Synthesis, tunable two and three-photon absorption properties of triazine derivatives by branches

Three novel triazine derivatives, (E)-4-(2-(4,6-dimethyl-1,3,5-triazin-2- yl)vinyl)- N,N-di-p-tolylaniline (a), 4,4′–((1E,1′E)-(6-methyl-1,3,5-triazine-2,4-diyl) bis(ethene-2,1-diyl))bis(N,N-di-p-tolylaniline) (b), and 4,4′,4′′–((1E,1′E,1′′E)-(1,3,5- triazine-2,4,6-triyl)tris(ethene-2,1-diyl))tris(N,N-di-p-tolylaniline) (c), were designed and synthesized. Their photophysical and photochemical properties were investigated systematically including single-photon absorption, nonlinear optical absorption (NOA) and up-converted fluorescence. Interestingly, the compound a with single branch showed pure three-photon absorption phenomenon, while the corresponding b and c indicated two-photon induced excited-state absorption properties, showing strong structure-dependence relationship. The results offer a method to design and synthesize organic molecules for multiphoton materials. It was noted that the three-photon cross-section value (δ3) of a was up to 1.35 × 10−76 cm6 s2. Correspondingly, the two-photon (δ2) and excited-state cross-section (δe) values of b and c also were obtained, and value of them were 485 GM and 1.03 × 10−17 cm2 for b, and 1100 GM and 1.27 × 10−18 cm2 for c, respectively.

► Novel triphenylamine-based dendrimers were synthesized and characterized.
► Photophysical properties and two-photon induced fluorescence were investigated.
► Two and three-photon absorption cross-section of dendrimers were obtained.
► Two-photon induced excited-state absorption cross-section of dendrimers were obtained.
► We find strong structure-dependence relationship by tuning the number of branches in molecules.