Experimental and theoretical study of a new class of acceptor group in chromophores for nonlinear optics:: 2-substituted 4-methylene-4H-oxazol-5-ones

Push-pull organic molecules that combine a polyfunctionalized electron-donating carbazole moiety with a new acceptor group, 4-methylene-4H-oxazol-5-ones, were synthesized and characterized as nonlinear optical chromophores with promising mubeta values. First-order hyperpolarizability and dipole moments were calculated by MNDO, AM1 and PM3 methods. Theoretical mubeta values were compared to experimental data measured in solution by electric-field-induced second-harmonic generation (EFISH). The different factors that could influence the NLO response, especially the gain or loss of aromatization stabilization during the charge-transfer process, were studied. The thermal stability of these new chromophores is also reported.