Electronic Absorption, Emission and Two‐Photon Absorption Properties of Some Functional 1,3,5‐Triphenylbenzenes

We report herein the linear optical properties of some extended 1,3,5‐triphenylbenzene derivatives 1,3,5‐[(1, 4‐C6H4)C≡C(4‐C6H4X)]3(C6H3) (3‐X; X=NO2, CN, H, OMe, NMe2, NPh2) and briefly discuss the two‐photon absorption (2PA) cross‐sections determined for the derivatives featuring the most electron‐rich substituents, contrasting their 2PA performance with the 2PA values previously gathered for their triphenylisocyanurate analogues N,N’,N”‐[(1, 4‐C6H4)C≡C(4‐C6H4X)]3(N3{C(O)}3) (1‐X). When functionalized by electron‐releasing substituents at their periphery, 3‐X derivatives are potent substitutes for 1‐X compounds in NLO applications, especially when maximal transparency is not required in the visible range. Some rationalization of this unexpected outcome is proposed based on DFT calculations. Selected optical properties of six extended triphenylbenzene derivatives are studied experimentally and theoretically (DFT). Comparison with their isocyanurate analogues reveals that in spite of the change in central spacer, similar cross‐sections are found for the most efficient two‐photon absorbers. Possible explanations for our observations are proposed.