear optical (NLO) activity of all the 15 compounds, under identical conditions. The second harmonics generation (SHG) efficiencies for all the compounds have also been evaluated using the Kurtz-Perry powder method. Among the compounds that we have synthesized here, the ones with A–A–D architecture show the highest NLO activity. Our results show that the NLO activity of a compound with A–A–D architecture can be further enhanced by incorporating a substituent with strong electron withdrawing ability on ring A and strong electron donating substituent on ring B. The results of the in silico studies that we have carried out correlate well with our experimental findings. The compounds (E)-3-(4-(dimethylamino)phenyl)-1-(4-nitrophenyl)prop-2-en-1-one with the compound code (4-N(CH3)2–4′-NO2) and (E)-3-(4-methoxyphenyl)-1-(4-nitrophenyl)prop-2-en-1-one with the compound code (4-MeO-4′-NO2) show the highest NLO activity among the compounds we have reported here.
通过Claisen-Schmidt缩合反应合成了15种具有D-A-D、D-A-A和A-A-D构型的
查耳酮衍
生物,并通过UV-Vis、IR、1H-NMR、13C-NMR和质谱法进行了表征。为了明确建立这些化合物的非线性光学活性的结构-活性关系,据我们所知,首次使用飞秒简并四波混频(DFWM)技术,在相同条件下定量并比较了所有15种化合物的三阶非线性光学(NLO)活性。同时,利用Kurtz-Perry粉末法评估了所有化合物的二次谐波产生(S
HG)效率。在我们合成的化合物中,具有A-A-D构型的化合物显示出最高的NLO活性。我们的结果表明,通过在A环上引入具有强吸电子能力的取代基,在B环上引入具有强供电子能力的取代基,可以进一步提高具有A-A-D构型化合物的NLO活性。我们所进行的计算机模拟研究结果与实验发现高度相关。其中,化合物代号为(4-N(
CH3)2-4'-
NO2)的(E)-3-(4-(
二甲氨基)苯基)-1-(4-
硝基苯基)丙-2-烯-1-酮和代号为(4-MeO-4'- )的(E)-3-(4-
甲氧基苯基)-1-(4-
硝基苯基)丙-2-烯-1-酮,在我们所报道的化合物中显示出最高的NLO活性。