Synthesis and optical properties of cationic cyclopentadienyl iron complexes with diphenylacetylene chromophores

Cationic cyclopentadienyl iron complexes of arenes are applied in photopolymerization and photocatalysis because of their good photophysical and photochemical properties. In this study, a series of cationic cyclopentadienyl iron complexes with diphenylacetylene chromophores (Aky-Fc) was obtained via nucleophilic substitution and Suzuki coupling reactions. The linear and nonlinear optical properties of the obtained molecules were tuned by phenylethynyl linkages. The UV-Vis absorption spectra showed that increasing the conjugation by substituting phenylacetylene spacer resulted in a red shift in the absorption bands and much stronger absorption in Aky-Fc than in (eta(6)-cumene) (eta(5)-cyclopentadienyl) iron hexafluorophosphate (I-261). With the single-beam Z-scan technique, the nonlinear absorption of Aky-Fc showed that Aky-Fc (8), (9), and (10) had good nonlinear optical ability, and the two photon absorption (TPA) cross section sigma was approximately 10 times that of I-261. (C) 2015 Elsevier B.V. All rights reserved.